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{{About|the space probe|other uses|New Horizons (disambiguation)}}
{{Use mdy dates|date=November 2016}}
{{italic title}}
{{Infobox spaceflight
| name = ''New Horizons''
| image = New Horizons Transparent.png
| image_caption = ''New Horizons'' space probe
| image_size = 300px
| insignia = New Horizons - Logo2 big.png
| insignia_size = 150x150px

| mission_type = Flyby ([[Jupiter]]{{dot}}[[Pluto]]{{dot}}{{mpl|2014 MU|69}})
| operator = [[NASA]]
| COSPAR_ID = 2006-001A
| SATCAT = 28928
| website = {{URL|http://pluto.jhuapl.edu/}} <br /> {{URL|1=https://www.nasa.gov/newhorizons/|2=nasa.gov/newhorizons}}
| mission_duration = Primary mission: 9.5&nbsp;years <br /> <small>Elapsed: {{Age in years, months and days|2006|01|19}}</small>

| manufacturer = [[Applied Physics Laboratory|APL]]{{\}}[[Southwest Research Institute|SwRI]]
| launch_mass = {{cvt|478|kg|lb}}
| dry_mass = {{cvt|401|kg|lb}}
| payload_mass = {{cvt|30.4|kg|lb}}
| dimensions = {{cvt|2.2|xx|2.1|xx|2.7|m|ft}}
| power = 228 watts

| launch_date = {{start-date|January 19, 2006, 19:00}}&nbsp;UTC
| launch_rocket = [[Atlas V]] 551
| launch_site = [[Cape Canaveral Air Force Station|Cape Canaveral]] [[Cape Canaveral Air Force Station Space Launch Complex 41|SLC-41]]
| launch_contractor = [[United Launch Alliance]]

| disposal_type = <!--deorbited, decommissioned, placed in a graveyard orbit, etc-->
| deactivated = <!--when craft was decommissioned-->
| last_contact = <!--when last signal received if not decommissioned-->

| orbit_eccentricity = 1.41905
| orbit_inclination = 2.23014°
| orbit_RAAN = 225.016°
| orbit_arg_periapsis = 293.445°
| orbit_epoch = January 1, 2017 ([[Julian day|JD]] 2457754.5)<ref>{{cite web |url=http://ssd.jpl.nasa.gov/horizons.cgi |title=HORIZONS Web-Interface |publisher=NASA/JPL |accessdate=July 25, 2016}} To find results, change Target Body to "New Horizons" and change Time Span to include "2017-01-01".</ref>

|interplanetary =
{{Infobox spaceflight/IP
|type = flyby
|object = {{ats|132524|APL}}
|note = incidental
|distance = {{cvt|101867|km|mi}}
|arrival_date = June 13, 2006, 04:05&nbsp;UTC
}}
{{Infobox spaceflight/IP
|type = flyby
|object = [[Jupiter]]
|note = gravity assist
|distance = {{cvt|2300000|km|mi}}
|arrival_date = February 28, 2007, 05:43:40&nbsp;UTC
}}
{{Infobox spaceflight/IP
|type = flyby
|object = [[Pluto]]
|distance = {{cvt|12500|km|mi}}
|arrival_date = July 14, 2015, 11:49:57&nbsp;UTC
}}
{{Infobox spaceflight/IP
|type = flyby
|object = {{mpl|486958|2014 MU|69}}
|arrival_date = January 1, 2019 (planned)
|distance =
}}
| instruments_list = {{Infobox spaceflight/Instruments
|acronym1 = Alice |name1 = Ultraviolet Imaging Spectrometer
|acronym2 = LORRI |name2 = Long-Range Reconnaissance Imager
|acronym3 = SWAP |name3 = Solar Wind at Pluto
|acronym4 = PEPSSI |name4 = Pluto Energetic Particle Spectrometer Science Investigation
|acronym5 = REX |name5 = Radio Science Experiment
|acronym6 = Ralph |name6 = Ralph Telescope
|acronym7 = SDC |name7 = Venetia Burney Student Dust Counter
}}

| programme = '''[[New Frontiers program]]'''
| previous_mission =
| next_mission = ''[[Juno (spacecraft)|Juno]]''
}}

'''''New Horizons''''' is an interplanetary [[space probe]] that was launched as a part of [[NASA]]'s [[New Frontiers program]].<ref name="NYT-20150718">{{cite news |last=Chang |first=Kenneth |title=The Long, Strange Trip to Pluto, and How NASA Nearly Missed It |url=https://www.nytimes.com/2015/07/19/us/the-long-strange-trip-to-pluto-and-how-nasa-nearly-missed-it.html |date=July 18, 2015 |work=[[New York Times]] |accessdate=July 19, 2015}}</ref> Engineered by the [[Johns Hopkins University]] [[Applied Physics Laboratory]] (APL) and the [[Southwest Research Institute]] (SwRI), with a team led by [[Alan Stern|S. Alan Stern]],<ref name="tri">{{cite podcast |url=https://twit.tv/shows/triangulation/episodes/215 |title=Alan Stern: principal investigator for New Horizons |website=[[TWiT.tv]] |publisher=[[TWiT.tv]] |host=[[Leo Laporte]] |date=August 31, 2015 |access-date=September 1, 2015}}</ref> the spacecraft was launched in 2006 with the primary mission to perform a [[Planetary flyby|flyby]] study of the [[Pluto]] system in 2015, and a secondary mission to fly by and study one or more other [[Kuiper belt]] objects (KBOs) in the decade to follow.<ref name="nhtp">{{cite web |url=http://www.nasa.gov/mission_pages/newhorizons/main/ |title=New Horizons to Pluto, Mission Website |publisher=US National Aeronautics and Space Administration (NASA) |date=July 2, 2015 |accessdate=July 7, 2015}}</ref><ref name="NYT-20150713">{{cite news |last=Chang |first=Kenneth |title=A Close-Up for Pluto After Spacecraft's 3-Billion-MileTrip |url=https://www.nytimes.com/2015/07/14/science/a-close-up-for-pluto-after-spacecrafts-3-billion-mile-trip.html |date=July 13, 2015 |work=[[New York Times]] |accessdate=July 13, 2015}}</ref><ref name="NYT-20150706">{{cite news |last=Chang |first=Kenneth |title=Almost Time for Pluto's Close-Up |url=https://www.nytimes.com/2015/07/07/science/space/almost-time-for-plutos-close-up.html |date=July 6, 2015 |work=[[New York Times]] |accessdate=July 6, 2015}}</ref><ref name="NYT-20150706-db">{{cite news |last=Overbye |first=Dennis |authorlink=Dennis Overbye |title=Reaching Pluto, and the End of an Era of Planetary Exploration |url=https://www.nytimes.com/2015/07/07/science/space/reaching-pluto-and-the-end-of-an-era-of-planetary-exploration.html |date=July 6, 2015 |work=[[New York Times]] |accessdate=July 7, 2015}}</ref><ref name="NYT-20150828">{{cite news |last=Roston |first=Michael |title=NASA's Next Horizon in Space |url=https://www.nytimes.com/interactive/2015/08/25/science/space/nasa-next-mission.html |date=August 28, 2015 |work=[[New York Times]] |accessdate=August 28, 2015}}</ref>

On January 19, 2006, ''New Horizons'' was launched from [[Cape Canaveral Air Force Station]] directly into an Earth-and-solar [[Escape velocity|escape trajectory]] with a speed of about {{convert|16.26|km/s|km/h mph|0|abbr=out|sp=us}}. After a brief encounter with asteroid [[132524 APL]], ''New Horizons'' proceeded to [[Jupiter]], making its closest approach on February 28, 2007, at a distance of {{convert|2.3|e6km|abbr=off|sp=us}}. The Jupiter flyby provided a [[gravity assist]] that increased ''New Horizons''{{'}} speed; the flyby also enabled a general test of ''New Horizons''{{'}} scientific capabilities, returning data about [[Atmosphere of Jupiter|the planet's atmosphere]], [[Moons of Jupiter|moons]], and [[Magnetosphere of Jupiter|magnetosphere]].

Most of the post-Jupiter voyage was spent in hibernation mode to preserve on-board systems, except for brief annual checkouts.<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/index.php |title=New Horizons: NASA's Mission to Pluto |work=NASA |accessdate=April 15, 2015}}</ref> On December 6, 2014, ''New Horizons'' was brought back online for the Pluto encounter, and instrument check-out began.<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20141206 |title=New Horizons - News |work=Johns Hopkins Applied Physics Laboratory |date=December 6, 2014 |accessdate=April 15, 2015}}</ref> On January 15, 2015, the ''New Horizons'' spacecraft began its approach phase to Pluto.

On July 14, 2015, at 11:49&nbsp;[[UTC]], it flew {{cvt|12500|km}} above the surface of Pluto,<ref name="NYT-20150714-kc">{{cite news |last=Chang |first=Kenneth |title=NASA's New Horizons Spacecraft Completes Flyby of Pluto |url=https://www.nytimes.com/2015/07/15/science/space/nasa-new-horizons-spacecraft-reaches-pluto.html |date=July 14, 2015 |work=[[The New York Times]] |accessdate=July 14, 2015}}</ref><ref name="AP-20150714">{{cite news |last=Dunn |first=Marcia |title=Pluto close-up: Spacecraft makes flyby of icy, mystery world |url=http://apnews.excite.com/article/20150714/us-sci--pluto-1a20f848e7.html |date=July 14, 2015 |work=[[Excite]] |agency=Associated Press (AP) |accessdate=July 14, 2015}}</ref> making it the first spacecraft to explore the dwarf planet.<ref name="NYT-20150706-db" /><ref name="NASA-20150714-kn">{{cite web |last1=Brown |first1=Dwayne |last2=Cantillo |first2=Laurie |last3=Buckley |first3=Mike |last4=Stotoff |first4=Maria |title=15-149 NASA's Three-Billion-Mile Journey to Pluto Reaches Historic Encounter |url=http://www.nasa.gov/press-release/nasas-three-billion-mile-journey-to-pluto-reaches-historic-encounter |date=July 14, 2015 |work=[[NASA]] |accessdate=July 14, 2015}}</ref> On October 25, 2016, at 21:48&nbsp;UTC, the last of the recorded data from the Pluto flyby was received from ''New Horizons''.<ref name="NYT-20161028">{{cite news |url=https://www.nytimes.com/2016/10/29/science/pluto-nasa-new-horizons.html |title=No More Data From Pluto |work=[[The New York Times]] |last=Chang |first=Kenneth |date=October 28, 2016 |accessdate=October 28, 2016}}</ref> Having completed its flyby of Pluto,<ref name="NYT-20151211-rj">{{cite news |last=Jayawardhana |first=Ray |title=Give It Up for Pluto |url=https://www.nytimes.com/2015/12/13/opinion/give-it-up-for-pluto.html |date=December 11, 2015 |work=[[New York Times]] |accessdate=December 11, 2015}}</ref> ''New Horizons'' has maneuvered for a flyby of Kuiper belt object {{mpl|486958|2014 MU|69}},<ref name="NASA-20150828-tt">{{cite web |last=Talbert |first=Tricia |title=NASA's New Horizons Team Selects Potential Kuiper Belt Flyby Target |url=http://www.nasa.gov/feature/nasa-s-new-horizons-team-selects-potential-kuiper-belt-flyby-target |date=August 28, 2015 |work=[[NASA]] |accessdate=September 4, 2015}}</ref><ref name="SP-20150828">{{cite web |last1=Cofield |first1=Calla |title=Beyond Pluto: 2nd Target Chosen for New Horizons Probe |url=http://www.space.com/30415-new-horizons-pluto-mission-next-target.html |date=August 28, 2015 |work=[[Space.com]] |accessdate=August 30, 2015}}</ref><ref name="AP-20151022">{{cite news |last=Dunn |first=Marcia |title=NASA's New Horizons on new post-Pluto mission |url=http://apnews.excite.com/article/20151022/us-sci--pluto-next_stop-3b1bf3f8fc.html |date=October 22, 2015 |work=[[AP News]] |accessdate=October 25, 2015}}</ref> expected to take place on January 1, 2019, when it will be 43.4&nbsp;[[Astronomical unit|AU]] from the Sun.<ref name="NASA-20150828-tt" /><ref name="SP-20150828" />
{{clear|left}}

== History ==
{{main article|Exploration of Pluto}}
[[File:USPS Pluto Stamp - October 1991.jpg|thumb|right|[[USPS]] stamp issued in 1991 that served as motivation for planetary scientists to send a probe to Pluto]]
[[File:New horizons (NASA).jpg|thumb|right|Early concept art of the ''New Horizons'' spacecraft. The mission, led by the [[Applied Physics Laboratory]] and [[Alan Stern]], would become the first mission to Pluto successfully funded and launched, after years of delays and cancellations.]]

Stamatios "Tom" Krimigis, head of the [[Applied Physics Laboratory]]'s space division, one of many entrants in the New Frontiers Program competition, formed the ''New Horizons'' team with Alan Stern in December 2000. Appointed as the project's [[principal investigator]], Stern was described by Krimigis as "the personification of the Pluto mission".<ref name="alan-stern">{{cite web |last1=Hand |first1=Eric |title=Feature: How Alan Stern's tenacity, drive, and command got a NASA spacecraft to Pluto |url=http://news.sciencemag.org/people-events/2015/06/feature-how-alan-stern-s-tenacity-drive-and-command-got-nasa-spacecraft-pluto |website=[[Science (journal)|Science]] |publisher=[[American Association for the Advancement of Science]] |date=June 25, 2015 |accessdate=July 8, 2015}}</ref> ''New Horizons'' was based largely on Stern's work since ''Pluto 350'' and involved most of the team from ''Pluto Kuiper Express''.<ref name="newhorizonsbook">[[Alan Stern|Stern, Alan]]; {{cite book |last1=Christopher |first1=Russell |title=New Horizons: Reconnaissance of the Pluto-Charon System and the Kuiper Belt |date=2009 |publisher=[[Springer Publishing]] |isbn=978-0-387-89518-5 |pages=6, 7 |url=https://books.google.com.au/books?id=oZfpYIUKDrUC&pg |accessdate=July 8, 2015}}</ref> The ''New Horizons'' proposal was one of five that were officially submitted to NASA. It was later selected as one of two finalists to be subject to a three-month concept study, in June 2001. The other finalist, POSSE (Pluto and Outer Solar System Explorer), was a separate, but similar Pluto mission concept by the [[University of Colorado Boulder]], led by principal investigator [[Larry W. Esposito]], and supported by the JPL, [[Lockheed Martin]] and the [[University of California]].<ref name="new-frontiers-finalists">{{cite news |last1=Savage |first1=Donald |url=http://nssdc.gsfc.nasa.gov/planetary/text/pluto_pr_20010606.txt |title=NASA Selects Two Investigations for Pluto-Kuiper Belt Mission Feasibility Studies |publisher=[[NASA|National Aeronautics and Space Administration (NASA)]] |date=June 6, 2001 |accessdate=July 9, 2015 |archiveurl=http://www.webcitation.org/6ZsBVxTQw |archivedate=July 9, 2015 |deadurl=no}}</ref> However, the APL, in addition to being supported by ''Pluto Kuiper Express'' developers at the Goddard Space Flight Center and [[Stanford University]],<ref name="new-frontiers-finalists"/> were at an advantage; they had recently developed ''NEAR Shoemaker'' for NASA, which had successfully entered orbit around [[433 Eros]] earlier in the year, and would later land on the asteroid to scientific and engineering fanfare.<ref>{{cite web |last1=Savage |first1=Donald |title=NEAR Shoemaker's Historic Landing on Eros Exceeds Science, Engineering Expectations |url=https://solarsystem.nasa.gov/news/display.cfm?News_ID=683 |website=[[NASA|National Aeronautics and Space Administration (NASA)]] |date=February 14, 2001 |accessdate=July 8, 2015}}</ref>

In November 2001, ''New Horizons'' was officially selected for funding as part of the New Frontiers program.<ref>{{cite news |last1=Savage |first1=Donald |url=http://nssdc.gsfc.nasa.gov/planetary/text/pluto_pr_20011129.txt |title=NASA Selects Pluto-Kuiper Belt Mission Phase B Study |publisher=[[NASA|National Aeronautics and Space Administration (NASA)]] |date=November 29, 2001 |accessdate=July 9, 2015 |archiveurl=http://www.webcitation.org/6ZsCefQyx |archivedate=July 9, 2015 |deadurl=no}}</ref> However, the new NASA Administrator appointed by the [[Presidency of George W. Bush|Bush Administration]], [[Sean O'Keefe]], was not supportive of ''New Horizons'', and effectively cancelled it by not including it in NASA's budget for 2003. NASA's Associate Administrator for the Science Mission Directorate [[Ed Weiler]] prompted Stern to lobby for the funding of ''New Horizons'' in hopes of the mission appearing in the [[Planetary Science Decadal Survey]]; a prioritized "wish list", compiled by the [[United States National Research Council]], that reflects the opinions of the scientific community. After an intense campaign to gain support for ''New Horizons'', the Planetary Science Decadal Survey of 2003-2013 was published in the summer of 2002. ''New Horizons'' topped the list of projects considered the highest priority among the scientific community in the medium-size category; ahead of missions to the Moon, and even Jupiter. Weiler stated that it was a result that "[his] administration was not going to fight".<ref name="alan-stern"/> Funding for the mission was finally secured following the publication of the report, and Stern's team were finally able to start building the spacecraft and its instruments, with a planned launch in January 2006 and arrival at Pluto in 2015.<ref name="alan-stern"/> Alice Bowman became Mission Operations Manager.<ref>{{Cite web |url=http://www.jhuapl.edu/employment/meet/bowman.asp |title=Alice Bowman: APL's First Female MOM |publisher=Johns Hopkins Applied Physics Laboratory |access-date=April 11, 2016}}</ref>

==Mission profile==
[[File:15-011a-NewHorizons-PlutoFlyby-ArtistConcept-14July2015-20150115.jpg|thumb|left|upright|Artist's impression of ''New Horizons''{{'}} [[#Pluto system encounter|close encounter with the Pluto–Charon system]].]]

''New Horizons'' is the first mission in NASA's New Frontiers mission category, larger and more expensive than the Discovery missions but smaller than the Flagship Program. The cost of the mission (including spacecraft and instrument development, launch vehicle, mission operations, data analysis, and education/public outreach) is approximately $700 million over 15 years (2001–2016).<ref>{{Cite journal |url=http://www.forbes.com/sites/alexknapp/2015/07/14/how-do-new-horizons-costs-compare-to-other-space-missions/ |date=July 14, 2015 |title=How Do New Horizons Costs Compare To Other Space Missions? |first=Alex |last=Knapp |magazine=[[Forbes]]}}</ref> The spacecraft was built primarily by [[Southwest Research Institute]] (SwRI) and the [[Johns Hopkins University|Johns Hopkins]] Applied Physics Laboratory. The mission's principal investigator is Alan Stern of the Southwest Research Institute (formerly NASA Associate Administrator).

After separation from the launch vehicle, overall control was taken by Mission Operations Center (MOC) at the Applied Physics Laboratory in [[Howard County, Maryland]]. The science instruments are operated at Clyde Tombaugh Science Operations Center (T-SOC) in [[Boulder, Colorado]].<ref name="DoSS">{{cite web |title=Departments of Space Studies & Space Operations |work=Southwest Research Institute Planetary Science Directorate website |publisher=Southwest Research Institute |url=http://www.boulder.swri.edu/swri_boulder_2009a.pdf |accessdate=March 14, 2010}}</ref> Navigation is performed at various contractor facilities, whereas the navigational positional data and related celestial reference frames are provided by the [[United States Naval Observatory Flagstaff Station|Naval Observatory Flagstaff Station]] through Headquarters NASA and [[JPL]]; [[KinetX]] is the lead on the ''New Horizons'' navigation team and is responsible for planning trajectory adjustments as the spacecraft speeds toward [[Solar System#Trans-Neptunian region|the outer Solar System]]. Coincidentally the Naval Observatory Flagstaff Station was where the photographic plates were taken for the discovery of Pluto's moon [[Charon (moon)|Charon]]; and the Naval Observatory is itself not far from the [[Lowell Observatory]] where Pluto was discovered.

''New Horizons'' was originally planned as a voyage to the only unexplored planet in the Solar{{space}}System. When the spacecraft was launched, Pluto was still classified as a [[planet]], later to be [[IAU definition of planet|reclassified]] as a dwarf planet by the [[International Astronomical Union]] (IAU). Some members of the ''New Horizons'' team, including Alan Stern, disagree with the IAU definition and still describe Pluto as the ninth planet.<ref>{{cite web |title=Unabashedly Onward to the Ninth Planet |work=New Horizons website |url=http://pluto.jhuapl.edu/overview/piPerspective.php?page=piPerspective_09_06_2006. |publisher=Johns Hopkins/APL |accessdate=October 25, 2008 |archiveurl=http://www.webcitation.org/5x3rrNEcY |archivedate=March 9, 2011 |deadurl=no}}</ref> Pluto's satellites [[Nix (moon)|Nix]] and [[Hydra (moon)|Hydra]] also have a connection with the spacecraft: the first letters of their names (N and H) are the initials of ''New Horizons''. The moons' discoverers chose these names for this reason, plus Nix and Hydra's relationship to the mythological [[Pluto (mythology)|Pluto]].<ref>{{Cite press release |title=Pluto's Two Small Moons Christened Nix and Hydra |work=New Horizons website |publisher=Johns Hopkins APL |url=http://www.jhuapl.edu/newscenter/pressreleases/2006/060622.asp |accessdate=October 25, 2008 |archiveurl=http://www.webcitation.org/5x3rrTZyz |archivedate=March 9, 2011}}</ref>

In addition to the science equipment, there are several cultural artifacts traveling with the spacecraft. These include a collection of 434,738 names stored on a compact disc,<ref>{{cite web |title=Send Your Name to Pluto |work=New Horizons website |publisher=Johns Hopkins APL |url=http://pluto.jhuapl.edu/spacecraft/searchName.php |accessdate=January 30, 2009 |archiveurl=http://www.webcitation.org/5x3rrdwvd |archivedate=March 9, 2011 |deadurl=no}}</ref> a piece of [[Scaled Composites]]'s ''[[SpaceShipOne]]'',<ref>{{Cite news |title=Pluto Mission to Carry Piece of SpaceShipOne |date=December 20, 2005 |work=Space.com |url=http://www.space.com/astronotes/astronotes.html |archiveurl=http://www.webcitation.org/5x3rsWTNq |archivedate=March 9, 2011 |deadurl=no}}</ref> a "Not Yet Explored" USPS stamp,<ref name="stamp-betz">{{cite web |last1=Betz |first1=Eric |title=Postage for Pluto: A 29-cent stamp pissed off scientists so much they tacked it to New Horizons |url=http://www.astronomy.com/year-of-pluto/2015/06/postage-for-pluto-a-29-cent-stamp-pissed-off-scientists-enough-they-tacked-it-to-new-horizons |website=[[Astronomy (magazine)|Astronomy]] |publisher=[[Kalmbach Publishing]] |date=June 26, 2015 |accessdate=July 8, 2015}}</ref><ref name="stamp-070715">{{cite web |title='Not Yet Explored' no more: New Horizons flying Pluto stamp to dwarf planet |url=http://www.collectspace.com/news/news-070715a-newhorizons-pluto-explored-stamp.html |website=[[collectSPACE]] |publisher=Robert Pearlman |date=July 7, 2015 |accessdate=July 8, 2015}}</ref> and a [[Flag of the United States]], along with other mementos.<ref>{{Cite news |title=To Pluto, With Postage |date=October 28, 2008 |work=collectSPACE |url=http://www.collectspace.com/news/news-102808a.html |archiveurl=http://www.webcitation.org/5x3rsr1Ur |archivedate=March 9, 2011 |deadurl=no}}</ref>

About {{convert|1|oz|g|sigfig=1|order=flip}} of Clyde Tombaugh's ashes are aboard the spacecraft, to commemorate his discovery of Pluto in 1930.<ref>{{cite news |title=New Horizons launches on voyage to Pluto and beyond |url=http://www.spaceflightnow.com/atlas/av010/060119launch.html |work=spaceFlightNow |date=January 19, 2006 |accessdate=December 1, 2010 |archiveurl=http://www.webcitation.org/5x3rtPlke |archivedate=March 9, 2011 |deadurl=no}}</ref><ref>{{cite web |url=http://www.collectspace.com/news/news-102808a.html |title=To Pluto, with postage: Nine mementos fly with NASA's first mission to the last planet |publisher=collectSPACE |date= |accessdate=October 29, 2013}}</ref> A Florida-[[50 State Quarters|state quarter]] coin, whose design commemorates human exploration, is included, officially as a trim weight.<ref>{{cite web |url=http://www.nasa.gov/mission_pages/newhorizons/main/fl_quarter.html |title=NASA - A 'State' of Exploration |publisher=Nasa.gov |date=March 8, 2006 |accessdate=October 29, 2013}}</ref> One of the science packages (a dust counter) is named after [[Venetia Burney]], who, as a child, suggested the name "Pluto" after its discovery.

== Goal ==
[[File:15-150-NasaTeam-NewHorizonsCallsHomeAfterPlutoFlyby-20150714.jpg|thumb|right|View of Mission Operations at the [[Applied Physics Laboratory]] in [[Laurel, Maryland]] (July 14, 2015).]]
The goal of the mission is to understand the formation of the Pluto system, the Kuiper belt, and the transformation of the early Solar System.<ref>{{cite web |url=http://www.nasa.gov/sites/default/files/files/AGU-NH-Workshop.pdf |title=The Everest of Planetary Exploration: New Horizons Explores The Pluto System 2015 |format=PowerPoint Presentation |work=NASA |accessdate=April 15, 2015}}</ref> The spacecraft collected data on the atmospheres, surfaces, interiors and environments of Pluto and its moons. It will also study other objects in the Kuiper belt.<ref>{{cite web |url=https://solarsystem.nasa.gov/missions/profile.cfm?MCode=PKB |title=Solar System Exploration - New Horizons |work=NASA |date=February 27, 2015 |accessdate=April 15, 2015}}</ref> "By way of comparison, ''New Horizons'' gathered 5,000 times as much data at Pluto as [[Mariner program|Mariner]] did at the [[Mars|Red Planet]]."<ref>[http://www.bbc.com/news/science-environment-33440926 New Horizons: Pluto map shows 'whale' of a feature] by Jonathan Amos, on July 8, 2015 ([[BBC]] - Science & Environment section)</ref>

Some of the questions the mission attempts to answer are: What is Pluto's atmosphere made of and how does it behave? What does its surface look like? Are there large geological structures? How do [[solar wind]] particles interact with Pluto's atmosphere?<ref>{{cite web |url=http://www.nasa.gov/mission_pages/newhorizons/spacecraft/index.html |title=New Horizons Spacecraft and Instruments |work=NASA |date=November 10, 2014 |accessdate=April 15, 2015}}</ref>

Specifically, the mission's science objectives are to:<ref>{{cite web |url=http://discoverynewfrontiers.nasa.gov/missions/missions_nh.cfml |title=New Frontiers Program: New Horizons Science Objectives |work=NASA - New Frontiers Program |accessdate=April 15, 2015}}</ref>

*map the surface composition of Pluto and [[Charon (moon)|Charon]]
*characterize the geology and morphology of Pluto and Charon
*characterize the neutral [[atmosphere of Pluto]] and its escape rate
*search for an atmosphere around Charon
*map surface temperatures on Pluto and Charon
*search for rings and additional satellites around Pluto
*conduct similar investigations of one or more [[Kuiper belt]] objects

== Design and construction ==

=== Spacecraft subsystems ===
[[File:New Horizons 1.jpg|thumb|''New Horizons'' at [[Kennedy Space Center]] in 2005]]
The spacecraft is comparable in size and general shape to a [[grand piano]] and has been compared to a piano glued to a cocktail bar-sized satellite dish.<ref name="Moore-2010"/> As a point of departure, the team took inspiration from the [[Ulysses probe|Ulysses]] spacecraft,<ref>{{Cite journal |last1=Fountain |first1=G. H. |last2=Kusnierkiewicz |first2=D. Y. |last3=Hersman |first3=C. B. |last4=Herder |first4=T. S. |last5=Coughlin |first5=T. B. |last6=Gibson |first6=W. C. |last7=Clancy |first7=D. A. |last8=Deboy |first8=C. C. |last9=Hill |first9=T. A. | last10=Kinnison |first10=J. D. |last11=Mehoke |first11=D. S. |last12=Ottman |first12=G. K. |last13=Rogers |first13=G. D. |last14=Stern |first14=S. A. |last15=Stratton |first15=J. M. |last16=Vernon |first16=S. R. |last17=Williams |first17=S. P. |title=The New Horizons Spacecraft |arxiv=0709.4288 |doi=10.1007/s11214-008-9374-8 |journal=Space Science Reviews |volume=140 |pages=23 |year=2008 |pmid= |pmc= |bibcode=2008SSRv..140...23F}}</ref> which also carried a [[radioisotope thermoelectric generator]] (RTG) and dish on a box-in-box structure through the outer Solar System. Many subsystems and components have flight heritage from APL's [[CONTOUR]] spacecraft, which in turn had heritage from APL's [[TIMED]] spacecraft.

''New Horizons''{{'}} body forms a triangle, almost {{cvt|2.5|ft|m|order=flip}} thick. (The ''Pioneers'' have [[hexagon]]al bodies, whereas the [[Voyager program|''Voyagers'']], ''Galileo'', and ''[[Cassini–Huygens]]'' have [[decagon]]al, hollow bodies.) A [[7075 aluminium alloy]] tube forms the main structural column, between the launch vehicle adapter ring at the "rear," and the {{cvt|2.1|m}} radio [[dish antenna]] affixed to the "front" flat side. The [[titanium]] fuel tank is in this tube. The RTG attaches with a 4-sided titanium mount resembling a gray pyramid or stepstool. Titanium provides strength and thermal isolation. The rest of the triangle is primarily sandwich panels of thin aluminium facesheet (less than {{cvt|1/64|in|mm|2|disp=or}}) bonded to aluminium honeycomb core. The structure is larger than strictly necessary, with empty space inside. The structure is designed to act as [[Radiation hardening|shielding]], reducing electronics [[Single event upset|errors caused by radiation]] from the RTG. Also, the mass distribution required for a spinning spacecraft demands a wider triangle.

The interior structure is painted black to equalize temperature by [[Thermal radiation|radiative]] heat transfer. Overall, the spacecraft is thoroughly blanketed to retain heat. Unlike the ''Pioneers'' and ''Voyagers'', the radio dish is also enclosed in blankets that extend to the body. The heat from the RTG adds warmth to the spacecraft while it is in the outer Solar System. While in the inner Solar System, the spacecraft must prevent overheating, hence electronic activity is limited, power is diverted to [[Shunt (electrical)|shunts]] with attached radiators, and [[louver]]s are opened to radiate excess heat. While the spacecraft is cruising inactively in the cold outer Solar System, the louvers are closed, and the shunt regulator reroutes power to electric [[resistor|heaters]].

==== Propulsion and attitude control ====
''New Horizons'' has both spin-stabilized (cruise) and three-axis stabilized (science) modes controlled entirely with [[hydrazine]] [[Monopropellant rocket|monopropellant]]. Additional post launch [[delta-v]] of over {{cvt|290|m/s|km/h mph}} is provided by a {{cvt|77|kg}} internal tank. Helium is used as a pressurant, with an [[elastomer]]ic diaphragm assisting expulsion. The spacecraft's on-orbit mass including fuel is over {{cvt|470|kg}} on the Jupiter flyby trajectory, but would have been only {{cvt|445|kg}} for the backup direct flight option to Pluto. Significantly, had the backup option been taken, this would have meant less fuel for later Kuiper belt operations.

There are 16 [[reaction control system|thrusters]] on ''New Horizons'': four {{cvt|4.4|N|lbf|1|lk=on}} and twelve {{cvt|0.9|N|lbf|1}} plumbed into redundant branches. The larger thrusters are used primarily for trajectory corrections, and the small ones (previously used on ''Cassini'' and the ''Voyager'' spacecraft) are used primarily for [[attitude control]] and spinup/spindown maneuvers. Two star cameras are used to measure the spacecraft attitude. They are mounted on the face of the spacecraft and provide attitude information while in spin-stabilized or 3-axis mode. In between the time of star camera readings, spacecraft orientation is provided by dual redundant [[miniature inertial measurement unit]]s. Each unit contains three solid-state [[gyroscope]]s and three [[accelerometer]]s. Two Adcole [[Attitude control#Sun sensor|Sun sensor]]s provide attitude determination. One detects the angle to the Sun, whereas the other measures spin rate and clocking.

==== Power ====
[[File:RTG and New Horizons in background.jpg|thumb|upright|''New Horizons''{{'}} [[Radioisotope thermoelectric generator|RTG]]]]

A cylindrical [[radioisotope thermoelectric generator]] (RTG) protrudes in the plane of the triangle from one vertex of the triangle. The RTG provided {{val|245.7|ul=W}} of power at launch, and was predicted to drop approximately 5% every 4{{space}}years, decaying to {{val|200|u=W}} by the time of its encounter with the [[Plutonian system]] in 2015 and will decay too far to power the transmitters in the 2030s.<ref name="tri"/> There are no onboard batteries. RTG output is relatively predictable; load transients are handled by a capacitor bank and fast circuit breakers.

The RTG, model "[[GPHS-RTG]]," was originally a spare from the ''Cassini'' mission. The RTG contains {{cvt|9.75|kg|lb}} of [[plutonium-238]] oxide pellets.<ref name="newhorizonsbook"/> Each pellet is clad in [[iridium]], then encased in a graphite shell. It was developed by the U.S. [[United States Department of Energy|Department of Energy]] at the Materials and Fuels Complex, a part of the [[Idaho National Laboratory]].<ref>{{Cite news |first=Steven |last=Friederich |title=Argonne Lab is developing battery for NASA missions |date=December 16, 2003 |publisher=Idaho State Journal |url=http://www.journalnet.com/articles/2003/12/16/news/local/news02.txt |archiveurl=http://www.matr.net/article-9139.html |archivedate=December 17, 2003}}</ref>
The original RTG design called for {{cvt|10.9|kg|lb}} of plutonium, but a unit less powerful than the original design goal was produced because of delays at the United States Department of Energy, including security activities, that delayed plutonium production.<ref name=radioshow>{{cite web |last1=Betts |first1=Bruce |title=Planetary Radio trivia question at 38m28s |url=http://www.planetary.org/multimedia/planetary-radio/show/2015/0728-the-royal-observatory-greenwich-quest-for-longitude.html |website=The Planetary Society |accessdate=August 7, 2015}}</ref> The mission parameters and observation sequence had to be modified for the reduced wattage; still, not all instruments can operate simultaneously. The Department of Energy transferred the space battery program from Ohio to Argonne in 2002 because of security concerns.

The amount of radioactive plutonium in the RTG is about one-third the amount on board the Cassini–Huygens probe when it launched in 1997. That Cassini launch was protested by some. The United States Department of Energy estimated the chances of a New Horizons launch accident that would release radiation into the atmosphere at 1 in 350, and monitored the launch<ref>{{cite news |url=http://www.foxnews.com/story/0,2933,181880,00.html |title=Pluto Probe Launch Scrubbed for Tuesday |work=Fox News |date=January 18, 2006 |archiveurl=http://www.webcitation.org/5x3s2FqQW |archivedate=March 9, 2011}}</ref> as it always does when RTGs are involved. It was estimated that a worst-case scenario of total dispersal of on-board plutonium would spread the equivalent radiation of 80% the average annual dosage in North America from background radiation over an area with a radius of {{cvt|105|km}}.<ref>{{cite web |title=Draft Environmental Impact Statement for the New Horizons Mission |url=http://pluto.jhuapl.edu/overview/deis/docs/NH_DEIS_Full.pdf |publisher=Johns Hopkins APL |accessdate=May 16, 2014 |archive-url=https://web.archive.org/web/20141113230746/http://pluto.jhuapl.edu/overview/deis/docs/NH_DEIS_Full.pdf |archive-date=November 13, 2014 |format=pdf}}</ref>

==== Flight computer ====
The spacecraft carries two [[computer]] systems: the Command and Data Handling system and the Guidance and Control processor. Each of the two systems is duplicated for [[Redundancy (engineering)|redundancy]], for a total of four computers. The processor used for its flight computers is the [[Mongoose-V]], a 12 [[Megahertz|MHz]] radiation-hardened version of the [[R3000|MIPS R3000]] [[Central processing unit|CPU]]. Multiple redundant clocks and timing routines are implemented in hardware and software to help prevent faults and downtime. To conserve heat and mass, spacecraft and instrument electronics are housed together in IEMs (integrated electronics modules). There are two redundant IEMs. Including other functions such as instrument and radio electronics, each IEM contains 9{{space}}boards.<ref>{{cite web |url=http://pluto.jhuapl.edu/Mission/Spacecraft/Systems-and-Components.php |title=New Horizons |work=jhuapl.edu}}</ref> The software of the probe runs on [[Nucleus RTOS]] operating system.<ref>{{cite web |last1=Voica |first1=Alexandru |title=MIPS in space: Inside NASA's New Horizons mission to Pluto |url=http://blog.imgtec.com/mips-processors/mips-in-space-inside-nasa-new-horizons-mission-to-pluto |website=Imagination}}</ref>

There have been two "safing" events, that sent the spacecraft into [[safe mode (spacecraft)|safe mode]]:
* On March 19, 2007 the Command and Data Handling computer experienced an uncorrectable memory error and rebooted itself, causing the spacecraft to go into safe mode. The craft fully recovered within two days, with some data loss on Jupiter's [[magnetotail]]. No impact on the subsequent mission was expected.<ref>{{cite web |title=The PI's Perspective: Trip Report |url=http://pluto.jhuapl.edu/News-Center/PI-Perspectives.php?page=piPerspective_3_26_2007 |date=March 27, 2007 |accessdate=August 5, 2009 |publisher=NASA/Johns Hopkins University/APL/New Horizons Mission |archivedate=March 9, 2011}}</ref>
* On July 4, 2015 there was a CPU safing event caused by over assignment of commanded science operations.<ref>{{cite web |url=http://www.latimes.com/science/sciencenow/la-sci-sn-pluto-encounter-mode-20150706-story.html |title=Computer glitch doesn't stop New Horizons: Pluto encounter almost a week away |author=Los Angeles Times |date=July 6, 2015 |work=latimes.com |accessdate=July 13, 2015}}</ref><ref>{{cite web |url=http://www.space.com/29853-new-horizons-glitch-pluto-flyby.html |title=Pluto Probe Suffers Glitch 10 Days Before Epic Flyby |work=Space.com |accessdate=July 13, 2015}}</ref>

==== Telecommunications and data handling ====
[[File:New Horizons - REX.jpeg|thumb|''New Horizons''{{'}} [[Antenna (radio)|antennas]]]]

Communication with the spacecraft is via [[X band]]. The craft had a communication rate of {{val|38|u=kbit/s}} at Jupiter; at Pluto's distance, a rate of approximately {{val|1|ul=kbit/s}} per transmitter is expected. Besides the low bandwidth, Pluto's distance also causes a [[Latency (engineering)|latency]] of about 4.5&nbsp;hours (one-way). The {{cvt|70|m|adj=on|sp=us}} [[NASA Deep Space Network]] (DSN) dishes are used to relay commands once it is beyond Jupiter. The spacecraft uses [[dual modular redundancy]] transmitters and receivers, and either right- or left-hand [[circular polarization]]. The downlink signal is amplified by dual redundant 12-watt [[traveling-wave tube]] amplifiers (TWTAs) mounted on the body under the dish. The receivers are new, low-power designs. The system can be controlled to power both TWTAs at the same time, and transmit a dual-polarized downlink signal to the DSN that nearly doubles the downlink rate. DSN tests early in the mission with this dual polarization combining technique were successful, and the capability is now considered operational (when the spacecraft power budget permits both TWTAs to be powered).

In addition to the [[high-gain antenna]], there are two backup low-gain antennas and a medium-gain dish. The high-gain dish has a [[Cassegrain reflector]] layout, composite construction, and a {{convert|2.1|m|ft|0|adj=on|sp=us}} diameter providing over {{val|42|ul=dBi}} of gain, has a half-power beam width of about a degree. The prime-focus, medium-gain antenna, with a {{convert|0.3|m|ft|0|adj=on|sp=us}} aperture and 10° half-power beam width, is mounted to the back of the high-gain antenna's secondary reflector. The forward low-gain antenna is stacked atop the feed of the medium-gain antenna. The aft low-gain antenna is mounted within the launch adapter at the rear of the spacecraft. This antenna was used only for early mission phases near Earth, just after launch and for emergencies if the spacecraft had lost attitude control.

''New Horizons'' recorded scientific instrument data to its solid-state memory buffer at each encounter, then transmitted the data to Earth. Data storage is done on two low-power [[Flash memory|solid-state recorders]] (one primary, one backup) holding up to {{val|8|ul=gigabyte}}s each. Because of the extreme distance from Pluto and the Kuiper belt, only one buffer load at those encounters can be saved. This is because ''New Horizons'' will require approximately 16 months after it has left the vicinity of Pluto to transmit the buffer load back to Earth.<ref name="JHU APL News Center 20150414">{{cite web |title=NASA's New Horizons Nears Historic Encounter with Pluto |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150414 |date=April 14, 2015 |publisher=The Johns Hopkins University Applied Physics Laboratory LLC |accessdate=June 27, 2015}}</ref> At Pluto's distance, transmissions from the space probe back to Earth took four hours and 25 minutes to traverse 4.7 billion km of space.<ref>{{cite news |last1=Rincon |first1=Paul |title=New Horizons: Spacecraft survives Pluto encounter |url=http://www.bbc.com/news/science-environment-33531811 |publisher=BBC |date=July 15, 2015}}</ref>

Part of the reason for the delay between the gathering of and transmission of data is that all of the ''New Horizons'' instrumentation is body-mounted. In order for the cameras to record data, the entire probe must turn, and the one-degree-wide beam of the high-gain antenna was not pointing toward Earth. Previous spacecraft, such as the ''Voyager'' program probes, had a rotatable instrumentation platform (a "scan platform") that could take measurements from virtually any angle without losing radio contact with Earth. ''New Horizons''{{'}} elimination of excess mechanisms was implemented to save weight, shorten the schedule, and improve reliability during its 15-year lifetime.

The ''Voyager 2'' spacecraft experienced platform jamming at Saturn; the demands of long time exposures at Uranus led to modifications of the mission such that the entire probe was rotated to make the time exposure photos at Uranus and Neptune, similar to how ''New Horizons'' rotated.

=== Science payload ===
''New Horizons'' carries seven instruments: three optical instruments, two plasma instruments, a dust sensor and a radio science receiver/radiometer. The instruments are to be used to investigate the global geology, surface composition, surface temperature, atmospheric pressure, atmospheric temperature and escape rate of Pluto and its moons. The rated power is {{val|21|u=watts}}, though not all instruments operate simultaneously.<ref>{{Cite journal |author=Y. Guo |author2=R. W. Farquhar |journal=[[Acta Astronautica]] |volume=58 |issue=10 |date=2006 |pages=550–559 |doi=10.1016/j.actaastro.2006.01.012 |title=Baseline design of New Horizons mission to Pluto and the Kuiper belt |url=http://www.sciencedirect.com/science/article/pii/S0094576506000294 |bibcode=2006AcAau..58..550G}}</ref> In addition, ''New Horizons'' has an Ultrastable Oscillator subsystem, which may be used to study and test the [[Pioneer anomaly]] towards the end of the spacecraft's life.<ref>{{Cite journal |author=M.M. Nieto |journal=Physics Letters B |volume=659 |issue=3 |date=2008 |pages=483–485 |doi=10.1016/j.physletb.2007.11.067 |title=New Horizons and the onset of the Pioneer anomaly |bibcode=2008PhLB..659..483N |arxiv=0710.5135}}</ref>

==== Long-Range Reconnaissance Imager (LORRI) ====
[[File:New Horizons LORRI.jpg|thumb|LORRI—long-range camera]]
The Long-Range Reconnaissance Imager (LORRI) is a long-focal-length imager designed for high resolution and responsivity at visible wavelengths. The instrument is equipped with a 1024×1024 pixel by 12-bits-per-pixel monochromatic [[Charge-coupled device|CCD]] imager with a {{cvt|208.3|mm|in}} aperture giving a resolution of 5{{space}}[[microradian|μrad]] (~1{{space}}[[arcsecond|arcsec]]).<ref name=jhuapl-lorri>{{cite web |title=About LORRI Images |url=http://pluto.jhuapl.edu/soc/lorri_about.html |publisher=The Johns Hopkins University - Applied Physics Laboratory}}</ref> The CCD is chilled far below freezing by a passive radiator on the antisolar face of the spacecraft. This temperature differential requires insulation, and isolation from the rest of the structure. The [[Ritchey-Chrétien telescope|Ritchey–Chretien]] mirrors and metering structure are made of [[silicon carbide]], to boost stiffness, reduce weight, and prevent warping at low temperatures. The optical elements sit in a composite light shield, and mount with titanium and fiberglass for thermal isolation. Overall mass is {{cvt|8.6|kg}}, with the optical tube assembly (OTA) weighing about {{cvt|5.6|kg}},<ref>{{cite web |url=http://www.boulder.swri.edu/pkb/ssr/ssr-lorri.pdf |title=Long-Range Reconnaissance Imager on New Horizons |first=A. F. |last=Cheng |display-authors=etal |archiveurl=https://web.archive.org/web/20090709151428/http://www.boulder.swri.edu/pkb/ssr/ssr-lorri.pdf |archivedate=July 9, 2009 |deadurl=no}}</ref> for one of the largest silicon-carbide telescopes flown at the time (now surpassed by [[Herschel Space Observatory|Herschel]]). For viewing on public web sites the 12-bit per pixel LORRI images are converted to 8-bit per pixel [[JPEG]] images.<ref name=jhuapl-lorri/> These public images do not contain the full [[dynamic range]] of brightness information available from the raw LORRI images files.<ref name=jhuapl-lorri/>
:{{small|''Principal investigator: Andy Cheng, [[Applied Physics Laboratory]]''}}, {{small|''Data: LORRI image search at jhuapl.edu''<ref>{{cite web |url=http://pluto.jhuapl.edu/Multimedia/Science-Photos/search.php?form_keywords=60 |title=Science Photos: LORRI |work=JHUAPL.edu |access-date=May 2, 2015}}</ref>}}

==== Solar Wind At Pluto (SWAP) ====
[[File:New Horizons SWAP.jpg|thumb|SWAP—Solar Wind At Pluto]]

Solar Wind At Pluto (SWAP) is a toroidal [[electrostatic analyzer]] and retarding potential analyzer (RPA), that makes up one of the two instruments comprising ''New Horizons''{{'}} [[Plasma (physics)|Plasma]] and high-energy particle spectrometer suite (PAM), the other being PEPSSI. SWAP measures particles of up to 6.5{{space}}keV and, because of the tenuous solar wind at Pluto's distance, the instrument is designed with the largest [[aperture]] of any such instrument ever flown.{{citation needed|date=July 2015}}
:{{small|''Principal investigator: David McComas, [[Southwest Research Institute]]''}}

==== Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) ====
Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) is a [[time-of-flight mass spectrometry|time of flight]] [[ion]] and [[electron]] sensor that makes up one of the two instruments comprising ''New Horizons''{{'}} plasma and high-energy particle spectrometer suite (PAM), the other being SWAP. Unlike SWAP, which measures particles of up to 6.5{{space}}keV, PEPSSI goes up to 1{{space}}MeV.{{citation needed|date=July 2015}}
:{{small|''Principal investigator: Ralph McNutt Jr., Applied Physics Laboratory''}}

==== Alice ====
''Alice'' is an [[ultraviolet]] imaging [[spectrometer]] that is one of two photographic instruments comprising ''New Horizons''{{'}} Pluto Exploration Remote Sensing Investigation (PERSI); the other being the ''Ralph'' telescope. It resolves 1,024{{space}}wavelength bands in the far and extreme ultraviolet (from 50–{{val|180|ul=nm}}), over 32{{space}}view fields. Its goal is to determine the composition of Pluto's atmosphere. This Alice instrument is derived from another Alice aboard [[European Space Agency|ESA]]'s [[Rosetta space probe#Nucleus|Rosetta]] spacecraft.{{citation needed|date=July 2015}}
:{{small|''Principal investigator: Alan Stern, Southwest Research Institute''}}

==== Ralph telescope ====
[[File:New Horizons - Ralph.png|thumb|''Ralph''—telescope and color camera]]
The ''Ralph'' telescope, {{cvt|6|cm}} in aperture, is one of two photographic instruments that make up ''New Horizons''{{'}} Pluto Exploration Remote Sensing Investigation (PERSI), with the other being the Alice instrument. ''Ralph'' has two separate channels: a visible-light [[Charge-coupled device|CCD]] imager (MVIC- Multispectral Visible Imaging Camera) with broadband and color channels, and a near-[[infrared]] imaging spectrometer, LEISA (Linear Etalon Imaging Spectral Array). LEISA is derived from a similar instrument on the [[New Millennium program|EO-1]] mission. ''Ralph'' was named after Alice's husband on ''[[The Honeymooners]]'', and was designed after Alice.<ref name=sn20150711>
{{cite news |last1=David |first1=Leonard |title=Meet Ralph, the New Horizons Camera Bringing Pluto into Sharp Focus |url=http://spacenews.com/new-horizons-about-to-bring-an-unknown-world-into-sharp-focus/ |accessdate=July 16, 2015 |work=Space News |date=July 11, 2015}}</ref>
:{{small|''Principal investigator: Alan Stern, Southwest Research Institute''}}

==== Venetia Burney Student Dust Counter (VBSDC) ====
[[File:New Horizons sdc.jpeg|thumb|VBSDC—Venetia Burney Student Dust Counter]]

The Venetia Burney Student Dust Counter (VBSDC), built by students at the University of Colorado Boulder, is operating continuously to make [[Cosmic dust|dust]] measurements.<ref>{{cite web |title=Pluto-Bound, Student-Built Dust Detector Renamed "Venetia," Honoring Girl Who Named Ninth Planet |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=062906 |publisher=The Johns Hopkins University Applied Physics Laboratory}}</ref> It consists of a detector panel, about {{cvt|18|x|12|in|mm|order=flip}}, mounted on the anti-solar face of the spacecraft (the ram direction), and an electronics box within the spacecraft. The detector contains fourteen [[polyvinylidene difluoride]] (PVDF) panels, twelve science and two reference, which generate voltage when impacted. Effective collecting area is {{cvt|0.125|m2}}. No dust counter has operated past the orbit of [[Uranus]]; models of dust in the outer Solar System, especially the Kuiper belt, are speculative. The VBSDC is always turned on measuring the masses of the interplanetary and interstellar dust particles (in the range of nano- and picograms) as they collide with the PVDF panels mounted on the ''New Horizons'' spacecraft. The measured data is expected to greatly contribute to the understanding of the dust spectra of the Solar System. The dust spectra can then be compared with those from observations of other stars, giving new clues as to where Earth-like planets can be found in the universe. The dust counter is named for [[Venetia Burney]], who first suggested the name "Pluto" at the age of 11. A thirteen-minute short film about the VBSDC garnered an Emmy Award for student achievement in 2006.<ref>{{cite web |url=https://www.youtube.com/watch?v=nes3cAh8_DI |title=Destination: Pluto and Beyond |work=YouTube.com |archiveurl=http://www.webcitation.org/5x3s3be1g |archivedate=March 9, 2011}}</ref>
:{{small|''Principal investigator: Mihaly Horanyi, [[University of Colorado Boulder]]''}}

==== Radio Science Experiment (REX) ====
The Radio Science Experiment (REX) used an ultrastable [[crystal oscillator]] (essentially a calibrated crystal in a miniature [[Crystal oven|oven]]) and some additional electronics to conduct radio science investigations using the communications channels. These are small enough to fit on a single card. Because there are two redundant communications subsystems, there are two, identical REX circuit boards.
:{{small|''Principal investigators: Len Tyler and Ivan Linscott,. [[Stanford University]]''}}
{{Clear}}

== Journey to Pluto ==

=== Launch ===
{{multiple image
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|image1=NewHorizons Rocket Bly.jpg |width1=1944 |height1=2592
|image2=Atlas V 551 roars into blue sky.jpg |width2=1960 |height2=3008
|footer=Launch of ''New Horizons''. The [[Atlas V]] rocket on the launchpad (left) and lift off from Cape Canaveral.
}}

On September 24, 2005, the spacecraft arrived at the Kennedy Space Center on board a [[C-17 Globemaster III]] for launch preparations.<ref name="SpaceDaily">{{cite web |title=NASA'S Pluto Space Probe Begins Launch Preparations |publisher=SpaceDaily |date=September 27, 2005 |url=http://www.spacedaily.com/reports/NASAS_Pluto_Space_Probe_Begins_Launch_Preparations.html |accessdate=January 12, 2011 |archiveurl=http://www.webcitation.org/5x3s0CNZv |archivedate=March 9, 2011 |deadurl=no}}</ref> The launch of ''New Horizons'' was originally scheduled for January 11, 2006, but was initially delayed until January 17, 2006 to allow for [[borescope]] inspections of the [[Atlas V]]'s [[kerosene]] tank. Further delays related to low cloud ceiling conditions [[downrange]], and high winds and technical difficulties—unrelated to the rocket itself—prevented launch for a further two days.<ref name="nytimes.com">{{cite news |title=Winds Delay Launching for NASA Mission to Pluto |url=https://www.nytimes.com/2006/01/17/science/17cnd-pluto.html |newspaper=New York Times |date=January 17, 2006}}</ref><ref name="Space.com">{{cite web |url=http://www.space.com/1957-launch-nasa-pluto-probe-delayed-24-hours.html |title=Launch of NASA's Pluto Probe Delayed for 24 Hours |publisher=Space.com |date=January 17, 2006 |accessdate=June 3, 2013}}</ref> Although there were backup launch opportunities in February 2006 and February 2007, only the first twenty-three days of the 2006 window permitted the Jupiter flyby. Any launch outside that period would have forced the spacecraft to fly a slower trajectory directly to Pluto, delaying its encounter by 2–4 years. The probe finally lifted off from [[Cape Canaveral Air Force Station Space Launch Complex 41|Pad 41]] at [[Cape Canaveral Air Force Station]], [[Florida]], directly south of [[Space Shuttle]] [[Launch Complex 39]], at 19:00&nbsp;UTC on January 19, 2006.<ref name="Amir">{{cite web |last=Amir |first=A. |title=Planetary News: New Horizons (2006) New Horizons launched on its way to Pluto |publisher=The Planetary Society |date=January 19, 2006 |url=http://www.planetary.org/news/2006/0119_New_Horizons_Launched_on_its_Way_to.html |accessdate=March 14, 2011 |archiveurl=http://www.webcitation.org/5vghu3MjX |archivedate=January 12, 2011}}</ref><ref name="Harwood">{{cite news |url=http://spaceflightnow.com/atlas/av010/060119launch.html |title=New Horizons launches on voyage to Pluto and beyond |work=Spaceflight Now |last=Harwood |first=W. |date=January 19, 2006 |accessdate=January 12, 2011 |archiveurl=http://www.webcitation.org/5vgiNNwFm |archivedate=January 12, 2011}}</ref>

The [[Centaur (rocket stage)|Centaur]] second stage reignited at 19:30&nbsp;UTC, followed by the [[Alliant Techsystems|ATK]] [[Star 48]]B third stage, successfully sending the probe on a solar-escape trajectory. ''New Horizons'' took only nine hours to pass the Moon's orbit.

The probe was launched by a Lockheed Martin Atlas V 551 rocket, with a third stage added to increase the heliocentric (escape) speed. This was the first launch of the Atlas V 551 configuration, which uses five [[solid rocket booster]]s, and the first Atlas V with a third stage. Previous flights had used zero, two, or three solid boosters, but never five. The vehicle, AV-010, weighed {{convert|1.26|e6lb|kg}} at lift-off, and had earlier been slightly damaged when [[Hurricane Wilma]] swept across Florida on October 24, 2005. One of the solid rocket boosters was hit by a door. The booster was replaced with an identical unit, rather than inspecting and requalifying the original.<ref>{{cite news |url=http://spaceflightnow.com/atlas/av010/051102srbreplace.html |title=Damage prompts booster replacement for Pluto probe |work=Spaceflight Now |accessdate=July 31, 2007 |archiveurl=http://www.webcitation.org/5x3rtsNOS |archivedate=March 9, 2011}}</ref>

''New Horizons'' has been called "the fastest spacecraft ever launched" because it left Earth at {{convert|36000|mph|km/h|order=flip|sp=us}}, faster than any other spacecraft to date.<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/Resources/Press-Kits/011607_JupiterPressKit.pdf |title=New Horizons, The First Mission to Pluto and the Kuiper Belt: Exploring Frontier Worlds |publisher=Johns Hopkins University Applied Physics Laboratory |type=Press Kit |date=January 16, 2007}}</ref> It is also the first spacecraft launched directly into a solar escape trajectory, which requires an approximate speed while near Earth of {{cvt|16.5|km/s|km/h mph}},<ref group=lower-alpha>To escape the sun the spacecraft needs a speed relative to the sun of the square root of 2 times the speed of the earth (29.78 km/s), or 42.1 km/s. Relative to the earth this is just 12.3 km/s. But the kinetic energy when near the surface of the earth must include the energy to exit the gravity well of the earth, which requires a speed of about 11 km/s. The total speed needed is the square root of the sum of the squares of these two speeds.</ref> and additional [[delta-v]] to cover [[air drag|air]] and [[gravity drag]], all to be provided by the launcher, but it is not the fastest spacecraft to leave the Solar System. {{as of|2015|01}}, this record is held by ''Voyager 1'', traveling at {{cvt|17.027|km/s|km/h mph}} relative to the Sun.<ref>{{cite web |url=http://voyager.jpl.nasa.gov/mission/weekly-reports/ |title=Voyager Mission Operations Status Report # 2015-01-16, Week Ending January 16, 2015 |work=Jet Propulsion Laboratory (NASA) |date=January 16, 2015 |accessdate=September 26, 2015}}</ref> ''Voyager 1'' attained greater [[hyperbolic trajectory#Hyperbolic excess velocity|hyperbolic excess velocity]] from Jupiter and Saturn [[gravitational slingshot]]s than ''New Horizons''. Other spacecraft, such as the [[Helios (spacecraft)|Helios probes]], can also be measured as the fastest objects, because of their orbital speed relative to the Sun at [[Apsis|perihelion]]. Because they remain in solar orbit, their [[specific orbital energy]] relative to the Sun is lower than ''New Horizons'' and other [[List of artificial objects escaping from the Solar System|artificial objects escaping the Solar System]].

The Star 48B third-stage is also on a [[hyperbolic trajectory|hyperbolic Solar System escape trajectory]], and reached Jupiter before the ''New Horizons'' spacecraft. The Star 48B was expected to cross Pluto's orbit on October 15, 2015.<ref name="star48">{{Cite news |last1=Malik |first1=Tariq |url=http://www.space.com/1991-derelict-booster-beat-pluto-probe-jupiter.html |title=Derelict Booster to Beat Pluto Probe to Jupiter |work=Space.com |accessdate=September 22, 2006 |archiveurl=http://www.webcitation.org/5x3rug20b |archivedate=March 9, 2011 |deadurl=no}}</ref> Because it is not in controlled flight, it did not receive the correct gravity assist, and passed within 200 million km ({{convert|200|km|mi|disp=output number only|sp=us}} million mi) of Pluto.<ref name="star48"/> The Centaur stage did not achieve solar escape velocity, and is in heliocentric orbit.<ref>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20101028.php |title=Where Is the New Horizons Centaur Stage? |publisher=Johns Hopkins APL}}</ref> The launch was dedicated to the memory of launch conductor [[Daniel Sarokon]], who was described by space program officials as one of the most influential people in the history of space travel.<ref>{{cite web |url=http://triblive.com/x/leadertimes/news/s_414000.html |title=Spacecraft will carry memory of Sagamore native |publisher=TribLIVE |date= |accessdate=June 3, 2013}}</ref>

=== Inner Solar System ===

====Trajectory corrections====
On January 28 and 30, 2006, mission controllers guided the probe through its first [[trajectory]]-correction maneuver (TCM), which was divided into two parts (TCM-1A and TCM-1B). The total velocity change of these two corrections was about {{convert|18|m/s|km/h mph|sp=us}}. TCM-1 was accurate enough to permit the cancellation of TCM-2, the second of three originally scheduled corrections.<ref>{{cite web |url=http://pluto.jhuapl.edu/overview/piPerspectives/piPerspective_1_31_2006.php |title=Our Aim Is True |work=The PI's Perspective |publisher=Johns Hopkins APL |first=Alan |last=Stern |date=January 31, 2006 |accessdate=June 11, 2006 |archiveurl=http://www.webcitation.org/5x3rv1vYz |archivedate=March 9, 2011 |deadurl=no}}</ref> On March 9, 2006, controllers performed TCM-3, the last of three scheduled course corrections. The engines burned for 76&nbsp;seconds, adjusting the spacecraft's velocity by about {{cvt|1.16|m/s|km/h mph}}.<ref>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/030906.php |title=New Horizons Adjusts Course Towards Jupiter |publisher=Johns Hopkins APL |date=March 9, 2006 |accessdate=May 29, 2011 |archiveurl=http://www.webcitation.org/5x3rvNKXn |archivedate=March 9, 2011}}</ref> Further trajectory maneuvers were not needed until September 25, 2007 (seven months after the Jupiter flyby), when the engines were fired for 15&nbsp;minutes and 37&nbsp;seconds, changing the spacecraft's velocity by {{cvt|2.37|m/s|km/h mph}},<ref>{{cite press release |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=092707 |title=Maneuver Puts New Horizons on a Straight Path to Pluto |publisher=Johns Hopkins APL |date=September 27, 2007 |accessdate=July 16, 2015 |archiveurl=http://www.webcitation.org/5wrXs2Wcx |archivedate=March 1, 2011}}</ref> followed by another TCM, almost three years later on June 30, 2010, that lasted 35.6&nbsp;seconds, when ''New Horizons'' had already reached the halfway point (in time traveled) to Pluto.<ref>{{cite press release |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20100701 |title=Course Correction Keeps New Horizons on Path to Pluto |publisher=Johns Hopkins APL |date=July 1, 2010 |accessdate=July 16, 2015 |archiveurl=http://www.webcitation.org/5x3rvRhBv |archivedate=March 9, 2011 |deadurl=no}}</ref>

====In-flight tests and Mars orbit====
During the week of February 20, 2006, controllers conducted initial in-flight tests of three onboard science instruments, the Alice ultraviolet imaging spectrometer, the PEPSSI plasma-sensor, and the LORRI long-range visible-spectrum camera. No scientific measurements or images were taken, but instrument electronics, and in the case of Alice, some electromechanical systems were shown to be functioning correctly.<ref>{{cite web |author=Stern, Alan |date=February 27, 2006 |title=Boulder and Baltimore |work=The PI's Perspective |url=http://pluto.jhuapl.edu/overview/piPerspectives/piPerspective_2_27_2006.php |publisher=Johns Hopkins APL |accessdate=June 11, 2006 |archiveurl=http://www.webcitation.org/5x3rv6OyU |archivedate=March 9, 2011 |deadurl=no}}</ref>

On April 7, 2006, the spacecraft passed the orbit of Mars, moving at roughly {{cvt|21|km/s|km/h mph}} away from the Sun at a solar distance of 243 million kilometers.<ref name="Malik">{{cite web |last=Malik |first=T. |title=Pluto-Bound Probe Passes Mars' Orbit |publisher=Space.com |date=April 7, 2006 |url=http://www.space.com/2263-pluto-bound-probe-passes-mars-orbit.html |accessdate=January 14, 2011 |archiveurl=http://www.webcitation.org/5x3s0cgTw |archivedate=March 9, 2011 |deadurl=no}}</ref><ref>{{Cite news |title=Outbound for the Frontier, New Horizons Crosses the Orbit of Mars |date=April 7, 2006 |publisher=Johns Hopkins APL |url=https://solarsystem.nasa.gov/news/display.cfm?News_ID=14396}}</ref><ref>{{cite web |title=Outbound for the Frontier, NASA New Horizons Crosses the Orbit of Mars |work=Pluto Today |publisher=SpaceRef Interactive Inc. |date=April 7, 2006 |url=http://www.plutotoday.com/news/viewsr.html?pid=20190 |accessdate=February 3, 2013 |archiveurl=https://web.archive.org/web/20060426224005/http://www.plutotoday.com/news/viewsr.html?pid=20190 |archivedate=April 26, 2006}}</ref>

====Asteroid 132524 APL====
{{multiple image
|direction=horizontal |align=right
|total_width=300
|image1=Asteroid 2002 JF56.jpg |width1=300 |height1=300 |caption1=Asteroid [[132524 APL]] viewed by ''New Horizons'' in June 2006
|image2=First Pluto sighting from New Horizons.gif |width2=896 |height2=896 |caption2=First images of Pluto in September 2006
}}

Because of the need to conserve fuel for possible encounters with Kuiper belt objects subsequent to the Pluto flyby, intentional encounters with objects in the [[asteroid belt]] were not planned. After launch, the ''New Horizons'' team scanned the spacecraft's trajectory to determine if any asteroids would, by chance, be close enough for observation. In May 2006 it was discovered that ''New Horizons'' would pass close to the tiny asteroid [[132524 APL]] on June 13, 2006. Closest approach occurred at 4:05&nbsp;UTC at a distance of {{cvt|101,867|km|mi}}. The asteroid was imaged by ''Ralph'' (use of LORRI was not possible because of proximity to the Sun), which gave the team a chance to test ''Ralph''{{'s}} capabilities, and make observations of the asteroid's composition as well as light and phase curves. The asteroid was estimated to be {{cvt|2.5|km|mi}} in diameter.<ref>{{cite web |author=Stern, Alan |date=June 1, 2006 |title=A Summer's Crossing of the Asteroid Belt |series=The PI's Perspective |publisher=Johns Hopkins APL |url=http://pluto.jhuapl.edu/overview/piPerspective.php?page=piPerspective_6_1_2006 |accessdate=June 20, 2010 |archiveurl=http://www.webcitation.org/5x3s3l3BI |archivedate=March 9, 2011 |deadurl=no}}</ref><ref>{{cite web |title=JF56 Encounter, Encounter Date June 13, 2006 UT |work=Pluto New Horizons Mission, Supporting Observations for 2002 |publisher=International Astronomical Union |url=http://smass.mit.edu/2002jf56.html |archiveurl=https://web.archive.org/web/20070805184931/http://smass.mit.edu/2002jf56.html |archivedate=August 5, 2007 |accessdate=June 20, 2010}}</ref><ref name="JHAPL61506">{{cite web |title=New Horizons Tracks an Asteroid |publisher=Johns Hopkins APL |url=http://pluto.jhuapl.edu/news_center/news/061506.php |date=June 15, 2006 |accessdate=June 20, 2010 |archiveurl=http://www.webcitation.org/5x3s42XaX |archivedate=March 9, 2011 |deadurl=no}}</ref> The spacecraft successfully tracked the rapidly moving asteroid over June 10–12, 2006.

====First Pluto sighting====
The first images of Pluto from ''New Horizons'' were acquired September 21–24, 2006, during a test of LORRI. They were released on November 28, 2006.<ref name="LORRI">{{cite web |author=K. Beisser |title=New Horizons, Not Quite to Jupiter, Makes First Pluto Sighting |url=http://pluto.jhuapl.edu/news_center/news/112806.php |publisher=JHU/APL |date=November 28, 2006 |accessdate=January 13, 2011 |archiveurl=http://www.webcitation.org/5x3ryrA7R |archivedate=March 9, 2011 |deadurl=no}}</ref> The images, taken from a distance of approximately {{convert|4.2|e9km|e9mi+AU|abbr=unit}}, confirmed the spacecraft's ability to track distant targets, critical for maneuvering toward Pluto and other Kuiper belt objects.

=== Jupiter encounter ===
{{Main article|Exploration of Jupiter}}
[[File:NH Jupiter IR (contrast enhanced).jpg|thumb|upright=0.6|Infrared image of Jupiter by ''New Horizons'']]
''New Horizons'' used LORRI to take its first photographs of Jupiter on September 4, 2006, from a distance of {{convert|291|e6km|abbr=off|sp=us}}.<ref>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/092606.html |title=Jupiter Ahoy! |publisher=Johns Hopkins APL |date=September 26, 2006 |accessdate=October 27, 2008 |archiveurl=http://www.webcitation.org/5x3rxJi16 |archivedate=March 9, 2011}}</ref> More detailed exploration of the system began in January 2007 with an infrared image of the moon [[Callisto (moon)|Callisto]], as well as several black-and-white images of Jupiter itself.<ref name=jupiter-encounter>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/011007.php |title=Jupiter Encounter Begins |publisher=Johns Hopkins APL |date= |accessdate=December 17, 2013}}</ref> ''New Horizons'' received a gravity assist from Jupiter, with its closest approach at 05:43:40 UTC on February 28, 2007, when it was {{convert|2.3|e6km|abbr=off|sp=us}} from Jupiter. The flyby increased ''New Horizons''{{'}} speed by {{cvt|4|km/s|km/h mph|-3}}, accelerating the probe to a velocity of {{cvt|23|km/s|km/h mph|-3}} relative to the Sun and shortening its voyage to Pluto by three years.<ref name=boost>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/022807.php |title=Pluto-Bound New Horizons Spacecraft Gets a Boost from Jupiter |publisher=Johns Hopkins APL |date=February 28, 2007 |accessdate=December 17, 2008 |archiveurl=https://web.archive.org/web/20141113224828/http://pluto.jhuapl.edu/news_center/news/022807.php |archivedate=November 13, 2014}}</ref>

The flyby was the center of a four-month intensive observation campaign lasting from January to June. Being an ever-changing scientific target, Jupiter has been observed intermittently since the end of the ''Galileo'' mission in September 2003. Knowledge about Jupiter benefited from the fact that ''New Horizons''{{'}} instruments were built using the latest technology, especially in the area of cameras, representing a significant improvement over ''Galileo''{{'s}} cameras, which were modified versions of ''Voyager'' cameras, which, in turn, were modified ''Mariner'' cameras. The Jupiter encounter also served as a shakedown and dress rehearsal for the Pluto encounter. Because Jupiter is much closer to Earth than Pluto, the communications link can transmit multiple loadings of the memory buffer; thus the mission returned more data from the Jovian system than it was expected to transmit from Pluto.<ref>{{cite web |url=http://www.msnbc.msn.com/id/17381933/ |title=Pluto probe gets an eyeful in Jupiter flyby |work=MSNBC |first=Tariq |last=Malik |date=February 28, 2007 |accessdate=May 29, 2011 |archiveurl=http://www.webcitation.org/5x3ryMYjH |archivedate=March 9, 2011}}</ref>

One of the main goals during the Jupiter encounter was observing its [[Atmosphere of Jupiter|atmospheric conditions]] and analyzing the structure and composition of its clouds. Heat-induced lightning strikes in the polar regions and "waves" that indicate violent storm activity were observed and measured. The [[Atmosphere of Jupiter#Oval BA|Little Red Spot]], spanning up to 70% of Earth's diameter, was imaged from up close for the first time.<ref name=boost/> Recording from different angles and illumination conditions, ''New Horizons'' took detailed images of Jupiter's faint [[Rings of Jupiter|ring system]], discovering debris left over from recent collisions within the rings or from other unexplained phenomena. The search for undiscovered moons within the rings showed no results. Travelling through Jupiter's [[Magnetosphere of Jupiter|magnetosphere]], ''New Horizons'' collected valuable particle readings.<ref name=boost/> "Bubbles" of plasma that are thought to be formed from material ejected by the moon Io, were noticed in the [[Magnetosphere#Magnetotail|magnetotail]].<ref name=surf>{{cite news |last=Than |first=Ker |date=October 9, 2007 |title=Spacecraft Surfs Jupiter's Magnetic Tail |url=http://www.space.com/4446-spacecraft-surfs-jupiter-magnetic-tail.html |newspaper=Space.com |publisher= |accessdate=December 17, 2013}}</ref>

==== Jovian moons ====
The four largest moons of Jupiter were in poor positions for observation; the necessary path of the gravity-assist maneuver meant that ''New Horizons'' passed millions of kilometers from any of the [[Galilean moons]]. Still, its instruments were intended for small, dim targets, so they were scientifically useful on large, distant moons. Emphasis was put on Jupiter's innermost Galilean moon, [[Io (moon)|Io]], whose active volcanoes shoot out tons of material into Jupiter's magnetosphere, and further. Out of eleven observed eruptions, three were seen for the first time. That of [[Tvashtar Paterae|Tvashtar]] reached an altitude of up to {{cvt|330|km}}. The event gave scientists an unprecedented look into the structure and motion of the rising plume and its subsequent fall back to the surface. Infrared signatures of a further 36 volcanoes were noticed.<ref name=boost/> Callisto's surface was analyzed with LEISA, revealing how lighting and viewing conditions affect infrared spectrum readings of its surface water ice.<ref>{{cite web |url=http://pluto.jhuapl.edu/gallery/sciencePhotos/image.php?page=4&gallery_id=2&image_id=21 |title=Capturing Callisto |publisher=Johns Hopkins APL |date= |accessdate=December 17, 2013}}</ref> Minor moons such as [[Amalthea (moon)|Amalthea]] had their orbit solutions refined. The cameras determined their positions, acting as "reverse optical navigation".

{{Gallery
|title=Jovian moons imaged by ''New Horizons''
|width=210 |height=150 |align=center
|footer={{Commons category-inline|Photos of Jupiter system by New Horizons}}
|File:PIA09245 modest.jpg | [[Ganymede (moon)|Ganymede]] imaged on February 27, 2007 (10:01&nbsp;UTC) from a distance of {{convert|3.5|e6km|abbr=unit}}. Image scale is {{cvt|17|km|mi|disp=x| per pixel (|/pixel)}}.
|File:PIA09246.jpg | [[Europa (moon)|Europa]] imaged on February 27 from a distance of {{convert|3.1|e6km|abbr=unit}}. Image scale is {{cvt|15|km|mi|disp=x| per pixel (|/pixel)}}.
|File:PIA09258 Callisto.jpg | [[Callisto (moon)|Callisto]] imaged on February 27 from a distance of {{convert|4.7|e6km|abbr=unit}}.
|File:Tvashtar volcano on Io from New Horizons.jpg | [[Io (moon)|Io]] imaged on February 28. The feature near the north pole of the moon is a {{cvt|290|km|sp=us}} high plume from the Tvashtar volcano.
}}

=== Outer Solar System ===
After passing Jupiter, ''New Horizons'' spent most of its journey towards Pluto in hibernation mode: redundant components as well as guidance and control systems were shut down to extend their life cycle, decrease operation costs and free the [[Deep Space Network]] for other missions.<ref name=hibernation1>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/062807.php |title=New Horizons Slips into Electronic Slumber |publisher=Johns Hopkins APL |date=2007 |accessdate=December 14, 2013}}</ref> During hibernation mode, the onboard computer monitored the probe's systems and transmitted a signal back to Earth: a "green" code if everything was functioning as expected or a "red" code if mission control's assistance was needed.<ref name=hibernation1/> The probe was activated for about two months a year so that the instruments could be calibrated and the systems checked. The first hibernation mode cycle started on June 28, 2007,<ref name=hibernation1/> the second cycle began on December 16, 2008,<ref>[http://pluto.jhuapl.edu/news_center/news/121908.php New Horizons Earns a Holiday] JHUAPL December 19, 2008</ref> the third cycle on August 27, 2009,<ref>[http://pluto.jhuapl.edu/news_center/news/20090828.php New Horizons Checks Out, Enters Hibernation] JHUAPL August 28, 2009</ref> and the fourth cycle on August 29, 2014 after a 10-week test.<ref>[http://pluto.jhuapl.edu/news_center/news/20140829.php New Horizons Commanded into Last Pre-Pluto Slumber] JHUAPL August 29, 2014</ref>

''New Horizons'' crossed the orbit of [[Saturn]] on June 8, 2008,<ref name=saturn>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/060808.php |title=New Horizons Ventures Beyond Saturn's Orbit |publisher=Johns Hopkins APL |date=2008 |accessdate=December 14, 2013}}</ref> and Uranus on March 18, 2011.<ref name=uranus>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20110318.php |title=Later, Uranus: New Horizons Passes Another Planetary Milestone |publisher=Johns Hopkins APL |date=2011 |accessdate=December 14, 2013}}</ref> After astronomers announced the discovery of two new moons in the Pluto system, [[Kerberos (moon)|Kerberos]] and [[Styx (moon)|Styx]], mission planners started contemplating the possibility of the probe running into unseen debris and dust left over from ancient collisions between the moons. A study based on 18 months of computer simulations, Earth-based telescope observations and occultations of the Pluto system revealed that the possibility of a catastrophic collision with debris or dust was less than 0.3% on the probe's scheduled course.<ref name=debris1>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20121016.php |title=At Pluto, Moons and Debris May Be Hazardous to New Horizons |publisher=Johns Hopkins APL |date=2012 |accessdate=December 14, 2013}}</ref><ref name=debris2>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20130614.php |title=New Horizons Team Sticking to Original Flight Plan at Pluto |publisher=Johns Hopkins APL |date=2013 |accessdate=December 14, 2013}}</ref> If the hazard increased, ''New Horizons'' could have used one of two possible contingency plans, the so-called SHBOTs (Safe Haven by Other Trajectories): the probe could have continued on its present trajectory with the antenna facing the incoming particles so the more vital systems would be protected, or, it could have positioned its antenna to make a course correction that would take it just 3000&nbsp;km from the surface of Pluto where it was expected that the [[atmospheric drag]] would clean the surrounding space of possible debris.<ref name=debris2/>

While in hibernation mode in July 2012, ''New Horizons'' started gathering scientific data with SWAP, PEPSSI and VBSDC. Although it was originally planned to activate just the VBSDC, other instruments were powered on the initiative of principal investigator Alan Stern who decided they could use the opportunity to collect valuable heliospheric data. Before activating the other two instruments, ground tests were conducted to make sure that the expanded data gathering in this phase of the mission would not limit available energy, memory and fuel in the future and that all systems are functioning during the flyby.<ref name=new_instruments>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20120709.php |title=New Horizons Doing Science in Its Sleep |publisher=Johns Hopkins APL |date=2012 |accessdate=December 14, 2013}}</ref> The first set of data was transmitted in January 2013 during a three-week activation from hibernation. The command and data handling software was updated to address the problem of computer resets.<ref name=data>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20130110.php |title=New Horizons Gets a New Year's Workout |publisher=Johns Hopkins APL |date=2013 |accessdate=December 14, 2013}}</ref>

==== Possible Neptune trojan targets ====
Other possible targets were [[Neptune trojan]]s. The probe's trajectory to Pluto passed near Neptune's trailing [[Lagrangian point|Lagrange point]] ("{{L5}}"), which may host hundreds of bodies in 1:1 [[orbital resonance|resonance]]. In late 2013, ''New Horizons'' passed within {{cvt|1.2|AU|km mi}} of the high-inclination L5 Neptune trojan {{mpl|2011 HM|102}},<ref name=parker2012>{{cite journal |last1=Parker |first1=Alex H. |author2=and 21 co-authors. |title=2011 HM102: Discovery of a High-Inclination L5 Neptune Trojan in the Search for a post-Pluto New Horizons Target |journal= |date=2013 |arxiv=1210.4549}}</ref> which was identified shortly before by the ''New Horizons KBO Search Survey'' team while searching for more distant objects for ''New Horizons'' to fly by after its 2015 Pluto encounter. At that range, {{mp|2011 HM|102}} would have been bright enough to be detectable by ''New Horizons''{{'}} LORRI instrument; however, the ''New Horizons'' team eventually decided that they would not target {{mp|2011 HM|102}} for observations because the preparations for the Pluto approach took precedence.<ref>{{cite news |last=Parker |first=Alex |url=http://www.planetary.org/blogs/guest-blogs/2013/0430-2011hm102-new-neptune-companion.html |title=2011 HM102: A new companion for Neptune |work=The Planetary Society |date=April 30, 2013 |accessdate=October 7, 2014}}</ref>

====Observations of Pluto and Charon 2013–14====
Images from July 1 to 3, 2013 by LORRI were the first by the probe to resolve Pluto and Charon as separate objects.<ref>{{cite news |last=Atkinson |first=Nancy |url=http://www.universetoday.com/103429/new-horizons-i-spy-pluto-and-charon/ |title=New Horizons: I Spy Pluto and Charon! |work=Universe Today |date=July 10, 2013 |accessdate=October 7, 2014}}</ref> On July 14, 2014, mission controllers performed a sixth trajectory-correction maneuver (TCM) since its launch to enable the craft to reach Pluto.<ref>[http://pluto.jhuapl.edu/news_center/news/20140715.php New Horizons Marks a 'Year Out' with a Successful Course Correction], New Horizons NASA July 17, 2014</ref> Between July 19–24, 2014, ''New Horizons''{{'}} LORRI snapped 12 images of Charon revolving around Pluto, covering almost one full rotation at distances ranging from about {{convert|429|to|422|e6km|mi|sp=us}}.<ref>{{Cite web |url=http://pluto.jhuapl.edu/Multimedia/Science-Photos/pics/PR_E12_proper_nosat_3fps.png |title=A Moon over Pluto (Close up) |date=August 7, 2014 |publisher=Johns Hopkins APL}}</ref> In August 2014, astronomers made high-precision measurements of Pluto's location and orbit around the Sun using the Atacama Large Millimeter/submillimeter Array ([[Atacama Large Millimeter Array|ALMA]]) to help NASA's ''New Horizons'' spacecraft accurately home in on Pluto.<ref>{{cite news |title=ALMA Pinpoints Pluto to Help Guide New Horizons Spacecraft |url=http://www.eso.org/public/announcements/ann14059/ |accessdate=August 7, 2014 |work=ESO Announcement}}</ref> On December 6, 2014, mission controllers sent a signal for the craft to "wake up" from its final Pluto-approach hibernation and begin regular operations. The craft's response that it was "awake" arrived to Earth on December 7, 2014, at 02:30&nbsp;UTC.<ref name="awoketwitter">{{cite web |url=https://twitter.com/NASANewHorizons |title=NASA New Horizons (@NASANewHorizons) - Twitter}}</ref><ref name="awokeAST"/><ref>{{cite web |url=http://www.nbcnews.com/science/space/its-alive-nasas-new-horizons-pluto-probe-wakes-work-n262996 |title=It's Alive! NASA's New Horizons Pluto Probe 'Wakes Up' for Work |work=NBC News}}</ref>

=== Pluto approach ===
{{multiple image
|direction=horizontal |align=right
|total_width=300
|image1=PlutoCharon-1stColorImage-NewHorizons-Ralph-20150409.png |width1=640 |height1=640
|image2=Pluto-System-June-29.png |width2=399 |height2=386
|footer=Pluto and Charon photographed on April 9 ''(left)'' by Ralph and on June 29 ''(right)'' by LORRI
}}
Distant-encounter operations at Pluto began on January 4, 2015.<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20140829 |title=New Horizons Commanded into Last Pre-Pluto Slumber |publisher=Applied Physics Laboratory |date=August 29, 2014 |accessdate=October 7, 2014}}</ref> At this date images of the targets with the onboard LORRI imager plus ''Ralph'' telescope would only be a few [[pixel]]s in width. Investigators began taking Pluto and background starfield images to assist mission navigators in the design of course-correcting engine maneuvers that would precisely modify the trajectory of ''New Horizons'' to aim the approach. On January 15, 2015, NASA gave a brief update of the timeline of the approach and departure phases.<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150115 |title=New Horizons Begins First Stages of Pluto Encounter |publisher=Applied Physics Laboratory |date=January 15, 2015 |accessdate=November 5, 2016}}</ref>

On February 12, 2015, NASA released new images of Pluto (taken from January 25 to 31) from the approaching probe.<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150204 |title=Happy Birthday Clyde Tombaugh: New Horizons Returns New Images of Pluto |publisher=Applied Physics Laboratory |date=February 4, 2015 |accessdate=November 5, 2016}}</ref><ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150212 |title=The View from New Horizons: A Full Day on Pluto-Charon |publisher=Applied Physics Laboratory |date=February 12, 2015 |accessdate=November 5, 2016}}</ref> ''New Horizons'' was more than {{convert|203|e6km|mi|sp=us}} away from Pluto when it began taking the photos, which showed Pluto and its largest moon, Charon. The exposure time was too short to see Pluto's smaller, much fainter, moons.

Investigators compiled a series of images of the moons Nix and Hydra taken from January 27 through February 8, 2015, beginning at a range of {{convert|201|e6km|mi|sp=us}}.<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150218 |title=85 Years after Pluto’s Discovery, New Horizons Spots Small Moons Orbiting Pluto |publisher=Applied Physics Laboratory |date=February 18, 2015 |accessdate=November 5, 2016}}</ref> Pluto and Charon appear as a single overexposed object at the center. The right side image has been processed to remove the background starfield. The yet smaller two moons, Kerberos and Styx were seen on photos taken on April 25.<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150512 |title=New Horizons Spots Pluto’s Faintest Known Moons |publisher=Applied Physics Laboratory |date=May 12, 2015 |accessdate=November 5, 2016}}</ref> Starting May 11 a hazard search was performed, by looking for unknown objects that could be a danger to the spacecraft, such as rings or more moons, which were possible to avoid by a course change.<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150528 |title=So Far, All Clear: New Horizons Team Completes First Search for Pluto System Hazards |publisher=Applied Physics Laboratory |date=May 28, 2015 |accessdate=November 5, 2016}}</ref>

Also in regards to the approach phase during January 2015, on August 21, 2012, the team announced that they would spend mission time attempting long-range observations of the Kuiper belt object temporarily designated [[VNH0004]], when the object was at a distance from ''New Horizons'' of {{convert|75|Gm|AU|sp=us}}.<ref name="vnh"/> The object would be too distant to resolve surface features or take spectroscopy, but it would be able to make observations that cannot be made from Earth, namely a [[phase curve (astronomy)|phase curve]] and a search for small moons. A second object was planned to be observed in June 2015, and a third in September after the flyby; the team hoped to observe a dozen such objects through 2018.<ref name="vnh">{{cite news |url=http://www.americaspace.com/?p=24691 |title=New Horizons to Encounter KBO Ahead of Pluto Flyby |website=Americaspace.com |date=2012 |accessdate=April 22, 2014}}</ref> On April 15, 2015, Pluto was imaged showing a possible polar cap.<ref name="NASA-20150429">{{cite web |last1=Brown |first1=Dwayne |last2=Buckley |first2=Michael |title=NASA's New Horizons Detects Surface Features, Possible Polar Cap on Pluto |url=http://www.nasa.gov/press-release/nasa-s-new-horizons-detects-surface-features-possible-polar-cap-on-pluto |date=April 29, 2015 |publisher=[[NASA]] |accessdate=April 30, 2015}}</ref>

====Software glitch====
On July 4, 2015, ''New Horizons'' experienced a software anomaly and went into safe mode, preventing the spacecraft from performing scientific observations until engineers could resolve the problem.<ref>{{cite web |last1=Gipson |first1=Lillian |title=New Horizons Team Responds to Spacecraft Anomaly |url=http://www.nasa.gov/nh/new-horizons-responds-spacecraft-anomaly |publisher=[[NASA]] |date=July 4, 2015 |accessdate=July 5, 2015}}</ref><ref>{{cite web |author=Klotz, Irene |url=http://www.reuters.com/article/2015/07/05/us-space-pluto-idUSKCN0PF0HW20150705 |title=New Horizons space probe suffers glitch on approach to Pluto |agency=[[Reuters]] |date=July 5, 2015}}</ref> On July 5, NASA announced that the problem was determined to be a timing flaw in a command sequence used to prepare the spacecraft for its flyby, and the spacecraft would resume scheduled science operations on July 7. The science observations lost because of the anomaly were judged to have no impact on the mission's main objectives and minimal impact on other objectives.<ref name="NASA-new-horizons-2015-07-05">{{cite web |title=NASA's New Horizons Plans July 7 Return to Normal Science Operations |url=http://www.nasa.gov/nh/new-horizons-plans-july-7-return-to-normal-science-operations |website=NASA.gov |publisher=[[NASA]] |date=July 5, 2015}}</ref>

The timing flaw consisted of performing two tasks simultaneously—compressing previously acquired data to release space for more data, and making a second copy of the approach command sequence—that together overloaded the spacecraft's primary computer. After the overload was detected, the spacecraft performed as designed: it switched from the primary computer to the backup computer, entered safe mode, and sent a distress call back to Earth. The distress call was received the afternoon of July 4, which alerted engineers that they needed to contact the spacecraft to get more information and resolve the issue. The resolution was that the problem happened as part of preparations for the approach, and was not expected to happen again because no similar tasks were planned for the remainder of the encounter.<ref name="NASA-new-horizons-2015-07-05"/><ref>{{cite news |last=Feltman |first=Rachel |title=New Horizons computer overload won't hurt the mission to Pluto, NASA says |url=http://www.washingtonpost.com/news/speaking-of-science/wp/2015/07/06/after-a-heart-stopping-glitch-nasas-new-horizons-prepares-for-its-historic-pluto-flyby/ |newspaper=[[The Washington Post]] |date=July 6, 2015}}</ref>

== Pluto system encounter ==
[[File:Alan Stern and New Horizons Team Celebrate Pluto Flyby.jpg|thumb|right|[[Alan Stern]] and the ''New Horizons'' team celebrate after the spacecraft successfully completed its flyby of Pluto.]]
The closest approach of the ''New Horizons'' spacecraft to Pluto occurred at 11:49 UTC on July 14, 2015 at a range of 7,750 miles (12,472&nbsp;km) from the surface<ref>{{cite web |title=NASA's Three-Billion-Mile Journey to Pluto Reaches Historic Encounter |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150714-2 |publisher=[[Johns Hopkins University Applied Physics Laboratory]] |date=July 14, 2015}}</ref> and 8,487 miles (13,658&nbsp;km) from the center of Pluto. [[Telemetry]] data confirming a successful flyby and a healthy spacecraft were received on Earth from the vicinity of the Pluto system on July 15, 2015, 00:52:37 UTC,<ref>{{cite web |author=Lakdawalla, Emily |title=New Horizons "phones home" after Pluto flyby |url=http://www.planetary.org/blogs/emily-lakdawalla/2015/07142231-new-horizons-phones-home.html |publisher=[[The Planetary Society]] |date=July 15, 2015}}</ref> after 22 hours of planned [[Radio silence#Non-military radio silence|radio silence]] due to the spacecraft being pointed toward the Pluto system. Mission managers estimated a one in 10,000 chance that debris could have destroyed it during the flyby, preventing it from sending science data to Earth.<ref>{{cite news |author=Phipps, Claire |title=Pluto: New Horizons probe makes contact with Earth |url=https://www.theguardian.com/science/2015/jul/15/new-horizons-pluto-probe-makes-contact-with-earth |newspaper=[[The Guardian]] |date=July 15, 2015}}</ref> The first details of the encounter were received the next day, but the download of the complete data set took just over 15 months,<ref name="NYT-20161028" /> and analysis of the data will take longer.

=== Objectives ===
The mission's science objectives are grouped in three distinct priorities. The "primary objectives" are required; the "secondary objectives" are expected to be met but are not demanded. The "tertiary objectives" are desired. These objectives may be attempted, though they may be skipped in favor of the above objectives. An objective to measure any magnetic field of Pluto was dropped. A [[magnetometer]] instrument could not be implemented within a reasonable mass budget and schedule, and [[#Science payload|SWAP and PEPSSI]] could do an indirect job detecting some magnetic field around Pluto.{{citation needed|date=July 2015}}

* '''Primary objectives (required)'''
** Characterize the global geology and morphology of Pluto and Charon
** Map chemical compositions of Pluto and Charon surfaces
** Characterize the neutral (non-[[ion]]ized) [[atmosphere of Pluto]] and its escape rate
* '''Secondary objectives (expected)'''
** Characterize the time variability of Pluto's surface and atmosphere
** Image select Pluto and Charon areas in [[Stereoscopy|stereo]]
** Map the [[Terminator (solar)|terminators]] (day/night border) of Pluto and Charon with high resolution
** Map the chemical compositions of select Pluto and Charon areas with high resolution
** Characterize Pluto's [[ionosphere]] (upper layer of the atmosphere) and its interaction with the [[solar wind]]
** Search for neutral species such as [[molecular hydrogen]], [[hydrocarbon]]s, [[hydrogen cyanide]] and other [[nitrile]]s in the atmosphere
** Search for any Charon atmosphere
** Determine [[bolometric]] [[Bond albedo]]s for Pluto and Charon
** Map surface temperatures of Pluto and Charon
** Map any additional surfaces of outermost moons: [[Nix (moon)|Nix]], [[Hydra (moon)|Hydra]], [[Kerberos (moon)|Kerberos]], and [[Styx (moon)|Styx]]
* '''Tertiary objectives (desired)'''
** Characterize the energetic particle environment at Pluto and Charon
** Refine bulk parameters (radii, masses) and orbits of Pluto and Charon
** Search for additional [[Natural satellite|moons]] and any [[Planetary ring|rings]]

=== Flyby details ===
{{multiple image
|direction=horizontal |align=right
|total_width=300
|image1=Pluto by LORRI and Ralph, 13 July 2015.jpg |width1=700 |height1=700 |caption1=Pluto's "encounter hemisphere" viewed by ''New Horizons'' on July 13, 2015
|image2=Pluto by LORRI, 11 July 2015.jpg |width2=599 |height2=599 |caption2=Pluto's Charon-facing opposing hemisphere viewed on July 11, 2015
}}

''New Horizons'' passed within {{cvt|12500|km|mi}} of Pluto, with this closest approach on July 14, 2015 at 11:50 UTC. ''New Horizons'' had a relative velocity of {{cvt|13.78|km/s|km/h mph}} at its closest approach, and came as close as {{cvt|28800|km|mi}} to Charon. Starting 3.2 days before the closest approach, long-range imaging included the mapping of Pluto and Charon to {{cvt|40|km|mi}} resolution. This is half the rotation period of the Pluto–Charon system and allowed imaging of all sides of both bodies. Close range imaging was repeated twice per day in order to search for surface changes caused by localized snow fall or surface [[cryovolcanism]]. Because of Pluto's tilt, a portion of the northern hemisphere would be in shadow at all times. During the flyby, engineers expected LORRI to be able to obtain select images with resolution as high as {{cvt|50|m|ft|disp=x| per pixel (|/px)}} if closest distance were around 12,500&nbsp;km, and MVIC was expected to obtain four-color global dayside maps at {{cvt|1.6|km|mi|0}} resolution. LORRI and MVIC attempted to overlap their respective coverage areas to form stereo pairs. LEISA obtained hyperspectral near-infrared maps at {{cvt|7|km|mi|disp=x|/px (|/px)}} globally and {{cvt|0.6|km|mi|disp=x|/px (|/px)}} for selected areas.

[[File:Snakeskin terrain on Pluto (PIA19957).png|thumb|left|Patterns of blue-gray ridges and reddish material observed in the Tartarus Dorsa region on July 14]]

Meanwhile, Alice characterized the atmosphere, both by emissions of atmospheric molecules ([[airglow]]), and by dimming of background stars as they pass behind Pluto ([[occultation]]). During and after closest approach, SWAP and PEPSSI sampled the high atmosphere and its effects on the solar wind. VBSDC searched for dust, inferring meteoroid collision rates and any invisible rings. REX performed active and passive radio science. The communications dish on Earth measured the disappearance and reappearance of the [[radio occultation]] signal as the probe flew by behind Pluto. The results resolved Pluto's diameter (by their timing) and atmospheric density and composition (by their weakening and strengthening pattern). (Alice can perform similar occultations, using sunlight instead of radio beacons.) Previous missions had the spacecraft transmit through the atmosphere, to Earth ("downlink"). Pluto's mass and mass distribution were evaluated by the gravitational tug on the spacecraft. As the spacecraft speeds up and slows down, the radio signal exhibited a [[Doppler shift]]. The Doppler shift was measured by comparison with the ultrastable oscillator in the communications electronics.

Reflected sunlight from Charon allowed some imaging observations of the nightside. Backlighting by the Sun gave an opportunity to highlight any rings or atmospheric hazes. REX performed radiometry of the nightside.
{{clear}}

=== Satellite observations ===
''New Horizons''{{'}} best spatial resolution of the small satellites is {{cvt|330|m|ft|disp=x| per pixel (|/px)}} at Nix, {{cvt|780|m|ft|disp=x|/px (|/px)}} at Hydra, and approximately {{cvt|1.8|km|mi|disp=x|/px (|/px)}} at Kerberos and Styx. Estimates for the diameters of these bodies are: Nix at {{cvt|54|xx|41|xx|36|km|mi}}; Hydra at {{cvt|43|xx|33|km|mi}}; Kerberos at {{cvt|12|xx|4.5|km|mi}}; and Styx at {{cvt|7|xx|5|km|mi}}. This translates to a resolution of 164/124/109, 55/42/?, 7/3/?, and 4/3/? pixels in width for Nix, Hydra, Kerberos, and Styx, respectively.

Initial predictions envisioned Kerberos as a relatively large and massive object whose dark surface led to it having a faint reflection. This proved to be wrong as images obtained by ''New Horizons'' on July 14 and sent back to Earth in October 2015 revealed an object just {{cvt|8|km|mi}} across with a highly reflective surface suggesting the presence of relatively clean water ice.<ref name=kerberos>{{cite web |url=http://www.astronomy.com/news/2015/10/last-of-plutos-moons--mysterious-kerberos--revealed-by-new-horizons |title=Last of Pluto's moons — mysterious Kerberos — revealed by New Horizons |work=[[Astronomy (magazine)|Astronomy.com]] |date=October 23, 2015 |access-date=December 6, 2015}}</ref>

{{Gallery
|title=Satellites of Pluto imaged by ''New Horizons''
|width=150 |height=150 |align=center
|footer={{Commons category-inline|Photos of Pluto system by New Horizons}}
|File:Charon in Color (HQ).jpg| [[Charon (moon)|Charon]]
|File:Nix best view.jpg|[[Nix (moon)|Nix]]
|File:HydraHires.jpg |[[Hydra (moon)|Hydra]]
|File:Kerberos (moon).jpg|[[Kerberos (moon)|Kerberos]]
|File:Styx (moon).jpg|[[Styx (moon)|Styx]]
}}

== Post-Pluto events ==
[[File:Blue hazes over backlit Pluto.jpg|thumb|left|View of Pluto as ''New Horizons'' left the system, catching the Sun's rays passing through Pluto's atmosphere, forming a ring]]
Soon after the Pluto flyby, ''New Horizons'' reported that the spacecraft was healthy, its flight path was within the margins, and science data of the Pluto–Charon system had been recorded.<ref name="NYT-20150714-kc2">{{cite news |url=https://www.nytimes.com/2015/07/15/science/space/nasa-new-horizons-spacecraft-reaches-pluto.html |title=NASA's New Horizons Spacecraft Sends Signal From Pluto to Earth |work=[[The New York Times]] |last=Chang |first=Kenneth |date=July 14, 2015 |accessdate=July 14, 2015}}</ref><ref>{{cite news |url=http://www.nbcnews.com/science/space/nasas-new-horizons-probe-phones-home-after-pluto-flyby-n391611 |title=NASA's New Horizons Probe Phones Home After Historic Pluto Flyby |work=[[NBC News]] |first=Alan |last=Boyle |date=July 14, 2015 |accessdate=July 14, 2015}}</ref> The spacecraft's immediate task was to begin returning the 6.25 gigabytes of information collected.<ref name="NYT-20161028" /> The [[FSPL|free space path loss]] at its distance of 4.5 light-hours (3,017,768,400 km) is approximately 303 [[Decibel|dB]] at 7 GHz. Using the [[high gain antenna]] and transmitting at full power, New Horizons' [[EIRP]] is +83 dBm, and at this distance the signal reaching Earth is -220 dBm. The received signal level (RSL) using one, un-arrayed [[Deep Space Network]] antenna with 72 dBi of forward gain equals -148 dBm. <ref>http://planetfox.net/microwaves/bandwidth.html</ref> Because of the extremely low RSL, it could only transmit data at 1 to 2 [[Data rate units#Kilobit per second|kb/s]].<ref name="jhuhub20150717">{{cite web |url=http://hub.jhu.edu/2015/07/17/new-horizons-data-transmission/ |title=How exactly does New Horizons send all that data back from Pluto? |work=The Hub |publisher=Johns Hopkins University |first=Greg |last=Rienzi |date=July 17, 2015 |accessdate=July 17, 2015}}</ref>

By March 30, 2016, ''New Horizons'' had reached the halfway point of transmitting this data.<ref name="airspace20160330">{{cite news |url=http://www.airspacemag.com/daily-planet/new-horizons-still-only-halfway-through-its-download-pluto-180958617/ |title=New Horizons is Still Only Halfway Through Its Download from Pluto |work=[[Air & Space/Smithsonian]] |first=Kiona |last=Smith-Strickland |date=March 30, 2016 |accessdate=November 5, 2016}}</ref> The transfer was completed on October 25, 2016 at 21:48&nbsp;UTC, when the last piece of data—part of a Pluto–Charon observation sequence by the Ralph/LEISA imager—was received by the Johns Hopkins University [[Applied Physics Laboratory]].<ref name="NYT-20161028" /><ref name="nasa20161027">{{cite news |url=http://www.nasa.gov/feature/new-horizons-returns-last-bits-of-2015-flyby-data-to-earth |title=New Horizons Returns Last Bits of 2015 Flyby Data to Earth |publisher=NASA |editor-first=Tricia |editor-last=Talbert |date=October 27, 2016 |accessdate=October 27, 2016}}</ref>

At a distance of {{convert|36.88|AU|e9km+e9mi|2|abbr=unit}} from the Sun and {{convert|3.83|AU|e6km+e6mi|abbr=unit}} from Pluto as of November 2016,<ref name="currentposition">{{cite web |url=http://pluto.jhuapl.edu/Mission/Where-is-New-Horizons/index.php |title=New Horizons Current Position |publisher=[[Applied Physics Laboratory]] |accessdate=November 6, 2016}}</ref> ''New Horizons'' is [[commons:File:New Horizons Full Trajectory.jpg|heading in the direction]] of the constellation [[Sagittarius (constellation)|Sagittarius]]<ref name="Peat-20130614" /> at {{cvt|14.35|km/s|mi/s AU/year|lk=on}} relative to the Sun.<ref name="currentposition" /> The brightness of the Sun from the spacecraft is [[Magnitude (astronomy)|magnitude]] −18.9.<ref name="Peat-20130614">{{cite web |url=http://www.heavens-above.com/SolarEscape.aspx |title=Spacecraft escaping the Solar System |work=[[Heavens-Above]] |last=Peat |first=Chris |accessdate=November 5, 2016}}</ref>

== Mission extension ==
[[File:Oort cloud Sedna orbit.svg|thumb|Big picture: from the [[Solar System#Inner Solar System|inner Solar System]] to the [[Oort cloud]] with the Kuiper belt in between]]

The ''New Horizons'' team requested, and received, a mission extension through 2021 to explore additional Kuiper belt objects (KBOs). During this Kuiper Belt Extended Mission (KEM), the spacecraft will perform a close fly-by of {{mpl|486958|2014 MU|69}} and conduct more distant observations on an additional two dozen objects.<ref name="extension request">{{cite news |url=http://www.space.com/32660-new-horizons-extended-mission-kuiper-belt.html |title=New Horizons Encore? Pluto Probe's Team Proposes Extension |work=Space.com |last=Wall |first=Mike |date=April 25, 2016 |accessdate=April 27, 2016}}</ref><ref name="Mission Extension">{{cite news |url=http://www.space.com/33332-new-horizons-pluto-probe-mission-extension.html |title=It's Official! NASA Pluto Probe to Fly by Another Object in 2019 |work=Space.com |last=Wall |first=Mike |date=July 1, 2016 |accessdate=July 3, 2016}}</ref><ref name="verge20160701">{{cite news |url=http://www.theverge.com/2016/7/1/11686404/nasa-new-horizons-mission-funding-extension-mu69 |title=NASA extends the New Horizons mission to fly by another small world beyond Pluto |work=The Verge |first=Loren |last=Grush |date=July 1, 2016 |accessdate=September 11, 2016}}</ref>

=== Kuiper belt object mission ===

==== Target background ====
Mission planners searched for one or more additional Kuiper belt objects (KBOs) of the order of {{cvt|50|–|100|km|mi}} in diameter as targets for flybys similar to the spacecraft's Plutonian encounter, but, despite the large population of KBOs, many factors limit the number of possible targets. Because the flight path is determined by the Pluto flyby, and the probe only has 33 kilograms of hydrazine remaining, the object to be visited needs to be within a cone, extending from Pluto, of less than a degree's width. This ruled out any possibility for a flyby of [[Eris (dwarf planet)|Eris]], a trans-Neptunian object comparable in size to Pluto.<ref>{{cite web |url=http://www.universetoday.com/78334/video-stellar-occultation-by-eris/#more-78334 |title=Stellar Occultation by Eris |work=Universe Today |first=Nancy |last=Atkinson |date=November 11, 2010 |accessdate=May 29, 2011 |archiveurl=http://www.webcitation.org/5x3rzqSik |archivedate=March 9, 2011}}</ref> It will also need to be within 55{{space}}AU, because beyond 55{{space}}AU, the communications link will become too weak, and the RTG power output will have decayed significantly enough to hinder observations. Desirable KBOs would be well over {{cvt|50|km|-1}} in diameter, neutral in color (to compare with the reddish Pluto), and, if possible, have a moon that imparts a wobble. After a search along ''New Horizon''{{'s}} flight path using the Hubble Space Telescope, only three KBOs were found in range, and one of those objects was later dropped from consideration.<ref name=Extended>{{cite web |url=http://spacenews.com/extended-timetable-for-decision-on-new-horizons-extended-mission/ |title=Extended Timetable for Decision on New Horizons Extended Mission |work=Space News |last1=Foust |first1=Jeff |date=July 22, 2015 |accessdate=July 22, 2015}}</ref>

==== Search ====
In 2011 a dedicated search for suitable KBOs using ground telescopes was started by mission scientists. Large ground telescopes with wide-field cameras, notably the twin 6.5-meter [[Magellan Telescopes]] in Chile, the 8.2-meter [[Subaru Telescope|Subaru Observatory]] in Hawaii, and the [[Canada–France–Hawaii Telescope]]<ref name=parker2012/><ref name="Pluto-bound probe faces crisis">[http://www.nature.com/news/pluto-bound-probe-faces-crisis-1.15261 Pluto-bound probe faces crisis] (nature.com May 20, 2014)</ref> were used to search for potential targets. Through the [[citizen-science]] project, the public helped to scan telescopic images for possible suitable mission candidates by participating in the [[Zooniverse (citizen science project)#Ice Hunters|Ice Hunters]] project.<ref name="icehunters">{{cite web |url=http://demo.icehunters.org/ |title=IceHunters |publisher=Zooniverse |date=2011 |accessdate=June 27, 2011}}</ref><ref name="icehuntersdone">{{cite web |url=https://www.zooniverse.org/project/icehunters |title=IceHunters project complete |publisher=Zooniverse |date=2012 |accessdate=August 7, 2012}}</ref><ref>{{cite web |title=Ice Hunters web site |url=http://www.icehunters.org |publisher=[[Zooniverse (citizen science project)|Zooniverse.Org]] |accessdate=July 8, 2011}}</ref><ref name=nasaice>{{cite web |title=Citizen Scientists: Discover a New Horizons Flyby Target |url=http://solarsystem.nasa.gov/news/display.cfm?News_ID=37726 |publisher=[[NASA]] |accessdate=August 23, 2011 |date=June 21, 2011}}</ref><ref name = "exciting">{{cite web |last=Lakdawalla |first=Emily |date=June 21, 2011 |title=The most exciting citizen science project ever (to me, anyway) |publisher=[[The Planetary Society]] |url=http://planetary.org/blog/article/00003073/ |accessdate=August 31, 2011}}</ref> The ground-based search resulted in the discovery of about 143 KBOs of potential interest,<ref>{{cite web |title=Confirmed KBOs |url=http://www.icehunters.org/catalogue.php?task=6&page=1 |website=New Horizons Ice Hunters |publisher=Zooniverse |accessdate=August 21, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20141211123836/http://www.icehunters.org/catalogue.php?task=6&page=1 |archivedate=December 11, 2014}}</ref> but none of these were close enough to the flight path of ''New Horizons''.<ref name="Pluto-bound probe faces crisis"/> Only the [[Hubble Space Telescope]] was deemed likely to find a suitable target in time for a successful KBO mission.<ref name="witze20140520">{{cite news |url=http://www.scientificamerican.com/article/pluto-bound-spacecraft-faces-crisis/ |title=Pluto-Bound Spacecraft Faces Crisis |work=Nature |date=May 20, 2014 |accessdate=May 26, 2014 |author=Witze, Alexandra}}</ref> On June 16, 2014, time on Hubble was granted.<ref>{{cite web |url=http://www.nasaspaceflight.com/2014/06/hubble-recruited-new-horizons-pluto-target/ |title=Hubble recruited to find New Horizons probe post-Pluto target |work=nasaspaceflight.com}}</ref> Hubble has a much greater ability to find suitable KBOs than ground telescopes. The probability that a target for ''New Horizons'' would be found was estimated beforehand at about 95%.<ref>[http://www.spacenews.com/article/civil-space/40944hubble-to-lend-pluto-probe-helping-hand-in-search-for-secondary-target Hubble To Lend Pluto Probe Helping Hand in Search for Secondary Target] spacenews.com June 25, 2014.</ref>

==== Suitable KBOs ====
[[File:KBO 2014 MU69 HST.jpg|thumb|{{mpl|486958|2014 MU|69}}, the announced target for the Kuiper belt object mission]]

On October 15, 2014, it was revealed that Hubble's search had uncovered three potential targets,<ref name="NASA-20141015">{{cite web |last=Brown |first=Dwayne |last2=Villard |first2=Ray |title=RELEASE 14-281 NASA's Hubble Telescope Finds Potential Kuiper Belt Targets for New Horizons Pluto Mission |url=http://www.nasa.gov/press/2014/october/nasa-s-hubble-telescope-finds-potential-kuiper-belt-targets-for-new-horizons |date=October 15, 2014 |work=[[NASA]] |accessdate=October 16, 2014}}</ref><ref name = "Lakdawalla2014"/><ref>{{cite web |title=NASA's Hubble Telescope Finds Potential Kuiper Belt Targets for New Horizons Pluto Mission |work=press release |publisher=Johns Hopkins [[Applied Physics Laboratory]] |date=October 15, 2014 |accessdate=October 16, 2014 |archivedate=October 16, 2014 |url=http://www.jhuapl.edu/newscenter/pressreleases/2014/141015_2.asp |archiveurl=https://web.archive.org/web/20141016023345/http://www.jhuapl.edu/newscenter/pressreleases/2014/141015_2.asp}}</ref><ref name = "Wall2014">{{cite web |last=Wall |first=Mike |title=Hubble Telescope Spots Post-Pluto Targets for New Horizons Probe |publisher=Space.com |date=October 15, 2014 |accessdate=October 15, 2014 |archivedate=October 15, 2014 |url=http://www.space.com/27445-hubble-telescope-new-horizons-kuiper-belt.html |archiveurl=https://web.archive.org/web/20141015233156/http://www.space.com/27445-hubble-telescope-new-horizons-kuiper-belt.html}}</ref><ref>{{cite web |author=Buie, Marc |authorlink=Marc W. Buie |title=New Horizons HST KBO Search Results: Status Report |url=http://www.stsci.edu/institute/stuc/oct-2014/New-Horizons.pdf |publisher=[[Space Telescope Science Institute]] |date=October 15, 2014 |page=23}}</ref> temporarily designated PT1 ("potential target 1"), PT2 and PT3 by the ''New Horizons'' team. All are objects with estimated diameters in the {{cvt|30|-|55|km|mi}} range, too small to be seen by ground telescopes, at distances from the Sun of 43–44 AU, which would put the encounters in the 2018–2019 period.<ref name = "Lakdawalla2014"/> The initial estimated probabilities that these objects are reachable within ''New Horizons''{{'}} fuel budget are 100%, 7%, and 97%, respectively.<ref name = "Lakdawalla2014"/> All are members of the "cold" (low-[[orbital inclination|inclination]], low-[[orbital eccentricity|eccentricity]]) [[classical Kuiper belt]], and thus very different from Pluto. [[(486958) 2014 MU69|PT1]] (given the temporary designation "1110113Y" on the HST web site<ref>{{cite web |title=Hubble to Proceed with Full Search for New Horizons Targets |work=HubbleSite news release |publisher=[[Space Telescope Science Institute]] |date=July 1, 2014 |accessdate=October 15, 2014 |url=http://hubblesite.org/newscenter/archive/releases/2014/35/image/a/}}</ref>), the most favorably situated object, is magnitude 26.8, {{cvt|30|-|45|km|mi}} in diameter, and will be encountered around January 2019.<ref name="VOX-20150414">{{cite web |last=Stromberg |first=Joseph |title=NASA's New Horizons probe is visiting Pluto — and just sent back its first color photos |url=https://www.vox.com/2015/4/14/8412031/pluto-new-horizons |date=April 14, 2015 |work=[[Vox (website)|Vox]] |accessdate=April 14, 2015}}</ref> A course change to reach it required about 35% of ''New Horizons''{{'}} available [[delta-v budget|trajectory-adjustment fuel supply]]. A mission to PT3 was in some ways preferable, in that it is brighter and therefore probably larger than PT1, but the greater fuel requirements to reach it would have left less for maneuvering and unforeseen events.<ref name = "Lakdawalla2014">{{cite web |last=Lakdawalla |first=Emily |authorlink=Emily Lakdawalla |title=Finally! New Horizons has a second target |work=Planetary Society blog |publisher=[[Planetary Society]] |date=October 15, 2014 |accessdate=October 15, 2014 |archivedate=October 15, 2014 |url=http://www.planetary.org/blogs/emily-lakdawalla/2014/10151024-finally-new-horizons-has-a-kbo.html |archiveurl=https://web.archive.org/web/20141015230432/http://www.planetary.org/blogs/emily-lakdawalla/2014/10151024-finally-new-horizons-has-a-kbo.html |deadurl=no}}</ref> Once sufficient orbital information was provided, the [[Minor Planet Center]] gave [[Provisional designation in astronomy|provisional designations]] to the three target KBOs: {{mpl|2014 MU|69}} (PT1), {{mpl|2014 OS|393}} (PT2), and {{mpl|2014 PN|70}} (PT3). By the fall of 2014, a possible fourth target, {{mpl|2014 MT|69}}, had been eliminated by follow-up observations. PT2 was out of the running before the Pluto flyby.<ref>{{cite web |author=Corey S. Powell |title=Alan Stern on Pluto's Wonders, New Horizons' Lost Twin, and That Whole "Dwarf Planet" Thing |url=http://blogs.discovermagazine.com/outthere/2015/03/29/alan-stern-on-plutos-wonders/ |magazine=[[Discover (magazine)|Discover]] |date=March 29, 2015}}</ref><ref>http://www.hou.usra.edu/meetings/lpsc2015/pdf/1301.pdf</ref> The spacecraft will also study almost 20 KBOs from afar.<ref>{{cite journal |first=Alan |last=Stern |url=http://www.skyandtelescope.com/astronomy-news/new-horizons-a-billion-miles-to-2014-mu69-10012015/ |title=New Horizons: A Billion Miles to 2014 MU<sub>69</sub> |magazine=[[Sky & Telescope]] |date=October 1, 2015 |accessdate=October 7, 2015}}</ref>

==== KBO selected ====
On August 28, 2015, {{mp|486958|2014 MU|69}} (PT1) was chosen as the flyby target. The necessary course adjustment was performed with four engine firings between October 22 and November 4, 2015.<ref name=wired-20151104>{{cite news |url=https://www.wired.com/2015/11/how-nasa-is-steering-new-horizons-toward-a-tiny-space-rock-in-the-kuiper-belt/ |title=How NASA Is Steering New Horizons Toward a Tiny Space Rock in the Kuiper Belt |magazine=[[Wired (magazine)|Wired]] |first=Nick |last=Stockton |date=November 4, 2015 |access-date=May 30, 2017}}</ref><ref>https://www.nasaspaceflight.com/2017/01/new-horizons-2019-kuiper-belt-encounter/</ref> The flyby is scheduled for January 1, 2019.<ref>{{cite news |title=NASA's New Horizons Team Selects Potential Kuiper Belt Flyby Target |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150828 |publisher=[[Johns Hopkins University Applied Physics Laboratory]] |date=August 15, 2015}}</ref><ref>{{cite web |author=McKinnon, Mika |title=New Horizons Locks Onto Next Target: Let's Explore the Kuiper Belt! |url=http://space.io9.com/new-horizons-locks-onto-next-target-lets-explore-the-k-1727298103 |publisher=[[io9]] |date=August 28, 2015}}</ref> Funding was secured on July 1, 2016.<ref name="Mission Extension"/>

===Encounter with {{mp|486958|2014 MU|69}} ===
[[File:New Horizons Full Trajectory Sideview.png|thumb|''New Horizons''{{'}} position as of July 2016<ref name="currentposition" />]]

Objectives of this mission include:<ref name="skytel20151001">{{cite news |url=http://www.skyandtelescope.com/astronomy-news/new-horizons-a-billion-miles-to-2014-mu69-10012015/ |title=New Horizons: A Billion Miles to {{mp|486958|2014 MU|69}} |work=[[Sky & Telescope]] |last=Stern |first=Alan |date=October 1, 2015 |accessdate=October 3, 2015}}</ref>

*Mapping the surface geology to learn how it formed and has evolved
*Measuring the surface temperature
*Mapping the 3D surface topography and surface composition to learn how it is similar to and how it is different from comets like 67P and dwarf planets such as Pluto
*Searching for any signs of activity, such as a cloud-like coma
*Searching for, and studying, any satellites or rings
*Measuring or constraining its mass

The new mission began on October 22, 2015, when ''New Horizons'' carried out the first in a series of four initial targeting maneuvers designed to send it toward {{mpl|486958|2014 MU|69}}. The maneuver, which started at approximately 19:50&nbsp;UTC on October 22, used two of the spacecraft's small hydrazine-fueled thrusters, lasted approximately 16 minutes and changed the spacecraft's trajectory by about {{convert|10|m/s|ft/s|sp=us}}. The remaining three targeting maneuvers took place on October 25, October 28, and November 4, 2015.<ref name="spdaily20151106">{{cite news |url=http://www.spacedaily.com/reports/New_Horizons_Completes_Targeting_Maneuvers_999.html |title=New Horizons Completes Targeting Maneuvers |work=Space Daily |date=November 6, 2015 |accessdate=December 19, 2015}}</ref><ref name="jhuapl20151029">{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20151029 |title=On Track: New Horizons Carries Out Third KBO Targeting Maneuver |publisher=Johns Hopkins University Applied Physics Laboratory |date=October 29, 2015 |accessdate=December 19, 2015}}</ref>

=== Observations of other KBOs ===
[[File:PIA205891994 JR1newhorizons.gif|thumb||April 2016 observations of [[15810 Arawn]]]]

Aside from its flyby of {{mp|486958|2014 MU|69}}, the extended mission for ''New Horizons'' calls for the spacecraft to conduct observations of and look for ring systems around some two dozen KBOs. In addition, it will continue to study the gas, dust and plasma composition of the Kuiper belt before the mission extension ends in 2021.<ref name="extension request" /><ref name="verge20160701" />

On November 2, 2015, ''New Horizons'' imaged KBO [[15810 Arawn]] with the LORRI instrument from {{convert|280|e6km|e6mi+AU|abbr=unit|disp=x| away (|)}}, showing the shape of the object and one or two details.<ref name="spdaily20151207">{{cite news |url=http://www.spacedaily.com/reports/New_Horizons_catches_a_wandering_Kuiper_Belt_Object_not_far_off_999.html |title=New Horizons' catches a wandering Kuiper Belt Object not far off |work=Space Daily |date=December 7, 2015 |accessdate=December 19, 2015}}</ref> This KBO was again imaged by the LORRI instrument on April 7–8, 2016, from a distance of {{convert|111|e6km|e6mi+AU|abbr=unit}}. The new images allowed the science team to further refine the location of 15810 Arawn to within {{cvt|1000|km|mi}} and to determine its rotational period of 5.4 hours.<ref name="unitoday20160613">{{cite news |url=http://www.universetoday.com/129014/new-horizons-sends-back-first-science-distant-kuiper-belt-object/ |title=New Horizons Sends Back First Science On Distant Kuiper Belt Object |work=Universe Today |first=Evan |last=Gough |date=June 13, 2016 |accessdate=November 5, 2016}}</ref><ref name="jhuapl20160518">{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20160518-2 |title=New Horizons Collects First Science on a Post-Pluto Object |publisher=[[Applied Physics Laboratory]] |date=May 18, 2016 |accessdate=November 5, 2016}}</ref>

In July 2016, the LORRI camera captured some distant images of [[50000 Quaoar|Quaoar]] from {{convert|2.1|e9km|e9mi+AU|abbr=unit|disp=x| away (|)}}; the oblique view will complement Earth-based observations to study the object's light-scattering properties.<ref>{{cite web |url=http://www.nasa.gov/image-feature/new-horizons-spies-a-kuiper-belt-companion |title=New Horizons Spies a Kuiper Belt Companion |publisher=[[NASA]] |first=Tricia |last=Talbert |date=August 31, 2016 |access-date=September 12, 2016}}</ref>

== Speed ==
Even though it was launched far faster than any outward probe before it, ''New Horizons'' will never overtake either ''[[Voyager 1]]'' or ''[[Voyager 2]]'' as the most distant human-made object from Earth. Close flybys of Saturn and Titan gave ''Voyager 1'' an advantage with their gravity assist. When ''New Horizons'' reaches the distance of {{val|100|ul=AU}}, it will be travelling at about {{cvt|13|km/s|mph}}, around {{cvt|4|km/s|mph}} slower than ''Voyager 1'' at that distance.<ref name="jhuapl2006" />

== Gallery ==

=== Images of the launch ===
{{Gallery |align=center |width=180 |lines=3
|File:Atlas 551 rocket prepared for launch.jpg|{{small|The [[Atlas V#Variants|Atlas V 551]] rocket, used to launch ''New Horizons'', being processed a month before launch.}}
|File:Atlas V 551 at Launch Pad 41.jpg|{{small|View of [[Cape Canaveral Air Force Station Space Launch Complex 41|Cape Canaveral Launch Complex 41]], with the Atlas V carrying ''New Horizons'' on the pad.}}
|File:D6-17018ML.jpg|{{small|Distant view of Cape Canaveral during the launch of ''New Horizons'' on January 19, 2006.}}
|File:NASA TV - New Horizons Pluto Launch (January 19, 2006).ogg|{{small|[[NASA TV]] footage of ''New Horizons''{{'}} launch from Cape Canaveral. (4:00)}}
}}

=== Videos ===
{{multiple image |header=Pluto flyover (July 14, 2015) |caption_align=center |align=center |width=300 |direction=horizontal
|image1=Pluto-FlyoverAnimation-20150918.webm
|caption1=<center>(00:30; [[:File:Pluto-FlyoverAnimation-20150918.webm|released September 18, 2015]])</center>
|image2=15-02652-PlutoFilm-50sec-20150714.webm
|caption2=<center>(00:50; [[:File:15-02652-PlutoFilm-50sec-20150714.webm|released December 5, 2015]])</center>
}}
{{clear}}

== Timeline ==

{| class="wikitable" style="margin: 1em auto 1em auto;" width="95%"
|+Timeline of the ''New Horizons'' mission
! style="width:10%;" |Phase
! style="width:15%;" |Date
! style="width:30%;" |Event
! style="width:40%;" | Description
! style="width:5%;" |References

|- style="background:#ffc;"
| rowspan=12 | Preparation Phase
|January 8, 2001
| Proposal team meets face-to-face for the first time at the Johns Hopkins University Applied Physics Laboratory
|
| <ref name="Stern2006">{{cite web |url=http://www.boulder.swri.edu/pkb/ssr/ssr-intro.pdf |title=The New Horizons Pluto Kuiper belt Mission: An Overview with Historical Context |publisher=Southwest Research Institute |last=Stern |first=Alan |date=November 20, 2006 |accessdate=May 20, 2015 |archiveurl=http://www.webcitation.org/6YfbfsiGI |archivedate=May 20, 2015}}</ref>

|- style="background:#ffc;"
|February 5, 2001
| ''New Horizons'' name chosen.
|
| <ref name="Stern2006"/><ref name="Stern2005">[http://www.thespacereview.com/article/369/1 New Horizons indeed] The Space Review, May 9, 2005</ref>

|- style="background:#ffc;"
|April 6, 2001
| ''New Horizons'' proposal submitted to NASA.
| It was one of five proposals submitted, which were later narrowed to two for Phase&nbsp;A study: POSSE (Pluto and Outer Solar System Explorer) and ''New Horizons''.
| <ref name="Stern2006"/>

|- style="background:#ffc;"
|November 29, 2001
| ''New Horizons'' proposal selected by NASA.
| Started Phase&nbsp;B study.
| <ref name="Savage">{{cite web |url=http://nssdc.gsfc.nasa.gov/planetary/text/pluto_pr_20011129.txt |title=NASA Selects Pluto-Kuiper Belt Mission For Phase B Study |publisher=NASA |last=Savage |first=D. |date=November 29, 2001 |accessdate=January 12, 2011 |archiveurl=http://www.webcitation.org/5vgjYJlC0 |archivedate=January 12, 2011}}</ref>

|- style="background:#ffc;"
| March 2002
| Budget zeroed by Bush administration, later overridden
|
| <ref>{{cite web |title=Cuts threaten mission to Pluto |url=http://articles.baltimoresun.com/2002-03-04/news/0203040036_1_study-pluto-pluto-mission-apl |accessdate=May 13, 2015}}</ref><ref>{{cite web |title=The Planetary Society |url=http://www.planetary.org/explore/projects/pluto/ |accessdate=May 13, 2015}}</ref>

|- style="background:#ffc;"
| June 13, 2005
| Spacecraft departed [[Applied Physics Laboratory]] for final testing.
| Spacecraft undergoes final testing at [[Goddard Space Flight Center]] (GSFC).
| <ref>[http://www.jhuapl.edu/newscenter/pressreleases/2005/050926.asp New Horizons at the Cape] The Johns Hopkins Applied Physics Laboratory September 26, 2005</ref>

|- style="background:#ffc;"
| September 24, 2005
| Spacecraft shipped to [[Cape Canaveral]]
| It was moved through [[Andrews Air Force Base]] aboard a [[C-17 Globemaster III]] [[cargo aircraft]].
| <ref name="SpaceDaily"/>

|- style="background:#ffc;"
| December 17, 2005
| Spacecraft ready for in rocket positioning
| Transported from Hazardous Servicing Facility to Vertical Integration Facility at Space Launch Complex 41.
| {{citation needed|date=March 2011}}

|- style="background:#ffc;"
| January 11, 2006
| Primary launch window opened
| The launch was delayed for further testing.
| {{citation needed|date=March 2011}}

|- style="background:#ffc;"
| January 16, 2006
| Rocket moved onto launch pad
| [[Atlas V]] launcher, serial number AV-010, rolled out onto pad.
| <ref name="NASA-20150306">{{cite web |last=Cooper |first=Ben |title=New Horizons Rollout |url=http://www.launchphotography.com/NewHorizonsRollout.html |date=January 2006 |publisher=Launch Photography |accessdate=July 5, 2015}}</ref>

|- style="background:#ffc;"
| January 17, 2006
| Launch delayed
| First day launch attempts scrubbed because of unacceptable weather conditions (high winds).
| <ref name="nytimes.com"/><ref name="Space.com"/>

|- style="background:#ffc;"
| January 18, 2006
| Launch delayed again
| Second launch attempt scrubbed because of morning power outage at the [[Applied Physics Laboratory]].
| <ref>{{cite web |last1=Malik |first1=Tariq |title=Power Outage Delays Launch of NASA's Pluto Probe |url=http://www.space.com/1962-power-outage-delays-launch-nasa-pluto-probe.html |website=Space.com |accessdate=May 12, 2015}}</ref>

|- style="background:#cfc;"
| Launch Phase
| January 19, 2006
| Successful launch at 19:00 [[UTC]]
| The spacecraft was successfully launched after a brief delay due to cloud cover.
|<ref name="Amir"/><ref name="Harwood"/>

|- style="background:#edf3fe;"
| rowspan=21 | Pre-Encounter Phase
| April 7, 2006
| Passes [[Mars]] orbit
| The probe passed Mars' orbit: 1.7 [[Astronomical unit|AU]] from Earth.
| <ref name="Malik"/><ref>{{cite web |url=http://www.wolframalpha.com/input/?i=mars+7+april+2006 |title=Distance between Mars and Earth on April 7, 2006}}</ref>

|- style="background:#edf3fe;"
| June 13, 2006
| Flyby of asteroid [[132524 APL]]
| The probe passed closest to the asteroid 132524 APL in the Belt at about 101,867&nbsp;km at 04:05 UTC. Pictures were taken.
| <ref>{{cite journal |title=The New Horizons Distant Flyby of Asteroid 2002 JF56 |journal=Bulletin of the American Astronomical Society |first1=Catherine B. |last1=Olkin |volume=38 |page=597 |bibcode=2006DPS....38.5922O |display-authors=4 |last2=Reuter |last3=Lunsford |last4=Binzel |last5=Stern |date=2006}}</ref>

|- style="background:#edf3fe;"
| November 28, 2006
| First image of Pluto
| The image of Pluto was taken from a great distance.
| <ref name="LORRI" />

|- style="background:#edf3fe;"
| January 10, 2007
| Navigation exercise near [[Jupiter]]
| Long-distance observations of Jupiter's outer moon [[Callirrhoe (moon)|Callirrhoe]] as a navigation exercise.
| <ref name="callirrhoe">{{cite web |url=http://www.planetary.org/blogs/emily-lakdawalla/2007/jupiter_timeline.html |title=New Horizons Jupiter Encounter Timeline |publisher=The Planetary Society |accessdate=October 24, 2014}}</ref>

|- style="background:#edf3fe;"
| February 28, 2007
| Jupiter flyby
| Closest approach occurred at 05:43:40 UTC at 2.305 million km, 21.219&nbsp;km/s.
| <ref name="Timeline">{{cite web |url=http://www.pluto.jhuapl.edu/mission/mission_timeline.php |title=Mission Timeline |publisher=Johns Hopkins APL |accessdate=August 1, 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20080723174449/http://www.pluto.jhuapl.edu/mission/mission_timeline.php |archivedate=July 23, 2008}}</ref>

|- style="background:#edf3fe;"
| June 8, 2008
| Passing of [[Saturn]]'s orbit
| The probe passed Saturn's orbit: 9.5 AU from Earth.
| <ref name="Timeline"/><ref>{{cite web |url=http://www.wolframalpha.com/input/?i=saturn+on+8+june+2008 |title=Distance between Saturn and Earth on June 8, 2008 |accessdate=March 14, 2011}}</ref>

|- style="background:#edf3fe;"
| December 29, 2009
| The probe becomes closer to Pluto than to Earth
| Pluto was then 32.7 AU from Earth, and the probe was 16.4 AU from Earth
|<ref>{{cite web |last=Villard |first=R. |title=New Horizons Crosses Halfway Point to Pluto |publisher=Discovery Communications, LLC. |date=December 29, 2009 |url=http://news.discovery.com/space/new-horizons-crosses-halfway-point-to-pluto.html |accessdate=January 12, 2011 |archiveurl=http://www.webcitation.org/5x3s1UlIF |archivedate=March 9, 2011 |deadurl=no}}</ref><ref>{{cite web |url=http://www.wolframalpha.com/input/?i=pluto+29+december+2009 |title=Distance between Pluto and Earth on December 29, 2009 |accessdate=March 14, 2011}}</ref><ref>{{cite web |url=http://www.wolframalpha.com/input/?i=new+horizons+probe+29+december+2009 |title=New Horizon properties on December 29, 2009 |accessdate=March 14, 2011}}</ref>

|- style="background:#edf3fe;"
| February 25, 2010
| Half mission distance reached
| Half the travel distance of {{convert|1480000000|mi|order=flip|sp=us}} was completed.
| <ref>{{cite web |url=http://www.space.com/7979-spacecraft-hits-midpoint-flight-pluto.html |title=Spacecraft Hits Midpoint on Flight to Pluto |publisher=Space.com |date=February 26, 2010 |accessdate=August 11, 2011}}</ref>

|- style="background:#edf3fe;"
| March 18, 2011
| The probe passes [[Uranus]]'s orbit
| This is the fourth planetary orbit the spacecraft crossed since its start. ''New Horizons'' reached Uranus's orbit at 22:00&nbsp;UTC.
| <ref>{{cite web |title=Space Spin&nbsp;– New Horizons ventures beyond Saturn's orbit |date=June 9, 2008 |url=http://spacespin.org/article.php/80636-new-horizons-beyond-saturn-orbit |accessdate=March 14, 2011}}</ref><ref>{{cite web |url=http://www.space.com/11171-nasa-spacecraft-passes-uranus-orbit.html |title=NASA Pluto Probe Passes Orbit of Uranus |date=March 18, 2011 |accessdate=March 19, 2011 |publisher=SPACE.com |author=SPACE.com Staff}}</ref>

|- style="background:#edf3fe;"
| December 2, 2011
| ''New Horizons'' draws closer to Pluto than any other spacecraft has ever been.
| Previously, ''[[Voyager 1]]'' held the record for the closest approach. (~10.58 AU)
| <ref>{{cite web |url=https://twitter.com/NewHorizons2015/status/142249340247879681 |title=Twitter.com&nbsp;– NewHorizons2015}}</ref>

|- style="background:#edf3fe;"
| February 11, 2012
| 10 AU distance
| ''New Horizons'' reaches the distance of 10 AU from the Pluto system, at around 4:55 UTC.
| <ref name="news20120210">{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20120210.php |title=New Horizons on Approach: 22 AU Down, Just 10 to Go |publisher=JHU/APL |date=February 10, 2012 |accessdate=March 22, 2012}}</ref>

|- style="background:#edf3fe;"
| July 1, 2013
| ''New Horizons'' captures its first image of [[Charon (moon)|Charon]]
| Charon is clearly separated from Pluto using the Long-Range Reconnaissance Imager (LORRI).
| <ref name="news20130711">
{{cite news |url=http://www.slate.com/blogs/bad_astronomy/2013/07/11/new_horizons_pluto_s_moon_charon_now_visible.html |title=New Horizons Gets a First Glimpse of Pluto's Moon Charon |first=Phil |last=Plait |date=July 11, 2013 |work=[[Slate (magazine)|Slate]]}}</ref><ref>
{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20130710.php |title=Charon Revealed! New Horizons Camera Spots Pluto's Largest Moon |date=July 10, 2013 |website=New Horizons; Headlines |publisher=[[Applied Physics Laboratory|The Johns Hopkins University Applied Physics Laboratory]]}}</ref>

|- style="background:#edf3fe;"
| October 25, 2013
| 5 AU distance
| ''New Horizons'' reaches the distance of 5 AU from the Pluto system.
| <ref name="news20120210" /><ref>
{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20131025.php |title=On the Path to Pluto, 5 AU and Closing |date=October 25, 2013 |website=New Horizons; Headlines |publisher=[[Applied Physics Laboratory|The Johns Hopkins University Applied Physics Laboratory]]}}</ref>

|- style="background:#edf3fe;"
| July 20, 2014
| Photos of Pluto and Charon
| Images obtained showing both bodies orbiting each other, distance 2.8 AU.
| <ref>{{cite web |url=http://pluto.jhuapl.edu/news_center/news/20140807.php |title=New Horizons Spies Charon Orbiting Pluto |publisher=Johns Hopkins APL}}</ref>

|- style="background:#edf3fe;"
| August 25, 2014
| The probe passes [[Neptune]]'s orbit
| This was the fifth planetary orbit crossed.
| <ref>{{cite web |url=http://pluto.jhuapl.edu/mission/passingplanets/passingPlanets_current.php |title=Passing the Planets |publisher=Johns Hopkins APL |date=March 18, 2011 |accessdate=April 3, 2012}}</ref>

|- style="background:#edf3fe;"
| December 7, 2014
| ''New Horizons'' awakes from hibernation.
| NASA's Deep Sky Network station at Tidbinbilla, Australia received a signal confirming that it successfully awoke from hibernation.
| <ref name="awoketwitter" /><ref name="awokeAST">{{cite journal |last1=Nally |first1=Jonathan |title=Ready for a Close Encounter |journal=Australian Sky & Telescope |issue=83 |page=14 |issn=1832-0457}}</ref>

|- style="background:#edf3fe;"
| January 2015
| Observation of [[Kuiper belt]] object {{mpl|2011 KW|48}}
| Distant observations from a distance of roughly 75 million km (~0.5 AU)
| <ref name="VNH0004">{{cite web |author=NewHorizons2015 |title=About the Jan 21o5 KBO, It's VNH0004 |url=https://twitter.com/NewHorizons2015/status/237925999982034944 |accessdate=August 21, 2012}} <br /> • {{cite web |last=Buie |first=Marc W. |title=Orbit Fit and Astrometric record for VNH0004 |work=User pages |url=http://www.boulder.swri.edu/~buie/kbo/astrom/VNH0004.html |publisher=Southwest Research Institute Planetary Science Directorate |accessdate=August 21, 2012}}</ref>

|- style="background:#edf3fe;"
| January 15, 2015
| Start of Pluto observations
| ''New Horizons'' is now close enough to Pluto and begins observing the system.
| <ref name="NASA-20150115">{{cite web |last1=Brown |first1=Dwayne |last2=Buckley |first2=Michael |last3=Stothoff |first3=Maria |title=January 15, 2015 Release 15-011 - NASA's New Horizons Spacecraft Begins First Stages of Pluto Encounter |url=http://www.nasa.gov/press/2015/january/nasa-s-new-horizons-spacecraft-begins-first-stages-of-pluto-encounter |date=January 15, 2015 |work=[[NASA]] |accessdate=January 15, 2015}}</ref><ref>{{cite web |url=http://discoverynewfrontiers.nasa.gov/news/index.cfml?ID=33 |title=New Frontier News |date=December 6, 2014 |accessdate=January 8, 2015}}</ref>

|- style="background:#edf3fe;"
|March 10–11, 2015
| 1 AU distance
| ''New Horizons'' reaches the distance of 1 AU from the Pluto system.
|<ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150310 |title=New Horizons |work=jhuapl.edu |accessdate=July 13, 2015}}</ref>

|- style="background:#edf3fe;"
| March 20, 2015
| NASA invitation
| NASA invites the general public to suggest names to surface features that will be discovered on Pluto and Charon.
| <ref>{{cite web |url=http://www.ourpluto.org/ |title=pluto-update |work=ourpluto.org |accessdate=July 13, 2015}}</ref>

|- style="background:#edf3fe;"
| May 15, 2015
| Better than Hubble
| Images exceed best [[Hubble Space Telescope]] resolution.
| <ref name="seeplutonow.com">{{cite web |url=http://www.seeplutonow.com/ |title=Countdown to Pluto Encounter! |work=seeplutonow.com |accessdate=July 13, 2015}}</ref>

|- style="background:#cfc;"
| rowspan=8 | Science Phase
| July 14, 2015
| Flyby of the Pluto system: [[Pluto]], [[Charon (moon)|Charon]], [[Hydra (moon)|Hydra]], [[Nix (moon)|Nix]], [[Kerberos (moon)|Kerberos]] and [[Styx (moon)|Styx]]
| {{*}} Flyby of Pluto around 11:49:57 UTC at 12,500&nbsp;km, 13.78&nbsp;km/s. <br/>{{*}} Pluto is 32.9 AU from Sun. <br/>{{*}} Flyby of Charon around 12:03:50 UTC at 28,858&nbsp;km, 13.87&nbsp;km/s.
| <ref name="presskit">{{cite web |url=http://pluto.jhuapl.edu/News-Center/Resources/Press-Kits/NHPlutoFlybyPressKitJuly2015.pdf |title=New Horizons Pluto Flyby Press Kit |work= |date=July 2, 2015 |accessdate=July 4, 2015}}</ref>

|- style="background:#cfc;"
| July 2015 to October 2016
| Transmission of collected data back to Earth, and ongoing science discovery based on the observations
| The [[bit rate]] of the [[downlink]] is limited to 1–2 [[Data rate units#Kilobit per second|kb/s]].<ref name="jhuhub20150717" />, so it took until October 25, 2016 to transmit all of the data.
| <ref name="NYT-20161028" /><ref>{{cite news |url=http://www.gizmag.com/new-horizons-downlink/39295/ |title=New Horizons begins massive 'treasure trove' data downlink |work=Gizmag |first=David |last=Szondy |date=September 7, 2015 |accessdate=February 28, 2016}}</ref><ref>{{cite web |url=http://www.planetary.org/blogs/emily-lakdawalla/2015/09101452-pluto-new-horizons-browse.html |title=Pretty Pictures: Downlink of the Full New Horizons Data Set Has Begun |publisher=The Planetary Society |first=Emily |last=Lakdawalla |date=September 10, 2015 |accessdate=February 28, 2016}}</ref><ref>{{cite web |url=https://www.nasa.gov/feature/new-pluto-images-from-nasa-s-new-horizons-it-s-complicated |title=New Pluto Images from NASA's New Horizons: It's Complicated |publisher=[[NASA]] |first=Tricia |last=Talbert |date=September 10, 2015 |accessdate=February 28, 2016}}</ref>

|- style="background:#cfc;"
| October 22–November 4, 2015
| Trajectory correction maneuver
| Course adjustment towards the January 2019 flyby of {{mpl|486958|2014 MU|69}} was performed in a series of four thruster firings of 22 minutes each.
| <ref name=wired-20151104 /><ref name=nsf-20170528>{{cite news |url=https://www.nasaspaceflight.com/2017/01/new-horizons-2019-kuiper-belt-encounter/ |title=New Horizons prepares for New Year’s Day 2019 Kuiper Belt Object encounter |work=[[NASASpaceflight.com]] |first=Chris |last=Gebhardt |date=January 3, 2017 |access-date=May 30, 2017}}</ref>

|- style="background:#cfc;"
| November 2, 2015
| Observation of KBO [[15810 Arawn]]
| Long-range observations from a distance of {{convert|170|e6mi|AU}}, the closest ever for any Trans-Neptunian Object other than Pluto. More images were taken on April 7–8, 2016, at a range of {{convert|111|e6mi|AU}} as well.
| <ref>{{cite web |url=http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20151204b |title=A Distant Close-up: New Horizons' Camera Captures a Wandering Kuiper Belt Object |website=New Horizons |publisher=NASA/JHUAPL |date=December 4, 2015 |accessdate=July 23, 2016}}</ref>

|- style="background:#cfc;"
| February 1, 2017
| Trajectory correction maneuver
| A small course adjustment towards the January 2019 flyby of {{mpl|486958|2014 MU|69}} was performed with a 44-second thruster firing.
| <ref>{{cite web |url=https://www.nasa.gov/feature/new-horizons-refines-course-for-next-flyby |title=New Horizons Refines Course for Next Flyby |publisher=[[NASA]] |first=Tricia |last=Talbert |date=February 1, 2017 |access-date=May 30, 2017}}</ref><ref name=wired-20151104 />

|- style="background:lightgrey;"
| 2016–2020
| Observations of Kuiper belt objects (KBOs)
| The probe will have opportunities to perform observations of 10 to 20 KBOs visible from the spacecraft's trajectory after the Pluto system flyby. Heliosphere data collection is expected to begin.
| <ref name="Lakdawalla-2015-09-01"/><ref name="Stern-2015-08">{{cite web |last=Stern |first=Alan |authorlink=Alan Stern |title=OPAG: We Did It! |work=Presentation to the Outer Planets Assessment Group (OPAG) of the [[Lunar and Planetary Institute]] |publisher=[[Universities Space Research Association]] |date=August 2015 |url=http://www.lpi.usra.edu/opag/meetings/aug2015/presentations/day-2/13_stern.pdf |pages=32, 35}}</ref><ref>{{cite web |url=http://pluto.jhuapl.edu/Pluto/Why-Pluto.php |title=Why Go to Pluto? |publisher=Johns Hopkins APL |accessdate=December 5, 2015}}</ref>

|- style="background:lightgrey;"
| January 1, 2019
| Flyby of Kuiper belt object (KBO) {{mpl|486958|2014 MU|69}}
| {{mp|486958|2014 MU|69}} (also labeled "PT1" <ref>{{cite web |author=Zangari, Amanda |title=Postcards from Pluto |url=http://plutopostcards.tumblr.com/post/114890975293/picture-from-the-colorado-dmv-im-super-excited |publisher=[[Tumblr]] |date=March 28, 2015}}</ref>) has been selected as a flyby target in the Kuiper belt.
| <ref name="Lakdawalla-2015-09-01">{{cite web |last=Lakdawalla |first=Emily |authorlink=Emily Lakdawalla |title=New Horizons extended mission target selected |work=Planetary Society blog |publisher=[[Planetary Society]] |date=September 1, 2015 |url=http://www.planetary.org/blogs/emily-lakdawalla/2015/09011608-new-horizons-extended-mission-pt1.html}}</ref><ref>{{cite journal |author=Powell, Corey S. |title=Alan Stern on Pluto's Wonders, New Horizons' Lost Twin, and That Whole "Dwarf Planet" Thing |url=http://blogs.discovermagazine.com/outthere/2015/03/29/alan-stern-on-plutos-wonders/ |magazine=[[Discover (magazine)|Discover]] |date=March 29, 2015}}</ref><ref name = "Lakdawalla2014-second-target">{{cite web |last=Lakdawalla |first=Emily |authorlink=Emily Lakdawalla |title=Finally! New Horizons has a second target |work=Planetary Society blog |publisher=[[Planetary Society]] |date=October 15, 2014 |archivedate=October 15, 2014 |url=http://www.planetary.org/blogs/emily-lakdawalla/2014/10151024-finally-new-horizons-has-a-kbo.html |archiveurl=https://web.archive.org/web/20141015230432/http://www.planetary.org/blogs/emily-lakdawalla/2014/10151024-finally-new-horizons-has-a-kbo.html |deadurl=no}}</ref>

|- style="background:lightgrey;"
| 2026
| Expected end of the mission, based on [[Radioisotope thermoelectric generator|RTG]] plutonium decay.
| Heliosphere data collection expected to be intermittent if instrument power sharing is required.
| <ref name='end of mission'>{{cite web |last=NASA |title=New Horizons |url=http://sse.jpl.nasa.gov/missions/profile.cfm?Sort=Chron&Target=Jupiter&MCode=PKB&StartYear=2020&EndYear=2029&Display=Dates |work=NASA Solar System Exploration |publisher=National Aeronautics and Space Administration |accessdate=February 21, 2012 |date=July 20, 2011}}</ref>

|- style="background:wheat;"
| Post-Mission Phase
| 2038
| ''New Horizons'' will be 100 AU from the [[Sun]].
| If still functioning, the probe will explore the outer [[heliosphere]] along with the [[Voyager spacecraft]].
|<ref name="jhuapl2006">{{cite web |url=http://pluto.jhuapl.edu/news_center/news/081706.php |title=New Horizons Salutes Voyager |date=August 17, 2006 |publisher=Johns Hopkins APL |accessdate=November 3, 2009 |archiveurl=http://www.webcitation.org/5x3s4O3KH |archivedate=March 9, 2011 |deadurl=no}}</ref>
|}

== See also ==
{{div col||30em}}
* [[2006 in spaceflight]]
* [[Exploration of Pluto]]
* [[List of artificial objects leaving the Solar System]]
* [[List of missions to the outer planets]]
* [[Mariner Mark II]], a planned family of NASA spacecraft including a Pluto mission
* ''[[New Horizons 2]]'', a proposed trans-Neptunian object flyby mission
* ''[[Pioneer 10]]''
* ''[[Pioneer 11]]''
* ''[[Pluto Kuiper Express]]'', a cancelled NASA Pluto flyby mission
* [[Timeline of Solar System exploration]]
* ''[[Voyager 1]]''
* ''[[Voyager 2]]''

{{div col end}}
{{Portal bar|Astronomy|Robotics|Spaceflight|Space|Solar System}}
{{Clear}}

==Notes==
{{reflist|group=lower-alpha}}

== References ==
{{Reflist|colwidth=30em|refs=
<ref name="Moore-2010">{{cite book |url=https://books.google.com/books?id=7u7k3qBd-boC&pg=PA35 |title=The Sky at Night |publisher=Springer |last=Moore |first=Patrick |page=35 |date=2010 |isbn=978-1-4419-6408-3}}<!-- not a quote in the article as there is a word-order misprint in the book which would distract if visibly corrected --></ref>
}}

== Further reading ==
* {{Cite journal |last1=Guo |first1=Y. |last2=Farquhar |first2=R. W. |url=http://www.boulder.swri.edu/~tcase/Guo_Acta56_2005.pdf |title=New Horizons Pluto–Kuiper Belt mission: design and simulation of the Pluto–Charon encounter |journal=Acta Astronautica |volume=56 |issue=3 |pages=421–429 |date=2005 |doi=10.1016/j.actaastro.2004.05.076 |bibcode=2005AcAau..56..421G}}
* {{cite book |title=New Horizons: Reconnaissance of the Pluto-Charon System and the Kuiper Belt |publisher=Springer |first=Christopher T. |last=Russell |date=2009 |isbn=978-0-387-89517-8}}

== External links ==
{{Commons category|New Horizons}}
* [https://www.nasa.gov/newhorizons/ ''New Horizons'' website] by NASA
* [http://pluto.jhuapl.edu/ ''New Horizons'' website] by the [[Applied Physics Laboratory]]
* [http://solarsystem.nasa.gov/missions/newhorizons ''New Horizons'' profile] by NASA's Planetary Science Division
* [http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=2006-001A ''New Horizons'' profile] by the [[National Space Science Data Center]]

{{Pluto}}
{{New Frontiers program}}
{{Asteroid spacecraft}}
{{Jupiter spacecraft}}
{{Planetary defense}}
{{Solar System probes}}
{{Orbital launches in 2006}}
{{NASA space program|state=collapsed}}
{{2015 in space}}

[[Category:New Horizons| ]]
[[Category:NASA space probes]]
[[Category:New Frontiers program]]
[[Category:Missions to Pluto]]
[[Category:Missions to Jupiter]]
[[Category:Missions to minor planets]]
[[Category:Radio frequency propagation]]
[[Category:Spacecraft escaping the Solar System]]
[[Category:Space probes launched in 2006]]
[[Category:Articles containing video clips]]

Revision as of 07:26, 18 June 2017

PRINSIPE YBARRO IS DEAD!!!!!!!!!!!!!!!!!!!

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