Parker Solar Probe

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Parker Solar Probe
Digital model of a spacecraft with a bus attached to a larger sun-shield. Two small solar panels are attached to the side of the bus, along with four rear-facing antennas.
Artistic rendition of the Parker Solar Probe.
Names Solar Probe (before 2002)
Solar Probe Plus (2010–17)
Parker Solar Probe (since 2017)
Mission type Heliophysics
Operator NASA · Applied Physics Laboratory
COSPAR ID 2018-065A
SATCAT no. 43592
Website parkersolarprobe.jhuapl.edu
Mission duration Planned: 6 years, 321 days
Elapsed: 1 month and 11 days
Spacecraft properties
Manufacturer Applied Physics Laboratory
Launch mass 685 kg (1,510 lb)[1]
Dry mass 555 kg (1,224 lb)
Payload mass 50 kg (110 lb)
Dimensions 1.0 m × 3.0 m × 2.3 m (3.3 ft × 9.8 ft × 7.5 ft)
Power 343 W (at closest approach)
Start of mission
Launch date August 12, 2018, 07:31 UTC[2][3][4]
Rocket Delta IV Heavy / Star-48BV[5]
Launch site Cape Canaveral SLC-37
Contractor United Launch Alliance
Orbital parameters
Reference system Heliocentric
Semi-major axis 0.388 AU (58.0 million km; 36.1 million mi)
Perihelion 0.046 AU (6.9 million km; 4.3 million mi; 9.86 R)[note 1]
Aphelion 0.73 AU (109 million km; 68 million mi)[6]
Inclination 3.4°[6]
Period 88 days[6]
Sun
Transponders
Band Ka band
X band
Artwork of the spacecraft next to the Sun, enclosed in a circle with a yellow border. The words "Parker Solar Probe" are placed around the interior of the border, while the words "a mission to touch the Sun" are written inline in a smaller font in the bottom right of the image.
Official insignia for the Parker Solar Probe mission

Parker Solar Probe (previously Solar Probe, Solar Probe Plus, or Solar Probe+, abbreviated PSP)[8] is a NASA robotic spacecraft en route to probe the outer corona of the Sun.[3][9][6] It will approach to within 8.86 solar radii (6.2 million kilometers or 3.85 million miles)[10] from the photosphere (surface) of the Sun and will travel, at closest approach, as fast as 700,000 km/h (430,000 mph).[10][11]

The project was announced in the fiscal 2009 budget year. The cost of the project is US$1.5 billion. Johns Hopkins University Applied Physics Laboratory designed and built the spacecraft,[12] which was launched on August 12, 2018.[2] It became the first NASA spacecraft named after a living person, honoring physicist Eugene Parker, professor emeritus at the University of Chicago.[13]

A memory card containing the names of over 1.1 million people was mounted on a plaque and installed below the spacecraft’s high-gain antenna on May 18, 2018.[14] The card also contains photos of Parker and a copy of his 1958 scientific paper predicting important aspects of solar physics.

History[edit]

Light bar testing in the Astrotech processing facility
Launch of the probe

The Parker Solar Probe concept originates from a predecessor Solar Orbiter project conceived in the 1990s. Similar in design and objectives, the Solar Probe mission served as one of the centerpieces of the eponymous Outer Planet/Solar Probe (OPSP) program formulated by NASA. The first three missions of the program were planned to be: the Solar Orbiter, the Pluto and Kuiper belt reconnaissance mission Pluto Kuiper Express, and the Europa Orbiter astrobiology mission focused on Europa.[15][16]

The original Solar Probe design used a gravity assist from Jupiter to enter a polar orbit which dropped almost directly toward the Sun. While this explored the important solar poles and came even closer to the surface (3 R, a perihelion of 4 R),[16] the extreme variation in solar irradiance made for an expensive mission and required a radioisotope thermal generator for power. The trip to Jupiter also made for a long mission (​3 12 years to first solar perihelion, 8 years to second).

Following the appointment of Sean O'Keefe as Administrator of NASA, the entirety of the OPSP program was canceled as part of President George W. Bush's request for the 2003 United States federal budget.[17] Administrator O'Keefe cited a need for a restructuring of NASA and its projects, falling in line with the Bush Administration's wish for NASA to refocus on "research and development, and addressing management shortcomings."[17]

The cancellation of the program also resulted in the initial cancellation of New Horizons, the mission that eventually won the competition to replace Pluto Kuiper Express in the former OPSP program.[18] That mission, which would eventually be launched as the first mission of the New Frontiers program, a conceptual successor to the OPSP program, would undergo a lengthy political battle to secure funding for its launch, which occurred in 2006.[19]

In the early 2010s, plans for the Solar Probe mission were incorporated into a lower-cost Solar Probe Plus.[20] The redesigned mission uses multiple Venus gravity assists for a more direct flight path, which can be powered by solar panels. It also has a higher perihelion, reducing the demands on the thermal protection system.

In May 2017, the spacecraft was renamed Parker Solar Probe in honor of astrophysicist Eugene Parker,[21][22] coiner of the term "solar wind". The solar probe cost NASA US$1.5 billion.[23][24]

Spacecraft[edit]

NASA's Parker Solar Probe during extensive environmental testing

The Parker Solar Probe will be the first spacecraft to fly into the low solar corona. It will assess the structure and dynamics of the Sun's coronal plasma and magnetic field, the energy flow that heats the solar corona and impels the solar wind, and the mechanisms that accelerate energetic particles.

The spacecraft's systems are protected from the extreme heat and radiation near the Sun by a solar shield. Incident solar radiation at perihelion is approximately 650 kW/m2, or 475 times the intensity at Earth orbit.[1][25]:31 The solar shield is hexagonal, mounted on the Sun-facing side of the spacecraft, 2.3 m (7.5 ft) in diameter,[26] 11.4 cm (4.5 in) thick, and is made of reinforced carbon–carbon composite, which is designed to withstand temperatures outside the spacecraft of about 1,370 °C (2,500 °F).[1] A white reflective alumina surface layer minimizes absorption. The spacecraft systems and scientific instruments are located in the central portion of the shield's shadow, where direct radiation from the Sun is fully blocked. If the shield were not between the spacecraft and the Sun, the probe would be damaged and become inoperative within tens of seconds. As radio communication with Earth will take about eight minutes, the Parker Solar Probe will have to act autonomously and rapidly to protect itself. This will be done using four light sensors to detect the first traces of direct sun light coming from the shield limits and engaging movements from fly wheels to reposition the spacecraft within the shadow again. According to project scientist Nicky Fox, the team describe it as "the most autonomous spacecraft that has ever flown".[8]

The primary power for the mission is a dual system of solar panels (photovoltaic arrays). A primary photovoltaic array, used for the portion of the mission outside 0.25 AU, is retracted behind the shadow shield during the close approach to the Sun, and a much smaller secondary array powers the spacecraft through closest approach. This secondary array uses pumped-fluid cooling to maintain operating temperature of the solar panels and instrumentation.[27][28]

Trajectory[edit]

Animation of Parker Solar Probe's trajectory from August 7, 2018 to August 29, 2025
  Parker Solar Probe ·   Sun ·   Mercury ·   Venus ·   Earth
Second flyby of Venus on December 26, 2019. The velocity decreases by 2.9 km/s to 26 km/s (red circle), shifting the spacecraft to a new orbit closer to the Sun.

The Parker Solar Probe mission design uses repeated gravity assists at Venus to incrementally decrease its orbital perihelion to achieve a final altitude (above the surface) of approximately 8.5 solar radii, or about 6×10^6 km (3.7×10^6 mi; 0.040 AU).[26] The spacecraft trajectory will include seven Venus flybys over nearly seven years to gradually shrink its elliptical orbit around the Sun, for a total of 24 orbits.[1] The science phase will take place during those 7 years, focusing on the periods when the spacecraft is closest to the Sun. The near Sun radiation environment is predicted to cause spacecraft charging effects, radiation damage in materials and electronics, and communication interruptions, so the orbit will be highly elliptical with short times spent near the Sun.[25]

The trajectory requires high launch energy, so the probe was launched on a Delta IV Heavy class launch vehicle and an upper stage based on the STAR 48BV solid rocket motor.[25] Interplanetary gravity assists will provide further deceleration relative to its heliocentric orbit, which will result in a heliocentric speed record at perihelion.[5][29] As the probe passes around the Sun, it will achieve a velocity of up to 200 km/s (120 mi/s), which will temporarily make it the fastest manmade object, almost three times as fast as the current record holder, Helios-B.[30][31][32] Like every object in an orbit, due to gravity the spacecraft will accelerate as it nears perihelion, then slow down again afterward until it reaches its aphelion.

Science goals[edit]

Apparent size of the Sun as seen from the orbit of the Parker Solar Probe compared to its apparent size seen from Earth.

The goals of the mission are:[25]

  • Trace the flow of energy that heats the corona and accelerates the solar wind.
  • Determine the structure and dynamics of the magnetic fields at the sources of solar wind.
  • Determine what mechanisms accelerate and transport energetic particles.

Investigations[edit]

To achieve these goals, the mission will perform five major experiments or investigations:[25]

  • Electromagnetic Fields Investigation (FIELDS) – This investigation will make direct measurements of electric and magnetic fields, radio waves, Poynting flux, absolute plasma density, and electron temperature. It consists of two flux-gate magnetometers, a search-coil magnetometer, and 5 plasma voltage sensors. The Principal investigator is Stuart Bale, at the University of California, Berkeley.
  • Integrated Science Investigation of the Sun (IS☉IS) – This investigation will measure energetic electrons, protons and heavy ions. The instrument suite is composed of two independent instruments, EPI-Hi and EPI-Lo. The Principal investigator is David McComas, at the Princeton University.
  • Wide-field Imager for Solar Probe (WISPR) – These optical telescopes will acquire images of the corona and inner heliosphere. The Principal Investigator is Russell Howard, at the Naval Research Laboratory.
  • Solar Wind Electrons Alphas and Protons (SWEAP) – This investigation will count the electrons, protons and helium ions, and measure their properties such as velocity, density, and temperature. Its main instruments are the Solar Probe Analyzers (SPAN, two electrostatic analyzers) and the Solar Probe Cup (SPC, a Faraday cup). The Principal Investigator is Justin Kasper at the University of Michigan and the Smithsonian Astrophysical Observatory.
  • Heliospheric Origins with Solar Probe Plus (HeliOSPP) – A theory and modeling investigation to maximize the scientific return from the mission. The Principal Investigator is Marco Velli at UCLA and the Jet Propulsion Laboratory (JPL).

Timeline[edit]

After the first Venus flyby, the probe will be in an elliptical orbit with a period of 150 days (two-thirds the period of Venus), making three orbits while Venus makes two. On the second flyby, the period shortens to 130 days. After less than two orbits (only 198 days later) it encounters Venus a third time at a point earlier in the orbit of Venus. This encounter shortens its period to half of that of Venus, or about 112.5 days. After two orbits it meets Venus a fourth time at about the same place, shortening its period to about 102 days. After 237 days it meets Venus for the fifth time and its period is shortened to about 96 days, three-sevenths that of Venus. It then makes seven orbits while Venus makes three. The sixth encounter, almost two years after the fifth, brings its period down to 92 days, two-fifths that of Venus. After five more orbits (two orbits of Venus) it meets Venus for the seventh and last time, decreasing its period to 88 or 89 days and allowing it to approach closer to the Sun.[33]

Speed of the probe and distance from the Sun, from launch until 2026. Events: : Perihelion; : Venus flyby
Scheduled events[33][25]:31[34]
Year Date Event Distance
from Sun (Gm)
Speed
(km/s)
Orbital period
(days)
2018 Aug 12 Launch 151.6 174
Oct 3 Venus flyby #1
Nov 5 Perihelion #1 24.8 95 150
2019 Apr 4 Perihelion #2 24.8 95 150
Sep 1 Perihelion #3 24.8 95 150
Dec 26 Venus flyby #2
2020 Jan 29 Perihelion #4 19.4 109 130
Jun 7 Perihelion #5 19.4 109 130
Jul 11 Venus flyby #3
Sep 27 Perihelion #6 14.2 129 112.5
2021 Jan 17 Perihelion #7 14.2 129 112.5
Feb 20 Venus flyby #4
Apr 29 Perihelion #8 11.1 147 102
Aug 9 Perihelion #9 11.1 147 102
Oct 16 Venus flyby #5
Nov 21 Perihelion #10 9.2 163 96
2022 Feb 25 Perihelion #11 9.2 163 96
Jun 1 Perihelion #12 9.2 163 96
Sep 6 Perihelion #13 9.2 163 96
Dec 11 Perihelion #14 9.2 163 96
2023 Mar 17 Perihelion #15 9.2 163 96
Jun 22 Perihelion #16 9.2 163 96
Aug 21 Venus flyby #6
Sep 27 Perihelion #17 7.9 176 92
Dec 29 Perihelion #18 7.9 176 92
2024 Mar 30 Perihelion #19 7.9 176 92
Jun 30 Perihelion #20 7.9 176 92
Sep 30 Perihelion #21 7.9 176 92
Nov 6 Venus flyby #7
Dec 24 Perihelion #22 6.9 192 88
2025 Mar 22 Perihelion #23 6.9 192 88
Jun 19 Perihelion #24 6.9 192 88
Sep 15 Perihelion #25 6.9 192 88
Dec 12 Perihelion #26 6.9 192 88

The perihelion distances above are from the center of the Sun. For altitude above the surface, subtract one solar radius ≈ 0.7 Gm.

Operational history[edit]

Launch occurred on August 12, 2018, at 3:31 a.m. EDT, 7:31 a.m. GMT. The spacecraft operated nominally after launching. During its first week in space it deployed its high-gain antenna, magnetometer boom, and its electric field antennas.[35] The spacecraft performed its first scheduled trajectory correction on 20 August 2018, while it was 5.5 million miles from Earth, and travelling at 63,569 km/h (39,500 mph).[36]

Instrument activation and testing began in early September 2018. On September 9, the two WISPR telescopic cameras performed a successful first-light test, transmitting wide-angle images of the background sky towards the galactic center.[37]

The first scientific observations are due to be transmitted in December 2018.[38]

See also[edit]

Sun observation spacecraft
Spacecraft design

Notes[edit]

  1. ^ Mission planning used a perihelion of 9.5 R (6.6 Gm; 4.1×10^6 mi), or 8.5 R (5.9 Gm; 3.7×10^6 mi) altitude above the surface,[6] but later documents all say 9.86 R. The exact value will not be finalized until the seventh Venus gravity assist in 2024. Mission planners might decide to alter it slightly before then.

References[edit]

  1. ^ a b c d Parker Solar Probe – Extreme Engineering. NASA.
  2. ^ a b Chang, Kenneth (August 12, 2018). "Parker Solar Probe Launches on NASA Voyage to 'Touch the Sun'". The New York Times. Retrieved August 12, 2018. 
  3. ^ a b Chang, Kenneth (August 11, 2018). "NASA Delays Parker Solar Probe Launch". The New York Times. Retrieved August 11, 2018. 
  4. ^ "Parker Solar Probe Ready for Launch on Mission to the Sun". NASA. Retrieved August 10, 2018. 
  5. ^ a b Clark, Stephen (March 18, 2015). "Delta 4-Heavy selected for launch of solar probe". Spaceflight Now. Retrieved March 18, 2015. 
  6. ^ a b c d e Applied Physics Laboratory (November 19, 2008). "Feasible Mission Designs for Solar Probe Plus to Launch in 2015, 2016, 2017, or 2018" (PDF). Johns Hopkins University. 
  7. ^ "Parker Solar Probe Science Gateway". sppgway.jhuapl.edu. Retrieved October 9, 2017. 
  8. ^ a b Clark, Stuart (July 22, 2018). "Parker Solar Probe: set the controls for the edge of the sun..." The Guardian. 
  9. ^ Chang, Kenneth (May 31, 2017). "Newly Named NASA Spacecraft Will Aim Straight for the Sun". New York Times. Retrieved June 1, 2017. 
  10. ^ a b "NASA Press Kit: Parker Solar Probe" (PDF). NASA. Retrieved 15 August 2018. 
  11. ^ Garner, Rob (August 9, 2018). "Parker Solar Probe: Humanity's First Visit to a Star". NASA. Retrieved August 9, 2018. 
  12. ^ Bogel-Burroughs, Nicholas; Dunn, Marcia. "NASA probe operated from Johns Hopkins lab in Laurel rockets toward sun for closest look yet". The Baltimore Sun. Retrieved 2018-08-16. 
  13. ^ "NASA Renames Solar Probe Mission to Honor Pioneering Physicist Eugene Parker". NASA. May 31, 2017. Retrieved May 31, 2017. 
  14. ^ "NASA's Solar Parker Probe To Carry Over 1.1 Million Names To The Sun". Headlines Today. Retrieved August 10, 2018. 
  15. ^ "McNamee Chosen to Head NASA's Outer Planets/Solar Probe Projects" (Press release). Jet Propulsion Laboratory. April 15, 1998. Archived from the original on January 2, 2017. Retrieved January 2, 2017. 
  16. ^ a b Maddock, Robert W.; Clark, Karla B.; Henry, Curt A.; Hoffman, Pamela J. (March 7, 1999). The Outer Planets/Solar Probe Project: "Between an ocean, a rock, and a hot place" (PDF). 1999 IEEE Aerospace Conference. Bibcode:1999aero....1..383M. 
  17. ^ a b Berger, Brian (February 4, 2002). "NASA Kills Europa Orbiter; Revamps Planetary Exploration". Space.com. Purch Group. Archived from the original on February 10, 2002. Retrieved January 2, 2017. 
  18. ^ Savage, Donald (November 29, 2001). "NASA Selects Pluto–Kuiper Belt Mission Phase B Study". National Aeronautics and Space Administration (NASA). Archived from the original on July 8, 2015. Retrieved July 9, 2015. 
  19. ^ Hand, Eric (June 25, 2015). "Feature: How Alan Stern's tenacity, drive, and command got a NASA spacecraft to Pluto". Science (journal). American Association for the Advancement of Science. Archived from the original on June 26, 2015. Retrieved July 8, 2015. 
  20. ^ Fazekas, Andrew (September 10, 2010). "New NASA Probe to Dive-bomb the Sun". National Geographic. 21st Century Fox / National Geographic Society. Archived from the original on January 2, 2017. Retrieved January 2, 2017. 
  21. ^ Chang, Kenneth (August 10, 2018). "NASA's Parker Solar Probe Is Named for Him. 60 Years Ago, No One Believed His Ideas About the Sun. Eugene N. Parker predicted the existence of solar wind in 1958. The NASA spacecraft is the first named for a living person". The New York Times. Retrieved August 12, 2018. 
  22. ^ Burgess, Matt (May 31, 2017). "Nasa's mission to Sun renamed after astrophysicist behind solar wind theory". Wired. Retrieved January 1, 2018. 
  23. ^ How NASA's New Solar Probe Will 'Touch' the Sun on Historic Mission. Meghan Bartels, Space.com. August 9, 2018.
  24. ^ Successful Launch of NASA's Parker Solar Probe. SatNews Daily. 12 August 2018.
  25. ^ a b c d e f Fox, N.J.; Velli, M.C.; Bale, S.D.; Decker, R.; Driesman, A.; Howard, R.A.; Kasper, J.C.; Kinnison, J.; Kusterer, M.; Lario, D.; Lockwood, M.K.; McComas, D. J.; Raouafi, N.E.; Szabo, A. (November 11, 2015). "The Solar Probe Plus Mission: Humanity's First Visit to Our Star". Space Science Reviews. 204 (1–4): 7–48. Bibcode:2016SSRv..204....7F. doi:10.1007/s11214-015-0211-6. ISSN 0038-6308. 
  26. ^ a b "Solar Probe Plus: A NASA Mission to Touch the Sun". Johns Hopkins University Applied Physics Laboratory. September 4, 2010. Retrieved September 30, 2010. 
  27. ^ Landis, Geoffrey A.; et al. (July 28–30, 2008). Solar Power System Design for the Solar Probe+ Mission (PDF). 6th International Energy Conversion Engineering Conference. Cleveland, Ohio. AIAA 2008-5712. 
  28. ^ Mehar, Pranjal (July 20, 2018). "Traveling to the Sun: Why won't Parker Solar Probe melt?". Tech Explorist. 
  29. ^ Scharf, Caleb A. "The Fastest Spacecraft Ever?". Scientific American Blog Network. 
  30. ^ "Aircraft Speed Records". Aerospaceweb.org. November 13, 2014. 
  31. ^ "Fastest spacecraft speed". guinnessworldrecords.com. July 26, 2015. Archived from the original on December 19, 2016. 
  32. ^ Parker Solar Probe – Check123, Video Encyclopedia, retrieved June 1, 2017 
  33. ^ a b See data and figure at "Solar Probe Plus: The Mission". Johns Hopkins University Applied Physics Laboratory. 2017. 
  34. ^ "HORIZONS System". Jet Propulsion Laboratoy, NASA.  Data file
  35. ^ "First milestones accomplished on NASA's newly-launched Parker Solar Probe – Spaceflight Now". spaceflightnow.com. Retrieved 2018-08-22. 
  36. ^ After Near-Perfect Trajectory Maneuver, Parker Solar Probe On Course To Touch The Sun. NASA. 21 August 2018.
  37. ^ "Illuminating First Light Data from Parker Solar Probe". NASA Blogs: Parker Solar Probe. September 19, 2018. Retrieved September 22, 2018. 
  38. ^ Brown, Geoffrey; Brown, Dwayne; Fox, Karen (August 12, 2018). "Parker Solar Probe Launches on Historic Journey to Touch the Sun". Parker Solar Probe. Retrieved August 13, 2018. 

External links[edit]