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Voyager 1

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This article is about the spacecraft. For the album by The Verve, see Voyager 1 (album). For fictional Voyager One from Space: 1999, see Voyager One (Space: 1999).

Template:Infobox Spacecraft

Voyager Golden Record
Voyager Golden Record

The Voyager 1 spacecraft is a 722-kilogram (1,592 lb) robotic space probe launched by NASA on September 5, 1977 to study the outer Solar System and eventually interstellar space. Operating for 46 years, 9 months and 23 days, the spacecraft receives routine commands and transmits data back to the Deep Space Network. Currently in extended mission, the spacecraft is tasked with locating and studying the boundaries of the Solar System, including the Kuiper belt, the heliosphere and interstellar space. The primary mission ended November 20th, 1980 after encountering the Jovian system in 1979 and the Saturnian system in 1980.[1] It was the first probe to provide detailed images of the two largest planets and their moons.

Mission Background

History

Conceived in the 1960s, a Grand Tour proposal to study the outer planets, prompted NASA to begin work on a mission in the early 1970s. The development of the interplanetary probes coincided with an alignment of the planets, making possible a mission to the outer Solar System by taking advantage of, the then-new technique, gravity assist.

Utilizing gravity assists would enable a single probe to visit the four gas giants (Jupiter, Saturn, Uranus, and Neptune) while requiring a minimal amount of propellant and a shorter transit duration between planets. Originally, Voyager 1 was planned as Mariner 11 of the Mariner program however, due to congressional budget cuts, the mission was scaled back to be a flyby of Jupiter and Saturn, and renamed the Mariner Jupiter-Saturn probes. As the program progressed, the name was later changed to Voyager as the probe designs began to differ greatly from previous Mariner missions.[2]

Spacecraft Design

For more details on the Voyager space probes' identical instrument packages, see the separate article on the overall Voyager Program.

Golden Record

Main article: Voyager Golden Record

Each Voyager space probe carries a gold-plated audio-visual disc in the event that either spacecraft is ever found by intelligent life-forms from other planetary systems. The discs carry photos of the Earth and its lifeforms, a range of scientific information, spoken greetings from the people (e.g. the Secretary-General of the United Nations and the President of the United States, and the children of the Planet Earth) and a medley, "Sounds of Earth", that includes the sounds of whales, a baby crying, waves breaking on a shore, and a variety of music.

Mission Profile

A rocket launching
Voyager 1 lifted off with a Titan IIIE/Centaur

Launch and Trajectory

The Voyager 1 probe was launched on September 5, 1977, by the National Aeronautics and Space Administration from Space Launch Complex 41 at Cape Canaveral, Florida, aboard a Titan IIIE/Centaur launch vehicle. Two weeks prior, the twin Voyager 2 probe had been launched on August 20, 1977. Despite being launched two weeks later, Voyager 1 reached both Jupiter and Saturn sooner after being launched into a shorter trajectory.

Timeline of travel

Trajectory of Voyager 1 primary mission
Trajectory of Voyager 1 primary mission.
Date Event
1977-09-05
 Spacecraft launched.
1977-12-10
 Entered asteroid belt.
1977-12-19
 Voyager 1 overtakes Voyager 2.
1978-09-08
 Exited asteroid belt.
1979-01-04
 Start Jupiter observation phase.
1979-03-05
 Encounter with Jovian system.
1980-08-22
 Start Saturn observation phase.
1980-11-12 /
1980-11-13
 Encounter with Saturnian system.

[3]

Encounter with Jupiter

Main article: Exploration of Jupiter

Voyager 1 began photographing Jupiter in January 1979. Its closest approach to Jupiter was on March 5, 1979, at a distance of about 349,000 kilometres (217,000 miles) from the planet's center. Due to the greater photographic resolution allowed by a closer approach, most observations of the moons, rings, magnetic fields, and the radiation belt environment of the Jovian system were made during the 48-hour period that bracketed the closest approach. Voyager 1 finished photographing the Jovian system in April 1979.

The two Voyager space probes made a number of important discoveries about Jupiter, its satellites, its radiation belts, and its never-before-seen planetary rings. The most surprising discovery in the Jovian system was the existence of volcanic activity on the moon Io, which had not been observed either from the ground, or by Pioneer 10 or 11.

Encounter with Saturn

Main article: Exploration of Saturn

The gravitational assist trajectories at Jupiter were successfully carried out by both Voyagers, and the two spacecraft went on to visit Saturn and its system of moons and rings. Voyager 1's Saturnian flyby occurred in November 1980, with the closest approach on November 12, 1980, when the space probe came within 124,000 kilometers (77,000 mi) of Saturn's cloud-tops. The space probe's cameras detected complex structures in the rings of Saturn, and its remote sensing instruments studied the atmospheres of Saturn and its giant moon Titan.

Because Pioneer 11 had one year earlier detected a thick, gaseous atmosphere over Titan, the Voyager space probes' controllers at the Jet Propulsion Laboratory elected for Voyager 1 to make a close approach of Titan, and of necessity end its Grand Tour there. (For the continuation of the Grand Tour, see the Uranus and Neptune sections of the article on Voyager 2.)

Its trajectory with a close fly-by of Titan caused an extra gravitational deflection that sent Voyager 1 out of the plane of the Ecliptic, thus ending its planetary science mission. Voyager 1 could have been commanded onto a different trajectory, whereby the gravitational slingshot effect of Saturn's mass would have steered and boosted Voyager 1 out to a fly-by of Pluto. However, this plutonian option was not exercised, because the other trajectory that led to the close fly-by of Titan was decided to have more scientific value and less risk.[4]

Interstellar mission

a set of grey squares trace roughly left to right. A few are labeled with single letters associated with a nearby coloured square. J is near to a square labeled Jupiter; E to Earth; V to Venus; S to Saturn; U to Uranus; N to Neptune. A small spot appears at the centre of each coloured square
The "family portrait" of the Solar system taken by Voyager 1

On February 14, 1990, Voyager 1 took the first ever "family portrait" of our solar system as seen from outside,[5] which includes the famous image known as "Pale blue dot". It is estimated that both Voyager craft have sufficient electrical power to operate their radio transmitters until at least 2025, which will be over 48 years after launch.

On November 17, 1998, Voyager 1 overtook Pioneer 10 as the most distant man-made object from Earth, at a distance of 69.419 AU. It is currently the most distant functioning space probe to receive commands and transmit information to Earth. Provided Voyager 1 does not collide with any stellar objects, the New Horizons space probe will never pass it, despite being launched from Earth at a faster speed than either Voyager spacecraft.[citation needed]

The current speed of New Horizons is slightly greater than Voyager 1 but when New Horizons reaches the same distance from the sun as Voyager 1 is now, its speed will be about 13 km/s (8 miles/sec) compared to Voyager's 17 km/s (10.5 miles/sec).[6] The close flyby of Saturn and Titan gave Voyager 1 a massive advantage with its extra gravity assist.

Year End of specific capabilities as a result of the available electrical power limitations
2007 Termination of plasma subsystem (PLS)
2008 Power off Planetary Radio Astronomy Experiment (PRA)
2010 Terminate scan platform and Ultraviolet spectrometer (UVS) observations
2015 Termination of Data Tape Recorder (DTR) operations (limited by ability to capture 1.4 kbit/s data using a 70 m/34 m antenna array. This is the minimum rate at which the DTS can read-out data.)
2016 approx Termination of gyroscopic operations
2020 Start shutdown of science instruments (as of 2008-03-18 the order is undecided but the Low-Energy Charged Particles, Cosmic Ray Subsystem, Magnetometer, and Plasma Wave Subsystem instruments are expected to still be operating)[citation needed]
2025 or after Can no longer power any single instrument.

Heliopause

a Bow Shock appears to wrap around the heliosphere that encompasses the solar system
Voyager 1 is currently within the heliosheath and approaching interstellar space.

As Voyager 1 heads for interstellar space, its instruments continue to study the solar system; Jet Propulsion Laboratory scientists are using the plasma wave experiments aboard Voyager 1 and 2 to look for the heliopause, the boundary at which the solar wind transitions into the interstellar medium.

Scientists at the Johns Hopkins University Applied Physics Laboratory believe that Voyager 1 entered the termination shock in February 2003.[7] Some other scientists have expressed doubt, discussed in the journal Nature of November 6, 2003.[8] In a scientific session at the American Geophysical Union meeting in New Orleans on the morning of May 25, 2005, Dr. Ed Stone presented evidence that Voyager 1 crossed the termination shock in December 2004.

The issue will not be resolved until other data becomes available, since Voyager 1's solar-wind detector ceased functioning in 1990. This failure has meant that termination shock detection must be inferred from the data from the other instruments on board.[citation needed]

However, in May 2005 a NASA press release said that consensus was that Voyager 1 was now in the heliosheath.[9] Scientists anticipate that the craft will reach the heliopause in 2015.

Voyager 1 is the farthest human-made object from Earth, traveling away from both the Earth and the Sun at a relatively faster speed than any other probe. [10]

Current status

yellow spot surrounded by three concentric light-blue ellipses labeled from inside to out: Saturn, Uranus and Neptune. A grey ellipse labeled Pluto overlaps Neptune's ellipse. Four colored lines trails outwards from the central spot: a short red line labeled Voyager 2 traces to the right and up; a green and longer line labeled Pioneer-11 traces to the right; a purple line labeled Voyager traces to the bottom right corner; and a dark blue line labeled Pioneer 10 traces left
Location and trajectories of Pioneer and Voyager spacecraft, as of July 7, 2007. Note Voyager 2 is further than Pioneer 11 and only appears closer here due to its -55 degree declination, and that Voyager 1's position is drawn too far away.


As of November 12, 2010, Voyager 1 was about 115.251 AU (17.242 billion km, or 10.712 billion miles) or 0.002 of a light-year from the Sun. Radio signals traveling at the speed of light between Voyager 1 and Earth take more than 16 hours to cross the distance between the two. (To compare, Proxima Centauri, the closest star to our Sun, is about 4.2 light-years distant = 265 thousand AU) Voyager 1's current relative velocity is 17.07 km/s, or 61,452 kilometres per hour (38,185 mph). This calculates as 3.6 AU per year, about 10% faster than Voyager 2. At this velocity, 73,600 years would pass before reaching the nearest star, Proxima Centauri, were the spacecraft traveling in the direction of that star.

NASA extrapolated the location and heliocentric coordinates of both Voyager space probes up to 2015.[11] On November 19, 2015, Voyager 1 will be approximately 133.15 Astronomical Units from the Sun.

Voyager 1 is not heading towards any particular star, but in about 40,000 years it will pass within 1.6 light years of the star AC+79 3888 in the constellation Camelopardalis. That star is generally moving towards our Solar System at about 119 kilometers per second.[12]

As of May 2008, Voyager 1 is at 12.45° declination and 17.125 hours right ascension, placing it in the constellation Ophiuchus as observed from the Earth. NASA continues its daily tracking of Voyager 1 with its Deep Space Network. This network measures both the elevation and azimuth angles of the incoming radio waves from Voyager 1, and it also measures the distance from the Earth to Voyager 1.

On March 31, 2006, the amateur radio operators from AMSAT in Germany tracked and received radio waves from Voyager 1 using the 20-meter (66 ft) dish at Bochum with a long integration technique. Retrieved data was checked and verified against data from the Deep Space Network station at Madrid, Spain.[13] This is believed to be the first such tracking of Voyager 1.

On December 13, 2010, it was confirmed that Voyager 1 passed the reach of the solar wind emanating from the Sun. Since June 2010, detection of solar wind has been consistently at zero. On this date, the spacecraft was approximately 17.3 billion km (10.8 billion miles) from the Sun.[14]

Information regarding updates about Voyager 1 (as well as Voyager 2, Pioneer 10, Pioneer 11 and New Horizons) are available online at Spacecraft Escaping the Solar System and Weekly Mission Reports.

See also

References

  1. ^ The term "visit" is used here in the sense of "approach".
  2. ^ Miller, E: From Engineering Science To Big Science, Chapter 11 "Voyager: The Grand Tour of Big Science" sec. 268. NASA, 1998 | url=http://history.nasa.gov/SP-4219/Chapter11.html
  3. ^ Muller, Daniel: "Voyager 1 Full Mission Timeline", 2010 | http://www.dmuller.net/spaceflight/mission.php?mission=voyager1&appear=black&showimg=yes
  4. ^ "Voyager - Frequently Asked Questions". Voyager.jpl.nasa.gov. 1990-02-14. Retrieved 2010-09-01.
  5. ^ "Photo Capion". Public Information Office. Retrieved 26 August 2010.
  6. ^ "New Horizons Salutes Voyager". New Horizons. August 17, 2006. Retrieved 2009-11-03.
  7. ^ Kate Tobin (November 5, 2003). "Spacecraft reaches edge of solar system". CNN.com. Retrieved 2007-08-07.
  8. ^ L A Fisk (2003). "Planetary Science: Over the edge?". Nature. 426 (6962): 21–22. doi:10.1038/426021a. PMID 14603294.
  9. ^ "Voyager Enters Solar System's Final Frontier". NASA. May 24, 2005. Retrieved 2007-08-07.
  10. ^ "Voyager 1 Sees Solar Wind Decline; Edges Closer to Interstellar Space". NASA. 2010-12-13. Retrieved 2010-12-15.
  11. ^ "NASA Voyager Location in Heliocentric Coordinates" (PDF). Retrieved 2010-09-01.
  12. ^ "Voyager - Mission - Interstellar Mission". Voyager.jpl.nasa.gov. 2010-08-09. Retrieved 2010-09-01.
  13. ^ AMSAT-DL article in German; ARRL article in English
  14. ^ Voyager 1 Sees Solar Wind Decline

External links

Media related to Voyager 1 at Wikimedia Commons

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