Mission Type: Flyby
Launch Vehicle: Atlas-Centaur (AC-27 / Atlas 3C no. 5007C / Centaur D-1A)
Launch Site: Eastern Test Range / launch complex 36A, Cape Canaveral, U.S.A.
NASA Center: Ames Research Center
Spacecraft Mass: 258 kg
Spacecraft Instruments: 1) imaging photopolarimeter; 2) magnetometer; 3) infrared radiometer; 4) plasma analyzer
5) ultraviolet photometer; 6) charged-particle-composition instrument; 7) cosmic-ray telescope; 8) Geiger tube telescopes; 9) asteroid/meteoroid detector; 10) Jovian trapped-radiation detector; and 11) meteoroid detector
Spacecraft Dimensions: Main compartment: 36-cm deep, with hexagonal top and bottom having sides 71-cm long
Spacecraft Power: Four SNAP-19 radioisotope thermonuclear generators (RTGs), backed up by batteries
Maximum Power: 155 W at launch, decaying to about 140 W at Jupiter, 21 months later
Antenna Diameter: 2.74 meters
S-Band Data Rate: Up to 2048 bps en route to Jupiter, and 16 bps near the end of the mission
Maximum Data Rate: 2048 bps
Program Manager: Dr. James B. Willett
Project Manager: Richard O. Fimmel
Principal Scientists: Dr. Palmer Dyal (Project Scientist); Dr. W. Vernon Jones (Program Scientist)
Total Cost: The total mission cost for Pioneer 10 through the 1997 end of official science operations was about $350 million in FY 2001 U.S. dollars.
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi

National Space Science Data Center, http://nssdc.gsfc.nasa.gov/

Solar System Log by Andrew Wilson, published 1987 by Jane's Publishing Co. Ltd.

Pioneer 10, the first NASA mission to the outer planets, garnered a series of firsts perhaps unmatched by any other robotic spacecraft in the space era: the first vehicle placed on a trajectory to escape the solar system into interstellar space, the first spacecraft to fly beyond Mars, the first to fly through the asteroid belt, the first to fly past Jupiter, the first to use all-nuclear electrical power, and the first human-made object to fly beyond the orbit of the outermost known planet in our solar system.

After launch by a three-stage version of the Atlas-Centaur (with a TE-M-364-4 solid-propellant engine modified from the Surveyor lander), Pioneer 10 reached an initial speed of 51,800 kilometers per hour, faster than any previous human-made object. There were some initial problems during the outbound voyage when direct sunlight caused heating problems.

On 15 July 1972, the spacecraft entered the asteroid belt, emerging in February 1973 after a 435-million-kilometer voyage through the relatively densely packed rings. During this period, the spacecraft encountered some meteoroid hits (although many fewer than expected) and also measured the density of Zodiacal light in interplanetary space. On 7 August, in conjunction with Pioneer 9 (in solar orbit), Pioneer 10 recorded details of one of the most violent solar storms in recent record.

The spacecraft entered Jupiter's bow-shock wave (where the solar wind interacts with the planet's magnetic field) on 26 November, crossed the magnetopause, reentered the magnetic field on 1 December, and then crossed the magnetopause for the second time. By the following day, the spacecraft was returning better quality photos than possible with the best Earth-based telescopes; it had already begun imaging as early as 6 November 1973. Also during this period, Pioneer 10 took about 300 photos of Jupiter that included images of the planet's terminator and the Great Red Spot.

Command-and-return time was up to 92 minutes by this time. Pioneer 10's closest approach to Jupiter was at 02:25 UT on 4 December 1973, when the spacecraft raced by the planet at a range of 130,354 kilometers and a speed of 132,000 kilometers per hour. Of the spacecraft's 11 scientific instruments, six operated continuously through the encounter. The spacecraft passed by a series of Jovian moons, obtaining photos of Callisto, Ganymede, and Europa (but not Io).

Pioneer 10 fulfilled all objectives except one (that one failure was due to false commands triggered by Jupiter's intense radiation). Based on incoming data, scientists identified plasma in Jupiter's magnetic field. The spacecraft crossed Saturn's orbit in February 1976, recording data that indicated that Jupiter's enormous magnetic tail, almost 800 million kilometers long, covered the whole distance between the two planets. Still operating nominally, Pioneer 10 crossed the orbit of Neptune (then the outermost planet) on 13 June 1983.

Now the spacecraft is generally heading in the direction of the red star Aldebaran, a star that forms the eye of the Taurus constellation. It is expected to pass by Aldebaran in about two million years. In case of an intercept by intelligent life, Pioneer 10 carries an aluminum plaque with diagrams of a man and a woman, the solar system, and its location relative to 14 pulsars. Pioneer 10 is flying toward the tail of the Solar System's heliomagnetosphere. This is the opposite direction from the two Voyager probes and Pioneer 11, which are flying toward the nose of the heliosphere in an upstream direction relative to the inflowing interstellar gas.

NASA officially terminated routine contact with the vehicle at 19:35 UT on 31 March 1997 for budgetary reasons, although intermittent contact continued (as permitted by the onboard power source) with collection of data from the Geiger tube telescope and the charged-particle instrument. The spacecraft signal was last detected on 23 January 2003.

Pioneer 10 was the farthest human-made object in existence until 17 February 1998, when Voyager 1 exceeded its range. By 1 July 2001, Pioneer 10 was 11.83 billion kilometers from Earth, traveling at 12.24 kilometers per second relative to the Sun.

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