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Pioneer 10, 11, H

Pioneer 10 [NASA]

The Pioneer 10 mission was the first to be sent to the outer solar system and the first to investigate the planet Jupiter, after which it followed an escape trajectory from the solar system. The spacecraft achieved its closest approach to Jupiter on 3 December 1973, when it reached approximately 2.8 Jovian radii (about 200,000 km).

Pioneer 11 was the second mission to investigate Jupiter and the outer solar system and the first to explore the planet Saturn and its main rings. Pioneer 11, like Pioneer 10, used Jupiter's gravitational field to alter its trajectory radically. It passed close to Saturn and then it followed an escape trajectory from the solar system.

Fifteen experiments were carried to study the interplanetary and planetary magnetic fields; solar wind parameters; cosmic rays; transition region of the heliosphere; neutral hydrogen abundance; distribution, size, mass, flux, and velocity of dust particles; Jovian aurorae; Jovian radio waves; atmosphere of Jupiter and some of its satellites, particularly Io; and to photograph Jupiter and its satellites. Instruments carried for these experiments were: 

  • Asteroid/Meteroid Detector (non-imaging telescopes with overlapping fields of view to detect sunlight reflected from passing meteoroids)
  • Meteroid Detector (sealed pressurized cells of argon and nitrogen gas for measuring the penetration of meteoroids)
  • Helium Vector Magnetometer (HVM)
  • Infrared Radiometer
  • Imaging Photopolarimeter (IPP)
  • Trapped Radiation Detector (TRD)
  • Plasma Analyzer (PA)
  • Charged Particle Instrument (CPI)
  • Cosmic Ray Telescope (CRT)
  • Geiger Tube Telescope (GTT)
  • Ultraviolet Photometer (UV)

The spacecraft body was mounted behind a 2.74-m-diameter parabolic dish antenna that was 46 cm deep. The spacecraft structure was a 36-cm-deep flat equipment compartment, the top and bottom being regular hexagons. Its sides were 71 cm long. One side joined a smaller compartment that carried the scientific experiments. The high-gain antenna feed was situated on three struts, which projected forward about 1.2 m. This feed was topped with a medium-gain antenna. A low-gain omnidirectional antenna extended about 0.76 m behind the equipment compartment and was mounted below the high-gain antenna. Power for the spacecraft was obtained by four SNAP-19 radioisotope thermonuclear generators (RTG), which were held about 3 m from the center of the spacecraft by two three-rod trusses 120 deg apart. A third boom extended 6.6 m from the experiment compartment to hold the magnetometer away from the spacecraft. The four RTG's generated about 155 W at launch and decayed to approximately 140 W by the time the spacecraft reached Jupiter, 21 months after launch. There were three reference sensors: a star sensor for Canopus which failed shortly after Jupiter encounter and two sun sensors. Attitude position could be calculated from the reference directions to the earth and the sun, with the known direction to Canopus as a backup. Three pairs of rocket thrusters provided spin-rate control and changed the velocity of the spacecraft, the spin period near the end of the mission being 14.1 seconds. These thrusters could be pulsed or fired steadily by command. The spacecraft was temperature-controlled between minus 23 deg C and plus 38 deg C. A plaque was mounted on the spacecraft body with drawings depicting a man, a woman, and the location of the sun and the earth in our galaxy.

Communications were maintained via 

  • the omnidirectional and medium-gain antennas which operated together while connected to one receiver and
  • the high-gain antenna which was connected to another receiver.

These receivers could be interchanged by command to provide some redundancy. Two radio transmitters, coupled to two traveling-wave tube amplifiers, produced 8 W at 2292 MHz each. Uplink was accomplished at 2110 MHz, while data transmission downlink was at 2292 MHz. The data were received by NASA's Deep Space Network (DSN) at bit rates up to 2048 bps enroute to Jupiter and at 16 bps near end of the mission.

A third set of parts has been assembled as a third probe, Pioneer H, as potential a back-up and was considered later for a Jupiter fly-by with a subsequent out-off-ecliptic mission. This mission was never approved and the probe is now on diplay at the National Air and Space Museum in Washington, D.C.

Nation: USA
Type / Application: Jupiter (10,11), Saturn (11) flyby
Operator: NASA
Contractors: TRW
Propulsion: ?
Power: 4 SNAP-19 RTGs
Orbit: Solar escape
Satellite COSPAR Date LS Launch Vehicle Remarks
Pioneer 10 (Pioneer Jupiter, Pioneer F) 1972-012A 03.03.1972 CC LC-36A Atlas-SLV3C Centaur-D Star-37E
Pioneer 11 (Pioneer Saturn, Pioneer G) 1973-019A 06.04.1973 CC LC-36B Atlas-SLV3D Centaur-D1A Star-37E
Pioneer H - cancelled CC LC-36 Atlas-SLV3D Centaur-D1A Star-37E


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