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  <Observatory>
    <ResourceID>spase://CNES/Observatory/CDPP-AMDA/Pioneer10</ResourceID>
    <ResourceHeader>
      <ResourceName>Pioneer 10</ResourceName>
      <AlternateName>1972-012A</AlternateName>
      <AlternateName>Pioneer-F</AlternateName>
      <ReleaseDate>2010-09-25T03:09:48Z</ReleaseDate>
      <Description>This 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 December 3, 1973, when it reached approximately 
        2.8 Jovian radii (about 200,000 km). As of Jan. 1, 1997
        Pioneer 10 was at about 67 AU from the Sun near the ecliptic 
        plane and heading outward from the Sun at 2.6 AU/year and 
        downstream through the heliomagnetosphere towards the tail 
        region and interstellar space. This solar system escape 
        direction is unique because the Voyager 1 and 2 spacecraft 
        (and the now terminated Pioneer 11 spacecraft mission) are 
        heading in the opposite direction towards the nose of the 
        heliosphere in the upstream direction relative to the 
        inflowing interstellar gas. The spacecraft is heading 
        generally towards the red star Aldebaran, which forms the eye 
        of Taurus (The Bull). The journey over a distance of 68 light
        years to Aldebaran will require about two million years to
        complete. Routine tracking and project data processing 
        operatations were terminated on March 31, 1997 for budget 
        reasons. Occasional tracking continued later under support 
        of the Lunar Prospector project at NASA Ames Research Center 
        with retrieval of energetic particle and radio science data. 
        The last successful data acquisitions through NASA's Deep 
        Space Network (DSN) occurred on March 3, 2002, the 30th 
        anniversary of Pioneer 10's launch date, and on 
        April 27, 2002. The spacecraft signal was last detected on
        Jan. 23, 2003 after an uplink was transmitted to turn 
        off the last operational experiment, the Geiger Tube 
        Telescope (GTT), but lock-on to the sub-carrier signal for 
        data downlink was not achieved. No signal at all was 
        detected during a final attempt on Feb. 6-7, 2003. Pioneer
        Project staff at NASA Ames then concluded that the spacecraft 
        power level had fallen below that needed to power the onboard 
        transmitter, so no further attempts would be made.

The history of the Pioneer 10 tracking status is available from the 
web site of the former Pioneer Project at the following location:

http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNhome.html

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 
magnetometer, plasma analyzer, charged particle detector, ionizing 
detector, non-imaging telescopes with overlapping fields of view 
to detect sunlight reflected from passing meteoroids, sealed 
pressurized cells of argon and nitrogen gas for measuring the 
penetration of meteoroids, UV photometer, IR radiometer, and an
imaging photopolarimeter, which produced photographs and measured 
polarization. Further scientific information was obtained from the 
tracking and occultation data.

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 (1) the omnidirectional and 
medium-gain antennas which operated together while connected 
to one receiver and (2) 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.

Space experiments mostly continued to operate for planetary or 
interplanetary measurements until failure or until insufficient 
spacecraft power from the RTG's was available for operation of all 
instruments, such that some were turned off permanently and others 
were cycled on and off in accordance with a power sharing plan 
implemented in September 1989. The Asteroid/Meteroid Detector 
failed in December 1973, followed by the Helium Vector Magnetometer
(HVM) in November 1975 and the Infrared Radiometer in January 1974.
The Meteroid Detector was turned off in October 1980 due to inactive
sensors at low temperatures. The spacecraft sun sensors became
inoperative in May 1986, and the Imaging Photopolarimeter (IPP) 
instrument was used to obtain roll phase and spin period information
until being turned off in October 1993 to conserve power. The 
Trapped Radiation Detector (TRD) and Plasma Analyzer (PA) were
respectively turned off in November 1993 and September 1995 for 
the same reason. As of January 1996 the final power cycling plan 
included part-time operations of the Charged Particle Instrument
(CPI), the Cosmic Ray Telescope (CRT), the Geiger Tube Telescope
(GTT), and the Ultraviolet Photometer (UV). As of August 2000, 
only the GTT instrument was still returning data.

Various other spacecraft subsystems also either failed or were
turned off for power or other reasons, and an account of these 
may be of interest for engineering design of long duration deep 
space missions. The primary antenna feed offset bellows failed 
sometime in 1976 but a redundant unit was available for use 
thereafter. The Program Storage and Execution (PSE) subsystem 
was turned off in September 1989 for power conservation, after
which spacecraft maneuvers were performed by ground command 
sequences. A receiver problem in mid-1992 prevented uplink to the
high gain antenna, after which uplink commands could only be sent
with 70-meter DSN antennas which also supported the 16 bps downlink.
The Backup Line Heater experienced a sticking thermostat operation 
in March 1993 for 30 days but the problem did not reoccur. 
Undervoltage Protection Logic was turned off in December 1993 to 
prevent loss of critical spacecraft systems in the event of a 
transient undervoltage condition. Duration and Steering Logic (DSL) 
was turned off in February 1995 to conserve power, after which it 
was turned on again only for spacecraft maneuvers. RTG power levels 
are low enough that the spacecraft occasionally relies in part on 
battery power (accumulated during inactive periods) to run 
experiments and other systems.

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. This included about 200 million dollars for pre-launch 
design and development, and another 150 million for launch, 
telemetry tracking, mission operations and data analysis. 
These estimates were provided by the former Pioneer Project at 
NASA Ames Research Center.</Description>
      <Contact>
        <PersonID>spase://SMWG/Person/Palmer.Dyal</PersonID>
        <Role>ProjectScientist</Role>
      </Contact>
      <InformationURL>
        <Name>NSSDC's Master Catalog</Name>
        <URL>http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1972-012A</URL>
        <Description>Information about the Pioneer 10 mission</Description>
      </InformationURL>
    </ResourceHeader>
    <ObservatoryGroupID>spase://CNES/Observatory/CDPP-AMDA/Pioneer</ObservatoryGroupID>
    <Location>
      <ObservatoryRegion>Jupiter</ObservatoryRegion>
    </Location>
  </Observatory>
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