Saturn Pioneer pic Saturn Pioneer pic
                                  Pioneer 11 Saturn Encounter                                                                                                   Pioneer 11 Spacecraft

    Spacecraft and Mission Description

    Pioneer 11 was launched on April 5, 1973 using the Atlas/Centaur/TE364-4 launch vehicle. The Saturn encounter began on April 2, 1979. The ensuing encounter involved a trajectory such that on September 1, 1979 the spacecraft passed through the ring plane at a distance of 35,400 km of the outer edge of the A Ring and swung under the rings, passing within 21,400 km of the cloud-tops. After passing Saturn the craft came within 355,000 km of Titan. The inclination of the spacecraft trajectory relative to the ring plane was 6.6°.

    The Pioneer spacecraft were lightweight spin-stabilized craft powered by SNAP-19 type radioisotope thermoelectric generators (RTGs). The high-gain antenna was 2.74 m in diameter, The two radio transmitters each produced 8 W of transmitted power at S-band.

    The Pioneer 11 Mission ended on 30 September 1995, when the last transmission from the spacecraft was received. The spacecraft is headed toward the constellation of Aquila (The Eagle), Northwest of the constellation of Sagittarius. Pioneer 11 will pass near one of the stars in the constellation in about 4 million years.

    Pioneer 11 Saturn Discoveries

    Established the existence of and quantified Saturn’s magnetic field. (note: the alignment of the field with Saturn's rotational axis does not provide a signature that could be detected by earth-based observers.)

    Set limits on ring-moon structure

    Obtained photometric and polarization measurements of Titan over a wide range of phase angles.

    Refined the gravity field of Saturn and obtained better value of the oblateness value and a measure of the ratio of emitted to absorbed energy.

    Obtained constraints on the structure of Saturn’s atmosphere

    Accessing the data

    Note: The Pioneer Missions were carried out before effective processes for archiving were in place. As a result documentation of the mission is incomplete and some data is missing. A NASA special report, designed for the general public may fill in some of the missing information. 

    Mission Description (See P11_MISSION.CAT)

    Spacecraft Description (See P11_INST_HOST.CAT)

    Understanding the Instruments and Archived Data

    UV - Ultraviolet Photometer

    IPP - Imaging Photopolarimeter See publications. See NASA Special Report – NASA SP 446

    PA - Plasma Analyzer Pioneer 11

    TRD - Trapped Radiation detector Pioneer 11

    FGM - Flux-Gate Magnetometer Pioneer 11

      HVM - Helium Vector Magnetometer Pioneer 11

    CPI - Charged Particle Instrument Pioneer 11

    GTT - Geiger Tube Telescope – See publications

    CRT - Cosmic Ray Telescope - See publications

    AMD - Asteroid Meteoroid Detector – No data – See publications for references

    POS - Spacecraft Position - See publications

    Other Useful Products for Interpreting the Data

    Publications – A listing of team members to facilitate literature searches.