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Multi-Coordinate System Ephemeris


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 1968-11-08 to 1972-04-16


Complete trajectory information was supplied by the Pioneer Project Office at Ames Research Center. The data are contained on an IBM 7094, binary magnetic tape. A Fortran IV program which reads the tape and prints out the data is available. The tape was generated by JPL. The tape consists of trajectory information described below, predicted from orbit elements which were themselves determined from observed trajectory data. Thus, the files overlap in time period covered. For the most accurate trajectory information the file whose start time is closest to the date required should be used. The Pioneer 9 trajectory data cover the following time periods -- 11/08/68 to 07/26/71, 11/10/68 to 06/08/69, 04/15/69 to 08/15/69, 08/15/69 to 08/16/71, 12/15/69 to 12/15/71, 04/15/70 to 04/16/71. The following information is available in intervals of 1 day (except for periods when the spacecraft is close to the earth when the interval may be shorter) on each of the trajectory files: (1) date, (2) time, (3) distance from earth to probe, (4) distance from the earth to the sun, (5) distance from the earth to the moon, (6) distance from the sun to the probe, (7) geocentric right ascension and declination of probe, sun, moon, (8) geocentric latitude, longitude, and altitude above the earth, (9) earth-sun-probe angle, (10) earth-probe-sun angle, (11) sun-probe-near limb of earth angle (sun-probe-earth angle minus the angular semi-diameter of earth where the angular semi-diameter would be the probe centered angle between earth limb and center of earth), (12) moon-earth-probe angle, (13) moon-probe-sun angle, (14) earth-probe-moon angle, (15) Canopus-probe-earth angle, (16) Canopus-probe-sun angle, (17) angle made by the sun to probe vector and the ecliptic plane of date, (18) X, Y, Z components of spacecraft in the sun-earth line coordinate system (sun centered system, X axis is along the sun to earth vector, Z axis is toward the ecliptic north pole), (19) longitude of spacecraft in the sun-earth line coordinate system, (20) X, Y, Z components of spacecraft in geocentric, selenocentric, heliocentric, Venus-centered, Mars-centered, Saturn-centered, and Jupiter-centered inertial coordinates (X points to vernal equinox, Z points along the north pole vector with the reference plane being the earth's true equator of date), (21) magnitude of the velocity vector and X, Y, Z components of the velocity vector in geocentric inertial coordinates, (22) geocentric inertial path angle (angle made by probe velocity vector and plane normal to earth to probe vector), (23) geocentric inertial azimuth angle (angle between the plane defined by the vector along the earth's spin axis and the earth to probe vector and the plane defined by the earth to probe vector and the geocentric inertial velocity vector), (24) heliocentric inertial velocity, (25) heliocentric inertial path angle (angle made by the heliocentric velocity vector and the plane normal to the sun to probe vector), (26) celestial longitude of probe (angular distance measured counter-clockwise along the ecliptic plane of date from the vernal equinox to the projection of the sun-probe vector on a plane as viewed from the ecliptic north pole), celestial longitude of earth, (28) celestial latitude of earth, and (29) various clock angles and hinge and swivel angles which are described in the documentation.

Alternate Names

  • Ephemeris Data


  • Ancillary: Ephemeris/Orbit/Attitude


  • 68-100A-00D

Additional Information


Questions and comments about this data collection can be directed to: Coordinated Request and User Support Office



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