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Trajectory Data Archive in SFDU Format


Availability: At NSSDC, Ready for Electronic Access

Time span: 1973-04-06 to 2000-01-01


Interplanetary and planetary encounter trajectory data are provided for the Pioneer 11 spacecraft mission from numerical output of the Jet Propulsion Laboratory's "Double Precision Trajectory" (DPTRAJ) computer program, an element of the JPL Navigation Software System. DPTRAJ creates a spacecraft ephemeris by integrating the equations of motion for a full set of acceleration models. DPTRAJ integration is limited to the N-body gravitational terms (planets, Sun, and Moon) with Earth oblateness, Jupiter oblateness (J2 and J4), Saturn oblateness (J2), and a simple solar pressure model also included, from which seven state vectors can be calculated for eleven phases of the mission from launch. Seventy-seven trajectory parameters are provided in each output record for various coordinate systems including geocentric inertial, heliocentric inertial, heliocentric earth-fixed, and body-centered body-fixed (Jupiter and Saturn). Time resolution varies from one day during interplanetary cruise to minutes in the vicinity of planets.

Each physical data record consists of four logical records with 512 ASCII bytes for a total of 2048 bytes per physical record. Each logical record contains 77 data fields in 24-byte ASCII, double precision format (D24.17). Each record can be read with the following FORTRAN format string: (4X,77(2X,D24.17),42X). Each dataset volume is packaged in SFDU format with two descriptive metadata files and separate data files for each six months of consecutive years from launch. The metadata include detailed descriptions of the spacecraft mission, ephemeris coordinate systems, data parameters, and dataset format. References to coordinate systems can be found in the following publication: M.E. Davies, et al.[1983].

These data are accessible at:

Alternate Names

  • Trajectory Data/SFDU Format


  • Ancillary: Ephemeris/Orbit/Attitude


  • 73-019A-00G

Additional Information


Questions and comments about this data collection can be directed to: Dr. John F. Cooper



NameRoleOriginal AffiliationE-mail
Mr. David W. LozierGeneral ContactNASA Ames Research

Selected References

  • NOCC navigation subsystem (NAV), NOCC navigation program, software operators manual - volume 1, overview of DPTRAJ and ODP software, JPL, Calif. Inst. Technol., SOM-NVI-5241-OP, Rev. D, Pasadena, CA, Apr. 1989.
  • Lozier, D. W., Technical coordination memorandum, DPTRAJ inputs for the Pioneer 10/11 NSSDC trajectory ephemeris archive, NASA-ARC, Pioneer Missions Office, SFP:244-14/2-003, Jan. 1992.
  • Davies, M. E., et al., Report of the IAU working group on cartographic coordinates and rotational elements of the planets and satellites: 1982, Celestial Mechanics, 29, 309-321, doi:10.1007/BF01228525, 1983.
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