PDS3_DATA_SET_ID = PVO-V-POS-5--VSOCOORDS-12SEC-V1.0 START_TIME = 1978-12-05T06:55:10.817Z STOP_TIME = 1992-10-08T18:14:07.018Z PDS3_DATA_SET_RELEASE_DATE = 1993-09-01 PRODUCER_FULL_NAME = DR. CHRISTOPHER RUSSELL, MURIEL KNIFFIN References ========== Colin, L., Pioneer Venus Overview, IEEE Transactions on Geoscience and Remote Sensing, Vol GE-18, No. 1, pp. 5-10, 1980. Nothwang, G.T., Pioneer Venus Spacecraft Design and Operation, IEEE Transactions on Geoscience and Remote Sensing, Vol GE-18, No. 1, pp. 5-10, January 1980. National Aeronautics and Space Administration Ames Research Center Moffett Field, California Pioneer Venus Project Specification PC-456.O4 Pioneer Venus: Data User Requirements for Supplementary Experimenter Data Records, May 15, 1976. R. O. Fimmel, L. Colin, and E. Burgess, 'Pioneering Venus: A Planet Unveiled', NASA SP-518, 1995. Collection Overview =================== This collection contains Pioneer Venus Orbiter (PVO) spacecraft position and orientation data in Venus Solar Orbital (VSO) coordinates. This collection is sampled every 12 seconds near periapsis, and at 1 minute or 10 minute rates in the solar wind, the lowest rates near apoapsis Planetocentric and heliocentric position vectors and solar zenith angle (Sun-Venus-PVO) are also provided. The VSO parameters are derived from the PVO Supplemental Experimenter Data Records (SEDR), other parameters are taken directly from the SEDR collection. Dataset Contents Column Description Unit ----------------------------------------------------------------------------------------------- UT: Universal Time given in seconds since 1966-01-01T00:00:00.000 where no attempt (s) has been made to account forleap seconds. X VSO: The X-component of the PVO spacecraft position in Venus Solar Orbital (Rv) Coordinates (VSO). The X component of the VSO coordinate system is taken to be positive in the direction of the Sun measured along the Venus- Sun line. The units are given in Venus Radii where Rv = 6050 km. Y VSO: The Y-component of the PVO spacecraft position in Venus Solar Orbital (Rv) Coordinates (VSO).The Y component of the VSO coordinate system is taken to be positive in the direction opposing orbital motion (dusk) and lying in the orbital plane of Venus. The units are given in Venus Radii where Rv = 6050 km Z VSO: The Z-component of the PVO spacecraft position in Venus Solar Orbital (Rv) Coordinates (VSO). The Z component of the VSO coordinate system is taken to be parallel to the pole of the Venus orbital plane and positive in the northward direction (upward normal). The units are given in Venus Radii where Rv = 6050 km. ALT: Spacecraft Altitude above the Venus surface. This value is computed by (Km) subtracting 6050 km from the centered Venus-to-PVO range given in the SEDR. SZA: Solar Zenith Angle. This is the three body angle Sun-Venus-PVO taken from the (degC) SEDR. PLONG: Venus centered longitude of the PVO spacecraft. (degC) PLAT: Venus centered latitude of the PVO spacecraft (degC) SPX VSO: The VSO X-component of the spacecraft spin axis (ISCC_Z) n/a SPY VSO: The VSO Y-component of the spacecraft spin axis (ISCC_Z). n/a SPZ VSO: The VSO Z-component of the spacecraft spin axis (ISCC_Z). n/a CLAT: Heliocentric Celestial Latitude of the PVO spacecraft. (degC) CLONG: Heliocentric Celestial Longitude of the PVO spacecraft. (degC) ELONG: Heliocentric Celestial Longitude of the Earth. (degC) RSUN: Sun - Spacecraft range.e 1 A.U. = 149,674,000 km AU (AU) This collection is used by the program PVROT to transform magnetic field vectors from Inertial Spacecraft Coordinates (ISC) to VSO Coordinates. Please refer to the coordinate system template for definitions of these two coordinate systems. An ASCII version of these data is available in the PVO Spacecraft VSO Ephemeris and Spacecraft Orientation ASCII Data Collection (urn:nasa:pds:pvo-ephem:data-vso-asc). Confidence Level Overview ========================= This collection contains parameters which are either taken directly from the Supplemental Experimenter Data Records (SEDR) or are derived entirely from those parameters. The SEDR does contain some gaps, spurious values, and other problems which may cause some data values to be untrustworthy."