urn:nasa:pds:magellan_scvdr:data_ohf:ohf04355 1.0 1.23.0.0 Product_Observational 2025-09-10 1.0 Initial PDS4 version 1992-03-09T01:21:45.201Z 1992-03-09T01:37:28.868Z Magellan Mission urn:nasa:pds:context:investigation:mission.magellan data_to_investigation The Magellan Spacecraft Host urn:nasa:pds:context:instrument_host:spacecraft.mgn is_instrument_host Magellan Spacecraft Radar System Instrument urn:nasa:pds:context:instrument:mgn.rdrs is_instrument Venus Planet urn:nasa:pds:context:target:planet.venus data_to_target SCVDR 1 4355 Mapping Cycle 3 mg_2145 urn:nasa:pds:magellan_scvdr:document:scvdr_sis data_to_document ohf04355_1.dat 1994-10-11T06:00:47Z The Orbit Header File (OHF) identifies the orbit number, time frame, and orbital geometry for one Magellan orbit. The OHF contains only a CCSD header, a keyword and value SFDU, and a binary header record SFDU.

0 20 7-Bit ASCII Text CCSD header.

20 350 7-Bit ASCII Text SFDU keyword label (K-type).

Orbit Header File 370 1 The single binary OHF data record contains the number of data records in the other data files, the starting and ending times of the data taking periods, and the predicted Keplerian elements of the orbit. 23 2 280 SFDU_LABEL_AND_LENGTH 1 1 ASCII_String 20 'NJPL1I00000400000260', the designator '0004' is registered with the NJPL SFDU authority as the 'Orbit Header Record'. '00000260' indicates that the remainder of the SFDU is 260 bytes in length. ORBIT_NUMBER 2 21 UnsignedMSB4 4 The Magellan Orbit Number corresponding to the following five files (altimetry inversion, inversion fit, sinusoidal image, oblique sinusoidal image, and emissivity). An orbit begins at apoapsis, and the number corresponds to the input data from the corresponding ALT-EDR and/or C-BIDR or F-BIDR tape(s). NUMBER_ALTIMETRY_INVERSION_RECS 3 25 UnsignedMSB4 4 The number of records this orbit's Altimetry Inversion File. NUMBER_INVERSION_FIT_RECS 4 29 UnsignedMSB4 4 The number of records in this orbit's Inversion Fit File. NUMBER_ALTIMETRY_INVERSION_RECS and NUMBER_INVERSION_FIT_RECS should be the same. NUMBER_SIN_IMAGE_DATA_RECS 5 33 UnsignedMSB4 4 The number of records in this orbit's Sinusoidal Image Data File. NUMBER_OBL_IMAGE_DATA_RECS 6 37 UnsignedMSB4 4 The number of records in this orbit's Oblique Image Data File. NUMBER_EMISSIVITY_DATA_RECS 7 41 UnsignedMSB4 4 The number of records in this orbit's Emissivity Data File. 1 4 1 0 45 4 SPARE 1 1 UnsignedByte 1 Spare. FIRST_INVERSION_FOOTPRINT_TIME 8 49 IEEE754MSBDouble 8 second The S/C ephemeris time (seconds of TDB since J2000) that represents the first altimeter inversion footprint of this orbit. It is equal to the value of FOOTPRINT_TIME in the first record of this orbit's Altimetry Inversion File. LAST_INVERSION_FOOTPRINT_TIME 9 57 IEEE754MSBDouble 8 second The S/C ephemeris time (seconds of TDB since J2000) that represents the last altimeter inversion footprint of this orbit. It is equal to the value of FOOTPRINT_TIME in the last record of this orbit's Altimetry Inversion File. FIRST_FIT_FOOTPRINT_TIME 10 65 IEEE754MSBDouble 8 second The S/C ephemeris time (seconds of TDB since J2000) that represents the first inversion fit footprint of this orbit. It is equal to the value of FOOTPRINT_TIME in the first record of this orbit's Altimetry Inversion File. LAST_FIT_FOOTPRINT_TIME 11 73 IEEE754MSBDouble 8 second The S/C ephemeris time (seconds of TDB since J2000) that represents the last inversion fit footprint of this orbit. It is equal to the value of FOOTPRINT_TIME in the last record of this orbit's Altimetry Inversion File. FIRST_SIN_IMAGE_FOOTPRINT_TIME 12 81 IEEE754MSBDouble 8 second The S/C ephemeris time (seconds of TDB since J2000 that represents the first sinusoidal image footprint of this orbit. It is equal to the value of FOOTPRINT_TIME in the first record of this orbit's sinusoidal image data file. LAST_SIN_IMAGE_FOOTPRINT_TIME 13 89 IEEE754MSBDouble 8 second The S/C ephemeris time seconds of TDB since J2000) that represents the last sinusoidal image footprint of this orbit. It is equal to the value of FOOTPRINT_TIME in the last record of this orbit's sinusoidal image data file. FIRST_OBL_IMAGE_FOOTPRINT_TIME 14 97 IEEE754MSBDouble 8 second The S/C ephemeris time (seconds of TDB since J2000) that represents the first oblique image footprint of this orbit. It is equal to the value of FOOTPRINT_TIME in the first record of this orbit's oblique image data file. LAST_OBL_IMAGE_FOOTPRINT_TIME 15 105 IEEE754MSBDouble 8 second The S/C ephemeris time (seconds of TDB since J2000) that represents the last oblique image footprint of this orbit. It is equal to the value of FOOTPRINT_TIME in the last record of this orbit's oblique image data file. FIRST_EMISSIVITY_FOOTPRINT_TIME 16 113 IEEE754MSBDouble 8 second The S/C ephemeris time (seconds of TDB since J2000) of the first emissivity measurement of this orbit. It is equal to the value of S_C_EMISSIVITY_EPOCH in the first record of this orbit's emissivity data file. LAST_EMISSIVITY_FOOTPRINT_TIME 17 121 IEEE754MSBDouble 8 second The S/C ephemeris time (seconds of TDB since J2000) of the last emissivity measurement of this orbit. It is equal to the value of S_C_EMISSIVITY_EPOCH in the last record of this orbit's emissivity data file. AVERAGE_ORBIT_PERIAPSIS_TIME 18 129 ASCII_String 15 The periapsis time of the predicted orbit in spacecraft clock units. AVERAGE_SEMI_MAJOR_AXIS 19 144 ASCII_String 23 km The semi-major axis of the predicted orbit. AVERAGE_ECCENTRICITY 20 167 ASCII_String 23 The eccentricity of the predicted orbit. AVERAGE_INCLINATION 21 190 ASCII_String 23 degree The inclination of the predicted orbit with respect to the xy-plane of the J2000 coordinate system. AVERAGE_ASCENDING_NODE_LONGITUDE 22 213 ASCII_String 23 degree The angle in the xy-plane of the J2000 coordinate system to the ascending node of the predicted orbit. AVERAGE_ARGUMENT_OF_PERIAPSIS 23 236 ASCII_String 23 degree The angle in the plane of the predicted orbit from the ascending node in the xy-plane of the J2000 coordinate system to the periapsis. 2 22 1 0 259 22 SPARE 1 1 UnsignedByte 1 Spare.