PVO Ion Mass Spectrometer high-resolution data are stored in single-orbit ASCII files. All of the data files have the same internal structure, which is described by the single format file OIMSDATA.FMT. File structure characteristics which may vary from file to file (# of records, start/stop time, etc.) are described in the individual PDS label files (*.LBL). Columns in all data files: ======================================================= name type description ------------------------------------------------------- PVO TIME char Date and time in format YYDOY FSEC, where YY is the year, DOY is the day-of-year & FSEC is the decimal second-of-day DWELL int Dwell time (time interval between samples, msec) DWELL = (TIME - UT)*1000/(n-1) BITS int Telemetry bit rate LAT float Venusian Latitude LON float Venusian Longitude ALT float Altitude SZA float Solar Zenith Angle SHA float Solar Hour Angle
MASS1 int Mass of Sample 1 DEN1 float Number density of Sample 1 MASS2 int Mass of Sample 2 DEN2 float Number density of Sample 2 . . . . . . . . . MASS55 int Mass of Sample 55 DEN55 float Number density of Sample 55 The values 999 and 9.9999e+04 are the missing data values for mass and density respectively. The value 99999.999 is the missing data value for the second-of-day part of the time column. Negative values in a density column indicate flagged (unreliable) data values. Data Files (.TAB extension) The high-resolution data files on this disk are ASCII table files, each having 118 columns and record length 953 bytes. Information about the individual files (number of records, start and stop times, etc.) can be obtained from the PDS label file accompanying each *.TAB file. This label file has the same filename as the data file but with .TAB replaced by .LBL. List of data files: ============================================================================ Name Records Cols Len Start Stop ---------------------------------------------------------------------------- ORB1633 155 118 953 1983-05-27T00:44:49.771Z 1983-05-27T01:09:04.761Z ORB1640 153 118 953 1983-06-03T00:45:34.274Z 1983-06-03T01:09:30.539Z ORB1656 331 118 953 1983-06-19T00:45:46.179Z 1983-06-19T01:31:05.397Z ORB1657 316 118 953 1983-06-20T00:45:57.257Z 1983-06-20T01:31:04.681Z ORB1659 11 118 953 1983-06-22T00:46:25.906Z 1983-06-22T00:47:59.947Z ORB1660 318 118 953 1983-06-23T00:45:38.513Z 1983-06-23T01:31:08.206Z ORB1661 318 118 953 1983-06-24T00:45:58.043Z 1983-06-24T01:31:07.719Z ORB1662 325 118 953 1983-06-25T00:45:48.112Z 1983-06-25T01:31:07.481Z ORB1663 324 118 953 1983-06-26T00:46:06.696Z 1983-06-26T01:31:06.661Z ORB1664 339 118 953 1983-06-27T00:45:44.474Z 1983-06-27T01:31:04.521Z ORB1667 321 118 953 1983-06-30T00:45:28.957Z 1983-06-30T01:30:57.423Z ORB1668 469 118 953 1983-07-01T00:34:35.004Z 1983-07-01T01:30:58.087Z ORB1669 404 118 953 1983-07-02T00:45:22.128Z 1983-07-02T01:30:50.145Z ORB1670 469 118 953 1983-07-03T00:30:51.156Z 1983-07-03T01:30:45.807Z ORB1671 467 118 953 1983-07-04T00:40:06.544Z 1983-07-04T01:30:43.163Z ORB1672 462 118 953 1983-07-05T00:37:37.619Z 1983-07-05T01:30:32.532Z ORB1673 158 118 953 1983-07-06T00:45:01.887Z 1983-07-06T01:09:45.403Z ORB1680 155 118 953 1983-07-13T00:44:20.470Z 1983-07-13T01:08:45.196Z ORB1682 492 118 953 1983-07-15T00:29:12.061Z 1983-07-15T01:28:56.684Z ORB1683 509 118 953 1983-07-16T00:35:09.248Z 1983-07-16T01:28:29.270Z Catalog Files (.CAT extension) Catalog data, which includes instrument, dataset, mission and spacecraft descriptions, can be found in the *.CAT files in the CATALOG directory on this disk.