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 <bits/sec>
LAT float Venusian Latitude <deg>
LON float Venusian Longitude <deg>
ALT float Altitude <km>
SZA float Solar Zenith Angle <deg>
SHA float Solar Hour Angle <hr>
MASS1 int Mass of Sample 1 <AMU>
DEN1 float Number density of Sample 1 <ions/cm^3>
MASS2 int Mass of Sample 2 <AMU>
DEN2 float Number density of Sample 2 <ions/cm^3>
. . .
. . .
. . .
MASS55 int Mass of Sample 55 <AMU>
DEN55 float Number density of Sample 55 <ions/cm^3>
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
----------------------------------------------------------------------------
ORB3800 560 118 953 1989-05-02T02:26:49.271Z 1989-05-02T04:25:46.563Z
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.