File: AAREADME.TXT Version: NSSDC 11/15/2001 JFC ------------------------------------------------------------------------- Interplanetary Solar Wind Plasma Data from Pioneer Venus Orbiter: 1977 - 1992 Date Coverage: 1978-05-21 to 1978-12-04 (cruise enroute to Venus) 1978-12-05 to 1992-10-07 (Venus orbit) Principal Investigator: Dr. Aaron Barnes, NASA Ames Research Center Moffett Field, California Data Contact: Dr. Paul R. Gazis, SJSU Research Associate NASA Ames Research Center Moffett Field, California Phone: (415) 604-5704 Fax: (415) 604-6779 Email: gazis@arwen.arc.nasa.gov Description: This directory holds hourly and high resolution data for the interplanetary solar wind near Venus from the Plasma Analyzer (OPA) experiment on the Pioneer Venus Orbiter spacecraft as described in file PVOPLA_NMC from the NSSDC Master Catalog. Data coverage includes cruise (enroute to Venus from Earth, May - Dec. 1978) and orbital (Dec. 1978 to Oct. 1992) mission phases up through loss of telemetry on Oct. 8, 1992 before atmospheric entry. High resolution (or summary) data include least square fits, as approximated by convecting Maxwellian distributions, to all valid solar wind ion energy spectra at full instrument resolution. Velocities have been corrected for abberation due to the motion of the spacecraft and all times are in spacecraft event time (SCET). Hourly averaged data files were created by averaging every valid parameter in each hour. Measurements made inside the Venusian bow shock were mostly excluded. The principal archival data set includes binary files for high resolution (summary) and hourly average fit parameters, whereas the ASCII version includes only hourly data. The binary data set is described by ASCII documentation (*.SFDU file) in Standard Formatted Data Unit (SFDU) text and label format, but the binary data must be retrieved from another site (see below). The ASCII hourly data here are described in plain text files (*.txt). Orbital data in heliocentric or Venus-centered coordinates are provided with both datatypes. The hourly data may also be browsed, plotted, and retrieved through the COHOWeb data system (see below). Merged solar wind magnetic field and plasma data from PVO, transformed into more convenient heliographic/RTN coordinates, are available in COHO directory PIONEER_VENUS/MERGED. Directory Description --------- ----------- ARCHIVE Complete archival data set with SDFU-type documentation (ASCII *.SFDU file) for high resolution (summary), hourly average, and spacecraft ephemeris data in binary format. Only the documentation are provided in this directory. The binary data file is available from the following Anonymous FTP site: anonymous@nssdca.gsfc.nasa.gov/COHO/PIONEER_VENUS/PLASMA/ARCHIVE. HOUR ASCII data (.asc) and text (*.txt) files for hourly averages of solar wind parameters for fits to high resolution ion spectra, including separate files for cruise and orbit mission phases. Related Information and Data: Further details on the spacecraft, experiment, data sets at NSSDC, and related WWW sites can be found on the Pioneer Venus flight project page: http://nssdc.gsfc.nasa.gov/space/ Hour averages of the interplanetary solar wind data from, and hourly heliocentric coordinates of, Pioneer Venus Orbiter and other interplanetary spacecraft may be also be accessed and plotted on-line through the COHOWeb service based at the same WWW site as above. Acknowledgement: Use of these data in publications should be accompanied at minimum by acknowledgements of the National Space Science Data Center and the responsible Principal Investigator defined in the experiment documentation provided here.