PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT NOTE = "Information on MESSENGER ancillary products." PUBLICATION_DATE = 2015-10-09 END_OBJECT = TEXT END MESSENGER Science Data Archive Radio Science Subsystem ANCINFO.TXT 11 June 2015 Johns Hopkins University Applied Physics Laboratory ============================================================================= INTRODUCTION ============================================================================= The ANCILLARY directory contains ancillary data products which support the MESSENGER Radio Science Subsystem (RSS) raw data archive. The various ancillary data products are provided in separate directories. Except where otherwise noted, the ancillary files follow the following naming convention: MESS_RS___. _ : the start and stop dates over which the data span. These are year and day of year. For some products that cover a point in time, the start and stop dates will be the same. : The type of product. LTF, ION, TRO, WEA, MPD, SFF or MDM. : The file extension indicating the PDS data type. TXT for unformatted text data or TAB for fixed record length table data. ============================================================================= DIRECTORY CONTENTS ============================================================================= ANCINFO.TXT The file you are reading. LTF/MESS_RS___LTF.TAB: Light Time Files. These files provide one way light travel time values for both the upleg and downleg directions between the MESSENGER spacecraft and the three Deep Space Communications Complex (DSCC) facilities. This product was produced by the navigation team. The data are in table form. See the LTF SIS (document/ltf_sis.htm) for a detailed description of this product. These are accompanied by detached full PDS labels. ION/MESS_RS____ION.TXT: Media Files (Ionosphere): These files are DSN TRK-2-23 Media Calibration files. These provide ionospheric calibration information. They are of two types, Doppler and range data and Delta Differenced One-way Ranging (VLBI). The file naming convention differs from the others in that the stop date contains only the day of year (not the year) and is either VL for the VLBI files and DP for the Doppler and range files. These are generated periodically by the DSMS and provided by JPL. These are accompanied by detached minimal PDS labels. This product is described in document/dsn_trk_2_23_tro_ion_sis.htm/.pdf included in this archive. TRO/MESS_RS___TRO.TXT: Media Files (Troposphere): These files are DSN TRK-2-23 Media Calibration files. These provide tropospheric calibration information. These are generated periodically by the DSMS and provided by JPL. These are accompanied by detached minimal PDS labels. This product is described in document/dsn_trk_2_23_tro_ion_sis.htm/.pdf included in this archive. WEA/MESS_RS____WEA.TXT: DSN Weather Files: These files are DSN TRK-2-24 Weather files. They give information about the weather conditions at a given DSCC. The file naming convention differs from the others in that the stop date contains only the day of year (not the year) and is the DSCC number (10 - Goldstone, 40 - Canberra, 60 - Madrid). These are generated periodically by the DSMS and provided by JPL. These are accompanied by detached minimal PDS labels. This product is described in the document/wea_sis.htm/.pdf included in this archive. ANT/MESS_RS_ANT.TXT: Antenna configuration state files: The MESSENGER project produces antenna configuration data from each contact for which they are available. They give the state of the antenna. The data file is accompanied by detached full PDS label. The file contains antenna configuration status indicators. For each day, there is an entry at 00:00 that describes the antenna configuration at the start of the day, and additional entries for each change in the antenna configuration. This product is cumulative over the course of the mission. SFF/MESS_RS___SFF.TAB: Small Forces Files: These are generated by the MESSENGER project when there is a propulsive event. They give information on the cumulative delta-V effect on the spacecraft due to thruster firing, mass loss due to the expenditure of propellant, and cumulative on-times for each individual thruster. These are accompanied by detached full PDS labels. This product is described in document/sff_sis.htm/.pdf included in this archive. MDM/MESS_RS_MDM.CSV: Momentum Dump Maneuver files: This is a cumulative file that contains angular momentum dump data associated with each propulsive event. It is updated with each release and the newer version replaces the older one. This product is described in the mdm/mdminfo.txt file included in this archive. MPD/MESS_RS___MPD.TAB: Maneuver Performance Data Files: These are generated by the MESSENGER project when there is a propulsive event. These contain estimates of spacecraft mass and center of mass; moments of inertia; thruster locations, directions, and magnitudes; and propellant flow rate. These are accompanied by detached full PDS labels. This product is described in the document/mpd_desc.txt included in this archive. MDM/MESS_RS_MDM.CSV: Momentum Dump Maneuver files: These are generated by the MESSENGER project from the command reconstruction reports and contain information on each momentum dump maneuver. These are commanded angular momentum dumps. This product is described in the document document/mdm_desc.txt included in this archive.