PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM SPACECRAFT_NAME = MAGELLAN TARGET_NAME = VENUS OBJECT = TEXT PUBLICATION_DATE = 1997-01-01 NOTE = "MAGELLAN LOSAPDR ARCHIVE CD-WO" END_OBJECT = TEXT END MAGELLAN LOSAPDR ARCHIVE CD-WO 1. Introduction This archive volume contains Magellan Cycle 4, 5 and 6 LOSAPDR (Line of Sight Acceleration Profile Data Record) products. It also contains documentation which describes the LOSAPDRs. Each LOSAPDR product contains the results from processing of radio tracking data of the Magellan spacecraft. There are 2669 LOSAPDRs in this archive. The Cycle 4 LOSAPDR data products in this archive represent the second version released. The first version can be accessed electronically via the World Wide Web and anonymous FTP transfer (http://pds-geophys.wustl.edu/pds/magellan/losapdr_old/data.html), and is also available at the National Space Sciences Data Center (NSSDC). This is the first official release of the Cycle 5 and 6 data products. The LOSAPDR products in this archive are the exact products released by the Magellan Project. Supporting documentation and label files conform to the Planetary Data System (PDS) Standards, Version 3.0, Jet Propulsion Laboratory (JPL) document JPL D-7669. Additional information about the Magellan gravity experiment, including the acquisition, processing, and quality of the LOSAPDR data, can be found in JPL documents that are available from the PDS Geosciences Node, Washington University, St. Louis, MO. 2. File Formats Each orbit for which gravity data exists is represented by one LOSAPDR data file. The LOSAPDR is an ASCII file. The data file contains 3 tables: 1) HEADER_TABLE; 2) TIMES_TABLE; and 3) RESULTS_TABLE. The HEADER_TABLE is a single-row multi-column table containing information on initial values, control parameters, and simple calculations required by the program that generates the data files. The TIMES_TABLE is a single column containing exact times bounding spline intervals to the Doppler residuals. The number of rows is variable. The RESULTS_TABLE contains the results from spline fits to Doppler residuals. Each row in the table contains times, Doppler residuals, spacecraft position, and inferred spacecraft acceleration. The data files are described by PDS labels embedded at the beginning of the file. Further information on LOSAPDR file formats and contents can also be obtained from the Magellan Software Interface Specification (SIS) document NAV-138. A copy of the document can be found in this archive as file LOSAPDR.TXT in the DOCUMENT directory. All document files and detached label files contain stream format records, with a carriage return character (ASCII 13) and a line feed character (ASCII 10) at the end of each line. This allows the files to be read by the MacOS, DOS, Unix, and VMS operating systems. All tabular files are also described by PDS detached labels. The detached PDS label file has the same name as the data file it describes, with the extension .LBL; for example, the file INDEX.TAB is accompanied by the detached label file INDEX.LBL in the same directory. Tabular files are formatted so that they may be read directly into many database management systems on various computers. All fields are separated by commas, and character fields are enclosed in double quotation marks ("). Character fields are left justified, and numeric fields are right justified. The "start byte" and "bytes" values listed in the labels do not include the commas between fields or the quotation marks surrounding character fields. The records are of fixed length, and the last two bytes of each record contain the ASCII carriage return and line feed characters. This allows a table to be treated as a fixed length record file on computers that support this file type and as a normal text file on other computers. PDS labels are object-oriented. The object to which the label refers (e.g., IMAGE, TABLE, etc.) is denoted by a statement of the form: ^object = location in which the carat character (^, also called a pointer in this context) indicates that the object starts at the given location. In an embedded label, the location is an integer representing the starting record number of the object (the first record in the file is record 1). In a detached label, the location denotes the name of the file containing the object, along with the starting record or byte number. For example: ^TABLE = "INDEX.TAB" indicates that the TABLE object points to the file INDEX.TAB, in the same directory as the detached label file. Below is a list of the possible formats for the ^object keyword. ^object = n ^object = n ^object = "filename.ext" ^object = ("filename.ext",n) ^object = ("filename.ext",n) where n is the starting record or byte number of the object, counting from the beginning of the file (record 1, byte 1) indicates that the number given is in units of bytes filename is the upper-case file name ext is the upper-case file extension 3. Archive Contents The files in this archive are organized in one top-level directory with several subdirectories. The following diagram shows the structure and content of these directories. In the diagram, directory names are enclosed in square brackets ([]), upper-case letters indicate an actual directory or file name, and lower-case letters indicate the general form of a set of directory or file names. FILE CONTENTS Top-level directory | |- AAREADME.TXT The file you are reading. | |- VOLDESC.CAT A description of the archive contents. | |- [CATALOG] A directory containing PDS catalog objects, | | and information about the LOSAPDR dataset. | | | |- CATINFO.TXT Description of files in the CATALOG | | directory. | | | |- MISSION.CAT A brief description of the mission. It | | includes a chronology of events, definition | | of mission phases, and science objectives. | | | |- INSTHOST.CAT A description of the Magellan spacecraft and | | an overview of the NASA Deep Space Network (DSN). | | | |- INST.CAT An overview of the spacecraft radio science | | system on Magellan and a summary description of | | the Deep Space Network instrumentation which | | supports radio science experiments. | | | |- DATASET.CAT PDS dataset catalog object. A description | | of the LOSAPDR dataset, parameters, | | processing, data coverage and quality. | | | |- REF.CAT A listing of references used elsewhere in | | the streamlined catalog files and of references | | that might be generally useful in working | | with these data. | | | |- PERSON.CAT A listing of key people involved in | generating and processing the archival dataset. | |- [DATA] A directory containing LOSAPDR data files. | | | |- [LAPXXXXX] Directories containing LOSAPDR data files, | | | where 'LAP' means Line of Sight Acceleration | | | Profile, and 'XXXXX' is the first orbit | | | number contained in them. | | | | | |- LXXXXX.001 LOSAPDR file for orbit number 'XXXXX'. | |- [DOCUMENT] A directory containing document files | | relating to this archive. | | | |- DOCINFO.TXT Description of files in the DOCUMENT | | directory. | | | |- LOSAPDR.TXT The LOSAPDR SIS document describing the | format and content of the data files. | | |- [INDEX] A directory containing index files relating | to this archive. | |- INDEX.LBL A PDS detached label describing INDEX.TAB. | |- INDEX.TAB Tabular summary of data files. | |- INDXINFO.TXT Description of files in the INDEX directory. 4. Whom to Contact for Information For questions concerning this archive, data products, associated PDS labels and documentation: Jim Alexopoulos Washington University Dept. of Earth and Planetary Sciences 1 Brookings Drive Campus Box 1169 St. Louis, MO 63130 314-935-8594 Internet e-mail address: jim@wuzzy.wustl.edu For questions concerning the generation of LOSAPDR products: William L. Sjogren Magellan Gravity Principal Investigator Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive MS 301-150 Pasadena, CA 91109 818-354-4868 Internet e-mail address: wls@kamel.jpl.nasa.gov For questions concerning LOSAPDR data: William L. Sjogren Jet Propulsion Laboratory Pasadena, CA Dr. Roger J. Phillips Washington University Dept. of Earth and Planetary Sciences 1 Brookings Dr. Campus Box 1169 St. Louis, MO 63130 314-935-6356 Internet e-mail address: phillips@wustite.wustl.edu This archive was produced by Jim Alexopoulos.