This is the AAREADME file from the Magellan LOSAPDR cycle 4 CD-WO

PDS_VERSION_ID                  = PDS3

RECORD_TYPE                     = FIXED_LENGTH
RECORD_BYTES                    = 80
TARGET_NAME                     = VENUS
OBJECT                          = TEXT
  PUBLICATION_DATE              = 1994-06-01
  NOTE                          = "MAGELLAN LOSAPDR ARCHIVE CD-WO"
END_OBJECT                      = TEXT


1.  Introduction

    This CD-WO contains Magellan Cycle 4 LOSAPDR (Line of Sight
Acceleration Profile Data Record) products.  It also contains
documentation which describe the LOSAPDRs.  Each LOSAPDR product
contains the results from processing of radio tracking data of the
Magellan spacecraft.  There are 866 LOSAPDRs on this volume.

    The LOSAPDR products archived on this volume 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.  Disk Format

    The disk has been formatted so that a variety of computer systems
(e.g. IBM PC, Macintosh, Sun) may access the data.  Specifically, it
is formatted according to the ISO 9660 level 1 Interchange Standard.
For further information, refer to the ISO 9660 Standard Document: RF#
ISO 9660-1988, 15 April 1988.

3.  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 velocity information, 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 is stored on this disk as file LOSAPDR.TXT in the
DOCUMENT directory.

    All document files and detached label files contain 80-byte
fixed-length records, with a carriage return character (ASCII 13) in
the 79th byte and a line feed character (ASCII 10) in the 80th byte.
This allows the files to be read by the MacOS, DOS, Unix, and VMS
operating systems.  All tabular files are also described by PDS
labels, either embedded at the beginning of the file or detached.  If
detached, the 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

    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.

    A PostScript file, REPORT.PS, is included on this volume.  This
PostScript document is a validation report that lists all LOSAPDRs,
and gives specific information, comments, and the status of each data
file after a quality check and validation at the PDS Geophysics
Subnode.  The document is described by the detached label file,
REPORT.LBL.  The document can also be viewed by a Display PostScript
program and can be printed out from a PostScript printer.  The ASCII
text version of the PostScript file is REPORT.ASC.

  PDS labels are object-oriented.  The object to which the label
refers (e.g., IMAGE, TABLE, etc.) is denoted by a statement of the

       ^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<BYTES>
       ^object = "filename.ext"
       ^object = ("filename.ext",n)
       ^object = ("filename.ext",n<BYTES>)


       n         is the starting record or byte number of the object,
                 counting from the beginning of the file (record 1,
                 byte 1)
       <BYTES>   indicates that the number given is in units of bytes
       filename  is the upper-case file name
       ext       is the upper-case file extension

4.  CD-ROM Contents

    The files on this CD-ROM are organized in one top-level directory
with several subdirectories.  The following table shows the structure
and content of these directories.  In the table, 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.
    |- ERRATA.TXT         Description of known anomalies and errors
    |                     present on this volume.
    |- VOLDESC.CAT        A description of the contents of this CD-ROM
    |                     volume in a format readable by both humans
    |                     and computers.
    |- [CATALOG]          A directory containing information about the
    |   |                 LOSAPDR dataset.
    |   |
    |   |- CATALOG.CAT    PDS catalog objects.  Mission, spacecraft
    |   |                 and instrument descriptions.
    |   |
    |   |- CATINFO.TXT    Description of files in the CATALOG
    |   |                 directory.
    |   |
    |   |- DATASET.CAT    PDS dataset catalog object.  A description
    |                     of the dataset, parameters, processing, data
    |                     coverage and quality.
    |- [DATA]             A directory containing LOSAPDR data files.
    |   |
    |   |- [mmmmnnnn]     Directories containing LOSAPDR data files
    |   |   |             for orbits between 'mmmm' and 'nnnn'.
    |   |   |
    |   |   |- L0mmmm.001 LOSAPDR file for orbit number 'mmmm'.
    |- [DOCUMENT]         A directory containing document files
    |   |                 relating to this disk.
    |   |
    |   |- DOCINFO.TXT    Description of files in the DOCUMENT
    |   |                 directory.
    |   |
    |   |- LOSAPDR.TXT    A machine readable version of the LOSAPDR
    |   |                 SIS document describing the format and
    |   |                 content of the data files.
    |   |
    |   |- REPORT.ASC     ASCII text version of REPORT.PS.
    |   |
    |   |- REPORT.LBL     A PDS detached label describing REPORT.ASC
    |   |                 and REPORT.PS.
    |   |
    |   |- REPORT.PS      A PostScript document that gives specific
    |                     information about each LOSAPDR after a
    |                     quality check and validation.
    |- [INDEX]            A directory containing index files relating
        |                 to this disk.
        |- 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.

5.  Recommended CD-ROM Drives and Driver Software

       Drive:  Digital Equipment Corporation (DEC) RRD42, RRD40 or
       Driver: DEC VMS CD-ROM driver V5.5 and up.

       Note:   For VMS V5.4 or earlier, contact Jason Hyon for VFS
               driver software which mounts a CD-ROM.  Once it's
               mounted, you should use the convert or exchange/network
               command to copy all files from CD-ROM to a local disk.

               For VMS V5.5 or above, you can obtain the driver
               software by contacting your local DEC representative.
               It is necessary to use this driver to access the files
               on the CD-ROM that do not contain Extended Attribute
               Records (XARs).

       Drive:  DEC RRD42, RRD40 or RRD50.
       Driver: Supplied with Ultrix 3.1.

       Note:   Internet users can obtain a copy of the "cdio" software
               package via anonymous ftp from the ""
               server in the file named "src/cdio.shar".  Contact Dr.
               Peter Ford at Massachusetts Institute of Technology
               for details (617-253-6485 or

    IBM PC
       Drive:  Toshiba (V. 2.2.1), Hitachi, Sony, NEC, Pioneer or
       Driver: Microsoft MSCDEX version 2.0 or later (2.21 is the
               latest version).

       Note:   Contact Jason Hyon for assistance in locating a copy
               of the latest version of MSCDEX.

    Apple Macintosh
       Drive:  Apple CD SC Plus (3.1.1b3), Toshiba (1.4), NEC (2.25),
               Pioneer DRM600 (CLD Access 1.1b1).
       Driver: Apple CD-ROM driver, or vendor specific driver.

    Sun Micro  (SunOS 4.0x and earlier)
       Drive:  Delta Microsystems SS-660 (Sony).
       Driver: Delta Microsystems driver.

       Note:   For questions concerning this driver, contact Denis
               Down at Delta Microsystems, 415-449-6881.

    Sun Micro  (SunOS 4.0.3 and later)
       Drive:  Sun Microsystems.
       Driver: SunOS sr.o driver.

       Note:   A patch to SunOS may be necessary before the Sun
               driver can access files on the CD-ROM.  A copy of this
               patch is available to Internet users via anonymous ftp
               from the "" server in the file named

    Silicon Graphics IRIS
       Drive:  SGI CD-ROM Drive.
       Driver: SGI CD-ROM driver.

       Note:   A patch to SGIOS may be necessary before the SGI
               driver can access files on the CD-ROM.  A copy of this
               patch is available by calling the Data Distribution
               Laboratory at JPL.  This patch is not needed for
               Version 4.0.5 and above.

    IBM RS6000

       In order to access PDS CD-ROMs, you need to contact IBM user
       support for the driver at 1-800-426-7378.  AIX 3.2 and above
       will work with PDS CD-ROMs.

6.  Errata and Disclaimer

    A cumulative list of anomalies and errors is maintained in the
file ERRATA.TXT at the root directory of this volume.

    Although considerable care has gone into making this volume,
errors are both possible and likely.  Users of the data are advised to
exercise the same caution as they would when dealing with any other
unknown data set.

    Reports of errors or difficulties would be appreciated.  Please
contact one of the persons listed herein.

7.  Whom to Contact for Information

    For questions concerning this volume set, data products and

              Jim Alexopoulos
              Washington University
              Dept. of Earth and Planetary Sciences
              1 Brookings Drive
              Campus Box 1169
              St. Louis, MO 63130

              Electronic mail address:

    For questions about how to read the CD-ROM:

              Jason J. Hyon
              Jet Propulsion Laboratory
              California Institute of Technology
              4800 Oak Grove Drive
              MS 525-3610
              Pasadena, CA 91109

              Electronic mail addresses:
              NASAmail:  JHYON
              NSI:       JPLPDS::JHYON

    For more information about CD-ROM Hardware and Software:

              Data Distribution Laboratory
              Jet Propulsion Laboratory
              4800 Oak Grove Drive
              MS 525-3610
              Pasadena, CA 91109

              Electronic mail address:

    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

              Electronic mail address:

    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

              Electronic mail address:

    For questions concerning LOSAPDR labels:

              Dr. Richard Simpson
              Stanford University
              Durand Bldg. Room 232
              Stanford, CA 94305-4055

              Electronic mail address:

    This disk was produced by Jim Alexopoulos.