THE MARS GLOBAL SURVEYOR PRE-MAPPING PHASE DVD-ROMS (AAREADME.TXT) February 10, 2000 ------------------------------------------ 1. Introduction 2. How to Locate Data Products of Interest 3. Volume Set Contents 4. File Formats 5. DVD-ROM Format 6. Whom to Contact for More Information 7. Cognizant Persons ------------------------------------------ 1. INTRODUCTION The Mars Global Surveyor (MGS) Pre-Mapping Phase DVD-ROM volume set consists of three DVD-ROMs containing data sets acquired by MGS instruments during the Pre-Mapping Phase of the mission. All the data sets on these DVD-ROM volumes have been previously released through the Planetary Data System (PDS). They are reissued on these volumes as a pilot project to demonstrate the use of DVD-ROM as an archive medium. The Pre-Mapping Phase was the phase of the mission during which the spacecraft was gradually moving from its initial, highly elliptical orbit around Mars to a nearly circular orbit for systematic mapping. Periods of aerobraking were used over approximately eighteen months to circularize the orbit. Science instruments acquired data during the times between the aerobraking periods, called Science Phasing Orbits. Some instruments also acquired data during aerobraking. The two periods of aerobraking are known as AB-1 and AB-2, and the two periods of Science Phasing Orbits are known as SPO-1 and SPO-2. The file MISSION.CAT in the CATALOG directory has more information about the phases of the mission. The MGS instruments and experiments represented in this archive are: Accelerometer (ACC) Magnetometer / Electron Reflectometer (MAG/ER) Mars Orbiter Camera (MOC) Mars Orbiter Laser Altimeter (MOLA) Radio Science Subsystem (RS) Thermal Emission Spectrometer (TES) SPICE kernels for the Pre-Mapping Phase are also provided. This archive includes all the previously released Pre-Mapping data sets from the above instruments, with the exception of level 0 (raw) Radio Science data which encompasses hundreds of CD-ROMs. Derived Radio Science data sets are included in the archive. In addition to the data sets, this archive also includes documentation, ancillary files, software, and browse data from the original archive volumes. For more information about specific data sets, refer to the original documentation in the DOCUMENT directory. 2. HOW TO LOCATE DATA PRODUCTS OF INTEREST For convenience in locating data products of interest, a search tool is provided in the form of HTML files that may be viewed using a Web browser such as Netscape Navigator or Internet Explorer. The tool allows searches across all data sets by selecting areas of interest on a map. The result of a search is a list of products that occur in the area of interest, with hyperlinks to browse images and data files. The search tool is found in the EXTRAS directory. To begin using it, open the file SEARCH.HTM in a Web browser. The search tool is present on all three volumes, so that it may be started from any volume to search the entire collection. Since the browse data are also present on all volumes, the tool may be used from any volume to display any browse image. The search tool may also be used to download data files that are on the volume currently in use. Some data products are not accessible through the search tool. These include products that were not observations of the Martian surface (e.g. those of Phobos and deep space) and observations from very high spacecraft altitudes. Also, the SPICE kernels are not accessible from the search tool. 3. VOLUME SET CONTENTS The volume set contains the directories and files listed below. The data sets are distributed among the three volumes as follows: Volume 1 - TES (AB-1) Volume 2 - ACC, MAG/ER, RS, SPICE, TES (AB-1, SPO-1) Volume 3 - MOC, MOLA, TES (SPO-2, AB-2) Most of the documentation and other supporting files are repeated on each of the three volumes, with exceptions as noted below. Top-level Directory ------------------- AAREADME.TXT, AAREADME.HTM, AAREADME.LBL AAREADME.TXT and AAREADME.HTM are the plain text and HTML versions of the file you are currently reading. AAREADME.LBL is a detached PDS label that describes the other two files. ERRATA.TXT This file lists known errors and anomalies on this volume set. It includes the errata files from the original archive volumes of each data set, plus any additional errata for the DVD-ROM set as a whole. VOLDESC.CAT This text file is a description of the volume contents as PDS objects. This is a required file on PDS archive volumes. ACC Directory ------------- The ACC directory appears only on volume 2. It contains the Accelerometer data products. See the file ACCINFO.TXT for details. BROWSE Directory ---------------- The BROWSE directory contains a subdirectory for each data set that has browse data. The browse data are repeated on each volume except for the MAG/ER browse data, which appear only on the volume containing MAG/ER standard products (MGS_1002). The browse subdirectories may be further subdivided; see the file BROWINFO.TXT for details. Subdirectories -------------- ACC MAGER MOC MOLA RS CALIB Directory --------------- This directory appears only on volume 2. It contains calibration data to accompany the Accelerometer data set. See the file CALINFO.TXT for details. CATALOG Directory ----------------- Files in the CATALOG directory are text files in PDS object description language, which is both human- and machine-readable. The files contain information about the MGS mission, instruments, data sets, personnel, and references. These files were copied from the original archive volumes without any alterations. See the file CATINFO.TXT for details. DOCUMENT Directory ------------------ The DOCUMENT directory contains the documentation files from the original archive volumes. There is a subdirectory for each instrument. The AAREADME.TXT files from the original archive volumes are included in the appropriate document subdirectories. See the file DOCINFO.TXT for details. Subdirectories -------------- ACC MAGER MOC MOLA RS SPICE TES EXTRAS Directory ---------------- The EXTRAS directory contains files for the HTML-based search tool described in section 2. See the file EXTRINFO.TXT or EXTRINFO.HTM for details. INDEX Directory --------------- The INDEX directory contains index tables that list all the products in this volume set, along with additional information for each product such as time, orbit, browse file name, etc. This directory includes cumulative index tables for each data set, copied from the original archive volumes without alteration. There are also index tables that list all the products with directory and file names specific to this DVD-ROM volume set. See the file INDXINFO.TXT for details. LABEL Directory --------------- This directory appears only on volumes 2 and 3. The files in this directory are PDS "format" files -- files that are referenced by PDS data product labels. Volume 2 has format files for the Accelerometer data set, and Volume 3 has format files for the MOLA data sets. See the LABINFO.TXT files on the two volumes. MAGER Directory --------------- The MAGER directory appears only on volume 2. It contains the Magnetometer / Electron Reflectometer data products. See the file MGERINFO.TXT for details. MOC Directory ------------- The MOC directory appears only on volume 3. It contains the Mars Orbiter Camera data products. See the file MOCINFO.TXT for details. MOLA Directory -------------- The MOLA directory appears only on volume 3. It contains the Mars Orbiter Laser Altimeter data products. See the file MOLAINFO.TXT for details. RS Directory ------------ The RS directory appears only on volume 2. It contains the Radio Science data products. See the file RSINFO.TXT for details. SOFTWARE Directory ------------------ The SOFTWARE directory contains programs for use with MOLA and TES data products. Both MOLA and TES data are stored as binary files with complex formats that require custom software to read them. The MOLA program "PEDR2TAB" and the TES program "vanilla" generate plain text tables of user-selected fields from the binary files. Source code, user's guides, and executable files for PC, UNIX, and Macintosh computers are included. For MOLA, an additional software tool is provided: "MPROF" is a script for use with the commercial image processing software IDL. It performs basically the same function as PEDR2TAB and also generates plots. See the file SOFTINFO.TXT for details. SPICE Directory --------------- The SPICE directory appears only on volume 2. It contains SPICE kernels for the Pre-Mapping Phase of the MGS mission. See the file SPCINFO.TXT for details. TES Directory ------------- The TES directory contains Thermal Emission Spectrometer data products and is split across all three volumes because of its large size. See the file TESINFO.TXT for details. 4. FILE FORMATS Data files in this volume set conform to PDS standards and are accompanied by PDS labels. Each data set has its own custom format, described by files in the document directory (e.g. Software Interface Specification documents). Some data products are straightforward image files or tables; some are complex binary files that come with specialized software to read them. For more information, see the documentation for specific data sets. Some data sets have browse data along with the standard data products. Browse data are derived versions of standard products in a form that is easily accessible for quick-look purposes. In this volume set, most browse data are GIF or JPEG images that can be viewed with a Web browser or with standard image processing software. The exception is the MAG/ER browse data, which are PostScript files. They cannot be viewed in a browser without appropriate plug-in software, but they can be printed on a printer that supports PostScript. Most documentation and other supporting files are plain text files or HTML files. Text and HTML files are stream format files, with a carriage return (ASCII 13) and a line feed character (ASCII 10) at the end of each line. This convention allows the files to be read by the MacOS, DOS/Windows, and UNIX operating systems. Some files in the DOCUMENT directory are in Adobe Portable Document Format (PDF) because they have content that cannot be rendered in plain text. PDF files can be read using the free Acrobat Reader software from Adobe (http://www.adobe.com). 5. DVD-ROM FORMAT This dual-layer DVD-ROM volume set requires the following operating system versions to operate properly. Windows 95, 98, NT 4.0, 2000 with the latest service patches installed. Macintosh MAC OS 8.5. Sun Solaris 2.7. Linux 6.0 with UDF kernel patches installed (http://trylinux.com/projects/udf/). HPUX - not supported yet, contact Hewlett Packard. IRIX - not supported yet, contact Silicon Graphics. The DVD-ROMs in this volume set conform to the level 2 ISO standard; therefore files may have names longer than the 12 character limit imposed by the level 1 ISO standard (the "8.3" rule). 6. WHOM TO CONTACT FOR MORE INFORMATION PDS Geosciences Node Washington University Dept. of Earth and Planetary Sciences 1 Brookings Drive, Campus Box 1169 St. Louis, MO 63130 http://wwwpds.wustl.edu geosci@wunder.wustl.edu 7. COGNIZANT PERSONS The MGS Pre-Mapping DVD-ROM volume set was produced by Edward A. Guinness, Susan Slavney, and Thomas C. Stein, the Planetary Data System Geosciences Node, Washington University, St. Louis, Missouri, and Mike Martin, Data Distribution Laboratory, Jet Propulsion Laboratory, Pasadena, California. Many people produced the individual data sets included on this volume set. See the original AAREADME.TXT files stored in the DOCUMENT directory on this volume set for contact and credit information for specific data sets.