PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 OBJECT = TEXT PUBLICATION_DATE = 2008-05-09 NOTE = "Software Interface Specification for the Mars Global Surveyor Radio Science EDS Archive. Formatted for display or printing with 58 lines per page and up to 78 constant-width characters per line." END_OBJECT = TEXT END Stanford Center for Radar Astronomy Mars Global Surveyor Project Software Interface Specification Radio Science Electron Density Profile Archive prepared by Richard A. Simpson Center for Radar Astronomy Stanford University Stanford, CA 94305-4020 650-723-3525 Version 1.0 9 May 2008 PREFACE |====================================================================| | | | DOCUMENT CHANGE LOG | | | |====================================================================| |REVISION|REVISION| SECTION | REMARKS | | NUMBER | DATE | AFFECTED | | |--------+--------+------------+-------------------------------------| | 1.0 |08/05/09| N/A | | |====================================================================| Acronyms and Abbreviations ADC Archival Data Collection ASCII American Standard Code for Information Interchange CD Compact Disc CD-WO Compact Disc - Write Once DOS Disk Operating System DSN Deep Space Network EDH Electron Density - high resolution processing EDS Electron Density - standard resolution processing IMG Image IPS Intensity Power Spectra ISO International Standards Organization JPL Jet Propulsion Laboratory kB Kilobytes LOS Line-of-Sight LOSAPDR Line-of-Sight Acceleration Profile Data Record MB Megabytes MGS Mars Global Surveyor NASA National Aeronautics and Space Administration NAV Navigation Subsystem/Team OCCSUM Occultation Summary (data file) OCS Occultation Summary - standard processing PDS Planetary Data System ROM Read-Only Memory RS Radio Science RSDMAP Radio Science Digital Map (product) RSIPS Radio Science Intensity Power Spectra (product) RST Radio Science Team RSTP Radio Science Temperature Pressure (profile) SDP Science Data Product SDVT Science Data Validation Team SHA Spherical Harmonics - ASCII SHADR Spherical Harmonics ASCII Data Record SHB Spherical Harmonics - Binary SHBDR Spherical Harmonics Binary Data Record SHM Spherical Harmonics Model SIS Software Interface Specification SOPC Science Operations Planning Computer SPAE Science Planning and Analysis Element SPDP Special Data Product SRG Surface Reflection Geometry SRI Surface Reflection Image SRT Surface Reflection Table STDP Standard Data Product TPS Temperature Pressure (profile) - standard processing 1. Introduction 1.1 Overview This Software Interface Specification (SIS) describes the format and content of the Mars Global Surveyor (MGS) Radio Science (RS) Electron Density (EDS) Profile Archive. This archive contains the MGS-M-RSS-5-EDS-V1.0 data set, the complete collection of ionospheric profiles derived from radio occultation data during the MGS mission. The archive is contained on a single Compact-Disc Write-Once (CD-WO) volume. The Mars Global Surveyor Mission was managed by the Jet Propulsion Laboratory (JPL) for NASA. The Team Leader for the MGS Radio Science Team was G.L. Tyler of Stanford University. 1.2 Scope The specifications in this document apply to all versions of the MGS RS EDS archive produced by the MGS Radio Science Team (RST) at Stanford University. This document provides a detailed description of the archive. 1.3 Applicable documents [1] ISO 9660-1988. Information Processing - Volume and File Structure on CD-ROM for Information Exchange, 15 April 1988. [2] Planetary Data System Standards Reference, JPL D-7669, Part 2, 20 March 2006 [3] Planetary Science Data Dictionary Document, JPL D-7116, Rev. E, 28 August 2002 1.4 System Siting 1.4.1 Interface Location and Medium The MGS RS EDS volume was created by the MGS RST at Stanford University using the MGS RS Science Operations and Planning Computer (SOPC) and its compact disc authoring subsystem. 1.4.2 Data Sources, Destinations, and Transfer Methods Each MGS RS EDS volume is a collection of products derived from raw Radio Science data by members of the RST. Each CD-WO is delivered using the most appropriate means to the Planetary Data System. 1.4.3 Generation Method and Frequency The MGS RS EDS archive was derived from the MGS-M-RSS-5-SDP-V1.0 archive by extracting the ionospheric electron density (EDS) profiles, reorganizing them chronologically into a set of subdirectories with no more than 1000 profiles each, generating an Occultation Summary (OCS) file for the entire collection, and writing the results to a single CD-WO volume. There are 5600 EDS profiles in this archive. Except for editing of labels needed to conform to the new archive structure, these data are identical to the profiles that were archived previously in the 38 volumes of the MGS-M-RSS-5-SDP-V1.0 data set. The CD-WO was evaluated internally by the Radio Science Team and, after receipt, by the Planetary Data System. 1.5 Assumptions and Constraints 1.5.1 Usage Constraints Access to the MGS RS EDS volume will be determined by PDS. 1.5.2 Documentation Conventions 1.5.2.1 Data Format Descriptions The reference data unit is the 8-bit byte. Data are stored in fields with various sizes and formats, but all are ASCII character strings. If a field is described as containing n bytes of ASCII character string data, this implies that the leftmost (lowest numbered) byte contains the first character, the next lowest byte contains the next character, and so forth. Character strings are written to CD-WO with lower numbered bytes preceding higher numbered bytes. 1.5.2.2 Limits of This Document This document applies only to the MGS RS EDS archive. 1.5.2.3 Typographic Conventions This document has been formatted for simple electronic file transfer and display. Line lengths are limited to no more than 80 ASCII characters, including line delimiters. No special fonts or structures are included within the file. Constant width characters are assumed for display. 2. Interface Characteristics 2.1 Hardware Characteristics and Limitations 2.1.1 Special Equipment and Device Interfaces The MGS RS EDS volume conforms to ISO 9660 standards for CD-ROM [1]. Users of the volumes must have access to systems which can read those media. 2.1.2 Special Set-Up Requirements None. 2.2 Volume and size The MGS RS EDS volume contains the results of approximately seven years of MGS radio occultation data collection -- about 180 Mbytes of data. 2.3 Labeling and Identification 2.3.1 External Labels Each MGS RS EDS volume delivered to PDS bears a label using the following format: ACRONYM_SEQUENCE;VERSION where ACRONYM = MORS SEQUENCE = 1102 VERSION = A single digit determining version number of the CD-WO volume. "1" is the original version. Example = MORS_1102;5 would be the fifth version of the EDS archive 2.3.2 Internal Labels The contents of the MGS RS EDS volume are labeled in accordance with PDS standards [2]. Labeling is described further in subsequent sections. 2.4 Interface Medium Characteristics The MGS RS EDS conforms to ISO 9660 standards [1]. The quantity of data stored is about 180 MB. 2.5 Backup and Duplicates At least five copies of the MGS RS EDS volume will be created. Three copies will be delivered to PDS, one copy will be delivered to NSSDC, and one copy will be retained by the MGS RST at Stanford. 3. Structure and Organization Overview 3.1 Disc Organization The MGS RS EDS volume contains a CATALOG directory, a DOCUMENT directory, an INDEX directory, and two data directories (Figure 3-1) 3.1.1 Root Directory The root directory contains the following files: AAREADME.TXT terse description of volume contents ERRATA.TXT overview of anomalies and errors VOLDESC.CAT volume object definition 3.1.2 CATALOG Directory The CATALOG directory contains the following files: CATINFO.TXT text description of the directory contents MISSION.CAT PDS catalog object for Mission INSTHOST.CAT PDS catalog object for instrument host INST.CAT PDS catalog object for RS instrument DATASET.CAT PDS catalog object for data set PERSON.CAT PDS catalog object for archive personnel REF.CAT PDS catalog object for references TARGET.CAT PDS catalog object for target(s) 3.1.3 DOCUMENT Directory The DOCUMENT directory contains the following files. DOCINFO.TXT text description of the directory contents EDS_VOLM.TXT this Software Interface Specification OCCLOG.TAB table of data acquisition parameters OCCLOG.LBL detached label for OCCLOG.TAB 3.1.4 INDEX Directory The INDEX directory contains the following files: INDXINFO.TXT text description of the directory contents INDEX.LBL PDS label for the volume index (INDEX.TAB); identifies the volume index and describes structure of the index table. INDEX.TAB volume index in tabular form |====================================================================| | | | Figure 3-1. Top-Level MGS RS EDS Directory Structure | | | |====================================================================| root | |- AAREADME.TXT |- ERRATA.TXT |- VOLDESC.CAT | |- CATALOG | | | |- CATINFO.TXT | |- MISSION.CAT | |- INSTHOST.CAT | |- INST.CAT | |- DATASET.CAT | |- PERSON.CAT | |- REF.CAT | `- TARGET.CAT | |- DOCUMENT* | | | |- DOCINFO.TXT | |- EDS_VOLM.TXT | |- OCCLOG.TAB | `- OCCLOG.LBL | |- INDEX | | | |- INDXINFO.TXT | |- INDEX.LBL | `- INDEX.TAB | |- EDS (see 4.3.1) Data Directories `- OCS (see 4.3.3) 3.1.5 Data Directories for RS Science Data Products The MGS RS EDS volume contains directories for the EDS and OCS data types. The EDS directory contains subdirectories with names of the form yyyy_ddd where yyyy and ddd are the year and day-of-year (respectively) of the first EDS profile in the subdirectory. Subdirectories were chosen so that they would be separated by periods with little or no radio science activity (solar conjunction, safe mode events, periods when no occultations occurred, etc.) or so that there would be fewer than 1000 profiles per directory when there were no better separation criteria. The OCS directory contains only the cumulative Occultation Summary file and its label. 3.2 Formats The MGS RS EDS volume conforms to the ISO 9660 level 1 Interchange Standard CD-WO format [1]. This format is compatible with common computer systems including MS-DOS, Macintosh, SunOS, Unix, and VMS. Data that comprise the MGS RS EDS volume are formatted in accordance with Planetary Data System specifications [2-3]. 3.3 File Naming Conventions In this document and on the discs themselves, file and directory names are in upper case characters. This ensures compatibility with operating systems in which these names are case insensitive (e.g., VMS and DOS) and operating systems in which names are automatically translated into one case or the other (e.g., Unix and MacOS). Within disc directories the characters ";1" are appended to all file names. VMS excepted, most operating systems will hide these suffixes from users. 3.3.1 PDS Labels All files contained on the MGS RS EDS volume are accompanied by PDS labels [2-3]. The label can either be prepended to the associated primary file or "detached", in which case the label becomes a file in its own right with the same name as the primary file except for the suffix ".LBL". Detached label files are in the same directory as the primary data file. PDS labels, whether prepended to or detached from their primary files provide descriptive information about the associated file. The PDS label is an object-oriented structure consisting of sets of "keyword=value" declarations. 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 where to find the object. In a prepended label, the location is an integer representing the starting record or byte number of the object, where counting starts from record or byte number 1. In a detached label, the location denotes the name of the file containing the object, along with the starting record or byte number if there is more than one object. For example: ^HEADER = ("F01.IMG",1) ^IMAGE = ("F01.IMG",1025 ) indicates that the IMAGE object begins at byte 1025 of the file F01.IMG, in the same directory as the detached label file. Below is a list of the possible formats for the ^object definition. ^object = n ^object = n ^object = "filename.ext" ^object = ("filename.ext",n) ^object = ("[dirlist]filename.ext",n) ^object = ("filename.ext",n) ^object = ("[dirlist]filename.ext",n) where n is the starting record or byte number of the object, counting from the beginning of the file (record 1 or byte 1), indicates that the number given is in units of bytes; default is RECORDS filename is the (up to) 8 character, alphanumeric upper-case file name, ext is the 3 character upper-case file extension, dirlist is a period-delimited path-list of parent directories, in upper case, that specifies the object file directory (used only when the object is not in the same directory as the label file). The list begins at the directory level below the root directory of the CD-WO volume. '[dirlist]' may be omitted when the object being described is located either in the same directory as the detached label, or in the subdirectory LABEL that is located in a higher level of the directory tree, typically the CD-WO volume root itself. All detached labels contain records with no more than 80 bytes, with a carriage return character (ASCII 13) in the next-to-last byte and a line feed character (ASCII 10) in the last byte. This allows the files to be read by the MacOS, DOS, Unix, OS2, and VMS operating systems. 3.3.2 Document Files and Document Objects Document files (.TXT suffix) may exist in the root, CATALOG, DOCUMENT, and INDEX directories. These files are ASCII files with prepended PDS labels which employ the TEXT object. All document files contain no more than 80- byte records, with a carriage return character (ASCII 13) and a line feed character (ASCII 10) in the final two byte positions. This allows the files to be read by the MacOS, DOS, Unix, OS2, and VMS operating systems. 3.3.3 Tabular Files ASCII tabular files (.TAB suffix) exist in the INDEX and DOCUMENT directories. They are formatted for direct reading into many data base management systems and consist of data "fields" separated by commas. Character fields are also enclosed in double quotation marks (") and are padded with spaces to keep quotation marks in the same columns of successive records. 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 in tabular files have 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 text file with embedded line delimiters on those that don't. All tabular files are accompanied by descriptive detached PDS labels. The PDS label 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. 3.3.4 Catalog files Catalog files (suffix .CAT) exist in the root and CATALOG directories. They are formatted in an object-oriented structure consisting of sets of "keyword=value" declarations. VOLDESC.CAT provides an overview of the contents of the volume in the form of a completed PDS template. The files in the CATALOG directory provide a top-level understanding of the Mars Global Surveyor Radio Science instrument and each of the Science Data Products included within the volume. They are presented in the form of completed PDS templates. 4. Detailed Interface Specifications 4.1 Root Files 4.1.1 AAREADME.TXT File The AAREADME.TXT file contains terse volume content and format information. This is an ASCII file with record lengths of 80 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file has an attached PDS label of the form shown in Figure 4-1-1. |================================================================| | | | Figure 4-1-1 Example Label for MGS RS EDS TXT Files | | | |================================================================| | | | PDS_VERSION_ID = PDS3 | | RECORD_TYPE = FIXED_LENGTH | | RECORD_BYTES = 80 | | OBJECT = TEXT | | PUBLICATION_DATE = 1998-01-25 | | NOTE = "Pre-launch description of science | | investigations, instruments, and | | experimental methods planned by | | the MGS Radio Science Team." | | END_OBJECT = TEXT | |================================================================| Labeling requirements applicable to Figure 4-1-1 are described in [2]; keywords are defined in [3]. For this application, the only keywords that change are PUBLICATION_DATE the date in YYYY-MM-DD format on which the document was published or released (see Section 1.5.3). NOTE a brief description of the document, including a title if available. 4.1.2 ERRATA.TXT File ERRATA.TXT contains a cumulative listing of comments and updates concerning the CD-WO volumes in the data set as of the publication date. This is an ASCII file with record lengths of 80 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file has an attached PDS label of the form shown in Figure 4-1-1. 4.1.3 VOLDESC.CAT File VOLDESC.CAT contains a description of the contents of the logical volume in a PDS format readable by both humans and computers. This is an ASCII file with record lengths of 80 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. An example VOLDESC.CAT file is shown in Figure 4-1-3. Keywords are defined below. |===========================================================================| | | | Figure 4-1-3 Example VOLDESC.CAT File | | | |===========================================================================| |PDS_VERSION_ID = PDS3 | |RECORD_TYPE = FIXED_LENGTH | |RECORD_BYTES = 80 | |OBJECT = VOLUME | | VOLUME_SERIES_NAME = "MISSION TO MARS" | | VOLUME_SET_NAME = "MGS RADIO SCIENCE - SCIENCE DATA PRODUCTS" | | VOLUME_SET_ID = USA_NASA_JPL_MORS_1102 | | VOLUMES = 1 | | MEDIUM_TYPE = "CD-WO" | | VOLUME_FORMAT = "ISO-9660" | | VOLUME_NAME = "MGS RS EDS ARCHIVE" | | VOLUME_ID = MORS_1102 | | VOLUME_VERSION_ID = "VERSION 1" | | PUBLICATION_DATE = 2007-09-27 | | DATA_SET_ID = "MGS-M-RSS-5-EDS-V1.0" | | DESCRIPTION = "MORS_1101 contains the complete collection | | of Mars Global Surveyor radio occultation | | ionosphere electron density profiles | | reorganized into a single archival volume." | | MISSION_NAME = "MARS GLOBAL SURVEYOR" | | INSTRUMENT_HOST_NAME = "MARS GLOBAL SURVEYOR" | | INSTRUMENT_HOST_ID = MGS | | OBJECT = DATA_PRODUCER | | INSTITUTION_NAME = "STANFORD UNIVERSITY" | | FACILITY_NAME = "MGS RST REMOTE MISSION SUPPORT AREA" | | FULL_NAME = "RICHARD A. SIMPSON" | | ADDRESS_TEXT = "PACKARD BUILDING - ROOM 332 | | STANFORD UNIVERSITY | | STANFORD, CA 94305-4020" | | END_OBJECT = DATA_PRODUCER | | OBJECT = CATALOG | | ^MISSION_CATALOG = "MISSION.CAT" | | ^INSTRUMENT_HOST_CATALOG = "INSTHOST.CAT" | | ^INSTRUMENT_CATALOG = "INST.CAT" | | ^DATA_SET_CATALOG = "DATASET.CAT" | | ^PERSONNEL_CATALOG = "PERSON.CAT" | | ^REFERENCE_CATALOG = "REF.CAT" | | ^TARGET_CATALOG = "TARGET.CAT" | | END_OBJECT = CATALOG | |END_OBJECT = VOLUME | |END | |===========================================================================| 4.2 Static Directories Static directories are those which do not change (or change very little) from one volume to another. They appear on all volumes. 4.2.1 CATALOG Directory 4.2.1.1 CATINFO.TXT File The CATINFO.TXT file contains a brief description of the contents of the CATALOG directory. This is an ASCII file with record lengths of 80 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file has an attached PDS label of the form shown in Figure 4-1-1. 4.2.1.2 MISSION.CAT File The MISSION.CAT file contains a brief description of the MGS mission, its phases, and its objectives. This is an ASCII file with record lengths of 72 bytes. Each line is terminated with a carriage-return (ASCII 13) line- feed (ASCII 10) pair. The file follows the format for 'streamlined' catalog files as described in [2]. 4.2.1.3 INSTHOST.CAT File The INSTHOST.CAT file contains a brief description of the spacecraft; it also includes a brief description of the NASA Deep Space Network (DSN) as it supports the MGS Radio Science investigations. This is an ASCII file with record lengths of 72 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file follows the format for 'streamlined' catalog files as described in [2]. 4.2.1.4 INST.CAT File The INST.CAT file contains a description of the spacecraft and DSN radio systems. This is an ASCII file with record lengths of 72 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file follows the format for 'streamlined' catalog files as described in [2]. 4.2.1.5 DATASET.CAT File The DATASET.CAT file contains a brief description of the reduced radio science data within the MGS RS EDS volume. This is an ASCII file with record lengths of 72 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file follows the format for 'streamlined' catalog files as described in [2]. 4.2.1.6 PERSON.CAT File The PERSON.CAT file contains a brief description of the key individuals involved in producing both the data and the archival volumes of the MGS RS EDS volume. This is an ASCII file with record lengths of 72 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file follows the format for 'streamlined' catalog files as described in [2]. 4.2.1.7 REF.CAT File The REF.CAT file contains full literature citations for publications referenced in other files in the CATALOG directory. This is an ASCII file with record lengths of 72 bytes. Each line is terminated with a carriage- return (ASCII 13) line-feed (ASCII 10) pair. The file follows the format for 'streamlined' catalog files as described in [2]. 4.2.1.8 TARGET.CAT File The TARGET.CAT file contains a brief description of the bodies which were the object of this scientific investigation (Mars). This is an ASCII file with record lengths of 72 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file follows the format for 'streamlined' catalog files as described in [2]. 4.2.2 DOCUMENT Directory The DOCUMENT directory contains ASCII files which describe in more detail the format and content of the data products in this archival volume. 4.2.2.1 DOCINFO.TXT File The DOCINFO.TXT file contains a brief description of the contents of the DOCUMENT directory. This is an ASCII file with record lengths of 80 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file has an attached PDS label of the form shown in Figure 4-1-1. 4.2.2.2 EDS_VOLM.TXT File The EDS_VOLM.TXT file (this document) is the Software Interface Specification for the MGS RS EDS volume. It describes both the format and content of this archival volume. This is an ASCII file with record lengths of 80 bytes. Each line is terminated with a carriage-return (ASCII 13) line- feed (ASCII 10) pair. The file has an attached PDS label of the form shown in Figure 4-1-1. 4.2.2.3 OCCLOG.TAB File The OCCLOG.TAB file gives parameters from data acquisition that may be useful in judging quality of radio occultation data. This is an ASCII file with fixed length records. Each line is terminated with a carriage- return (ASCII 13) line-feed (ASCII 10) pair. The file has a detached label with the name OCCLOG.LBL which completely describes its format and content. 4.2.3 INDEX Directory 4.2.3.1 INDXINFO.TXT File The INDXINFO.TXT file contains a brief description of the contents of the INDEX directory. This is an ASCII file with record lengths of 80 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The file has an attached PDS label of the form shown in Figure 4- 1-1. 4.2.3.2 INDEX.LBL File INDEX.LBL is a detached label that describes INDEX.TAB; it is an ASCII file with record lengths of 80 bytes. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. 4.2.3.3 INDEX.TAB File INDEX.TAB is a PDS TABLE listing all data files included in this volume. It is an ASCII file with fixed length records. Each line is terminated with a carriage-return (ASCII 13) line-feed (ASCII 10) pair. The format and content of INDEX.TAB are described in detail by INDEX.LBL. 4.3 Data Directories The MGS RS EDS volume includes electron density profiles for the ionosphere of Mars derived from radio occultation data. It also includes a cumulative summary of these profiles. 4.3.1 EDS Directory The EDS directory contains ionospheric electron density profiles derived from radio occultation data using standard processing techniques. Each EDS file is an ASCII table with fixed-length records giving results from a single occultation. Each file is accompanied by a detached PDS label which gives a detailed description of the EDS file. 4.3.2 OCS Directory The OCS directory contains a summary of EDS results. The OCS file is an ASCII table with fixed-length records. The file contains 5600 summary records, one for every EDS profile derived during the MGS mission. The OCS file is accompanied by a detached PDS label which gives a detailed description of the OCS file. 5. Support Staff and Cognizant Personnel The following persons may be contacted for information. Radio Science Team Richard A. Simpson, MGS Radio Science Team Experiment Engineer and PDS Radio Science Advisor Packard Building - Room 332 350 Serra Mall Stanford University Stanford, CA 94305-4020 Phone: 650-723-3525 FAX: 650-723-9251 Electronic mail: rsimpson@magellan.stanford.edu David P. Hinson, MGS RST Atmospheric Lead Investigator Packard Building - Room 333 350 Serra Mall Stanford University Stanford, CA 94305-4020 Phone: 650-723-3534 FAX: 650-723-9251 Electronic mail: dhinson@stanford.edu or David P. Hinson, MGS RST Atmospheric Lead Investigator SETI Institute 515 North Whisman Rd Mountain View, CA 94043 Phone: 650-810-0217 Electronic Maildhinson@seti.org G. Leonard Tyler, MGS Radio Science Team Leader Packard Building - Room 331 350 Serra Mall Stanford University Stanford, CA 94305-4020 Phone: 650-723-3535 FAX: 650-723-9251 Electronic mail: len.tyler@stanford.edu