PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 OBJECT = TEXT PUBLICATION_DATE = 2001-03-20 NOTE = "Software Interface Specification for the Mars Global Surveyor Radio Science Electron Density Profile (RSED) file. Formatted for display or printing at 58 lines per page with up to 78 constant width characters per line." END_OBJECT = TEXT END Stanford Center for Radar Astronomy Mars Global Surveyor Project Software Interface Specification Ionospheric Electron Density Profile Data File prepared by Richard A. Simpson Center for Radar Astronomy Stanford University Stanford, CA 94305-9515 650-723-3525 Version 1.0.1 20 March 2001 PREFACE |====================================================================| | | | DOCUMENT CHANGE LOG | | | |====================================================================| |REVISION|REVISION| SECTION | REMARKS | | NUMBER | DATE | AFFECTED | | |--------+--------+------------+-------------------------------------| | 1.0 |00/08/09| All |Adapted from RSTP V2.0.5 SIS | |--------+--------+------------+-------------------------------------| | 1.0.1 |01/03/20| 2.1.1 |Repair typos: double period; change | | | | 2.3 | "TP" and "temperature pressure" to | | | | 4.2.1 | "ED" and "electron density"; correct| | | | Fig 4-2 | line number for ^RSED_TABLE (twice).| |====================================================================| |====================================================================| | | | ITEMS TO BE DETERMINED | | | |====================================================================| | REVISION | SECTION | ITEM DESCRIPTION | RESOLUTION | | NUMBER | AFFECTED | | | |----------+----------+------------------------+---------------------| | 1.0 | | | | |====================================================================| Distribution PDS/JPL J. Wilf...............171-264 joel.wilf@jpl.nasa.gov M. Martin.............171-264 michael.d.martin@jpl.nasa.gov PDS/NMSU R. Beebe......Dept. Astronomy rbeebe@nmsu.edu L. Huber......Dept. Astronomy lhuber@nmsu.edu PDS/PPI R.J. Walker...........IGPP UCLA rwalker@igpp.ucla.edu S.P. Joy..............IGPP UCLA sjoy@igpp.ucla.edu Stanford University R. Simpson........Packard 332 rsimpson@magellan.stanford.edu L. Tyler..........Packard 331 len.tyler@stanford.edu D.P. Hinson.........Packard 333 hinson@nimbus.stanford.edu J.D. Twicken........Packard 321 joe@neptune.stanford.edu Jet Propulsion Laboratory S.W. Asmar...........MS 264-860 sami.w.asmar@jpl.nasa.gov A. Anabtawi........MS 264-860 aseel@godzilla.jpl.nasa.gov R. Springer........MS 264-214 richard.j.springer@jpl.nasa.gov R. Woo.............MS 238-725 richard@oberon.jpl.nasa.gov Contents Preface.............................................................ii Document Change Log...............................................ii Items to be Determined............................................ii Distribution.....................................................iii Contents..........................................................iv Acronyms and Abbreviations.........................................v 1. General Description...............................................1 1.1. Overview......................................................1 1.2. Scope.........................................................1 1.3. Applicable Documents..........................................1 1.4. System Siting.................................................1 1.4.1. Interface Location and Medium.............................1 1.4.2. Data Sources, Transfer Methods, and Destinations..........1 1.4.3. Generation Method and Frequency...........................1 1.5. Assumptions and Constraints...................................2 1.5.1. Usage Constraints.........................................2 1.5.2. Priority Phasing Constraints..............................2 1.5.3. Explicit and Derived Constraints..........................2 1.5.4. Documentation Conventions.................................2 1.5.4.1. Data Format Descriptions..............................2 1.5.4.2. Time Standards........................................2 1.5.4.3. Coordinate Systems....................................3 1.5.4.4. Limits of This Document...............................3 1.5.4.5. Typographic Conventions...............................3 2. Interface Characteristics.........................................4 2.1. Hardware Characteristics and Limitations......................4 2.1.1. Special Equipment and Device Interfaces...................4 2.1.2. Special Setup Requirements................................4 2.2. Volume and Size...............................................4 2.3. Labeling and Identification...................................4 2.4. Interface Medium Characteristics..............................5 2.5. Failure Protection, Detection, and Recovery Procedures........5 2.6. End-of-File Conventions.......................................5 3. Access............................................................6 3.1. Programs Using the Interface..................................6 3.2. Synchronization Considerations................................6 3.2.1. Timing and Sequencing Considerations......................6 3.2.2. Effective Duration........................................6 3.2.3. Priority Interrupts.......................................6 3.3. Input/Output Protocols, Calling Sequences.....................6 4. Detailed Interface Specifications.................................7 4.1. Structure and Organization Overview...........................7 4.2. Detached PDS Label............................................7 4.2.1. Label Header..............................................7 4.2.2. Label Body................................................9 4.3. Data File.....................................................9 Appendix A. Example Label..........................................10 Appendix B. Example Data Object................ ...................18 Figures 4-2. RSED Label Header.............................................7 Acronyms and Abbreviations ANSI American National Standards Institute ARCDR Altimetry and Radiometry Composite Data Record ASCII American Standard Code for Information Interchange CCSDS Consultative Committee for Space Data Systems CD Compact Disc CNES Centre National d'Etudes Spatiales dB Decibel DSN Deep Space Network EDH Electron Density High resolution (directory or file) EDS Electron Density Standard resolution (directory or file) FEA Front End Assembly GSFC Goddard Space Flight Center IEEE Institute of Electrical and Electronic Engineers IAU International Astronomical Union JPL Jet Propulsion Laboratory J2000 IAU Official Time Epoch K Degrees Kelvin kB Kilobytes km Kilometers MB Megabytes MGS Mars Global Surveyor MO Mars Observer NAIF Navigation and Ancillary Information Facility NASA National Aeronautics and Space Administration NAV Navigation Subsystem/Team PDB Project Data Base PDS Planetary Data System RS Radio Science RSED Radio Science Electron Density (profile) RSS Radio Science Subsystem RST Radio Science Team SCET Space Craft Event Time SIS Software Interface Specification SOPC Science Operations Planning Computer SPARC Sun Scaleable Processor Architecture TBD To Be Determined TDB Temps Dynamique Barycentrique - IAU Standard Ephemeris Time UTC Coordinated Universal Time WO Write Once 1. General Description 1.1. Overview This Software Interface Specification (SIS) describes Radio Science Ionospheric Electron Density Profile (RSED) data files from the Mars Global Surveyor (MGS) Mission. RSED files are created at Stanford University and contain results of processing MGS radio occultation data to obtain the structure of Mars' ionosphere [1]. The Mars Global Surveyor Mission is managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration (NASA). 1.2. Scope The format and content specifications in this SIS apply to all phases of the Mars Global Surveyor Mission for which the RSED is produced. 1.3. Applicable Documents [1] Tyler, G.L., G. Balmino, D.P. Hinson, W.L. Sjogren, D.E. Smith, R. Woo, S.W. Asmar, M.J. Connally, C.L. Hamilton, and R.A. Simpson, Radio Science Investigations with Mars Observer, J. Geophys. Res., 97, 7759-7779, 1992. [2] MO 642-321, Mars Global Surveyor Planetary Constants and Models, JPL D-3444, November 1990. [3] Planetary Science Data Dictionary, JPL D-7116, Rev. D, 15 July 1996. [4] Planetary Data System Standards Reference, JPL D-7669, part 2, 24 July 1995. 1.4. System Siting 1.4.1. Interface Location and Medium RSED files are created by the Stanford MGS RS processing system, which consists of Sun Ultra 2, Ultra 5, and SPARC-10 workstations; other computers; and associated peripherals. 1.4.2. Data Sources, Transfer Methods, and Destinations RSED files are created on the Stanford MGS RS processing system. They are distributed electronically by the MGS RS server and are written to compact disc write-once (CD-WO) volumes for archive with the Planetary Data System (PDS). 1.4.3. Generation Method and Frequency EDS products are generated by reformatting and manipulating output files from Stanford programs. Each RSED contains data from one occultation event. RSED files are generated when the data for the appropriate orbits become available. 1.5. Assumptions and Constraints 1.5.1. Usage Constraints None. 1.5.2. Priority Phasing Constraints None. 1.5.3. Explicit and Derived Constraints None. 1.5.4. Documentation Conventions 1.5.4.1. Data Format Descriptions The reference data unit is the byte. Data may be stored in fields with various sizes and formats, viz. one-, two-, and four-byte binary integers, four- and eight-byte binary floating-point numbers, and character strings. Data are identified throughout this document as char 8 bits character uchar 8 bits integer short 16 bits integer long 32 bits integer float 32 bits floating point (sign, exponent, and mantissa) double 64 bits floating point (sign, exponent, and mantissa) u (prefix) unsigned (as with ulong for unsigned 32-bit integer) other special data structures such as time, date, etc. which are described within this document The detailed formats of the numeric fields are defined in Appendix A. 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 second character, and so forth. An array of n elements is written as array[n]; the first element is array[0], and the last is array[n-1]. Array[n][m] describes an n x m element array, with first element array[0][0], second element array[0][1], and so forth. 1.5.4.2. Time Standards RSED calculations use the January 1.5, 2000 epoch as the standard time. Within the data files, all times are reported in Universal Coordinated Time (UTC) as strings of 23 ASCII characters. The time format is "YYYY-MM-DDThh:mm:ss.fff", where "-", "T", ":", and "." are fixed delimiters; "YYYY" is the year "19nn" or "20nn"; "MM" is a two-digit month of year; "DD" is a two-digit day of month; "T" separates the date and time segments of the string; "hh" is hour of day; "mm" is the minutes of hour (00-59); "ss" is the seconds of hour (00-59); and "fff" is in milliseconds. Optional suffix "Z" explicitly indicates use of the UTC reference. The date format is "YYYY-MM-DD", where the components are defined as above. 1.5.4.3. Coordinate Systems The RSED uses the Areocentric fixed body coordinate system [2]. 1.5.4.4. Limits of This Document This document applies only to the RSED product. 1.5.4.5. Typographic Conventions This document has been formatted for simple electronic file transfer and display. Line lengths are limited to 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 RSED files are created on Stanford MGS computers using IEEE formats and are stored on CD-WO media. 2.1.2. Special Setup Requirements None. 2.2. Volume and Size A standard resolution RSED file (Electron Density Standard, or EDS) requires about 15 kB for the label and 5 kB for the data -- or 20 kB total. A high resolution file (EDH) has the same size label and requires about 50 kB for the data. 2.3. Labeling and Identification Each file has a name which describes its contents. The name includes the following structure which uniquely identifies it among Mars Global Surveyor Radio Science products: ydddhmmC.EDx where y is the least significant digit of the year ddd is the day of year h is a one character representation of the hour on which data acquisition began (A = 00, B = 01, ... X = 23) mm is the minute on which the occultation data acquisition began (see note below for convention when two acquisition systems began at the same minute) C is a single character denoting the version of the file (first version is "A", second is "B", etc.) "ED" identifies the file as containing a Radio Science electron density profile, "x" indicates resolution "S" standard resolution "H" high resolution Note: Some occultations may be captured by more than one ground station with recording beginning at the same time. In those cases the least significant digit of mm will be modified as follows. Least Significant Digit of "mm" for Coincident Files First Data File Second Data File Third Data File --------------- ---------------- --------------- 0 A K 1 B L 2 C M 3 D N 4 E O 5 F P 6 G Q 7 H R 8 I S 9 J T 2.4. Interface Medium Characteristics RSED products are electronic files. 2.5. Failure Protection, Detection, and Recovery Procedures None. 2.6. End-of-File Conventions End of file labeling complies with standards for the media in use. 3. Access 3.1. Programs Using the Interface Data contained in RSED files will be accessed by programs at the home institutions of Mars Global Surveyor and other investigators. Those programs cannot be identified here. 3.2. Synchronization Considerations 3.2.1. Timing and Sequencing Considerations N/A 3.2.2. Effective Duration N/A 3.2.3. Priority Interrupts None. 3.3. Input/Output Protocols, Calling Sequences None. 4. Detailed Interface Specifications 4.1. Structure and Organization Overview The RSED is a file generated by Radio Science data reduction and analysis software at Stanford University. Each RSED file is accompanied by a detached PDS label. 4.2. Detached PDS Label The detached PDS label has two parts -- a header and body. The header contains information about the origin of the file and its general characteristics such as record type and size. The body is a complete bit-level definition of the RSED file; it includes object definitions for each component of the RSED file. Each detached PDS label is constructed of ASCII records; each record contains exactly 80 characters. The last two characters in each record are the carriage-return (ASCII 13) and line-feed (ASCII 10) characters. 4.2.1 Label Header The structure of the label file header is illustrated in Figure 4-2. Keyword definitions are given below. An example of a complete label file is given in Appendix B. |====================================================================| | | | Figure 4-2. RSED Label Header | | | |====================================================================| | | | PDS_VERSION_ID = PDS3 | | RECORD_TYPE = FIXED_LENGTH | | RECORD_BYTES = 56 | | FILE_RECORDS = nnn | | ^RSED_HDR_TABLE = ("ydddhmmC.EDx",1) | | ^RSED_TABLE = ("ydddhmmC.EDx",6) | | INSTRUMENT_HOST_NAME = "MARS GLOBAL SURVEYOR" | | TARGET_NAME = "MARS" | | INSTRUMENT_NAME = "RADIO SCIENCE SUBSYSTEM" | | DATA_SET_ID = "MGS-M-RSS-5-SDP-Vn.m" | | PRODUCT_ID = "ydddhmmC.EDx" | | PRODUCT_RELEASE_DATE = YYYY-MM-DD | | DESCRIPTION = "cccccccccccccccccc" | | START_TIME = YYYY-MM-DDThh:mm:ss.fffZ | | STOP_TIME = YYYY-MM-DDThh:mm:ss.fffZ | | SOFTWARE_NAME = "ccccccc;Vn.m" | | PRODUCT_CREATION_TIME = YYYY-MM-DDThh:mm:ss.fffZ | | PRODUCER_ID = "MGS RST" | | | |====================================================================| PDS_VERSION_ID = The version of the Planetary Data System for which these data have been prepared (set to PDS3 by agreement between the Mars Global Surveyor Project and PDS). RECORD_TYPE = The type of record. Set to "FIXED_LENGTH" to indicate that all logical records have the same length. RECORD_BYTES = The number of bytes per (fixed-length) record. Set to "56" for the RSED. FILE_RECORDS = The number of records in the RSED file; instance dependent. ^RSED_HDR_TABLE = File name and record number at which RSED_HDR_TABLE begins. The file naming convention is defined in Section 2.3; record number is 1. ^RSED_TABLE = File name and record number at which RSED_TABLE begins. The file naming convention is defined in Section 2.3; record number is 6. INSTRUMENT_HOST_NAME = Name of the spacecraft; set to "MARS GLOBAL SURVEYOR". TARGET_NAME = A character string which identifies the target body. For MGS RSED files, the character string "MARS". INSTRUMENT_NAME = Name of the instrument; set to "RADIO SCIENCE SUBSYSTEM". DATA_SET_ID = Identifier for the data set of which this RSED product is a member. Set to "MGS-M- RSS-5-SDP-Vn.m" for the RSED, where "Vn.m" indicates the version number of the data set. PRODUCT_ID = A unique identifier for the product within the MGS RST collection of data sets. The naming convention is defined in Section 2.3. PRODUCT_RELEASE_DATE = The date at which the product may be released by the Mars Global Surveyor Project to the Planetary Data System; entered in the format "YYYY-MM-DD", where components are defined in Section 1.5.4.2. DESCRIPTION = A short description of the RSED product. START_TIME = The Earth Receive Time at which the first sample was acquired expressed in the format "YYYY-MM-DDThh:mm:ss.fff" where the components are defined in Section 1.5.4.2. STOP_TIME = The Earth Receive Time at which the last sample was acquired expressed in the format "YYYY-MM-DDThh:mm:ss.fff" where the components are defined in Section 1.5.4.2. SOFTWARE_NAME = The name and version number of the program creating this RSED file; expressed as a character string in the format "PROGRAM_NAME;n.mm" where "PROGRAM_NAME" is the name of the software and "n.mm" is the version number. PRODUCT_CREATION_TIME = The time at which this RSED was created; expressed in the format "YYYY-MM- DDThh:mm:ss.fff" where the components are defined in Section 1.5.4.2. PRODUCER_ID = The entity responsible for creation of the RSED product; set to "MGS RST". 4.2.2 Label Body The body of the PDS label completely defines both the format and the content of the RSED file. It is written as a pair of OBJECT definitions -- one for the RSED header table and one for the RSED data table. An example of a complete label is given in Appendix B. Since the format and content of the RSED file may vary over the course of the MGS mission, users should always refer to the accompanying label for current specifications of the RSED file. 4.3. Data File The RSED data file contains ionospheric profile measurements from one occultation event. It comprises two PDS TABLE objects -- one containing summary information for an occultation and the other containing the electron density profile itself. The structure and content of each RSED file is defined by the accompanying detached PDS label (see Section 4.2 and Appendix B). Note that the format and content of the RSED file may evolve over the course of the MGS mission; users should always refer to the accompanying PDS label for current format and content specifications. Appendix A. Example RSED Label The following is an example label for a Radio Science Electron Density (RSED) file. In Appendix B, the corresponding data object is shown. PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 56 FILE_RECORDS = 87 ^RSED_HDR_TABLE = ("8358D47A.EDS",1) ^RSED_TABLE = ("8358D47A.EDS",6) INSTRUMENT_HOST_NAME = "MARS GLOBAL SURVEYOR" TARGET_NAME = "MARS" INSTRUMENT_NAME = "RADIO SCIENCE SUBSYSTEM" DATA_SET_ID = "MGS-M-RSS-5-SDP-V1.0" PRODUCT_ID = "8358D47A.EDS" PRODUCT_RELEASE_DATE = 2000-08-08 DESCRIPTION = "This file contains an ionospheric electron density profile derived from MGS radio occultation data. Raw samples of DSN receiver output were corrected for observing conditions and converted to bending angle as a function of impact parameter. These results were then inverted to refractive index as a function of radius via an Abel transform. Electron number density was obtained from refractive index using a conversion formula appropriate to the measurement frequency (8423 MHz). See Hinson et al. (J. Geophys. Res., 104, 26997-27012, 1999; J. Geophys. Res., 103, 9505-9520, 1998) for more details." START_TIME = 1998-12-24T03:47:00Z STOP_TIME = 1998-12-24T04:08:00Z SOFTWARE_NAME = "EDS; V1.1" PRODUCT_CREATION_TIME = 2000-08-08T23:11:36Z PRODUCER_ID = "MGS RST" OBJECT = RSED_HDR_TABLE ROWS = 1 COLUMNS = 25 ROW_BYTES = 280 INTERCHANGE_FORMAT = ASCII DESCRIPTION = "The RSED header contains ancillary data associated with ionospheric electron density profiles. Each header includes a single row of 25 data columns delimited by ASCII commas (263 total bytes), 15 ASCII blank characters to pad out the record, and an ASCII carriage-return line-feed pair at the end." OBJECT = COLUMN NAME = "START TIME" COLUMN_NUMBER = 1 DATA_TYPE = TIME START_BYTE = 1 BYTES = 23 UNIT = "N/A" DESCRIPTION = "The Earth Receive Time at which the first radio occultation data sample was acquired." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "STOP TIME" COLUMN_NUMBER = 2 DATA_TYPE = TIME START_BYTE = 25 BYTES = 23 UNIT = "N/A" DESCRIPTION = "The Earth Receive Time at which the last radio occultation data sample was acquired." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "OCCULTATION TIME" COLUMN_NUMBER = 3 DATA_TYPE = TIME START_BYTE = 49 BYTES = 23 UNIT = "N/A" DESCRIPTION = "The time at Mars when the experiment was sounding the ionosphere at 130 km altitude. This is computed by subtracting the Mars-to-Earth light time from the appropriate Earth Receive Time." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "ORBIT NUMBER" COLUMN_NUMBER = 4 DATA_TYPE = ASCII_INTEGER START_BYTE = 73 BYTES = 5 FORMAT = "I5" UNIT = "N/A" DESCRIPTION = "Orbit number from which the data were acquired; set to zero if not known." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "DSN ANTENNA NUMBER" COLUMN_NUMBER = 5 DATA_TYPE = ASCII_INTEGER START_BYTE = 79 BYTES = 2 FORMAT = "I2" UNIT = "N/A" DESCRIPTION = "Number of the DSN antenna used to collect the data (e.g., 14, 43, 65, ...)." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "RAY PATH DIRECTION" COLUMN_NUMBER = 6 DATA_TYPE = ASCII_REAL START_BYTE = 82 BYTES = 6 FORMAT = "F6.1" UNIT = "DEGREE" DESCRIPTION = "The angle between local north and the direction of radio signal propagation at the point of closest approach to Mars. Angle is measured positive from local north toward local east. A signal traveling from west toward east would have a ray-path-direction of 90 degrees." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "ANGLE FROM DIAMETRIC" COLUMN_NUMBER = 7 DATA_TYPE = ASCII_REAL START_BYTE = 89 BYTES = 6 FORMAT = "F6.1" UNIT = "DEGREE" DESCRIPTION = "Angle at which the spacecraft rises or sets behind the planet limb, measured clockwise from the planet radial direction as viewed from Earth. An angle- from-diametric equal to zero indicates a diametric occultation with motion of the ray away from the surface (e.g., occultation egress). A value near 180 degrees is a nearly diametric ingress occultation." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "LATITUDE OF PROFILE" COLUMN_NUMBER = 8 DATA_TYPE = ASCII_REAL START_BYTE = 96 BYTES = 7 FORMAT = "F7.3" UNIT = "DEGREE" DESCRIPTION = "Areocentric (north) latitude where the experiment sounded the ionosphere at 130 km altitude." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SIGMA LATITUDE" COLUMN_NUMBER = 9 DATA_TYPE = ASCII_REAL START_BYTE = 104 BYTES = 6 FORMAT = "F6.3" UNIT = "DEGREE" DESCRIPTION = "One standard deviation uncertainty in LATITUDE OF PROFILE. This value also serves as an estimate of the uncertainty in LATITUDE in RSED_TABLE. Set to -9.999 if not known." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "LONGITUDE OF PROFILE" COLUMN_NUMBER = 10 DATA_TYPE = ASCII_REAL START_BYTE = 111 BYTES = 8 FORMAT = "F8.3" UNIT = "DEGREE" POSITIVE_LONGITUDE_DIRECTION = "EAST" DESCRIPTION = "Areocentric east longitude where the experiment sounded the ionosphere at 130 km altitude." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SIGMA LONGITUDE" COLUMN_NUMBER = 11 DATA_TYPE = ASCII_REAL START_BYTE = 120 BYTES = 6 FORMAT = "F6.3" UNIT = "DEGREE" DESCRIPTION = "One standard deviation uncertainty in LONGITUDE OF PROFILE. This value also serves as an estimate of the uncertainty in LONGITUDE in RSED_TABLE. Set to -9.999 if not known." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SUB-SOLAR LATITUDE" COLUMN_NUMBER = 12 DATA_TYPE = ASCII_REAL START_BYTE = 127 BYTES = 6 FORMAT = "F6.2" UNIT = "DEGREE" DESCRIPTION = "Areocentric (north) latitude of the sun at OCCULTATION TIME." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SUB-SOLAR LONGITUDE" COLUMN_NUMBER = 13 DATA_TYPE = ASCII_REAL START_BYTE = 134 BYTES = 7 FORMAT = "F7.2" UNIT = "DEGREE" POSITIVE_LONGITUDE_DIRECTION = "EAST" DESCRIPTION = "Areocentric east longitude of the sun in body fixed coordinates at OCCULTATION TIME." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SOLAR LONGITUDE" COLUMN_NUMBER = 14 DATA_TYPE = ASCII_REAL START_BYTE = 142 BYTES = 6 FORMAT = "F6.2" UNIT = "DEGREE" DESCRIPTION = "Value of the angle between the Mars-Sun line at OCCULTATION TIME and the Mars-Sun line at the Mars vernal equinox. Measured positive with increasing time following the vernal equinox. Sometimes denoted L-sub-s." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SPACECRAFT TO LIMB DISTANCE" COLUMN_NUMBER = 15 DATA_TYPE = ASCII_REAL START_BYTE = 149 BYTES = 9 FORMAT = "E9.3" UNIT = "METER" DESCRIPTION = "Distance along ray path from spacecraft to point of closest approach to Mars. Measured at time when experiment was sounding the ionosphere at 130 km altitude." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SPACECRAFT TO DSN DISTANCE" COLUMN_NUMBER = 16 DATA_TYPE = ASCII_REAL START_BYTE = 159 BYTES = 9 FORMAT = "E9.3" UNIT = "METER" DESCRIPTION = "Distance from spacecraft to DSN receiving antenna at time when experiment was sounding the ionosphere at 130 km altitude." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "MARS TO SUN DISTANCE" COLUMN_NUMBER = 17 DATA_TYPE = ASCII_REAL START_BYTE = 169 BYTES = 9 FORMAT = "E9.3" UNIT = "METER" DESCRIPTION = "Distance from Mars to Sun at OCCULTATION TIME." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "LOCAL TRUE SOLAR TIME" COLUMN_NUMBER = 18 DATA_TYPE = ASCII_REAL START_BYTE = 179 BYTES = 6 FORMAT = "F6.3" UNIT = "HOUR" DESCRIPTION = "Local true solar time (LTST) at the time and location of the occultation measurement. LTST at the sub-solar longitude is defined as 12 solar hours. LTST on other meridians changes by one solar hour for each 15 degree increment in longitude. Thus, LTST for the occultation measurement is given by 12 + (LONGITUDE_OF_PROFILE - SUB-SOLAR_LONGITUDE)/15." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SOLAR ZENITH ANGLE" COLUMN_NUMBER = 19 DATA_TYPE = ASCII_REAL START_BYTE = 186 BYTES = 6 FORMAT = "F6.2" UNIT = "DEGREE" DESCRIPTION = "Angle between the direction to Sun and local vertical direction on Mars at time and location of the occultation measurement." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SUN-EARTH-SPACECRAFT ANGLE" COLUMN_NUMBER = 20 DATA_TYPE = ASCII_REAL START_BYTE = 193 BYTES = 5 FORMAT = "F5.1" UNIT = "DEGREE" DESCRIPTION = "Approximate angle between Sun and spacecraft as viewed from Earth during experiment." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "DSN ELEVATION ANGLE" COLUMN_NUMBER = 21 DATA_TYPE = ASCII_REAL START_BYTE = 199 BYTES = 5 FORMAT = "F5.1" UNIT = "DEGREE" DESCRIPTION = "Approximate angle between direction to spacecraft and local horizon at DSN receiving antenna during experiment." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "GRAVITY FIELD MODEL" COLUMN_NUMBER = 22 DATA_TYPE = CHARACTER START_BYTE = 206 BYTES = 12 FORMAT = "A12" UNIT = "N/A" DESCRIPTION = "File name of gravity field spherical harmonic model used in defining reference areoid." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "PCK FILE NAME" COLUMN_NUMBER = 23 DATA_TYPE = CHARACTER START_BYTE = 221 BYTES = 12 FORMAT = "A12" UNIT = "N/A" DESCRIPTION = "File name of the NAIF Planetary Constants File used in this retrieval and calculation (name of the PCK file as stored in the MGS RST data system)." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "TRAJECTORY FILE NAME" COLUMN_NUMBER = 24 DATA_TYPE = CHARACTER START_BYTE = 236 BYTES = 12 FORMAT = "A12" UNIT = "N/A" DESCRIPTION = "File name of the spacecraft and planetary ephemeris file used in this retrieval and calculation (name of the file as stored in the MGS RST data system)." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SPACECRAFT ATTITUDE FILE NAME" COLUMN_NUMBER = 25 DATA_TYPE = CHARACTER START_BYTE = 251 BYTES = 12 FORMAT = "A12" UNIT = "N/A" DESCRIPTION = "File name of the spacecraft attitude file used in this retrieval and calculation (name of the file as stored in the MGS RST data system). Left blank if not known or no attitude file was used." END_OBJECT = COLUMN END_OBJECT = RSED_HDR_TABLE OBJECT = RSED_TABLE ROWS = 82 COLUMNS = 6 ROW_BYTES = 56 INTERCHANGE_FORMAT = ASCII DESCRIPTION = "Table contains radio science ionospheric electron density profile. Each row in the table contains data for 6 columns delimited by ASCII commas (54 bytes total) and an ASCII carriage-return line-feed pair at the end." OBJECT = COLUMN NAME = "RADIUS" COLUMN_NUMBER = 1 DATA_TYPE = ASCII_REAL START_BYTE = 1 BYTES = 8 FORMAT = "F8.0" UNIT = "METER" DESCRIPTION = "Measurement radius." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "ALTITUDE" COLUMN_NUMBER = 2 DATA_TYPE = ASCII_REAL START_BYTE = 10 BYTES = 7 FORMAT = "F7.0" UNIT = "METER" DESCRIPTION = "Altitude of measurement above reference areoid. The reference areoid is the equipotential surface whose mean equatorial radius is 3,396,000 m." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "LATITUDE" COLUMN_NUMBER = 3 DATA_TYPE = ASCII_REAL START_BYTE = 18 BYTES = 7 FORMAT = "F7.3" UNIT = "DEGREE" DESCRIPTION = "Areocentric (north) latitude of measurement." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "LONGITUDE" COLUMN_NUMBER = 4 DATA_TYPE = ASCII_REAL START_BYTE = 26 BYTES = 8 FORMAT = "F8.3" UNIT = "DEGREE" POSITIVE_LONGITUDE_DIRECTION = "EAST" DESCRIPTION = "Areocentric (east) longitude of measurement in body fixed coordinates." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "ELECTRON NUMBER DENSITY" COLUMN_NUMBER = 5 DATA_TYPE = ASCII_REAL START_BYTE = 35 BYTES = 11 FORMAT = "E11.4" UNIT = "1 PER CUBIC METER" DESCRIPTION = "Electron number density of the ionosphere at RADIUS, LATITUDE, LONGITUDE." END_OBJECT = COLUMN OBJECT = COLUMN NAME = "SIGMA ELECTRON NUMBER DENSITY" COLUMN_NUMBER = 6 DATA_TYPE = ASCII_REAL START_BYTE = 47 BYTES = 8 FORMAT = "E8.2" UNIT = "1 PER CUBIC METER" DESCRIPTION = "One standard deviation uncertainty in ELECTRON NUMBER DENSITY." END_OBJECT = COLUMN END_OBJECT = RSED_TABLE END Appendix B. Example Data Object The RSED data object corresponding to the example label in Appendix A is shown below. Lines are wrapped after column 60; that is, the first five lines below correspond to RSED_HEADER_TABLE. 1998-12-24T03:47:00.000,1998-12-24T04:08:00.000,1998-12-24T0 3:48:05.698, 917,54, 23.3,-173.3, 64.725,-9.999, 325.191,- 9.999, 24.17, 81.25, 74.12,7.592E+06,2.348E+11,2.492E+11, 4 .263, 78.40, 77.7, 29.2,"GGM50A02.SHA","PCK3223A.TPC","83570 07A.SPK"," " 3585856.,204604., 64.785, 325.070, 7.4064E+09,1.96E+09 3584499.,203248., 64.784, 325.072, 6.9255E+09,1.96E+09 3583142.,201890., 64.783, 325.074, 7.2512E+09,1.97E+09 3581785.,200532., 64.781, 325.076, 8.1599E+09,1.97E+09 3580427.,199175., 64.781, 325.078, 9.3110E+09,1.98E+09 3579071.,197818., 64.779, 325.080, 9.2210E+09,1.98E+09 3577713.,196460., 64.778, 325.083, 9.5889E+09,1.99E+09 3576355.,195102., 64.777, 325.085, 1.0358E+10,1.99E+09 3574997.,193744., 64.776, 325.087, 1.0867E+10,2.00E+09 3573640.,192386., 64.775, 325.089, 1.0540E+10,2.00E+09 3572281.,191027., 64.774, 325.091, 1.0995E+10,2.01E+09 3570922.,189668., 64.773, 325.093, 1.1866E+10,2.01E+09 3569564.,188310., 64.772, 325.095, 1.1896E+10,2.02E+09 3568205.,186950., 64.771, 325.098, 1.3372E+10,2.02E+09 3566847.,185592., 64.770, 325.100, 1.3807E+10,2.02E+09 3565487.,184232., 64.769, 325.102, 1.5042E+10,2.03E+09 3564128.,182873., 64.768, 325.104, 1.5756E+10,2.04E+09 3562768.,181513., 64.766, 325.106, 1.6840E+10,2.04E+09 3561409.,180153., 64.766, 325.108, 1.7441E+10,2.04E+09 3560049.,178793., 64.764, 325.111, 1.7925E+10,2.05E+09 3558689.,177433., 64.763, 325.113, 1.9342E+10,2.05E+09 3557329.,176073., 64.762, 325.115, 2.0442E+10,2.06E+09 3555968.,174712., 64.761, 325.117, 2.2005E+10,2.06E+09 3554608.,173351., 64.760, 325.119, 2.2833E+10,2.07E+09 3553247.,171990., 64.759, 325.122, 2.4355E+10,2.07E+09 3551887.,170630., 64.758, 325.124, 2.4939E+10,2.08E+09 3550525.,169268., 64.757, 325.126, 2.6543E+10,2.08E+09 3549165.,167907., 64.756, 325.128, 2.7830E+10,2.09E+09 3547804.,166545., 64.755, 325.130, 2.8612E+10,2.09E+09 3546442.,165184., 64.754, 325.133, 2.9632E+10,2.10E+09 3545080.,163821., 64.752, 325.135, 3.1625E+10,2.10E+09 3543718.,162459., 64.751, 325.137, 3.3247E+10,2.10E+09 3542356.,161097., 64.750, 325.139, 3.4667E+10,2.11E+09 3540994.,159734., 64.749, 325.142, 3.6925E+10,2.11E+09 3539632.,158372., 64.748, 325.144, 3.8251E+10,2.12E+09 3538269.,157009., 64.747, 325.146, 4.0086E+10,2.12E+09 3536907.,155647., 64.746, 325.148, 4.1050E+10,2.13E+09 3535544.,154284., 64.745, 325.151, 4.2410E+10,2.13E+09 3534181.,152920., 64.744, 325.153, 4.4744E+10,2.14E+09 3532818.,151557., 64.743, 325.155, 4.7328E+10,2.14E+09 3531454.,150193., 64.742, 325.157, 4.9818E+10,2.15E+09 3530090.,148829., 64.740, 325.160, 5.2415E+10,2.15E+09 3528726.,147465., 64.739, 325.162, 5.5153E+10,2.16E+09 3527363.,146101., 64.738, 325.164, 5.7673E+10,2.16E+09 3525998.,144736., 64.737, 325.166, 6.1499E+10,2.16E+09 3524634.,143371., 64.736, 325.169, 6.4803E+10,2.17E+09 3523269.,142006., 64.735, 325.171, 6.8664E+10,2.17E+09 3521904.,140641., 64.734, 325.173, 7.3224E+10,2.18E+09 3520539.,139276., 64.733, 325.176, 7.7823E+10,2.18E+09 3519174.,137911., 64.732, 325.178, 8.1539E+10,2.19E+09 3517809.,136545., 64.731, 325.180, 8.5564E+10,2.19E+09 3516444.,135180., 64.729, 325.183, 8.9066E+10,2.20E+09 3515080.,133816., 64.728, 325.185, 9.1168E+10,2.20E+09 3513716.,132452., 64.727, 325.187, 9.0971E+10,2.20E+09 3512353.,131088., 64.726, 325.189, 8.8457E+10,2.21E+09 3510989.,129724., 64.725, 325.192, 8.4492E+10,2.21E+09 3509626.,128361., 64.724, 325.194, 7.8340E+10,2.22E+09 3508263.,126998., 64.723, 325.196, 6.9376E+10,2.22E+09 3506899.,125633., 64.722, 325.199, 6.0907E+10,2.23E+09 3505533.,124267., 64.720, 325.201, 5.3921E+10,2.23E+09 3504168.,122902., 64.719, 325.203, 4.6608E+10,2.24E+09 3502801.,121535., 64.718, 325.206, 4.0496E+10,2.24E+09 3501433.,120167., 64.717, 325.208, 3.7052E+10,2.24E+09 3500065.,118798., 64.716, 325.210, 3.5255E+10,2.25E+09 3498698.,117430., 64.715, 325.213, 3.4039E+10,2.25E+09 3497329.,116062., 64.714, 325.215, 3.4114E+10,2.26E+09 3495961.,114693., 64.713, 325.217, 3.4642E+10,2.26E+09 3494594.,113326., 64.711, 325.220, 3.3882E+10,2.27E+09 3493226.,111958., 64.710, 325.222, 3.2730E+10,2.27E+09 3491859.,110591., 64.709, 325.224, 3.0439E+10,2.28E+09 3490491.,109222., 64.708, 325.227, 2.8864E+10,2.28E+09 3489123.,107854., 64.707, 325.229, 2.7244E+10,2.28E+09 3487755.,106486., 64.706, 325.232, 2.4927E+10,2.29E+09 3486387.,105118., 64.704, 325.234, 2.2307E+10,2.29E+09 3485019.,103749., 64.703, 325.236, 1.9512E+10,2.30E+09 3483650.,102380., 64.702, 325.239, 1.7185E+10,2.30E+09 3482280.,101010., 64.701, 325.241, 1.5582E+10,2.30E+09 3480912., 99641., 64.700, 325.244, 1.3559E+10,2.31E+09 3479542., 98271., 64.699, 325.246, 1.1760E+10,2.31E+09 3478173., 96902., 64.698, 325.248, 9.8087E+09,2.32E+09 3476804., 95532., 64.697, 325.251, 7.4068E+09,2.32E+09 3475433., 94161., 64.695, 325.253, 6.1376E+09,2.33E+09