Data Set Overview  :  The Mars Global Surveyor (MGS) Radio Science (RS) Raw Data  Archive (RDA) is a time-ordered collection of raw and partially  processed data collected during the MGS Mission to Mars.  For more information on the investigations see  [TYLERETAL1992] and [TYLERETAL2001].   This data set was collected during the Mars Orbit Insertion  (MOI) Phase -- while the spacecraft was on final approach to  Mars, entering Mars orbit, and adjusting the orbit in  preparation for the Mapping Phase. Most of the radio data  supported MGS Navigation activities. Occultations captured  during January-April 1998, November-December 1998, and  February-March 1999 and low periapsis passes over the poles  have intrinsic science value of their own.   Two types of measurements were conducted during MOI; these  are known as closed-loop and open-loop recordings. The closed-  loop system used a phase-lock loop in the receiver to track the  downlink signal, reporting both amplitude and frequency at  rates typically of 1-10 times per second. In the open-loop  system, the signal was simply converted to a baseband frequency  range; the entire passband was sampled and recorded for later  processing. Typical open-loop sampling rates for MGS were  5000 samples per second. Closed-loop data are efficient for  characterizing slowly changing signals; open-loop data  (because of their much higher volume) are collected only  when the signal is very dynamic -- such as during an  occultation.   The data set includes three primary data types. Archival  Tracking Data Files (ATDFs or TDFs) are the most primitive (and  most voluminous) product of the closed-loop system. Orbit Data  Files (ODFs) are edited versions of ATDFs, specifically  targeted to spacecraft navigators and scientists interested in  gravity fields. Original Data Records (ODRs) are the primary  data type from the open-loop system.   Typical users of these data might analyze range and Doppler  measurements in ATDFs or ODFs to derive the spacecraft  trajectory during MOI. Relevant questions would include the  measurement uncertainties in range and Doppler at different DSN  antennas; these could set constraints on any model of Mars'  gravity field developed later, for example. During MOI the  spacecraft orbit was lower than at any other time during the  mission; gravity investigators interested in detecting and  measuring concentrations of mass at or near the surface could  find the ODF's in this data set to be particularly interesting.  Users of ODRs could identify and characterize anomalous signals  within the recorded passband, derive the drift of the  UltraStable Oscillator (USO), and calculate Allan Deviation for  various radio science configurations. Data collected during  aerobraking could be used to infer the structure of the upper  Mars atmosphere.    Parameters  :  The ATDF is the primary output from the MGS closed-loop system.  ATDFs have 150 fields, though not all had been assigned during  the MGS era. Each ATDF in the data set is accompanied by a  full PDS label which defines both the content and the format  (at the bit level) of the file. ATDF data fields include:  Range  High- or low-rate Doppler  High or low-rate downlink phase  Differential Range vs Integrated Doppler (DRVID)  Allan deviation  Smoothed noise  Uplink phase  Other information included in ATDF data records is date and  time; spacecraft ID; ground station and its configuration;  status flags and values reported by various ground systems;  calibration values, noise estimates, and tolerances (station  delay, transmitter power, etc.); and signal strength.   The ODF is an edited version of the ATDF; it is a smaller file,  issued more frequently than the ATDF. It contains the most  important information (range and Doppler) needed by spacecraft  navigators and investigators interested in determining  gravitational fields of bodies such as Mars. Each ODF is  accompanied by a full PDS label which describes both the  content and format of the associated file. ODF data fields  include:  Narrowband spacecraft VLBI, Doppler mode (cycles)  Narrowband spacecraft VLBI, phase mode (cycles)  Narrowband quasar VLBI, Doppler mode (cycles)  Narrowband quasar VLBI, phase mode (cycles)  Wideband spacecraft VLBI (nanoseconds)  Wideband quasar VLBI (nanoseconds)  One-way Doppler (Hertz)  Two-way Doppler (Hertz)  Three-way Doppler (Hertz)  One-way total count phase (cycles)  Two-way total count phase (cycles)  Three-way total count phase (cycles)  PRA planetary operational discrete spectrum range (range  units)  SRA planetary operational discrete spectrum range (range  units)  RE[GSTDN] range (nanoseconds)  Azimuth angle (degrees)  Elevation angle (degrees)  Hour angle (degrees)  Declination angle (degrees)   Open loop data records (ODRs) contain 8- or 12-bit samples of  receiver output. Each block of (typically) 1000 data samples  is accompanied by a 166 byte header. Each ODR is accompanied  by a full PDS label which describes both the content and format  of the file at the bit level. Header information includes:  Date and time of the first data sample  Sample rate and channel assignments  Receiver local oscillator (POCA) frequency  Attenuator settings  RMS voltages at several stages in the receiving chain    Processing  :  ATDFs are screened for 'bad' data points, which are removed  before the file is released by the Jet Propulsion Laboratory  (JPL) Radio Metric Data Conditioning Team (RMDCT).   ODFs are abstracted from subsets of ATDF data.   The open-loop data delivered to Stanford were usually in the  ODS (Original Data Stream) format. ODS packets were converted  to the older ODR (Original Data Record) format for consistency  in subsequent processing and archive. Headers applied by the  Ground Data System (GDS) during packet handling have not been  retained; they contained no additional information about the  data acquisition. In some cases, where the GDS corrupted the  ODS during delivery (or lost it entirely), data have been  recovered from tape in ODR format. The resultant data (whether  from ODS conversion or tape) accurately represent the output  of the DSCC Spectrum Processing (DSP) Subsystem at the DSN  station. A full PDS label accompanies each ODR file and gives  a bit level description of the content and format.   A 32-byte label at the beginning of each ODR tape is not  included in the data file. The 32-byte label gives the version  of the data taking software; this information has been copied  to the PDS label that accompanies the data file. The software  version recorded in the 'NOTE' keyword is more likely to be  accurate than the version recorded with the 'SOFTWARE_VERSION'  keyword. Because the 32-byte label is no longer part of the  data stream, users can treat the remaining file as an integral  number of fixed-length records. The 32-byte label was never  defined in the ODS.    Data  :  Data are stored on CD-WO volumes approximately chronologically.  CD volumes were usually defined by the dates of included  spacecraft engineering and DSN monitor data (data types ECH and  MCH, respectively). ECH and MCH files were the most regular,  and often the largest, collected on a daily basis. Files of  other types were sometimes delayed in delivery to Stanford and  may be out of strict chronological order on the CDs. Users  should consult listings in the INDEX/CUMINDEX.TAB file to  ascertain full coverage of each data type.   ATDFs were delivered approximately weekly during MGS MOI.  ATDFs are stored in the TDF directory on archival volumes.  File names are of the form ydddeeeC.TDF where y is the  one-digit year of the first data, ddd is the three-digit  day-of-year of the first data, eee is the three-digit day-  of-year of the last data, and C is a single letter (beginning  with 'A') denoting the sequence in which files with the same  ydddeee were handled. Generally ydddeeeB.TDF is a revised  version of ydddeeeA.TDF. The PDS label has file name  ydddeeeC.LBL. The typical ATDF contains about 39 Mbytes.   ODFs were issued at least daily throughout MGS MOI; during  periods of high spacecraft activity (such as around maneuvers)  ODFs were released as often as hourly. Most ODFs released  during MOI are included in the archival data set. Of those  that were missed, most were generated by special request, and  Stanford did not receive a release notice. ODFs are stored in  the ODF directory. File names are of the form ydddeeeC.ODF  where the file name components are the same as for the ATDF  (previous paragraph). In most cases ydddeeeB.ODF was NOT  simply a revised version of ydddeeeA.ODF; there were many  requests for special ODF processing -- to obtain higher time  resolution over short intervals, for example. The PDS label  has file name ydddeeeC.LBL. Typical ODF file sizes are small  multiples of 8064 bytes (e.g., less than 100 kB).   Original Data Records (ODRs) were produced whenever the DSP  was set to 'run' mode. These files are stored in the ODR  directory. In most cases, the entire DSP run was collected  into a single ODR file. But in other cases, it was more  convenient to subdivide the DSP data; queries were issued for  shorter time spans, and separate files were produced. File  names are of the form ydddhhmm.ODR where y is the one-digit  year of the first data, ddd is the day-of-year of the first  data, hh is the hour on which the first sample was taken, and  mm was the minute on which the first sample was taken. In  cases where two files had the same ydddhhmm (for example, two  DSN stations began recording at the same time, or a second query was submitted for data which appeared suspicious after the  first query was processed), the less significant digit in mm  of the second file was converted to a letter ('0' became 'A',  '1' became 'B', ..., '9' became 'J'). In cases were three files had the same ydddhhmm, the less significant mm digit was  converted to 'K', 'M', etc. The PDS label has file name  ydddhhmm.LBL.   At 5000 samples per second, a two-hour 12-bit test would yield  a 60 MB ODR -- one X-band (RCP) channel; 5 records per second,  each with 1000 12-bit samples and a 166-byte header. At  200 samples per second, an eight-hour 8-bit run would yield  a 33 MB ODR -- four channels (one X-RCP, the others null); 2  records per second with 100 8-bit samples per channel and a  166-byte header.    Ancillary Data  :  An extensive set of ancillary files is needed for proper  analysis and interpretation of the radio data (file types  TDF, ODF, and ODR). These are organized in parallel  directories and stored approximately chronologically. When  a file type is not represented on a CD-WO volume, the  corresponding directory has been omitted. With the exception  of files stored in the CALIB directory, ancillary files  appear on only one CD-WO volume. Users should refer to  the INDEX/CUMINDEX.TAB listing to locate ancillary files.   Files in the CALIB Directory  ----------------------------  Files in the CALIB directory are those likely to have wide  applicability in working with the raw data. They help  unpack and allow use of the raw data, rather than being  'instrument' calibration data per se. They include  decommutation maps, clock conversion files, files of  planetary constants, leapsecond files, and files needed for  display of data on the MGS Science Operations Planning  Computer (SOPC). Each file is accompanied by a PDS minimal  label.   Clock Conversion files were produced by the JPL/PDS  Navigation Ancillary Information Facility (NAIF) for use  with NAIF-developed and MGS-provided software. These are  ASCII files of variable length records. Each record is  delimited by an ASCII carriage-return  (ASCII 13)  line-feed pair  (ASCII 10), which may need to be  converted to either  or  before the file is used  on the local machine. File names have the form ydddeeeC.SCK  where y is the one-digit year of the first date covered,  ddd is the day-of-year of the first date covered, eee  is the day-of-year of the last date covered, and C is a  character denoting sequence when more than one file  with the same ydddeee is handled. C starts from 'A'  and progresses to 'B', 'C', etc. with increasing numbers  of similar coverage files. An alternate naming scheme was  adopted part way through MOI; those files have names of  the form TSCnnnnn.SCK, where nnnnn is a sequence number  beginning with 00001 and the file with the highest number  is the most recent. The value of nnnnn is set by NAIF.   Planetary Constants files were produced by the JPL/PDS  Navigation Ancillary Information Facility (NAIF) for use  with NAIF-developed and MGS-provided software. These are  ASCII files of variable length records. Each record is  delimited by an ASCII carriage-return  (ASCII 13)  line-feed pair  (ASCII 10), which may need to be  converted to either  or  before the file is used  on the local machine. File names have the form PCKydddC.TPC  where y is the one-digit year of the file creation date,  ddd is the day-of-year of the file creation date, and C  is a character denoting sequence when more than one file  with the same yddd is handled. C starts from 'A'  and progresses to 'B', 'C', etc. with increasing numbers  of similar coverage files.   Leapsecond files were produced by the JPL/PDS  Navigation Ancillary Information Facility (NAIF) for use  with NAIF-developed and MGS-provided software. These are  ASCII files of variable length records. Each record is  delimited by an ASCII carriage-return  (ASCII 13)  line-feed pair  (ASCII 10), which may need to be  converted to either  or  before the file is used  on the local machine. File names have the form LSKydddC.TLS  where y is the one-digit year of the file creation date,  ddd is the day-of-year of the file creation date, and C  is a character denoting sequence when more than one file  with the same yddd is handled. C starts from 'A'  and progresses to 'B', 'C', etc. with increasing numbers  of similar coverage files.   Channel Conversion Language files come in three types --  source, dependency, and binary. File names are of the  forms CCLydddS.SRC, CCLydddD.BIN, and CCLydddB.BIN,  respectively, where y is the one-digit year of the file  creation date and ddd is the day-of-year of the file  creation date. Source files are ASCII files of variable  length records. Each record is delimited by an ASCII  carriage-return  (ASCII 13) line-feed pair  (ASCII  10), which may need to be converted to either  or   before the file is used on the local machine. Dependency and  binary files are identical to those used on the SOPC. Source  and binary files are typically 500 kB; dependency files are  typically 15 kB. Channel Conversion Language files are used  in converting raw binary data in telemetry streams to  meaningful numbers.   Channel Parameter Table files come in two types -- source and  binary. File names are of the forms CPTydddS.SRC and  CCLydddB.BIN, respectively, where y is the one-digit year  of the file creation date and ddd is the day-of-year of the  file creation date. Source files are ASCII files of variable  length records. Each record is delimited by an ASCII  carriage-return  (ASCII 13) line-feed pair  (ASCII  10), which may need to be converted to either  or   before the file is used on the local machine. Binary files  are identical to those used on the SOPC. Source and binary  files are typically less than 1 MB. Channel Parameter Table  files are used in converting raw binary data in telemetry  streams to meaningful numbers.   Template Description Language files come in two types --  source and binary. File names are of the forms TDLydddS.SRC  and TDLydddB.BIN, respectively, where y is the one-digit  year of the file creation date and ddd is the day-of-year  of the file creation date. Source files are ASCII files of  variable length records. Each record is delimited by an  ASCII carriage-return  (ASCII 13) line-feed pair   (ASCII 10), which may need to be converted to either   or  before the file is used on the local machine. Binary  files are identical to those used on the SOPC. Source and  binary files are typically less than 1 MB. Template  Description Language files are used during display of data on  the SOPC.   Decommutation Map files come in two types -- source and  binary. File names are of the forms DCSxxxxx.SRC and  DCOxxxxx.BIN, respectively, where xxxxx is a mnemonic for  the map. Source files are ASCII files of variable length  records. Each record is delimited by an ASCII carriage-  return  (ASCII 13) line-feed pair  (ASCII 10), which  may need to be converted to either  or  before the  file is used on the local machine. Binary files are identical to those used on the SOPC. Source and binary files are  typically less than 200 kB. Decommutation Map files are used  in converting raw binary packet data to channelized formats.  On the SOPC, they are used with the MGS-provided program  mapx.   NB: CCL, CPT, TDL, and decommutation files were used with  software provided by the MGS project to extract and scale  'engineering' data from spacecraft and ground DSN systems.  In early 2007 a combined software/hardware upgrade mandated  by JPL left Stanford unable to process these telemetry  streams absent a significant recovery effort. Since the  spacecraft had gone silent three months earlier, it was  decided not to make the investment. Thus Stanford is no  longer able to extract these engineering data from ECH and  MCH binary files (see below). It is likely that other users  of the data would find this task to be equally challenging.  However, the CSV*.ECH, CSV*.MCH, ECS, and ECT files are  ASCII and should represent the most likely engineering  channels to be of interest to radio science.   Angular Momentum Desaturation Files (AMD Directory)  ---------------------------------------------------  Angular Momentum Desaturation files were produced by the MGS  Spacecraft Team (SCT). Each AMD file documents a set of AMD  events on the spacecraft. These are ASCII files of variable  length records. Each record is delimited by an ASCII  carriage-return  (ASCII 13) line-feed pair  (ASCII  10), which may need to be converted to either  or   before the file is used on the local machine. File names  have the form ydddeeeC.AMD where y is the one-digit year  of the first data in the file, ddd is the day-of-year of  the first data in the file, eee is the day-of-year of the  last data in the file, and C is a character denoting  sequence when more than one file with the same ydddeee  is handled. C starts from 'A' and progresses to 'B', 'C',  etc. with increasing numbers of similar coverage files.  Each AMD file is accompanied by a PDS minimal label with file  name ydddeeeC.LBL. Typical file sizes are less than 1500  bytes.   Channelized Engineering Data Files (ECH Directory)  ---------------------------------------------------  Channelized Engineering Data files were produced by the MGS  query server, operating on telemetry packets stored in the  MGS Central Data Base (CDB). These are binary files, usually  representing the collection of raw spacecraft engineering  data received from a 24 hour period; they are not readily  interpretable by end users. File names have the form  ydddeeeC.ECH where y is the one-digit year  of the first data in the file, ddd is the day-of-year of  the first data in the file, eee is the day-of-year of the  last data in the file, and C is a character denoting  sequence when more than one file with the same ydddeee  is handled. C starts from 'A' and progresses to 'B', 'C',  etc. with increasing numbers of similar coverage files.  Each ECH file is accompanied by a PDS minimal label with file  name ydddeeeC.LBL. File sizes can be as large as 200 MB.  In general, an ECH file can be derived from the corresponding  EPK file using MGS-provided software and a decommutation map.   Also in some ECH directories are ASCII tables of extracted  channel values--channelized state vectors, or CSV files.  These are values for a limited number of potentially  useful ECH channels that have been saved in tabular form.  CSV files in the ECH directory have names of the form  CSVydddC.ECH where y, ddd, and C are the same as for  the corresponding ECH file. Each CSV file is accompanied  by a detached PDS label with name CSVydddC.LBL which  completely describes the format and content of the CSV file.   NB: Stanford is no longer able to process binary ECH files;  see note above at the end of the section 'Files in the CALIB  Directory' for details.   Engineering Channelized Data Summary Files (ECS Directory)  ---------------------------------------------------  Engineering Channelized Summary Data Files were created at  Stanford during ingestion of spacecraft engineering data.  Each file contains a summary line for each channel processed  from the previous day's telemetry. The ECS file thus gives  a snapshot (mean and standard deviation) of each channel  on each day. ECS files are PDS TABLE objects; each is  fully described as to format and content by a detached PDS  label. File names are of the form ydddeeeC.ECS where  y is the one-digit year of the first data, ddd is the  three-digit day-of-year of the first data, eee is the  three-digit day-of-year of the last data, and C is a  character denoting sequence when more than one file with  the same ydddeee is handled. File sizes vary depending  on the number of channels processed; typical growth is  4000 bytes per day.   Engineering Channel Table Files (ECT Directory)  ---------------------------------------------------  Engineering Channel Table Data Files are created at Stanford  during ingestion of spacecraft engineering data. Each ECT  file is an ASCII table of time-ordered values from a single  spacecraft engineering channel, and each file is fully  described by a detached PDS label. File names are of the  form XXXydddC.ECT where XXX is a unique identifier for  the engineering channel, y is the one-digit year of the  first data, ddd is the three-digit day-of-year of the first  data, and C is a character denoting sequence when more  than one file with the same yddd is handled. File sizes  vary depending on the rate at which a channel was sampled;  they are typically under 100 kB. The detached label has  file name XXXydddC.LBL.   Experimenters Notebook Files (ENB Directory)  --------------------------------------------  Experimenters Notebook files are e-mail messages and other  notes collected during and shortly after data acquisition.  They document expectations of various measurements and  anomalies discovered in subsequent analysis. File names  have the form ENByyddd.TXT, where yy is the two-digit  year and ddd is the three-digit day-of-year. In general  the messages in file ENByyddd.TXT refer to activities on  that date regardless of when the message was sent. These  are ASCII files with variable length records. Each record  is delimited by an ASCII carriage-return line-feed pair.   Earth Orientation Parameter Files (EOP Directory)  ---------------------------------------------------  Earth Orientation Parameter files were produced by the Time  and Earth Motion Precision Observation (TEMPO) Group at JPL.  They documented and predicted Earth rotation (rate and axis).  These are ASCII files of variable length records. Each  record is delimited by an ASCII line-feed  (ASCII 10).  File names have the form ydddzeee.EOP where y is  the one-digit year of the first data in the file, ddd is  the day-of-year of the first data in the file, z is the  one-digit year of the last data, and eee is the day-of-year  of the last data in the file. EOP files were typically  released on Tuesdays and Fridays. There are both 'long'  and 'short' versions. The long file covered past motion  since about 1962 and a prediction for about three months into  the future; these files have typical sizes of 860 kB. The  short file covered the most recent nine months of past motion  and a prediction for three months into the future; these  files are typically 30 kB. Each EOP file is accompanied  by a PDS minimal label with file name ydddzeee.LBL.   Engineering Packet Data Files (EPK Directory)  ---------------------------------------------------  Engineering Packet Data files were produced by the MGS  query server, operating on telemetry packets stored in the  MGS Central Data Base (CDB). These are binary files, usually  representing the collection of raw spacecraft engineering  data received from a 24 hour period; they are not readily  interpretable by end users. File names have the form  ydddeeeC.EPK where y is the one-digit year  of the first data in the file, ddd is the day-of-year of  the first data in the file, eee is the day-of-year of the  last data in the file, and C is a character denoting  sequence when more than one file with the same ydddeee  is handled. C starts from 'A' and progresses to 'B', 'C',  etc. with increasing numbers of similar coverage files.  Each EPK file is accompanied by a PDS minimal label with file  name ydddeeeC.LBL. File sizes can be as large as 100 MB.   NB: No EPK files were collected during MOI.   Filtered Body Rate Files (FBR Directory)  ---------------------------------------------------  Filtered Body Rate Files were created at Stanford from  body rate data in the spacecraft engineering telemetry  stream. They give spacecraft attitude as a function of  time. FBR files are PDS TABLE objects; each is  fully described as to format and content by a detached PDS  label. File names are of the form ydddeeeC.FBR where  y is the one-digit year of the first data, ddd is the  three-digit day-of-year of the first data, eee is the  three-digit day-of-year of the last data, and C is a  character denoting sequence when more than one file with  the same ydddeee is handled. File sizes vary depending  on the time interval covered. FBR files were created  during MGS Cruise to support gravitational wave  experiments (GWE); as of the end of MOI, there was no  plan to generate them to support MOI analyses.   NB: No FBR files were collected during MOI.   GEODYN Trajectory Files (GDN Directory)  ---------------------------------------------------  GEODYN SPK files were quick look orbit reconstructions  produced by the MOLA Precise Orbit Determination Team. They  were used for preliminary analysis of MOLA data and some radio occultations. These files give spacecraft and planetary  ephemerides and are identical in format to SPK files (see  below) by the MGS NAV Team. Files with ORIGINAL_PRODUCT_ID  including 'qlnn' were based on the following gravity models:  ql15 mgm0989a  ql16 mgm0989c  ql17 gmm2b (with no one-way Doppler daya)  ql18 gmm2b (with one-way Doppler data if available) These are ASCII files of variable  length records in a special NAIF 'transfer' format. Each  record is delimited by a carriage-return (ASCII 13) line-feed   (ASCII 10) pair, which may need to be removed before the  file is used on the local machine. After delimiter conversion (if needed) the file would ordinarily be passed through the  NAIF utility SPACIT or TOBIN to convert it to the local  binary format. File names have the form ydddeeeC.GDN where y is the one-digit year of the first data in the file, ddd  is the day-of-year of the first data in the file, eee is the day-of-year of the last data in the file, and C is a  character denoting sequence when more than one file  with the same ydddeee is handled. C starts from 'A' and  progresses to 'B', 'C', etc. with increasing numbers of  similar coverage files. Each GDN file is accompanied by a  PDS minimal label with file name ydddeeeC.LBL. Typical file  sizes are less than 5 MB.   GEODYN Trajectory Files (GDF Directory)  ---------------------------------------------------  GDF files are the same as GDN files (above) except that they  are considered 'final' versions of the orbits. File names  end with the .GDF suffix.   NB: No GDF files were collected during MOI.   Daily Health Report Files (HEA Directory)  ---------------------------------------------------  Daily Health Report Files were created at Stanford; they  summarize spacecraft engineering data of interest for Radio  Science, list recently acquired radio data, summarize any  analysis performed on recent radio data, summarize anomalies  in recent radio science operations, and list files that have  been obtained from the MGS CDB or other sources. Daily  Health Report Files are PDS TEXT objects; each has an  attached PDS label. File names are of the form HEAydddC.TXT  where y is the one-digit year of the report, ddd is the  three-digit day-of-year of the report, and C is a  character denoting sequence when more than one file with  the same ydddeee is generated. The first report on a day  would be HEAydddA.TXT; subsequent revisions or updates  would be HEAydddB.TXT, HEAydddC.TXT, etc.   Some Health Reports are accompanied by plots, saved as  Type 1 PostScript files. File names for these plot files  have names of the form HEAydddC.PSn where y and ddd  are as defined above and n is the figure number.  Each PostScript file should be accompanied by a detached  PDS label, but that requirement was met only once in the  MOI data set. The label file has name HEAydddC.LBL,  meaning that the value of n is limited to 1 for any  single health report.   Both Health Reports themselves and accompanying PostScript  files have variable length records delimited by carriage-  return (ASCII 13) line-feed (ASCII 10) pairs.   Ionosphere Calibration Files (ION Directory)  ---------------------------------------------------  Ionosphere Calibration files were produced by the Tracking  System Analytic Calibration (TSAC) Group at JPL. They  documented and predicted Earth ionospheric conditions.  These are ASCII files of variable length records. Each  record is delimited by an ASCII line-feed  (ASCII 10).  File names have the form ydddeeeC.ION where y is  the one-digit year of the first data in the file, ddd is  the day-of-year of the first data in the file, eee is the  day-of-year of the last data in the file, and C is a  character denoting sequence when more than one file with the  same ydddeee is handled. C starts from 'A' and progresses  to 'B', 'C', etc. with increasing numbers of similar coverage  files. ION files were usually released at one week  intervals to cover a single month; ydddeeeA.ION would be  the file released during the first week, ydddeeeB.ION would  be the file released during the second week, etc. Each ION  file is accompanied by a PDS minimal label with file name  ydddeeeC.LBL. Typical file sizes are less than 50 kB.   Light Time Files (LIT Directory)  ---------------------------------------------------  Light Time files were produced by the MGS Navigation Team  (NAV). They gave radio propagation time from the spacecraft  to Earth vs time. These are ASCII files of fixed  length records. Each record is delimited by an ASCII  carriage-return  (ASCII 13) line-feed pair  (ASCII  10), which may need to be converted to either  or   before the file is used on the local machine. File names  have the form ydddeeeC.LIT where y is the one-digit year  of the first data in the file, ddd is the day-of-year of  the first data in the file, eee is the day-of-year of the  last data in the file, and C is a character denoting  sequence when more than one file with the same ydddeee  is handled. C starts from 'A' and progresses to 'B', 'C',  etc. with increasing numbers of similar coverage files.  Each LIT file is accompanied by a PDS minimal label with file  name ydddeeeC.LBL. Typical file sizes are less than 1 MB.   Channelized DSN Monitor Data Files (MCH Directory)  ---------------------------------------------------  Channelized DSN Monitor Data files were produced by the MGS  query server, operating on DSN Monitor packets stored in the  MGS Central Data Base (CDB). These are binary files, usually  representing the collection of DSN Monitor data received from  a 24 hour period; they are not readily interpretable by end  users. File names have the form ydddeeeC.MCH where y is  the one-digit year of the first data in the file, ddd is  the day-of-year of the first data in the file, eee is the  day-of-year of the last data in the file, and C is a  character denoting sequence when more than one file with the  same ydddeee is handled. C starts from 'A' and progresses  to 'B', 'C', etc. with increasing numbers of similar coverage  files. Each MCH file is accompanied by a PDS minimal label  with file name ydddeeeC.LBL. File sizes can be as large as  30 MB. In general, an MCH file can be derived from the  corresponding MPK file using MGS-provided software and a  decommutation map. Monitor data are collected according to  MST (Monitor Sample Time) measured in UTC.   Also in some MCH directories are ASCII tables of extracted  channel values--channelized state vectors, or CSV files.  These are values for a limited number of potentially  useful MCH channels that have been saved in tabular form.  CSV files in the MCH directory have names of the form  CSVydddC.MCH where y, ddd, and C are the same as for  the corresponding MCH file. Each CSV file is accompanied  by a detached PDS label with name CSVydddC.LBL which  completely describes the format and content of the CSV file.   NB: Stanford is no longer able to process binary MCH files;  see note above at the end of the section 'Files in the CALIB  Directory' for details.   Maneuver Implementation/Reconstruction Files (MIF Directory)  ---------------------------------------------------  Maneuver Implementation/Reconstruction files were produced by  the MGS Spacecraft Team (SCT); they documented spacecraft  maneuver events. These are ASCII files of variable length  records. Each record is delimited by an ASCII line-feed   (ASCII 10). File names have the form ydddeeeC.MIF where y  is the one-digit year of the first data in the file, ddd is  the day-of-year of the first data in the file, eee is the  day-of-year of the last data in the file, and C is a  character denoting sequence when more than one file with the  same ydddeee is handled. C starts from 'A' and progresses  to 'B', 'C', etc. with increasing numbers of similar coverage  files. Each MIF file is accompanied by a PDS minimal label  with file name ydddeeeC.LBL. Typical file sizes are 2327  bytes.   Maneuver Performance Data Files (MPD Directory)  ---------------------------------------------------  Maneuver Performance Data files were produced by the MGS  Spacecraft Team (SCT). They contain estimates of spacecraft  mass and center of mass; moments of inertia; thruster  locations, directions, and magnitudes; and propellant flow  rate. These are ASCII files of variable length records.  Each record is delimited by an ASCII line-feed   (ASCII 10). File names have the form ydddeeeC.MPD where  y is the one-digit year of the first data in the file,  ddd is the day-of-year of the first data in the file, eee  is the day-of-year of the last data in the file, and C is  a character denoting sequence when more than one file with  the same ydddeee is handled. C starts from 'A' and  progresses to 'B', 'C', etc. with increasing numbers of  similar coverage files. Each MPD file is accompanied by a  PDS minimal label with file name ydddeeeC.LBL. Typical  file sizes are 4 kB.   Maneuver Profile Files (MPF Directory)  ---------------------------------------------------  Maneuver Profile Files were produced by the MGS Navigation  Team (NAV). They are generic descriptions of orbit  adjustments used by MGS during aerobraking. These are ASCII  files of variable length records. Each record is delimited  by a carriage-return  (ASCII 13) line-feed   (ASCII 10) pair. File names have the form XnnnDDCC.MPF  where X is a character, nnn is a 3-digit number, DD  indicates the adjustment direction ('UP' or 'DN'), and  CC indicates the sequence if there is more than one file  with the same XnnnDD. CC starts from 'AA'. Each MPF  is accompanied by a PDS minimal label with file name  XnnnDDCC.LBL. Typical file sizes are less than 700 bytes.   DSN Monitor Packet Data Files (MPK Directory)  ---------------------------------------------------  DSN Monitor Packet Data files were produced by the MGS  query server, operating on DSN Monitor packets stored in the  MGS Central Data Base (CDB). Monitor data are records of  DSN status and radio measurements. These are binary files,  data received from a 24 hour period; they are not readily  interpretable by end users. File names have the form  ydddeeeC.MPK where y is the one-digit year  of the first data in the file, ddd is the day-of-year of  the first data in the file, eee is the day-of-year of the  last data in the file, and C is a character denoting  sequence when more than one file with the same ydddeee  is handled. C starts from 'A' and progresses to 'B', 'C',  etc. with increasing numbers of similar coverage files.  Each MPK file is accompanied by a PDS minimal label with file  name ydddeeeC.LBL. File sizes can be as large as 30 MB.   NB: No MPK files were collected during MOI.   Orbit Propagation and Time Generation Files (OPT Directory)  ---------------------------------------------------  Orbit Propagation and Time Generation files were produced by  the MGS Navigation Team (NAV). They contain estimates of  event timing (e.g., equator crossings) that depend on  precise knowledge of the spacecraft orbit. These are ASCII  files of variable length records. Each record is delimited  by an ASCII line-feed  (ASCII 10). File names  have the form ydddeeeC.OPT where y is the one-digit year  of the first data in the file, ddd is the day-of-year of  the first data in the file, eee is the day-of-year of the  last data in the file, and C is a character denoting  sequence when more than one file with the same ydddeee  is handled. C starts from 'A' and progresses to 'B', 'C',  etc. with increasing numbers of similar coverage files.  Each OPT file is accompanied by a PDS minimal label with file  name ydddeeeC.LBL. Typical file sizes are less than 100 kB.  Typical OPT files during MOI included one day of orbit  reconstructions followed by several days of orbit  predictions.   Solar Array Kernel Files (SAK Directory)  ---------------------------------------------------  Solar Array Kernel files were produced by the MGS Spacecraft  Team (SCT). They give the attitude of each solar array  panel as a function of time. These are ASCII files of  variable length records in a special NAIF 'transfer' format.  Each record is delimited by a carriage-return (ASCII 13)  line-feed  (ASCII 10) pair, which may need to be  removed before the file is used on the local machine.  After delimiter conversion (if needed) the file would  ordinarily be passed through the NAIF utility SPACIT or  TOBIN to convert it to the local binary format. File names  have the form ydddeeeC.TCK where y is the one-digit year  of the first data in the file, ddd is the day-of-year of  the first data in the file, eee is the day-of-year of the  last data in the file, and C is a character denoting  sequence when more than one file with the same ydddeee  is handled. C starts from 'A' and progresses to 'B', 'C',  etc. with increasing numbers of similar coverage files.  Each TCK file is accompanied by a PDS minimal label with  file name ydddeeeC.LBL. Typical file sizes are less than  5 MB.   Space Flight Operation Schedule Files (SFO Directory)  ---------------------------------------------------  Space Flight Operations Schedule Files were produced by the  MGS Mission Control Team (MCT), usually in parallel with  a corresponding Sequence of Events (SOE) file. They  graphically present parts of the SOE. These are  ASCII files of variable length records in a special format  that allows use with the MGS-provided sfosedt program.  Each record is delimited by a carriage-return (ASCII 13)  line-feed  (ASCII 10) pair, which may need to be removed  before the file is used on the local machine. File names  have the form ydddeeeC.SFO where y is the one-digit year  of the first data in the file, ddd is the day-of-year of  the first data in the file, eee is the day-of-year of the  last data in the file, and C is a character denoting  sequence when more than one file with the same ydddeee is  handled. C starts from 'A' and progresses to 'B', 'C', etc.  with increasing numbers of similar coverage files. Each SFO  file is accompanied by a PDS minimal label with file name  ydddeeeC.LBL. Typical file sizes are less than 100 kB.   NB: No SFO files were produced after 1998-08-20.   Sequence of Events Files (SOE Directory)  ---------------------------------------------------  Sequence of Events Files were produced by the MGS Mission  Control Team (MCT). These are ASCII files of variable length  records. Until 1998-08-20 SOE files were produced in a  special format that allowed use with the MGS-provided soeedt  program. After 1998-08-20, files were produced in a straight  ASCII format that required no special software; these may be  identified by the '.tsoe' suffix in the ORIGINAL_PRODUCT_ID.  Each record is delimited by a carriage-return (ASCII 13)  line-feed  (ASCII 10) pair, which may need to be removed  before the file is used on the local machine. File names  have the form ydddeeeC.SOE where y is the one-digit year  of the first data in the file, ddd is the day-of-year of  the first data in the file, eee is the day-of-year of the  last data in the file, and C is a character denoting  sequence when more than one file with the same ydddeee is  handled. C starts from 'A' and progresses to 'B', 'C',  etc. with increasing numbers of similar coverage files.  Each SOE file is accompanied by a PDS minimal label with  file name ydddeeeC.LBL. Typical file sizes are less than  1 MB.   Spacecraft/Planetary Ephemeris (SPK) Files (SPK Directory)  ---------------------------------------------------  Spacecraft/Planetary Ephemeris Files (also known as SP  kernels or SPK files) were produced by the MGS Navigation Team (NAV). These files give spacecraft and planetary ephemerides. These are ASCII files of variable length records in  a special NAIF 'transfer' format. Each record is delimited  by a carriage-return (ASCII 13) line-feed  (ASCII 10)  pair, which may need to be removed before the file is used on  the local machine. After delimiter conversion (if needed)  the file would ordinarily be passed through the NAIF utility  SPACIT or TOBIN to convert it to the local binary format.  File names have the form ydddeeeC.SPK where y is the  one-digit year of the first data in the file, ddd is the  day-of-year of the first data in the file, eee is the  day-of-year of the last data in the file, and C is a  character denoting sequence when more than one file  with the same ydddeee is handled. C starts from 'A' and  progresses to 'B', 'C', etc. with increasing numbers of  similar coverage files. Each SPK file is accompanied by a  PDS minimal label with file name ydddeeeC.LBL. Typical file  sizes are less than 5 MB. Typical SPK files during MOI  included one day of orbit reconstructions followed by several  days of orbit predictions.   Spacecraft Attitude (CK) Files (TCK Directory)  ---------------------------------------------------  Spacecraft Attitude Files (also known as C kernels or CK  files) were produced by the MGS Spacecraft Team (SCT).  These are ASCII files of variable length records in  a special NAIF 'transfer' format. Each record is delimited  by a carriage-return (ASCII 13) line-feed  (ASCII 10)  pair, which may need to be removed before the file is used on  the local machine. After delimiter conversion (if needed)  the file would ordinarily be passed through the NAIF utility  SPACIT or TOBIN to convert it to the local binary format.  File names have the form ydddeeeC.TCK where y is the  one-digit year of the first data in the  file, ddd is the day-of-year of the first data in the file,  eee is the day-of-year of the last data in the file, and C  is a character denoting sequence when more than one file  with the same ydddeee is handled. C starts from 'A' and  progresses to 'B', 'C', etc. with increasing numbers of  similar coverage files. Each TCK file is accompanied by a  PDS minimal label with file name ydddeeeC.LBL. Typical file  sizes are less than 5 MB.   Troposphere Calibration Files (TRO Directory)  ---------------------------------------------------  Troposphere Calibration files were produced by the  Tracking System Analytic Calibration (TSAC) Group at JPL.  They documented and predicted Earth tropospheric conditions.  These are ASCII files of variable length records. Each  record is delimited by an ASCII line-feed  (ASCII 10).  File names have the form ydddeeeC.TRO where y is  the one-digit year of the first data in the file, ddd is  the day-of-year of the first data in the file, eee is the  day-of-year of the last data in the file, and C is a  character denoting sequence when more than one file with the  same ydddeee is handled. C starts from 'A' and progresses  to 'B', 'C', etc. with increasing numbers of similar coverage  files. TRO files were typically released at the beginning of  a month and covered the previous month. Each TRO file is  accompanied by a PDS minimal label with file name  ydddeeeC.LBL. Typical file sizes are less than 50 kB.   UltraStable Oscillator Files (USO Directory)  --------------------------------------------  UltraStable Oscillator (USO) files are calibration data  derived from open-loop radio measurments. Files are PDS  table objects with detached labels. Examples include USO  Allan Deviation (type A files) and the piecewise-continuous  linear model of USO frequency (type M files). File names  are of the form USOtyddd.TAB, where t is the file type  (see above), y is the one-digit year in which the file was  created, and ddd is the three-digit day-of-year in which  the file was created. Each USO file is accompanied by a  detached PDS label with name USOtyddd.LBL which completely  describes the content and format of the file.   DSN Weather Files (WEA Directory)  ---------------------------------------------------  DSN Weather files were produced by the Tracking System  Analytic Calibration (TSAC) Group at JPL. Files give weather  calibration information for DSN complexes. These are ASCII  files of variable length records. Each record is delimited  by an ASCII line-feed  (ASCII 10). File names have  the form ydddeeeD.WEA where y is the one-digit year of  the first data in the file, ddd is the day-of-year of the  first data in the file, eee is the day-of-year of the last  data in the file, and D is a single digit denoting the  DSN complex at which the data were acquired ('1' for  Goldstone, '4' for Canberra, or '6' for Madrid). WEA files  were typically released weekly and contain all weather data  for the complex since 1 January. Each WEA file is  accompanied by a PDS minimal label with file name  ydddeeeC.LBL. The files grow at the rate of approximately  90 kB per month.    Coordinate System  :  SPK ephemeris files and TCK files were produced for the  J2000 inertial reference frame until the second orbit after  Mars Orbit Insertion, when the TCK files were referenced to  the Mars Mean Equator frame. SAK files presumably follow the  same format as TCK files. NAIF reader routines may be  used to convert these to other coordinate systems.   Other data types are not dependent on definition of a  coordinate system.    Software  :  Software for parsing, reducing, and analyzing data such as  these has been developed at Stanford University and elsewhere.  Because such software must usually operate at the bit-level and  is written for a narrow range of platforms, it is not suitable  for general distribution. No software is included with this  archival data set.    Media/Format  :  The archival data set is written on CD-WO media using the  Young Minds CD Studio or Yamaha/GEAR authoring system. The  CD-WO volumes conform to ISO 9660 standards.

Overview  :  Data in this archival data set have been processed as part of  health monitoring activities of the MGS Radio Science Team.  In general, this is a good data set.    Review  :  This archival data set was reviewed by the MGS Radio Science  Team prior to submission to the Planetary Data System (PDS).  The MGS Science Data Validation Team (SDVT) set standards and  procedures.   Prior to creation of the final version of the archival data  set, key elements of the archive were distributed for  preliminary review. These included electronic versions of  example PDS labels, CATALOG files, and Software Interface  Specifications. These materials were distributed to PDS  personnel, the experiment investigator, and others,  as appropriate.   ODR files on the CD-WO volumes were checked using Stanford  parsing and reduction software to ensure that they were both  complete and accurate replicas of the data contained in the  original files.    Data Coverage and Quality  :  Significant events for Radio Science during MGS MOI were as  follows. AB-1 and AB-2 stand for Aerobraking Phases I and II,  respectively. TMO was the Transition to Mapping Orbit  subphase of MOI.   YY/DDD Start DSP Stop DSP Comments  ------ -------- -------- ----------------  97/252 14:00:00 15:12:11 Pressurization  97/255 01:31:12 01:57:07 MOI Burn and Occultation  97/296 First periapsis LGA recording  98/024 19:15:36 19:32:15 First AB-1 occultation recording  98/076 13:19:18 (ET) Close Phobos approach (380 km)  98/087 02:44:09 First SPO-1 periapsis gravity pass 98/088 01:51:00 02:15:00 First egress recording (LGA)  98/107 23:01:28 23:18:00 Last good ingress recording  98/118 15:52:00 16:33:00 Last AB-1 occultation recording  98/119 Begin solar conjunction period  98/147 End solar conjunction period  98/289 08:52:48 09:27:50 First AB-2 occultation recording  98/365 09:35:00 09:55:00 Last AB-2 occultation recording  99/035 09:36:00 Begin Gravity Calibration Orbits  99/035 16:27:00 16:34:00 First TMO occultation  99/059 20:00:00 Last GCO orbit  99/067 20:01:00 20:14:00 Last TMO occultation   Quality of data was affected by anomalous conditions. Examples  include:   Open-Loop (ODR) Data Anomalies  ------------------------------  a) 2-6 dB lower carrier-to-noise level at SPC 60 antennas  throughout the occultation period (98/024-98/339)  b) 'Sawtooth' frequency residuals in approximately 10 percent  of the AB-1 data, less frequently in AB-2 data, and  infrequently in TMO data (all stations)  c) Amplitude baseline variations more than +/-0.1 dB  (various)  d) Spurs (occasional, no consistent pattern)  e) Unreliable POCA (wrong SPA-R software) (SPC 60,  98/084-98/106)  f) Poor frequency predictions because of inaccurate orbits  during AB-2 (all stations; scattered, 98/289-98/365)  g) Uplink ramping and telemetry ON during ingress  occultations (99/035-99/067)  h) HGA deployment. Bad data; various causes (99/087-99/094)  i) Solar conjunction with severe plasma effects superposed  on the radio signals (98/119-98/147)   Closed-Loop Data Anomalies (mostly observed in ODF)  ---------------------------------------------------  Thermal sensitivity of USO observed during one-way tracking.   Solar conjunction with severe plasma effects superposed on  the radio signals (98/119-98/147)   Note that the official beginning of the Orbit Insertion Phase  has been defined as 1999-09-12; when this data set was  assembled, the beginning date was understood to be 1999-09-02.  Thus, the first few volumes in this data set include files  which properly belong in the MGS-M-RSS-1-CRU-V1.0 data set.    Limitations  :  The limitations in this data set follow from the quality of  the execution, which is described above under Data Coverage  and Quality.