Data Set Overview  :  The Mars Global Surveyor (MGS) Radio Science (RS) Archive Data  Collection (ADC) of Science Data Products (SDP) includes data  products generated from radio occultation, gravity, and surface  reflection investigations conducted by members of the MGS Radio  Science Team (RST).   The archive includes both Standard Data Products (STDPs) and  Special Data Products (SPDPs). STDPs were defined prior to  Launch; with two exceptions, they were produced routinely  during the mission. The two exceptions were not created  regularly because suitable data were not available. SPDPs  were defined after Launch and/or were produced on an irregular  basis.   Radio occultation STDPs include temperature-pressure (T-p)  profiles, occultation summary files, and intensity power  spectra. T-p profiles were computed with standard vertical  resolution (approximately 200 m); an option to compute them  at high resolution (approximately 20 m, after correction for  diffraction effects) was never exercised. David Hinson at  Stanford University created all T-p profiles and occultation  summary files. Intensity power spectra were never computed  because no evidence for scintillations was ever found.  Richard Woo of the Jet Propulsion Laboratory (JPL) would  have created the intensity power spectra.   Gravity STDPs include spherical harmonic models, maps or images  of those models, and line-of-sight acceleration profiles.  Groups at the Goddard Space Flight Center (GSFC) under the  direction of David Smith and at JPL under the direction of  William Sjogren produced spherical harmonic models, maps, and  images. Sjogren's group also produced a small number of  line-of-sight acceleration profiles from pre-Mapping data  when periapsis was unusually low. Data collected during  Mapping showed little structure that was not captured in the  spherical harmonic model coefficients. A group at Centre  National d'Etudes Spatiales (CNES) under Georges Balmino also  worked with gravity data; but as of the end of the MGS mission  they had not delivered any gravity STDPs.   For more information on STDPs, see [TYLERETAL1992] and  [TYLERETAL2001].   Under certain conditions radio occultation data can be processed to yield profiles of electron density in the ionosphere. SPDPs  include profiles at standard vertical resolution created at  Stanford University by David Hinson. An option to produce high  resolution ionospheric profiles was never exercised.   The surface reflection investigation was developed only after  the spacecraft was in Mars orbit. SPDPs include summary tables  of observing geometry, summary tables of reconstructed antenna  pointing at the spacecraft, summary tables of signal  characteristics, and images of signals in time-frequency space.  The reflected signals were collected over 1-2 minutes  immediately before an ingress occultation or immediately after  an egress occultation at nearly grazing incidence angles.  These products were generated by Richard Simpson of Stanford  University.   Simpson also conducted a handful of forward scattering bistatic  radar experiments at incidence angles 50-70 degrees. Received  power spectra in the two orthogonal circularly polarized  receiver channels are included in the final volume of the  archive.   NB: The complete set of radio occultation temperature-pressure  profiles (21243 files) has been extracted from these 38 volumes  and archived separately as data set MGS-M-RSS-5-TPS-V1.0.  Users interested solely in the T-p profiles may find this  archive (a single CD volume) to be more convenient. A single  occultation summary file accompanies the MGS-M-RSS-5-TPS-V1.0  data set.   As MORS_1038 was being written, a plan was in motion to  extract the electron density profiles into a second, separate  archive with the data set ID of MGS-M-RSS-5-EDS-V1.0.   The gravity results are not so easily repackaged. Although  the later gravity models are presumably better than the early  ones, the assumptions made in generating each model varied.  The legacy data (e.g., from Viking) used in the solution also  varied. In some cases a model with lower resolution (lower  degree and order) may be more satisfactory than a later one;  the user must make these decisions. Information in the  labels for the specific products may be helpful in deciding.    Parameters  :  Temperature-pressure profiles are tables of atmospheric  temperature, pressure, and molecular number density versus  radius from Mars' center of mass. A header record prepended  to each table provides information on observing times and  geometry, surface conditions, and on files used in the data  processing. Header records from all of the T-p profiles  delivered at one time (typically every three months) are  collected together into a single occultation summary file.   Spherical harmonic models are tables of coefficients GM, Cmn,  and Smn -- as in equation (1) of [TYLERETAL1992]. These can  be used to represent gravitational potential of Mars, for  example. Both ASCII (data type SHA) and binary (data type  SHB) formats are defined, with the latter being preferred for  large files which also include covariance terms. Each file  contains up to four tables: a header table containing general  parameters for the model (gravitational constant, its  uncertainty, degree and order of the field, normalization  state, reference longitude, and reference latitude); a names  table, giving the order in which coefficients appear; a  coefficients table (degree m, order n, coefficients Cmn and  Smn, and their uncertainties); and a covariances table giving  the covariances of CijCmn, SijSmn, CijSmn, and SijCmn.   Radio Science Digital Map files are image representations  of gravity and other parameters. Free air gravity, geoid,  Bouguer anomaly, isostatic anomaly, and topographic values  may be displayed using this data type. Data are formatted  as PDS image objects.   The Line-of-Sight Acceleration Profile Data Record is a pair  of PDS tables. The first table contains header information  such as time and observing geometry, parameters used in  deriving acceleration from radio tracking measurements, and  first-order Keplerian orbit elements. The second table gives  spacecraft acceleration versus time. Also included at each  time is the spacecraft position in planetocentric coordinates.   Electron density profiles are very similar to temperature-  pressure profiles for the neutral atmosphere. Each is a  table of electron density versus radius from Mars' center of  mass. A header record prepended to each table provides  information on observing times and geometry and on files used  in the data processing. There is no summary file for the  electron density profiles delivered together.   Surface Reflection Tables list carrier frequency and power  and the estimated frequency and power in the surface echo.  Surface Reflection Images are series of power spectra  showing the progression of signal characteristics as a  function of time.   Surface Reflection Geometry tables summarize the observing  geometry at and near occultations at (typically) 1 second  intervals. Quantities include Earth receive time; the  transmit time (receive time corrected for one-way light time);  vectors to the spacecraft, Earth receiving station, and  several points on the surface; angles; and sensitivities of  some quantities to changes in assumed Mars radius. The  surface points include the specular point, the backscatter  point (the intersection of a line from the receiver through  the spacecraft to the surface), the raypath closest approach  point (the point where a line from the Earth to the spacecraft  is closest to the surface), and a user-defined 'target' on  the surface. For the surface reflection studies conducted  with MGS, only the specular point information is of interest.  The backscatter point is the point on Mars' disk behind the  spacecraft when viewed from Earth, while the raypath closest  approach point gives the latitude and longitude of the  occultation ray closest approach; the backscatter point and  the raypath closest approach point cannot exist simultaneously.  The 'target' point is meaningful only when a target has been  selected; it is usually set to a default value of (0.,0.).   Bistatic Radar Power Spectra are tables showing received power  versus frequency (rows) and time (columns).    Processing  :  T-p profiles and ionosphere profiles are derived from raw  receiver output in several steps.   First, deterministic sources of frequency change are identified  and removed coherently. These included motion of the spacecraft, motion of the Earth receiving station, drift of the UltraStable  Oscillator (USO), and relativistic effects associated with  gravity fields of solar system bodies. This leaves the carrier  signal at a known frequency except for phase drift associated  with passage of the radio ray through Mars' atmosphere and/or  ionosphere. Drift associated with passage through solar plasma  or the Earth's atmosphere or ionosphere is assumed to be  negligible over the time of a Mars occultation (approximately  two minutes).   Second, using an accurate reconstruction of the spacecraft  trajectory, the phase of the signal versus time is converted  into a measure of refraction angle versus impact parameter --  the perpendicular distance between the incoming raypath and the  center of curvature of the atmosphere.   Third, the index of refraction versus radius is obtained using  an Abel inversion [FJELDBOETAL1971]. From knowledge of the  composition of the atmosphere and laboratory measurements of  refractive index for major constituents, index of refraction  versus radius for the neutral atmosphere is converted to  vertical distribution of mass density.   Fourth, assuming hydrostatic equilibrium and an ideal gas law,  the mass density profile is converted to a profile of both  temperature and pressure for the neutral atmosphere.   For the ionosphere, refractive index versus radius is converted  to density of free electrons versus radius using a method  described by [YEH&LIU1972].   Spherical harmonic models, maps, and line-of-sight acceleration  profiles are derived from raw radio tracking data in several  steps.   The gravity field coefficients are obtained by solving systems  of equations with thousands of unknowns. Radio tracking data in long arcs delimited by propulsive maneuvers, occultations, etc.  are used in solutions which are obtained iteratively and by  least squares.   Maps of free air gravity and other quantities are generated from the spherical harmonic model(s) evaluated at regular grid  points.   Line-of-sight acceleration profiles are derived from single arcs of radio tracking data. Doppler residuals with respect to a  specific spherical harmonic model are spline-fitted; the splines are then differentiated analytically to obtain accelerations.   See [TYLERETAL1992] and [TYLERETAL2001] and references therein  for additional details on processing for the products listed  above.   Surface Reflection Geometry (SRG) tables are summaries of  observing geometry, typically at one second intervals. The  spacecraft-surface-Earth geometry is derived from an SPK (NAIF  spacecraft and planetary ephemeris) file.   Surface Reflection Antenna (SRA) tables are summaries of  high-gain antenna (HGA) pointing, typically at 1 second  intervals. The HGA pointing in J2000 is computed from  spacecraft attitude (TCK) and HGA gimbal (AGK) files; that  vector is then compared with the MGS-Earth vector in the SRG  file. Offset is listed as the total angle between the HGA  boresight and the MGS-Earth vector and in terms of the  components toward the surface and parallel to the limb.   The Surface Reflection Table (SRT) data are derived as follows.   (1) The occultation is located in time and its sense (ingress  or egress) is determined from the direction of change in the  receiver output: if ingress, the output should decrease; if  egress, the output should increase.   (2) Raw samples of receiver output are passed through  a digital 'equalizing' filter which flattens the output  spectral response over the central 80 percent of the  passband. The output is a string of double-precision  complex floating point time samples at the Nyquist sampling  rate (2500/s for data collected through mid-2001, 2000/s for  data collected starting in late 2001).   (3) 512-point power spectra (approximately 0.2 s each) are  computed around the transition point (1); approximately 30  spectra are saved on the occulted side of the transition and  270 are saved when the carrier is clearly visible (total of  300 spectra, spaced by 0.2 s and having 5 Hz frequency bins).   (4) A search within each spectrum for the bin with maximum  signal locates the carrier (when it is present).   (5) A second search within each spectrum for the strongest  signal at frequencies higher (lower) than the carrier if  ingress (egress) locates the surface echo. The surface echo  is transient, however, so not all results from this search  are valid. A predicted frequency curve (straight line) is  fitted to the DIFFERENCE between the peak echo bin and the  carrier bin; half of the points are thrown out (the worst  residuals). A new straight line is fitted to the remaining  points, and the single point with the worst residual is  thrown out. The process is repeated, tossing out the point  with the worst residual at each step, until only 10 points  remain. The final straight line is taken to be the actual  drift of the surface echo with respect to the carrier.   (6) An estimate of the noise power is made by averaging 64  frequency bins from 300 spectra on the side OPPOSITE the  surface echo and comparing the average with a system  temperature estimate provided by the DSN Monitor data.  The noise pedestal is removed and the remaining values are  scaled to units of watts.   (7) Five bins centered on the carrier are summed to obtain  the carrier power.   (8) Seven bins centered on the fitted straight line are  summed to obtain the echo power.   (9) The results are tabulated for each of the 300 spectra  and stored in the SRT file.   (10) The array of 300 512-point spectra is saved as the  SRI file.   (11) Fitting of the straight line to the echo trajectory is  not always successful. Column 25 in the header of the SRT  file is set to '0' when the fit is unsatisfactory. In most  cases, this results from a very weak surface echo; in a few  cases, the fitting algorithm simply fails.   Bistatic Radar Power Spectra are sums of 2929 individual  spectra (60 second averages). The spectra have 512 points  and cover 25000 Hz. The ground calibration procedure failed,  so a nominal system temperature of 30 K was assumed for each  channel and the spectra were scaled to have the equivalent  noise power density where there was no direct signal from the  spacecraft and no surface echo.    Data  :  Data are stored on CD-WO volumes approximately in order by the  time at which they were delivered for archiving. A CD volume  of reduced data was prepared approximately every 3-6 months  and forwarded to PDS.   Standard resolution temperature-pressure profiles are stored  in the TPS directory with file names of the form ydddhmmC.TPS  where y is the least significant digit of the year, ddd is  the three-digit day number, h is one-character which denotes  the hour, and mm is a two-character string denoting the  minute in which data acquisition began. h is 'A' if the  hour was 00, 'B' if the hour was 01, ... and 'X' if the hour  was 23. In most cases mm is the two-digit minute; but when  data were collected from two sources and the start time was  in the same minute, the second digit in mm was changed to a  letter in the second file name (minute 00 becomes 0A,  01 becomes 0B, etc.). C is a single character indicating  the version of the file, starting with 'A'.   Occultation summary files are stored in the OCS directory.  File names are of the form YMMymmCC.OCS, where Y is the  one-digit year of the first entry in the file, MM is the  two-digit month of the first entry, y is the one-digit year  of the last entry, and mm is the two-digit month of the last  entry. CC is a two-character string indicating the version  of the file.   ASCII spherical harmonic models are stored in the SHA directory  with file names of the form GTnnnnvv.SHA where  G denotes the generating institution  J for Jet Propulsion Laboratory  G for Goddard Space Flight Center  C for Centre National d'Etudes Spatiales  T denotes the type of data represented  G for gravity field  T for topography  M for magnetic field  nnnn is a 4-character modifier specified by the data producer  vv is a decimal version number, initialized to '01' and  SHA denotes that this is an ASCII file of spherical harmonic  coefficients. The distinction between 'nnnn' and 'vv' is not  enforced strictly, however; in some cases, it has been more  convenient to use all six characters to capture a model name  and/or number used by the data producer.   Binary spherical harmonic models are stored in the SHB  directory with file names of the form GTnnnnvv.SHB where  individual name components are as defined above except for the  SHB suffix.   Radio Science Digital Map products are stored in the IMG  directory with file names of the form GTnnnnnn.IMG where  G denotes the generating institution  J for Jet Propulsion Laboratory  G for Goddard Space Flight Center  C for Centre National d'Etudes Spatiales  S for Stanford University  T denotes the type of data represented  G for free air gravity field  O for geoid  B for Bouguer anomaly  I for isostatic anomaly  T for topography  M for magnetic field  nnnnnn is a 6-character modifier specified by the data  producer and IMG denotes that this is a PDS image object.   Line-of-sight acceleration profiles are stored in the LOS  directory with file names of the form MOnnnnnC.LOS where  nnnnn is the 5-digit orbit number and C is a character  indicating the version (starting from 'A').   Surface Reflection Antenna, Geometry, Image, and Table data  are stored in the SRA, SRG, SRI, and SRT directories,  respectively, with file names constructed using the same  procedure as for the TPS files except that file extensions  are SRA, SRG, SRI, and SRT.   Bistatic Radar Power Spectra are stored in the SPC directory  with file names BSR0135R.SPC and BSR0135L.SPC (there are  only two SPC files, and both are stored in volume MORS_1038).   Each data file is accompanied by a PDS label. If the name  of the data file is zzzzzzzz.ext, then the name of the label  file is zzzzzzzz.LBL.    Ancillary Data  :  When radio occultation data are present on the volume, one  or more files with names of the form OCCLOGxx.TAB may be  included in the DOCUMENT directory. These files list  parameters for each radio occultation data acquisition  opportunity. PDS detached labels OCCLOGxx.LBL describe  the format and contents of the files.    Coordinate System  :  MGS RST SDP files use a Mars centered body-fixed coordinate  system with positive east longitude.   Gravity models generally used the IAU 1991 [DAVIESETAL1992B]  or IAU 2000 [SEIDELMANNETAL2002] coordinate frame, depending  on when the model was constructed. See labels of specific  gravity products for details.    Software  :  None.    Media/Format  :  The archival data set was written on CD-WO media using the  Sun Ultra-5/Yamaha/GEAR CD authoring subsystem provided by  the MGS Project until June 2002. Volumes written later than  June 2002 and before the end of 2006 were written on a  Sun-Ultra5/PlexWriter/cdrtoaster system. Volumes written  in 2007 were written on a Sun-Ultra60/PlexWriter system.  The CD-WO volumes conform to ISO 9660 standards.

Overview  :  Data in this archive have been reduced as part of mission data  analysis activities of the MGS Radio Science Team. Products  of questionable validity have been flagged or omitted.    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) monitored the  submissions.   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, example data files, CATALOG files, and  Software Interface Specifications. These materials were  distributed to PDS personnel, the experiment investigator,  and others, as appropriate.    Data Coverage and Quality  :   MORS_1001  ---------  T-p profiles included in this volume were derived from data  collected while the spacecraft was at nearly maximum  Earth-Mars range; the observations ended just a few days  before solar conjunction. See [HINSONETAL1999] for  discussion of results.   Dates: 1998/01/28 - 1998/04/10  Number of TPS Files: 88  Occultation Sense: Ingress only  Latitudes: 29N - 64S  Solar Zenith Angles: 85 - 106   Significant events during this period were:   YY/DDD Start Stop Comments  ------ -------- -------- ----------------  98/024 19:15:36 19:32:15 First occultation recording  98/076 13:19:18 (ET) Close Phobos approach (380 km)  98/087 02:44:09 First SPO-1 periapsis gravity  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 occultation recording   Quality of data was affected by anomalous conditions during  data acquisition. Specifics are given in the OCCLOGA1.TAB  file in the DOCUMENT directory of MORS_1001; five general  types of problems dominated:   a) 2-6 dB lower carrier-to-noise level at Madrid antennas  throughout the occultation period (98/024-98/118), later  found to be from a weak oscillator in the front end of  the radio science receiver  b) 'Sawtooth' frequency residuals in approximately 10  percent of the data (all stations), later found to be  from an intermittent synchronization error in merging  two data streams at the DSN station  c) Amplitude baseline variations more than +/-0.1 dB  (various)  d) Spurs (occasional, no consistent pattern)  e) Unreliable local oscillator tuning (wrong controller  software) (Madrid antennas, 98/084-98/106)   Gravity models and maps included in this volume were generated from Mariner 9 and Viking data. They do not contain any data  from the Mars Global Surveyor mission; they do, however, serve as the baseline models from which the MGS models evolved.  Labels for each of the gravity products provide more  information on how the models were derived.   JGM50C01.SHA is the pre-MGS Mars gravity model produced at the Jet Propulsion Laboratory under supervision of Bill Sjogren.  JGM50C01.IMG is the free-air gravity map corresponding to this model. It is defined in IAU 1991 coordinates  [DAVIESETAL1992B].   GGM50A01.SHA is the pre-MGS Mars gravity model produced at  Goddard Space Flight Center under supervision of David Smith.  It is defined in IAU 1994 coordinates [DAVIESETAL1995].   GGM50A02.SHA is a slight variation on this model (a coordinate transformation to IAU 1991 coordinates [DAVIESETAL1992B]) used by David Hinson in reduction of radio occultation data  acquired during January-April 1998 and included in this  volume.   MORS_1002  ---------  This volume contains gravity models and maps generated from  Mariner 9, Viking Orbiter, and MGS data collected through  mid-September 1998. The MGS data included tracking results  from Orbit Insertion subphases Aerobraking 1, Science Phasing  Orbit 1, and Science Phasing Orbit 2. Orbit periapsis passed  near Mars' north pole during the summer of 1998, so the data  are particularly good in defining the gravity field of the  north polar region.   GGM0890A.SHA is an ASCII file of coefficients for a 70x70  degree and order field produced at Goddard Space Flight  Center. GGM0890A.IMG is a gridded representation of the  field. Derivation of the model is described by a paper in  both PostScript and LaTeX formats in the DOCUMENT directory  (see DOCUMENT/AAS99147.LBL for details).   JGM75A01.SHA is an ASCII file of coefficients for a 75x75  degree and order field produced at the Jet Propulsion  Laboratory. JGM75A01.SHB is a binary file of covariances.   MORS_1003  ---------  This volume contains gravity models and maps generated from  Viking Orbiter data and from MGS data collected through March  1999. The MGS data include tracking from Orbit Insertion  subphases Aerobraking 1, Science Phasing Orbit 1, Science  Phasing Orbit 2, the Gravity Calibration Orbit, and  approximately the first month of MGS Mapping operations,  while the high-gain antenna was still not deployed. Noise  produced by the control system after HGA deployment corrupted  the tracking data and several months were required before a  solution was found.   GGM0964A.SHA is an ASCII file of coefficients for a 70x70  degree and order field produced at Goddard Space Flight  Center. GGM0890A.IMG is a gridded representation of gravity  anomalies with respect to an evaluation of the Goddard model  to degree and order 50. Derivation of the model is  described by a paper in both PostScript and LaTeX formats in  the DOCUMENT directory (see DOCUMENT/AAS99328.LBL for  details). The Goddard group argues that the MGS data are of  sufficient quality that historic data (Mariner 9 and Viking  Orbiter) can be omitted. Their solution is based solely on  MGS data.   JGM75B01.SHA is an ASCII file of coefficients for a 75x75  degree and order field produced at the Jet Propulsion  Laboratory. JGM75B01.SHB is a binary file of coefficients  and covariances. JGD75B50.IMG is a gridded representation  of gravity anomalies with respect to an evaluation of the  JPL model to degree and order 50. The JPL solution  continues to include Viking Orbiter data.   The Goddard group has also provided a map of uncertainties  in their gravity anomalies; the JPL group has provided a  map of geoid height above a reference ellipsoid.   The BRO directory is new with this volume; it contains  PostScript representations of selected gravity results.   For a discussion of the major conclusions resulting from  study of the gravity field to this point, see [SMITHETAL1999].  MORS_1003 also contains 36 radio occultation profiles of  neutral atmosphere temperature and pressure derived from data  collected in late December 1998. These observations were  made while there was no telemetry modulation on the spacecraft carrier, providing some of the highest signal-to-noise prior  to circularization of the orbit (February 1999). See  [HINSONETAL2001] for more information.   Dates: 1998/12/24 - 1998/12/31  Number of TPS Files: 36  Occultation Sense: Ingress only  Latitudes: 64N - 67N  Solar Zenith Angles: 78 - 81   MORS_1004  ---------  This volume contains a gravity model and maps generated at  JPL from MGS tracking data collected through early November  1999. The MGS data included tracking results from the  following phases/subphases of the mission: Science Phasing  Orbit 1, Science Phasing Orbit 2, Gravity Calibration Orbit,  Fixed High-Gain Antenna Mapping, and the first seven months  of Mapping.   JGM75C01.SHA is an ASCII file of coefficients for a 75x75  degree and order field produced at the Jet Propulsion  Laboratory. JGM75C01.SHB is a binary file of coefficients  and covariances. JGD75C60.IMG is a gridded representation  of gravity anomalies with respect to an evaluation of the  JPL model to degree and order 60. JOD75C60.IMG is a  gridded representation of geoid height with respect to  a reference ellipsoid.   MORS_1004 also contains example files from the Surface  Reflection investigation. 9133H43A.SRG is a summary table  of observing geometry for an occultation starting  1999-133T07:43:00. 9133H43A.SRT is a tabulation of carrier  and surface echo signal characteristics. 9133H43A.SRI is  a two-dimensional array showing signal strength as a  function of both frequency and time around the occultation.  Surface echo was visible while the specular point moved  from about (69S, 91W) to about (68S, 83W).   MORS_1005  ---------  MORS_1005 contains 97 temperature-pressure profiles from  radio occultations acquired during March 1999 while the  spacecraft was in Fixed-High Gain Antenna operations. The  analysis was carried out using the JPL MGS75C gravity model  and associated trajectory reconstructions (see MORS_1004).   Dates: 1999/03/07 - 1999/03/27  Number of TPS Files: 97  Occultation Sense: 48 ingress; 49 egress  Latitudes: 73N - 68N; 74S - 75S  Solar Zenith Angles: 76 - 78; 101 - 98   There are also four sets of three files from the surface  reflection investigation. The new files accompany a single  set of three files which appeared on MORS_1004. All sample  Mars surface at latitudes 68-69S and longitudes 80-105W.   MORS_1006  ---------  MORS_1006 contains 440 temperature-pressure profiles from  radio occultations acquired during May and June 1999 after  the spacecraft recovered from the HGA azimuth anomaly and  resumed Mapping operations. The analysis was carried out  using the JPL MGS75C gravity model and associated trajectory  reconstructions (see MORS_1004).   Dates: 1999/05/06 - 1999/06/27  Orbit Numbers: 712 - 1356  Number of TPS Files: 440  Occultation Sense: Ingress only  Latitudes: 36N - 30S  Solar Zenith Angles: 98 - 119   This volume contains a gravity model and maps generated at JPL from MGS tracking data collected through late March 2000. The model also includes data from Mariner 9 and the two Viking  Orbiters.   JGM75D01.SHA is an ASCII file of coefficients for the 75x75  degree and order gravity field produced at JPL. JGM75D01.SHB  is a binary file of coefficients and covariances. JGD75D60.IMG is a gridded representation of gravity anomalies with respect  to an evaluation of the JPL model to degree and order 60.  JOD75D60.IMG is a gridded representation of geoid height with  respect to a reference ellipsoid.   There are also 105 sets of three files from the surface  reflection investigation. The new files were based on data  collected during March 1999 and sample the surface at  latitudes 70-75 in both the northern (ingress) and southern  (egress) hemispheres.   MORS_1007  ---------  This volume contains only Special Data Products (SPDPs).  Included are 32 electron density profiles derived from  ingress radio occultation data acquired 24-31 December  1998 (latitude approximately 65N). Profiles of the neutral  atmosphere appeared on MORS_1003.   There are also 696 sets of three files from the surface  reflection investigation. The new files were derived from  radio occultations acquired during April-May 1999 and sample  the surface at latitudes of approximately 15-65N (ingress)  and 60-70S (egress).   MORS_1008  ---------  MORS_1008 contains 442 temperature-pressure profiles from  egress radio occultations acquired during May and June 1999  while the spacecraft conducted Mapping operations. The  analysis was carried out using the JPL MGS75C gravity model  and associated trajectory reconstructions (see MORS_1004).  This set of profiles completes the collection based on the  first occultation season in MGS Mapping; the next occultations were obtained starting in December 1999.   Dates: 1999/05/06 - 1999/06/27  Orbit Numbers: 713 - 1348  Number of TPS Files: 442  Occultation Sense: Egress only  Latitudes: 70S - 67S  Solar Zenith Angles: 88 - 79   This volume contains the MGM0964C20 gravity model which was  developed at the Goddard Space Flight Center and which  provided a reference geoid used extensively by the MOLA  team in their data analysis. The model is archived on this  volume primarily for historical purposes. File GGM0964B.SHA  contains ASCII coefficients and uncertainties for the  spherical harmonic model.   Also on the volume is an 80x80 gravity model developed at  GSFC and based on MGS radio tracking data collected through  2000-02-29. No Viking or Mariner 9 data were used in the  solution. File GGM2BC80.SHA contains ASCII coefficients and  uncertainties for the spherical harmonic model. Gravity  anomaly is presented in gridded format in GGM2BA60.IMG at  1 degree resolution. GOM2BA60.IMG contains gridded geoid  values at 0.25 degree resolution. Also available are  three grids of error in the gravity anomaly based on  evaluation of the model using 60x60, 70x70, and 80x80  terms.   There are also 427 sets of three files from the surface  reflection investigation. The new files were based on  data collected during May-June 1999 and sample the surface  at latitudes 15S-15N (ingress) and 60-65S (egress). This  set of SRX files completes the collection based on the first  occultation season in MGS Mapping; the next surface  reflections were obtained starting in December 1999.   MORS_1009  ---------  MORS_1009 contains the 75x75 MGS75E gravity model developed  at JPL and based on MGS radio tracking data collected  through 2000-09-29. Both Viking Orbiter and Mariner 9 data  were also included in the solution. File JGM75E01.SHA  contains ASCII coefficients and uncertainties for the  spherical harmonic model; JGM75E01.SHB is a binary file  containing both coefficients and covariances. Gravity  anomaly is presented as gridded data in JGD75E60.IMG;  JOD75E60.IMG contains gridded geoid height values. The  gridded values were obtained by evaluating the spherical  harmonic coefficients to degree and order 60.   MORS_1010  ---------  MORS_1010 contains 800 atmospheric profiles from radio  occultations captured during late December 1999 through  early February 2000. This was the beginning of the second  MGS radio occultation season; the set ends when operations  began in 'Beta Supplement' -- a configuration that did not  allow routine collection of egress occultations.   Dates: 1999/12/16 - 2000/02/07  Orbit Numbers: 3458 - 4111  Number of TPS Files: 800  Occultation Sense: 389 ingress; 411 egress  Latitudes: 55N - 63N; 0S - 35S  Solar Zenith Angles: 112 - 92; 123 - 110   MORS_1010 also contains 43 profiles of electron density in  the Mars ionosphere. These were derived from occultations  captured during the first three weeks of MGS Mapping  (1999-03-09 through 1999-03-27). Profiles of the neutral  atmosphere appeared on MORS_1005.   MORS_1011  ---------  MORS_1011 contains 577 atmospheric profiles from ingress  radio occultations captured during November-December 2000.  This period included 'Campaign F' in mid-December when  Earth passed through the plane of the MGS orbit and joint  observations were conducted with TES to compare the two  atmospheric probing techniques. MORS_1011 includes 147  profiles from Campaign F.   The above data were reprocessed and released a second time  on MORS_1016. Users should use the results on MORS_1016.   MORS_1011 also includes 134 electron density profiles  derived from the Campaign F data. These data were later  reprocessed; the new results were archived on MORS_1019.   MORS_1012  ---------  MORS_1012 contains results from surface reflection analysis  of 725 radio occultations. These cover 19 December 1999  through 31 January 2000, inclusive. Both ingress and egress  occultations are included, but few of the egress occultations  produced detectable surface echoes.   MORS_1013  ---------  MORS_1013 contains 826 temperature-pressure profiles derived  from ingress radio occultation measurements acquired during  August-October 2000.   The above data were later reprocessed and released a second  time on MORS_1015. Users should use the files on MORS_1015.   MORS_1013 also includes 525 sets of three files from the  surface reflection investigation based on data collected  during February-March 2000. Latitudes sampled include  approximately 32-36S and 48-49S (egress) and 63-68N (ingress). Many more ingress occultations were captured during this  period because of HGA pointing limitations in Beta Supplement  mode.   MORS_1014  ---------  MORS_1014 contains results from surface reflection analysis  of 793 radio occultations. These cover January through March  2001, inclusive. Both ingress and egress occultations are  included, but the number of egress occultations is very small  because of HGA pointing limitations during Beta Supplement  operations. Latitudes sampled include approximately 73S  (egress) and 72-86N (ingress).   MORS_1015  ---------  MORS_1015 includes a new 85x85 degree and order solution for  the gravity field of Mars from the JPL Gravity Science Team  and a new 80x80 solution from the GSFC gravity group.   ASCII spherical harmonic coefficients for the JPL model are in SHA/JGM85F01.SHA; binary coefficients and covariances are in  SHB/JGM85F01.SHB. Images of gravity anomalies and the geoid  are in the IMG directory (files JGD85F60.IMG and JOD85F60.IMG, where each has been evaluated from degree 2 up to degree 60.  The 85F model was derived from Mariner 9, Viking 1/2, and MGS  data collected through 2001-08-14.   GSFC ASCII spherical harmonic coefficients are in the SHA  directory (file GGM1025A.SHA). Images of gravity anomalies  are in the IMG directory (files GGM1025A.IMG and GGM1025B.IMG, where the first was evaluated up to degree 60 and the second  up to degree 66). A Postscript file showing gravity anomalies is in BRO/GGM1025A.PS1. The MGM1025 model was derived solely  from MGS radio tracking data collected through 2001-07-21 and  from MOLA crossover analyses.   The EDS directory contains 220 ionospheric electron density  profiles derived from occultation data collected between  1999/126 and 1999/149. Latitudes ranged from 64S to 69S,  while solar zenith angle decreased from 87 to 78 degrees.  Profiles of the neutral atmosphere appear on MORS_1008.   The TPS directory holds 826 reprocessed atmospheric profiles  for ingress occultations between August (day 214) and October  (day 305) in 2000. The original profiles were released on  MORS_1013. The new profiles are more accurate than the  originals, which contained a small bias caused by motion of  the spacecraft high-gain antenna. The old files had names  of the form ydddHmmA.TPS; the new file names are ydddHmmB.TPS. The OCS directory contains an Occultation Summary File  (008010AB.OCS) for the reprocessed TPS profiles.   Dates: 2000/08/01 - 2000/10/31  Orbit Numbers: 6254 - 7379  Number of TPS Files: 826  Occultation Sense: Ingress only  Latitudes: 67N - 62N  Solar Zenith Angles: 91 - 86   MORS_1016  ---------  The TPS directory contains two sets of atmospheric occultation profiles. First are 125 egress profiles from fixed high-gain  antenna observations scattered through Beta Supplement  operations.   Dates: 2000/05/20 - 2000/05/22  Orbit Numbers: 5370 - 5393  Number of TPS Files: 12  Occultation Sense: Egress only  Latitudes: 75S - 77S  Solar Zenith Angles: 94 - 95   Dates: 2000/08/08 - 2000/08/09  Orbit Numbers: 6346 - 6357  Number of TPS Files: 12  Occultation Sense: Egress only  Latitudes: 73S - 74S  Solar Zenith Angles: 86 - 87   Dates: 2000/09/08 - 2000/09/09  Orbit Numbers: 6726 - 6737  Number of TPS Files: 4  Occultation Sense: Egress only  Latitudes: 67S - 68S  Solar Zenith Angles: 86 - 87   Dates: 2000/10/13 - 2000/10/14  Orbit Numbers: 7154 - 7165  Number of TPS Files: 12  Occultation Sense: Egress only  Latitudes: 64S - 65S  Solar Zenith Angles: 89 - 90   Dates: 2000/11/17 - 2000/11/20  Orbit Numbers: 7582 - 7618  Number of TPS Files: 24  Occultation Sense: Egress only  Latitudes: 65S - 66S  Solar Zenith Angles: 94 - 95   Dates: 2000/12/18 - 2000/12/21  Orbit Numbers: 7961 - 7997  Number of TPS Files: 25  Occultation Sense: Egress only  Latitudes: 69S - 70S  Solar Zenith Angles: 99 - 100   Dates: 2001/01/10 - 2001/01/11  Orbit Numbers: 8243 - 8254  Number of TPS Files: 12  Occultation Sense: Egress only  Latitudes: 73S - 74S  Solar Zenith Angles: 102 - 103   Dates: 2001/04/05 - 2001/04/06  Orbit Numbers: 8243 - 8254  Number of TPS Files: 12  Occultation Sense: Egress only  Latitudes: 89S - 90S  Solar Zenith Angles: 105 - 106   Dates: 2001/05/13 - 2001/05/14  Orbit Numbers: 9747 - 9758  Number of TPS Files: 12  Occultation Sense: Egress only  Latitudes: 83S - 84S  Solar Zenith Angles: 96 - 98   Second are 843 reprocessed profiles from November 2000 through January 2001. The November-December 2000 data were previously released on MORS_1011; the January 2001 data were released  through a Stanford website but were not previously delivered  to PDS. Files 0325Q18B.TPS and 1029D33B.TPS had appeared in  the earlier releases (MORS_1011 and web site, respectively)  but were withdrawn from this release because of severe  degradation by antenna motion and generally poor data quality, respectively.   Dates: 2000/11/01 - 2001/01/31  Orbit Numbers: 7380 - 8504  Number of TPS Files: 843  Occultation Sense: Ingress only  Latitudes: 63N - 78N  Solar Zenith Angles: 87 - 75   The OCS directory has two files. 005105AA.OCS summarizes  the newly released egress profiles from May 2000 through  May 2001. 011101AB.OCS summarizes the reprocessed profiles  from November 2000 through January 2001; it supersedes  011012AA.OCS on MORS_1011 though the earlier file did not  include the January 2001 data.   Also included in this volume are the first 687 Surface  Reflection Antenna (SRA) files. These cover 1999/127  through 1999/178 and may be used in conjunction with SRG,  SRI, and SRT files for the same occultations.   MORS_1017  ---------  The TPS directory contains 433 ingress occultation profiles  derived from data collected in April-May 2000. These data  were reprocessed to improve the correction for high-gain  antenna motion during the experiment, so have file names of  the form ydddHmmB.TPS. The corresponding ydddHmmA.TPS files  were generated, but were never archived.   Dates: 2000/04/01 - 2000/05/31  Orbit Numbers: 4761 - 5504  Number of TPS Files: 433  Occultation Sense: Ingress only  Latitudes: 68N - 74N  Solar Zenith Angles: 87 - 90   The OCS directory includes a single file 004005AB.OCS,  which contains summary data from the 433 TPS files.   The SRA directory contains 693 surface reflection antenna  files covering 1999/354-2000/038.   MORS_1018  ---------  The TPS directory contains 993 ingress occultation profiles  derived from data collected in February-June 2001. These  data have file names of the form ydddHmmA.TPS. Scattered  egress occultations from the same period are in MORS_1016.   Dates: 2001/02/01 - 2001/06/20  Orbit Numbers: 8505 - 10212  Number of TPS Files: 993  Occultation Sense: Ingress only  Latitudes: 85N - 51N  Solar Zenith Angles: 71 - 97   The OCS directory includes a single file 102106AA.OCS,  which contains summary data from the 993 TPS files.   The SRA directory contains 599 surface reflection antenna  files covering 2001/001 - 2001/090.   MORS_1019  ---------  The TPS directory contains 360 occultation profiles derived  from data collected in June and July 2000. These data have  file names of the form ydddHmmA.TPS.   Dates: 2001/06/21 - 2001/07/15  Orbit Numbers: 10221-10517  Number of TPS Files: 181  Occultation Sense: Ingress  Latitudes: 51N - 9N  Solar Zenith Angles: 97 - 114   Dates: 2001/06/21 - 2001/07/16  Orbit Numbers: 10221-10534  Number of TPS Files: 179  Occultation Sense: Egress  Latitudes: 70S - 47S  Solar Zenith Angles: 87 - 95   The OCS directory includes a single file 106107AB.OCS,  which contains summary data on the TPS files.   The EDS directory includes 134 reprocessed electron density  files from 9-21 December 2000; these have file names of the  form ydddHmmB.EDS and replace results originally released  on MORS_1011. The reprocessing included improved correction  for high-gain antenna motion, which may have left artifacts  in the earlier profiles. There are also 314 new electron  density files covering 22 December 2000 to 31 January 2001  with names ydddHmmA.EDS.   The SHA directory includes ASCII coefficients and uncertainties for the JPL 85x85 MGS85H2 spherical harmonic model of the Mars  gravity field. The model was derived from MGS, 2001 Mars  Odyssey, Mars Pathfinder, and Viking 1 Lander data. No Viking  Orbiter or Mariner 9 data are included. The model is  referenced to a Mars fixed frame similar to the Mars Pathfinder orientation model except that the prime meridian has been made  consistent with the IAU 2000 coordinate frame.   MORS_1020  ---------  The TPS directory contains 742 occultation profiles derived  from data collected in February 2000 and March-May 2002. The  data from 2000 were delayed because of problems in the  reconstructed spacecraft orbits. The TPS data have file names of the form ydddHmmA.TPS.   Dates: 2000/02/08 - 2000/02/29  Orbit Numbers: 4112 - 4380  Number of TPS Files: 170  Occultation Sense: Ingress  Latitudes: 63 - 64 N  Solar Zenith Angles: 92 - 89   Dates: 2002/03/14 - 2002/05/17  Orbit Numbers: 13470 - 14264  Number of TPS Files: 572  Occultation Sense: Ingress  Latitudes: 66 -63 N  Solar Zenith Angles: 88 - 91   The OCS directory includes two files (002002AA.OCS and  203205AA.OCS) which contain summary data on the TPS files.   MORS_1021  ---------  The TPS directory contains 1259 occultation profiles derived  from data collected in March 2000 and from 13 December 2001  through 13 March 2002. The data from 2000 were delayed  because of problems in the reconstructed spacecraft orbits.  The TPS data have file names of the form ydddHmmA.TPS. The  summary file is in the OCS directory.   Dates: 2000/03/01 - 2000/03/31  Orbit Numbers: 4381 - 4760  Number of TPS Files: 214 9  Occultation Sense: Ingress Egress  Latitudes: 64 - 68 N 47 - 48 S  Solar Zenith Angles: 89 - 88 106 - 105  Summary File: 003003AA.OCS   Dates: 2001/12/13 - 2002/03/13  Orbit Numbers: 12368 - 13470  Number of TPS Files: 563  Occultation Sense: Egress  Latitudes: 11 N - 45 S  Solar Zenith Angles: 132 - 114  Summary File: 112203AA.OCS   Dates: 2002/01/08 - 2002/03/13  Orbit Numbers: 12678 - 13469  Number of TPS Files: 473  Occultation Sense: Ingress  Latitudes: 62 - 66 N  Solar Zenith Angles: 96 - 88  Summary File: 201203AA.OCS   The SHA directory contains ASCII coefficients for a 90x90  gravity model (GGM1041C.SHA) developed by the group at  Goddard Space Flight Center. This model is based on MGS  data collected through 27 May 2002. The IMG directory  contains maps showing gravity anomalies and the geoid  evaluated from the first 60, 66, and 72 terms of the 90x90  model.   MORS_1022  ---------  The TPS directory contains 536 occultation profiles derived  from data collected from May to July 2002, immediately prior  to solar conjunction when signal-to-noise is lowest. All  occultations were ingress occultations. The TPS data  have file names of the form ydddHmmA.TPS. The summary file  is in the OCS directory.   Dates: 2002/05/18 - 2002/07/15  Orbit Numbers: 14265 - 14978  Occultation Sense: Ingress Egress  Number of TPS Files: 536 0  Latitudes: 55 - 63 N N/A  Solar Zenith Angles: 90 - 92 deg N/A  Summary File: 205207AA.OCS   MORS_1023  ---------  The TPS directory contains 523 occultation profiles derived  from data collected in September and October 2002, immediately  after solar conjunction when signal-to-noise is lowest. All  occultations were ingress occultations. The TPS data  have file names of the form ydddHmmA.TPS. The summary file  is in the OCS directory.   Dates: 2002/09/08 - 2002/10/31  Orbit Numbers: 15648 - 16307  Occultation Sense: Ingress Egress  Number of TPS Files: 523 0  Latitudes: 53 - 60 N N/A  Solar Zenith Angles: 83 - 89 deg N/A  Summary File: 209210AA.OCS   The EDS directory contains 284 profiles of electron density  from data collected in November and December 2000. All of  these were ingress ionospheric occultations. The EDS data  have file names of the form ydddHmmA.EDS.   Dates: 2000/11/04 - 2000/12/08  Orbit Numbers: 7380 - 7844  Occultation Sense: Ingress Egress  Number of Files: 284 0  Latitudes: 63 - 68 N N/A  Solar Zenith Angles: 82 - 87 deg N/A   MORS_1024  ---------  The TPS directory contains 1225 occultation profiles derived  from data collected between November 2002 and March 2003, as  Earth-Mars geometry moved from post-conjunction to near-  opposition. All occultations were ingress occultations. The  TPS data have file names of the form ydddHmmA.TPS. Two  summary files are in the OCS directory.   Dates: 2002/11/01 - 2003/03/21  Orbit Numbers: 16308 - 18030  Occultation Sense: Ingress  Number of TPS Files: 1225  Latitudes: 60N to 83 N  Solar Zenith Angles: 83 to 70  Summary Files: 211212AA.OCS (Nov-Dec 2002)  301303AA.OCS (Jan-Mar 2003)   The EDS directory includes 840 electron density profiles  from 1 February to 6 June 2001; these have file names of the  form ydddHmmB.EDS. All are ingress occultations with  solar zenith angles between 71 and 87 degrees.   The SHA directory includes ASCII coefficients and uncertainties for the JPL 85x85 MGS85F2 spherical harmonic model of the Mars  gravity field. The model has been adopted by several flight  projects including Mars Reconnaissance Orbiter and Mars  Express. The model is referenced to a Mars fixed frame similar to the Mars Pathfinder orientation model except that the prime  meridian has been made consistent with the IAU 2000 coordinate  frame. Also included is the JPL 95x95 model MGS95I, a more  recent and larger model.   MORS_1025  ---------  The TPS directory contains 697 occultation profiles derived  from data collected between March and June 2003, as  Earth-Mars geometry moved from post-conjunction to near-  opposition. All occultations were ingress occultations. The  TPS data have file names of the form ydddHmmA.TPS. One  summary file is in the OCS directory.   Dates: 2003/03/22 - 2003/06/10  Orbit Numbers: 18039 - 19020  Occultation Sense: Ingress  Number of TPS Files: 697  Latitudes: 81 N to 69N  Solar Zenith Angles: 70 - 81  Summary Files: 303306AA.OCS (Mar-Jun 2003)   MORS_1026  ---------  The TPS directory contains 640 occultation profiles derived  from data collected between June and September 2003, as  Earth-Mars geometry moved through opposition. All  occultations were ingress occultations. The TPS data have  file names of the form ydddHmmA.TPS. One summary file is  in the OCS directory.   Dates: 2003/06/18 - 2003/09/10  Orbit Numbers: 19114 - 20149  Occultation Sense: Ingress  Number of TPS Files: 640  Latitudes: 65 N to 70N  Solar Zenith Angles: 82 - 99  Summary File: 306309AA.OCS (Jun-Sep 2003)   MORS_1027  ---------  The TPS directory contains 84 egress occultation profiles  derived from data collected between September 2002 and  August 2003, as Earth-Mars geometry moved toward opposition.  All occultations were collected as part of special egress  campaigns. The TPS data have file names of the form  ydddHmmA.TPS. One summary file is in the OCS directory.   Dates: 2002/09/30 - 2003/08/18  Orbit Numbers: 15924 - 19857  Occultation Sense: Egress  Number of TPS Files: 84  Latitudes: 62 S to 90 S  Solar Zenith Angles: 83 - 105  Summary File: 209308AA.OCS   The EDS directory contains 526 ingress electron density  profiles collected between November and December 2002.  File names have the form ydddHmmA.EDS.   Dates: 2002/11/01 - 2002/12/31  Orbit Numbers: 16308 - 17051  Occultation Sense: Ingress  Number of EDS Files: 526  Latitudes: 60 - 74 N  Solar Zenith Angles: 84 to 76  Summary File: none   MORS_1028  ---------  The TPS directory contains 405 occultation profiles derived  from data collected between September and October 2003  as Earth-Mars geometry moved away from opposition. The TPS  file names have the form ydddHmmA.TPS. One summary file is  in the OCS directory.   Dates: 2003/09/11 - 2003/09/11 -  2003/09/28 2003/10/18  Orbit Numbers: 20150 - 20367 20151 - 20615  Occultation Sense: Ingress Egress  Number of TPS Files: 172 233  Latitudes: 60 - 66 N 1 - 45 S  Solar Zenith Angles: 105 - 98 92 - 124  Summary File: 309310AA.OCS 309310AA.OCS   The EDS directory contains 650 ingress electron density  profiles collected between January and March 2003.  File names have the form ydddHmmA.EDS.   Dates: 2003/01/01 - 2003/03/21  Orbit Numbers: 17057 - 18030  Occultation Sense: Ingress  Number of TPS Files: 650  Latitudes: 73 - 84 N  Solar Zenith Angles: 76 - 71  Summary File: none   MORS_1029  ---------  The TPS directory contains 436 occultation profiles derived  from data collected between November 2003 and January 2004  as Earth-Mars geometry moved away from opposition. The TPS  file names have the form ydddHmmA.TPS. One summary file is  in the OCS directory.   Dates: 2003/11/16 - 2004/01/19  Orbit Numbers: 20958 - 21752  Occultation Sense: Egress  Number of TPS Files: 436  Latitudes: 11 N to 11 S  Solar Zenith Angles: 130 -132  Summary File: 311401AA.OCS   The EDS directory contains 630 ingress electron density  profiles collected between March and June 2004. File names  have the form ydddHmmA.EDS.   Dates: 2003/03/22 - 2003/06/04  Orbit Numbers: 18039 - 18948  Occultation Sense: Ingress  Number of EDS Files: 630  Latitudes: 81 - 69 N  Solar Zenith Angles: 71-80  Summary File: none   MORS_1030  ---------  The TPS directory contains 1111 occultation profiles derived  from data collected between 1 March and 24 May as Mars moved  toward solar conjunction. Both ingress and egress  occultations are included, at virtually a constant 14 degree  angle from grazing. The TPS file names have the form  ydddHmmA.TPS. One summary file is in the OCS directory.   Dates: 2004/03/01 - 2004/05/24  Orbit Numbers: 22255 - 23292  Occultation Sense: Egress (691); Ingress (420)  Number of TPS Files: 1111  Latitudes: -26 to -61 (egr); 45 to 37 (ing)  Solar Zenith Angles: 125 to 109 (egr); 98 to 100 (ing) Summary File: 403405AA.OCS   The EDS directory contains 76 ingress electron density  profiles collected between 22 June and 2 July 2003, about two  months before opposition. File names have the form  ydddHmmA.EDS.   Dates: 2003/06/22 - 2003/07/02  Orbit Numbers: 19163 - 19289  Occultation Sense: Ingress  Number of EDS Files: 76  Latitudes: 68 N  Solar Zenith Angles: 83 - 85  Summary File: none   MORS_1031  ---------  The TPS directory contains 819 occultation profiles. Data  collected after 21 July were contaminated by anomalous HGA  motion and solar noise; conjunction was in mid-September.  Both ingress and egress occultations are included. TPS file  names have the form ydddHmmA.TPS. One summary file is in the  OCS directory.   Dates: 2004/05/25 - 2004/07/21  Orbit Numbers: 23293 - 24002  Occultation Sense: Egress (286); Ingress (533)  Number of TPS Files: 819  Latitudes: -72 to -69 (egr); 36 to 34 (ing)  Solar Zenith Angles: 100 to 92  Summary File: 405407AA.OCS   MORS_1032  ---------  The TPS directory contains 696 occultation profiles. Early  data were noisy because of the solar conjunction in September.  These are mostly ingress occultations; a handful of egress  occultations were captured in two special campaigns. TPS file  names have the form ydddHmmA.TPS. One summary file is in the  OCS directory.   Dates: 2004/10/10 - 2004/12/22  Orbit Numbers: 24982 - 25878  Occultation Sense: Egress (15); Ingress (681)  Number of TPS Files: 696  Latitudes: -66 and -76 (egr); 48 - 68 (ing)  Solar Zenith Angles: 91 and 96 (egr); 87 to 76 (ing)  Summary File: 410412AA.OCS   MORS_1033  ---------  The TPS directory contains 898 occultation profiles. Data  quality improved as the ray path moved away from the Sun  (solar superior conjunction in September 2004) and Earth-Mars  distance decreased. These are mostly ingress occultations; a  handful of egress occultations were captured in a special  campaign. TPS file names have the form ydddHmmA.TPS. One  summary file is in the OCS directory.   Dates: 2004/12/26 - 2005/04/01  Orbit Numbers: 25923 - 27096  Occultation Sense: Egress (9); Ingress (889)  Number of TPS Files: 898  Latitudes: -78 to -79 (egr); 69 to 79 (ing)  Solar Zenith Angles: 100 (egr); 72 to 76 (ing)  Summary File: 412504AA.OCS   The SHA directory includes ASCII coefficients and uncertainties for the JPL 95x95 MGS95J spherical harmonic model of the Mars  gravity field. The model is referenced to a Mars fixed frame  similar to the Mars Pathfinder orientation model except that  the prime meridian has been made consistent with the IAU 2000  coordinate frame. The model is based on radio tracking data  from MGS, 2001 Mars Odyssey, Pathfinder, and Viking Lander 1;  data from the Viking Orbiters and Mariner 9 were omitted  because they did not seem to improve the solution.   MORS_1034  ---------  The TPS directory contains 1568 occultation profiles. Data  quality improved as the ray path moved away from the Sun  (solar superior conjunction in September 2004) and Earth-Mars  distance decreased. These are mostly ingress occultations; a  handful of egress occultations were captured in special  campaigns. TPS file names have the form ydddHmmA.TPS. Two  summary files are in the OCS directory.   Dates: 2005/04/01 - 2005/08/26  Orbit Numbers: 27099 - 28902  Occultation Sense: Egress (14); Ingress (1554)  Number of TPS Files: 1568  Latitudes: -69, -64 (egr); 65 - 76 (ing)  Solar Zenith Angles: 99, 96 (egr); 75 - 106 (ing)  Summary Files: 504506AA.OCS, 507508AA.OCS   MORS_1035  ---------  The TPS directory contains 1011 occultation profiles, about  equally divided between ingress and egress. The dates were  September to mid-November 2005, bracketing opposition.  TPS file names have the form ydddHmmA.TPS. The summary file  is 509511AA.OCS in the OCS directory.   Dates: 2005/09/09 to 2005/11/10  Orbit Numbers: 29066 - 29836  Occultation Sense: Egress (567); Ingress (444)  Latitudes: 78-67 S (egr); 79-71 N (ing)  Solar Zenith Angles: 80-92 (egr); 106-89 (ing)   The EDS directory contains 947 electron density profiles  for the ionosphere from ingress occultations collected  between November 2004 (shortly after solar conjunction) to  mid-March 2005. EDS file names are of the form ydddHmmA.EDS.   Dates: 2004/11/23 to 2005/03/10  Orbit Numbers: 25523 - 26839  Occultation Sense: Ingress (947)  Latitudes: 62N to 80N, then back to 76N  Solar Zenith Angles: 81 to 73   MORS_1036  ---------  The TPS directory contains 997 occultation profiles, about  equally divided between ingress and egress. The dates were  mid-November through December 2005, after opposition.  TPS file names have the form ydddHmmA.TPS. The summary file  is 511512AA.OCS in the OCS directory.   Dates: 2005/11/11 to 2005/12/31  Orbit Numbers: 29836 - 30458  Occultation Sense: Egress (490); Ingress (507)  Latitudes: 67-34 S (egr); 71-63 N (ing)  Solar Zenith Angles: 92-122 (egr); 87-89 (ing)   The EDS directory contains 904 electron density profiles  for the ionosphere from ingress occultations collected  between mid-March 2005 and mid-June 2005. EDS file names  are of the form ydddHmmA.EDS.   Dates: 2005/03/11 to 2005/06/09  Orbit Numbers: 26840 - 27952  Occultation Sense: Ingress (904)  Latitudes: 76N to 65N  Solar Zenith Angles: 74 to 89 deg   MORS_1037  ---------  The TPS directory contains 690 occultation profiles in two  groups (January-February and May-June 2006), about equally  divided between ingress and egress. TPS file names have the  form GdddHmmA.TPS, where 'G' denotes 2006, a convention  adopted to avoid confusion with '6' which denotes 1996 in  some MGS file types. The summary files are G01G02AA.OCS  and G05G06AA.OCS in the OCS directory.   Dates: 2006/01/01 to 2006/02/19  Orbit Numbers: 30461 - 31068  Occultation Sense: Egress (206); Ingress (103)  Latitudes: 31-23 S (egr); 62-60 N (ing)  Solar Zenith Angles: 124-129 (egr); 88-91 (ing)   Dates: 2006/05/10 to 2006/06/30  Orbit Numbers: 32041 - 32673  Occultation Sense: Egress (248); Ingress (133)  Latitudes: 56-70 S (egr); 13-18 N (ing)  Solar Zenith Angles: 115-107 (egr); 103-97 (egr)   There are no data between 2006/02/19 and 2006/05/10 because  the observing geometry gave almost grazing occultations.  Although the raypath reached the surface, the cut through the  atmosphere was more horizontal than vertical and reliable  profiles could not be derived.   MORS_1038  ---------  The TPS directory contains 1423 occultation profiles, about  equally divided between ingress and egress. The dates were  early July through mid-September 2006, approaching solar  conjunction. TPS file names have the form GdddHmmA.TPS,  where 'G' denotes 2006, a convention adopted to avoid  confusion with '6' which denotes 1996 in some MGS file types.  The summary file is G07G09AA.OCS in the OCS directory.   Dates: 2006/07/01 to 2006/09/19  Orbit Numbers: 32673 - 33664  Occultation Sense: Egress (714); Ingress (709)  Latitudes: 70-63 S (egr); 18-36 N (ing)  Solar Zenith Angles: 97-88 (egr); 108-95 (ing)   The SPC directory has one pair of files containing bistatic  radar power spectra from an experiment conducted on  2000-05-14. Each file is a table holding spectra with either  right-circular or left-circular polarization (RCP or LCP  respectively). There are nine spectra in each file; each is  an average over 60 seconds. The ground track in this  experiment went very close to the target landing site of the  failed MPL/DS2 spacecraft [SIMPSON&TYLER2001].    Limitations  :  The limitations in this data set follow from the quality of  the execution, which is described above under Data Coverage  and Quality.