Data Set Information
DATA_SET_NAME MO MARS RADIO SCIENCE 1 ORIGINAL/INTERMEDIATE DATA REC V1.0
DATA_SET_ID MO-M-RSS-1-OIDR-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : The data set consists of several CD-WO volumes which contain radiometric and open loop data acquired from the Mars Observer spacecraft during its Cruise between Earth and Mars. The basic data are supplemented by ancillary data including DSN weather files and media calibrations, spacecraft maneuver information, and operations schedules. The fourteen data types are listed in the table below, then explained in more detail in the sections that follow. Angular Momentum Desaturation Files DSN Ionosphere Calibration Files DSN Troposphere Calibration Files DSN Time and Polar Motion Files DSN Weather Data Light Time Files Manuever Implementation Files Maneuver Performance Data Files Orbit Data Files Original Data Records Original Data Streams Space Flight Operations Schedules Sequence of Events Files Tracking Data Files Data : (1) ANGULAR MOMENTUM DESATURATION FILES Angular Momentum Desaturation files contain predicted times and durations of angular momentum desaturation events. The Mars Observer hydrazine thrusters were used to unload momentum stored by the spacecraft reaction wheels. The files were created by the Mars Observer Navigation Team under the direction of P. Esposito. They are used by Mars Observer Radio Science investigators to interpret non-gravitational changes in the spacecraft trajectory and/or orientation. The files are described by Mars Observer Software Interface Specification EAE003, except that the SFDU header record has been removed and the simple delimiter specified by the SIS after each record (line) has been replaced by a pair in this archival volume. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (2) DSN IONOSPHERE CALIBRATION FILES DSN Ionosphere Calibration Files are one of three types of Media Calibration Files generated by the DSN Tracking System Analytic Calibration Team. The calibrations comprise corrections for the effects of transmission media (troposphere, ionosphere, and solar plasma) on radiometric data and are used by Mars Observer Radio Science investigators and others. The files are described by Mars Observer Software Interface Specification DACE006, except that the SFDU header record has been removed and the simple delimiter specified by the SIS after each record (line) has been replaced by a pair in this archival volume. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (3) DSN TROPOSPHERE CALIBRATION FILES DSN Troposphere Calibration Files are one of three types of Media Calibration Files generated by the DSN Tracking System Analytic Calibration Team. The calibrations comprise corrections for the effects of transmission media (troposphere, ionosphere, and solar plasma) on radiometric data and are used by Mars Observer Radio Science investigators and others. The files are described by Mars Observer Software Interface Specification DACE006, except that the SFDU header record has been removed and the simple delimiter specified by the SIS after each record (line) has been replaced by a pair in this archival volume. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (4) DSN TIME AND POLAR MOTION FILES DSN Time and Polar Motion Files contain predictions and past history of Earth rotation, including rate of rotation and changes in the rotation axis. These data are used in performing precise orbit determinations by Mars Observer Radio Science investigators and others. The files are described by Mars Observer Software Interface Specification DACE007, except that the SFDU header record has been removed and the simple delimiter specified by the SIS after each record (line) has been replaced by a pair in this archival volume. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (5) DSN WEATHER DATA FILES DSN Weather Data files contain hourly records of temperature, barometric pressure, relative humidity, dew point, and water vapor partial pressure at each of the three DSN communication complexes. They are compiled by the DSN Tracking System Analysis Calibration Team and were deposited on a regular basis in the MO PDB. The files are described by Mars Observer Software Interface Specification DACE022, except that the SFDU header record has been removed and the simple delimiter specified by the SIS after each record (line) has been replaced by a pair in this archival volume. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (6) LIGHT TIME FILES Light Time Files contain one-way light time data (set of points SCE vs OWCT) between Earth (geocentric or topocentric) and the Mars Observer spacecraft. The files are produced by the Mars Observer Navigation Team. The files are described by Mars Observer Software Interface Specification NAE002, except that the SFDU header record has been removed and the simple delimiter specified by the SIS after each record (line) has been replaced by a pair in this archival volume. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (7) MANEUVER IMPLEMENTATION FILES Maneuver Implementation/Reconstruction Files contain commands, attitudes, velocities, and statistics associated with Trajectory Change Maneuvers. The files were produced by the Mars Observer Spacecraft Team. The files are described by Mars Observer Software Interface Specification EAE014, except that the SFDU header record has been removed and the simple delimiter specified by the SIS after each record (line) has been replaced by a pair in this archival volume. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (8) MANEUVER PERFORMANCE FILES Maneuver Performance Data Files contain data necessary for the Mars Observer Navigation Team to plan and design specific spacecraft maneuvers.Included are spacecraft physical parameters and thruster information such as mass, location of the center mass, moments of inertia, effective thruster directions and magnitudes, thruster locations, and propellant flow rate. Maneuver Performance Data Files were produced by the Mars Observer Spacecraft Team. The files are described by Mars Observer Software Interface Specification EAE008, except that the SFDU header record has been removed and the simple delimiter specified by the SIS after each record (line) has been replaced by a pair in this archival volume. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (9) ORBIT DATA FILES Orbit Data Files contain edited radiometric and VLBI data used to navigate the spacecraft. They may also contain calibrations and corrections to range data for a tracking station and spacecraft signal time-delay. Each ODF is made up of 36-byte records, of which there are 13 types: 6 header types, 6 data types, and one end-of-file marker. The ODF is produced by the DSN Radio Metric Data Conditioning Team. Record formats are described in Mars Observer Software Interface Specification DACE005. The archival form of the ODF has been modified by removal of its SFDU header. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (10) ORIGINAL DATA RECORD and ORIGINAL DATA STREAM Original Data Records and Original Data Streams are time- ordered 8- or 12-bit samples of Open-Loop Receiver baseband amplifier output voltages. Individual records vary from 466 to 4166 bytes (not including SFDU headers), of which the first 166 bytes contain header information (time tags, settings for the receiver, channel assignments, local oscillator frequency) and the remaining bytes are the samples from up to four separate receiver outputs. The length of the individual records depends on the sampling rate and the channel assignments. The ODS is an electronic file, the successor to the (magnetic tape) Original Data Record (ODR). The ODS is constructed from packets stored in the Mars Observer Project Data Base. The format is described by Mars Observer Software Interface DACE046. The ODR is described by DSN SIS RSC-11-11. Radio science investigators use the digital data to derive amplitude and phase of the signal received from the spacecraft by the Deep Space Network antenna. In mid-April 1993 electronic transmission of Open-Loop data between the DSN stations and the Mars Observer PDB was enabled. With one exception, when electronic transmission failed, ODS data were obtained after that rather than ODR. Unless independent information is available, each ODS must be self-calibrated to determine the original signal strength, frequency, and phase. Summary notes on individual tests: Test #1: 1992-296 (22 Oct 92) at DSS 15 Equipment incorrectly configured: DSP mode 1 at 5000 samples per channel was set up instead of mode 2 at 2000 samples per channel. This proved useful in analysis, however. One A-D converter was defective; the others were not linear; redundancy from mode 1 configuration allowed quantitative measurement of errors. It also became apparent that the A-D converters had never been used/tested for 12-bit output; DSN personnel later admitted that accuracy was never guaranteed for more than about 7 bits. No signal for approximately the first 1000 seconds; operator adjustments continued in both frequency and amplitude until about 1600 secs. Four tapes received, but none were contiguous. Modulation on the signal is apparent at long periods (100 min from spacecraft rotation), medium periods (a few minutes, perhaps from CONSCAN), and short periods. Test #2: 1992-312 (7 Nov 92) at DSS 15 Similar problems to Test #1, but configuration was for 2000 samples per second per channel instead of 5000. In addition, pulse modulation (17 percent duty cycle, 0.6 sec period with 90 deg phase shift) appears on signal output. POCA frequencies and rates were inconsistent at break points. Three tapes. Test #3: 1992-325 (20 Nov 92) at DSS 15 This test was run with the spacecraft in occultation configuration -- with telemetry off. Ground problems were similar to those encountered during Test #1. The first tape (of 3 total) was unreadable after about 4 minutes of data and was returned to JPL for analysis. 60 Hz modulation was detected on the carrier. Test #4: 1992-340 (5 Dec 92) at DSS 15 A-D failure was repaired, but A-Ds remain non-linear and are not well matched. One tape was delivered to Stanford; two others were received at JPL but were not copied because they contained only about a minute of data. Long- and medium-period modulation remains, presumably from spacecraft and/or ground antenna motions. Inconsistent POCA frequency and rate readings are noted at POCA break points. HGA Calibration: 1993-008 (8 Jan 93) at DSS 65 Data acquired for radio science analysis, but this was not an official test. First test using facility other than DSS 15. Many operator-initiated gain changes, many artifacts of A-D non- linearity, and 60 Hz modulation on carrier. On the other hand, there were no problems in POCA reading at break points in tuning profile. Three tapes received at Stanford. USO Test #5: 1992-354 (19 Dec 92) at DSS 45 Failed. No tapes received. USO Test #6: 1993-014 (14 Jan 93) at DSS 65 Similar to HGA Calibration, but more spurious signals identified during analysis. May still be the best USO Test data so far. Sticksion events identified; 1 Hz modulation found. One ODR tape covers almost 2 hrs. USO Test #7: 1993-049 (18 Feb 93) at DSS 15 Similar to Test #6. POCA inconsistencies seen previously at DSS 15 not present. 60 Hz modulation not present, but 180 Hz spurs seen. Overall, good data. USO Test #8: 1993-064 (5 Mar 93) at DSS 45 Single tape received, but its block size was far smaller than expected.DSN personnel were unable to explain how software settings could be over-ridden. No analysis performed; tape returned to JPL for investigation. USO Test #9: 1993-079 (20 Mar 93) at DSS 65 Antenna stopped tracking after 35 minutes; resumed after about 1 hour.Four tapes of contiguous data were obtained covering more than 2-1/2 hrs.Spurious signals 665 Hz from carrier. Among the best data to date. USO Test #10: 1993-107 (17 Apr 93) No data USO Test #11: 1993-116 (26 Apr 93) at DSS 65 First attempt to transfer test data electronically (ODS). Initially many records did not get through, but later queries resulted in almost complete recovery of data (36001 full records). Many POCA offsets during test. RS ORT Test #1: 1993-129 (9 May 93) Spacecraft in contingency mode; test canceled. USO Test #12: 1993-131 (11 May 93) Spacecraft in contingency mode; test canceled. USO Test #13: 1993-146 (26 May 93) at DSS 45 All ODS records expected (28800) were recovered within 14 hrs. Data quality, with the exception of A-D conversion artifacts, was excellent. Some modulation sidebands on carrier from unknown sources. A-D #3 was not operating correctly in low bits. RS ORT Test #2: 1993-154 (3 Jun 93) at DSS 45 Test data were collected continuously over 7 hrs rather than in short bursts because Event File could not be loaded at station. ODS transfer failed after first hour; resumed 90 minutes later. None of early data could ever be located, however. Of the later data, only the 10 minutes of each scheduled test interval were analyzed. Minor timing anomalies, some low level spurs, and one ailing A-D converter. USO Test #14: 1993-161 (10 Jun 93) at DSS 65 A few samples lost at the beginning. Otherwise, this was a very good test. RS ORT Test #3: 1993-175 (24 Jun 93) at DSS 65 Nearly complete ODS data recovery. Anomalous short records found at the end of data acquisition periods. CONSCAN state was not always as requested. USO Test #15: 1993-177 (26 Jun 93) at DSS 45 Scattered records lost, but data quality excellent otherwise. Usual problems with A-D artifacts. 170 Hz modulation spurs on each side of carrier USO Test #16: 1993-191 (10 Jul 93) at DSS 65 Data collected in occultation configuration (spacecraft telemetry off), but ODS transmission was not enabled so all data went to tape (3 tapes). Some data appeared in the MO PDB NERT Cache a few days later, however, but it had bad record numbers and time tags. Second (ODR) tape had scattered added samples; third tape had extra byte. USO Test #17: 1993-203 (22 Jul 93) at DSS 15 Incorrect configuration at station for first 22 minutes; otherwise data quality is good. (11) SPACE FLIGHT OPERATIONS SCHEDULES Space Flight Operations Schedule Files contain information about states and events of importance to the Mars Observer Project. Although the SFOS file itself is ASCII, it is intended to be used in conjunction with the sfosedt application program, which displays the operations schedule graphically. SFOS Files were produced by the Mars Observer Planning and Sequencing Team, typically covering two week periods but issued every seven days. The SFOS file format is described by Mars Observer Software Interface Specification PSE003. The archival form of the SFOS File has been modified by removal of its original SFDU header, by removal of a leading character at the beginning of the data file, and by substitution of pairs for the original record/line delimiters. The SFOS File must be returned to its original format before it can be used with the sfosedt utility. Other than the comments above, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (12) SEQUENCE OF EVENT FILES Sequence of Events Files are time-ordered lists of activities of interest to the Mars Observer Project. Although the SOE file itself is ASCII, it is intended to be used in conjunction with the soeedt application program, which displays the schedule in a formatted table. SOE Files were produced by the Mars Observer Planning and Sequencing Team, typically covering more than two week periods but issued every seven days. The SOE File format is described by Mars Observer Software Interface Specification PSE002. The archival form of the SOE File has been modified by removal of its original SFDU header, by removal of a leading character at the beginning of the data file, and by substitution of pairs for the original record/line delimiters. The SOE File must be returned to its original format before it can be used with the soeedt utility. Other than the comments above, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files. (13) TRACKING DATA FILES Tracking Data Files contain all raw radiometric and VLBI data, subject to minor editing of 'bad' points. Data include angle, Doppler measurements, range measurements, differenced range vs integrated Doppler (DRVID) values, programmed frequency data, pseudo-residual data, and validation data. A single TDF will contain data for only one spacecraft, but it may contain data collected from several tracking stations and for several days. Each TDF is produced by the DSN Radio Metric Data Conditioning Team. Each TDF is made up of one File Identification Logical Record, one Transponder Logical Record, and many time-ordered Tracking Data Logical Records. Each record has a length of 288 bytes. Record formats are described in Mars Observer Software Interface Specification DACE004. The archival form of the TDF has been modified by removal of its SFDU header. Otherwise, the MO Radio Science Team has no independent knowledge of the content, format, or accuracy of the data in these files.
DATA_SET_RELEASE_DATE 1994-07-01T00:00:00.000Z
START_TIME 1971-01-01T12:00:00.000Z
STOP_TIME 1993-12-31T12:00:00.000Z
MISSION_NAME MARS OBSERVER
MISSION_START_DATE 1992-09-25T12:00:00.000Z
MISSION_STOP_DATE 1993-08-21T12:00:00.000Z
TARGET_NAME MARS
TARGET_TYPE PLANET
INSTRUMENT_HOST_ID MO
INSTRUMENT_NAME RADIO SCIENCE SUBSYSTEM
INSTRUMENT_ID RSS
INSTRUMENT_TYPE RADIO SCIENCE
NODE_NAME Engineering
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : Quality of the ODR/ODS data from the Mars Observer Cruise tests is variable. Initially hardware failures and incorrect configurations corrupted the data. That is, the digital samples largely reflected the receiver output, but were not accurate representations of the microwave signal being captured by the antenna. During later tests, the performance improved but it never reached the level required for Mars Observer Mapping. See comments in DATA_SET_DESC on individual test results; spacecraft operations were always nominal, but ground performance varied. Quality of the other data sets is unknown.
CITATION_DESCRIPTION Simpson, R.A., MO MARS RADIO SCIENCE 1 ORIGINAL/INTERMEDIATE DATA REC V1.0, MO-M-RSS-1-OIDR-V1.0, NASA Planetary Data System, 1994
ABSTRACT_TEXT The data set consists of several CD-WO volumes which contain radiometric and open loop data acquired from the Mars Observer spacecraft during its Cruise between Earth and Mars. The basic data are supplemented by ancillary data including DSN weather files and media calibrations, spacecraft maneuver information, and operations schedules. There are fourteen data types.
PRODUCER_FULL_NAME RICHARD A. SIMPSON
SEARCH/ACCESS DATA
  • NSSDC
    		•