Data Set Information
DATA_SET_NAME NEAR EROS RADIO SCIENCE DATA SET - EROS/ORBIT V1.0
DATA_SET_ID NEAR-A-RSS-1/5-EROS/ORBIT-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : The Near Earth Asteroid Rendevous (NEAR) Eros Radio Science (RS) Data Set is a time-ordered collection of raw and partially processed data collected during the NEAR orbital mapping of the asteroid 433 Eros. For more information on the investigation conducted, including gravity field and spin-state determinations, see references [YEOMANSETAL2000], [MILLERETAL2001] and [KONOPLIVETAL2001]. The radiometric data also supported NEAR Navigation. The data set includes: Directory Description --------- ----------- ODF Orbit Data Files containing closed-loop (two-way) Doppler and sequential range measurements. EOP Earth-Orientation Parameter file ION Ionosphere calibration file TRO Troposphere calibration file TXT Text files describing physical model inputs and estimated solution parameters Typical users of these data might analyze range and Doppler measurements in the ODF to derive the NEAR trajectory during the rendevous/mapping phase, determining gravity field, mass, and spin-state. Parameters : The ODF contains the most important information (range and Doppler) needed by spacecraft navigators and those interested in determining gravitational parameters of Eros. Each ODF is accompanied by a full PDS label which describes both the content and format of the associated file. ODF data types can include those listed below. Only those marked below with an asterisk are present in this data set ODF. 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) X angle (where +X is east) (degrees) Y angle (where +X is east) (degrees) X angle (where +X is south) (degrees) Y angle (where +X is south) (degrees) Processing : ODF's are screened for 'bad' data points, which are removed prior to analysis by the navigation or radio science teams. However, all data is included in these archived ODF's files, including 'bad' data that may have been excluded during radio science or navigation analysis. Data : ODFs were issued approximately daily during the orbit phase, occasionally more often to support critical events such as engine-firings (for maneuvers). These ODFs are stored in the ODF directory. File name is of the form ydddeeeC.ODF where y is the one-digit year (2000-2001 implicit) 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. Symbol C denotes an alphabetic character distinguishing separate files issued during the same day. The preliminary results of this investigation (the solved-for Eros ephemeris corrections, pole direction, rotation state, GM (in km^3/s^2), spherical harmonic gravity coefficients and surface crater landmarks), are summarized in PARAMSUM.TXT in the TXT directory. Ancillary Data : Ancillary files are needed for proper analysis and interpretation of the radio data (file type ODF). These are organized in parallel directories and stored approximately chronologically. Earth Orientation Parameter Files (EOP Directory) --------------------------------------------------- Earth Orientation Parameter files are produced by the Time and Earth Motion Precision Observation (TEMPO) Group at JPL. They are ASCII files with variable length records. Each record is delimited by an ASCII line-feed (ASCII 10). EOP files, issued three times a week, include results based on fits to historical data as well as extrapolated predictions into the future. Subsequent file releases gradually replaced predict-intervals with data-based actual values. In this archive, three files have been selected such that they cover the NEAR orbit phase with data-based actual values. File names have the form ydddzeee.EOP where y is the one-digit year of the first data in the file (2000-2001 is implicit), 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. Each file covers the previous nine months of past motion, with prediction for three months into the future; files are typically 30 KB. Each EOP file is accompanied by a PDS minimal label with file name ydddzeee.LBL. Ionosphere Calibration Files (ION Directory) --------------------------------------------------- Ionosphere Calibration files are produced by the Tracking System Analytic Calibration (TSAC) Group at JPL. These are ASCII files of variable length records. Each record is delimited by an ASCII line-feed (ASCII 10). The file name has the form ydddzeee.ION where y is the one-digit year of the first data in the file (2000 is implicit), ddd is the day-of-year of the first data in the file, z is the one-digit year of the last data in the file (2001 is implicit), and eee is the day-of-year of the last data in the file. ION files were released at one week intervals to cover a single month and included predicts for the rest of the month. The single file archived here is a concatenation of file releases that were issued at the start of a month, containing actual measured values for the month just past. The ION file is accompanied by a PDS minimal label with file name ydddzeee.LBL. Troposphere Calibration Files (TRO Directory) --------------------------------------------------- Troposphere Calibration files are produced by the Tracking System Analytic Calibration (TSAC) Group at JPL. 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.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, z is the one-digit year of the last data in the file and eee is the day-of-year of the last data in the file. File 00011060.TRO contains measured data from 2000-Jan-1 to 2001-Mar-1. It is a concatenation of individual files released at the beginning of each month, covering the previous month. File 20018001.TRO contains a seasonal/cylical adjustment for each site, interpreted by software as being applicable from 1972-Jan-1 to 2048-Jan-1. Each TRO file is accompanied by a PDS minimal label with file name ydddzeee.LBL. Text Files (TXT Directory) -------------------------- Two file types are included in the TXT directory. The first type is NMLMODL.TXT and is accompanied by a minimal PDS label NMLMODL.LBL. It is the nominal set of namelist parameters used to define physical characteristics of the spacecraft's motion and tracking observables used by the JPL orbit determination software suite. These are initial starting models only; final solution models are not represented. The second file is PARAMSUM.TXT, accompanied by minimal PDS label PARAMSUM.LBL. This is a summary of the preliminary solved-for parameter set. DMW_433, DP_433, DQ_433, EDW_433, DA_433, DE_433 are the corrections to the Eros ephemeris in Brouwer and Clemence Set III coordinates. ZACPL2000433, ZDEPL2000433 and WDP2000433 are the pole RA, DEC and Prime Meridian angle with respect to the Equinox and Mean Equator of Epoch J2000.0, in degrees. GM2000433 is the solved-for Eros GM in units of km^3/s^2. This is followed by spherical harmonic gravity coefficients to degree and order 15, then (x,y,z) Cartesian landmark coordinates (km) in the Eros body frame. The 'NEW SOLUTION' column contains the preliminary estimated values, with 'SIGMA' being the formal one standard-deviation uncertainty of those estimates. The full and final geophysical parameter solution set will be archived separately with the DATA_SET_ID of 'NEAR-A-RSS-5-GRAVITY-V1.0' Coordinate System : Analysis was conducted in the frame of the DE-403 solar system model, aligned with the 1993 ICRF/J2000 reference frame. Software : Software for parsing, reducing, and analyzing data such as these has been developed at several institutions 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.
DATA_SET_RELEASE_DATE 2001-06-28T00:00:00.000Z
START_TIME 2000-01-01T12:00:00.000Z
STOP_TIME 2001-03-01T12:00:00.000Z
MISSION_NAME NEAR EARTH ASTEROID RENDEZVOUS
MISSION_START_DATE 1996-02-17T12:00:00.000Z
MISSION_STOP_DATE 2001-02-28T12:00:00.000Z
TARGET_NAME EROS
TARGET_TYPE ASTEROID
INSTRUMENT_HOST_ID NEAR
INSTRUMENT_NAME RADIO SCIENCE SUBSYSTEM
INSTRUMENT_ID RSS
INSTRUMENT_TYPE RADIO SCIENCE
NODE_NAME Small Bodies
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Overview : Data in this archival data set have been processed as part of the activities of the NEAR Radio Science Team. This is an excellent data set. Review : This archival data set was reviewed by the NEAR Radio Science Team prior to submission to the Planetary Data System (PDS). 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 (SIS). These materials were distributed to PDS personnel, the experiment investigator, and others, as appropriate. Data Coverage and Quality : Significant events for Radio Science during Eros Orbit phase are as follows: Summary of NEAR Shoemaker Orbits and Maneuvers at 433 Eros 2000 February 14 to 2001 February 28 (GM:4.463 x 10-4 km^3/s^2) Time lng DV Orbit Period Inc Duration Event Date (UTC) sec m/s (km) (days) ATE (days) ----- ------------ ---- --- --------- ------ ------- ------ OIM 2000 14 Feb 15:33 57 10 366 x 321 28.4 29 10 OCM-1 24 Feb 17:00 8.2 .14 365 x 204 16.5 34 8 OCM-2 03 Mar 18:00 16 .22 203 x 206 10.0 37 29 OCM-3 02 Apr 02:03 37.5 .50 210 x 100 6.6 57 9 OCM-4 11 Apr 21:20 5.3 .37 101 x 99 3.4 59 11 OCM-5 22 Apr 15:22 20.4 .45 101 x 50 2.3 64 8 OCM-6 30 Apr 15:31 155 1.9 51 x 49 1.2 90 68 OCM-7 07 Jul 18:00 32 .32 50 x 35 1.0 90 7 OCM-8 14 Jul 04:44 22.7 .24 39 x 35 0.7 90 10 OCM-9 24 Jul 17:00 23.1 .34 50 x 37 1.0 90 7 OCM-10 31 Jul 20:00 48 .50 51 x 49 1.2 90 8 OCM-11 08 Aug 23:25 76.7 1.0 52 x 50 1.2 105 18 OCM-12 26 Aug 23:25 112 1.4 49 x 102 2.3 113 10 OCM-13 05 Sep 23:00 75.5 1 100 x 103 3.5 115 37 OCM-14 13 Oct 05:45 107 1.3 98 x 50 2.2 130 8 OCM-15 20 Oct 21:40 43.8 .58 52 x 50 1.2 133 5 OCM-16 25 Oct 22:10 4.3 .76 51 x 19 0.73 133 0.8 OCM-17 26 Oct 17:40 162 1.7 67 x 198 5.2 144 7 OCM-18 03 Nov 03:00 3.1 .54 198 x 195 9.4 146 34 OCM-19 07 Dec 15:20 94.8 .96 196 x 35 4.3 179 6 OCM-20 13 Dec 20:15 118 1.2 36 x 34 0.7 179 43 OCM-21 2001 24 Jan 16:05 3.0 .54 35 x 22 0.6 179 3.39 OCM-22 28 Jan 01:25 23.6 .56 37 x 19 0.5 179 0.70 OCM-23 28 Jan 18:05 3.8 .68 36 x 35 0.7 178 4.62 OCM-24 02 Feb 08:51 63 .02 36 x 36 0.7 178 4.38 OCM-25 06 Feb 17:44 1.3 .01 36 x 36 0.7 176 5.90 EMM-1 12 Feb 15:14 14.6 2.6 35 x 7.5 --- 130 0.16 EMM-2 12 Feb 18:58 35.4 6.5 5 km alt --- 50 0.01 EMM-3 12 Feb 19:14 N/A N/A 3 km alt --- 46 0.01 EMM-4 12 Feb 19:30 N/A N/A 1.5 km alt --- 36 0.01 EMM-5 12 Feb 19:41 N/A N/A 0.4 km alt --- 36 0.01 Contact 12 Feb 19:44:30 0 km alt --- 36S,81E -- Last Track 28 Feb Landing site determination is preliminary. Other values: -35.36, 81.33 (nominal planned) -38.57, 79.04 (landing trajectory based) -35.73, 80.513 (surface estimation) EMM-5 engine burn was executing at surface contact. Table Column meanings: lng: solved-for duration of engine firing in seconds DV: solved-for velocity change (delta-V) in m/s Period: time for spacecraft to complete one orbit around Eros ATE: Asteroid True Equator (inclination, landing in degrees) OIM: Orbit Insertion Maneuver OCM: Orbit Correction Maneuver EMM: End Mission Maneuver duration: time spent in that orbit Limitations : The limitations in this data set derive from tracking geometry and measurement data types. There are no known general or systematic defects in the data.
CITATION_DESCRIPTION Yeomans D.K., Giorgini J.D., A. Konopliv, and E. Grayzeck, NEAR EROS RADIO SCIENCE DATA SET - EROS/ORBIT V1.0, NEAR-A-RSS-1/5-EROS/ORBIT-V1.0, NASA Planetary Data System, 2001.
ABSTRACT_TEXT The NEAR Eros Radio Science Data Set is a time-ordered collection of raw and partially processed data collected during the NEAR orbital mapping of the asteroid 433 Eros.
PRODUCER_FULL_NAME JON D. GIORGINI
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