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NASA Space Science Data Coordinated Archive Header

NEAR COLLECTED TARGET MODELS V1.0 (PDS)

NSSDCA ID: PSSB-00366

Availability: Archived at NSSDC, accessible from elsewhere

Description

This description was generated automatically using input from the Planetary Data System.

Data Set Overview ================= Several instrument teams from the Near Earth Asteroid Rendezvous (NEAR) mission derived models of the main mission target, 433 Eros. In addition, the Multi-Spectral Imager team also derived a shape model of the secondary target 253 Mathilde. These models and their associated data and descriptions have been collected into this data set for ease of distribution. The models are divided into groups based on the source of the files: MSI - Produced by the MSI team --- Numerical shape model and mosaic shape map of 253 Mathilde - Plate models of 433 Eros in 6 resolutions - A plate model of Eros in the Thomas RGST format NAV - Produced by the Navigation team from NLR data --- Spherical harmonic coefficients for shape and gravity of Eros - Triangular plate model of Eros from NLR measurements NLR - Produced by the NLR team --- Global numerical shape model of Eros - Shape map of Eros - NLR coverage map - Spherical harmonic shape model of Eros RSS - Produced by the Radio Science Subsystem, using combined NLR --- and radar tracking data - Gravity map of Eros - Maps of the Bouguer anomaly of Eros in 3 increasing orders - Two spherical harmonic models of Eros with covariance matrices - Landmark files for Eros Modification History ==================== These data were culled from the version 1.0 NEAR archive. The data set descriptions from that delivery were converted to document files to accompany this data set. Data labels were updated: 1. Information and references that became available in the months following the original archive delivery have been added. In some cases reference publication years have been changed. 2. Extrema have been found and added to data product labels where they seemed useful. 3. DATA_SET_ID, PRODUCT_ID, PRODUCT_NAME and related fields have been changed to reflect the new data set being created. In many cases file names have been changed to something shorter and more mnemonic. The original spherical harmonic model files all contained degenerate tables listing parameters relevant to the model. These lines have been removed from the data file and the parameters included in the description at the top of the labels. The following additional changes were made to specific data file labels included in this collection: MSI Shape Models - Eros ----------------------o The FILE_RECORDS value, which was incorrect in all but two cases, was corrected. MSI Shape Models - Mathilde --------------------------o Existing files were extracted from the Thomas optical shape models already in the SBN archives. NLR Shape and Gravity models ---------------------------o The NLR125AR.IMG file was converted to two FITS files: 1. A signed 2-byte integer version; and 2. An IEEE-real floating-point version. In both cases the scaling factor and offset from the original label was applied to the data. For the integer file, the result was rounded to the nearest integer. Minimal FITS headers were created in both cases, and the PDS labels modified accordingly. [Name in this data set: NLR/SHAPEMAP*.FIT] o The structure included in the NLRT180A.LBL file seemed to bear only a slight resemblance to the actual structure of the data (wrong record size, wrong number of columns, wrong field sizes, etc.). The following changes were made to the data (and reflected in the label): + All records were trimmed to a fixed length (48 bytes). + Embedded blanks were removed from the first record to fit it into the 48-byte length. + Blank coefficient fields were filled with the equivalent representation of zero. + All 'D' exponentiation operators in the data file were changed to 'E'. [NLR/SHCOEFF.TAB] o The JGE15A01 (ASCII and binary) files were reformatted to follow the style used in the NLR spherical harmonic files. Specifically: + The SHA coefficients file was reformatted to remove trailing zeros and field delimiters. The constants in the header line were moved into the label. + The SHB (binary) covariance file was converted to ASCII, output using the same record format and sorted into the same order as the other covariance file. [RSS/N15ACOEFF.TAB and RSS/N15ACOVAR.TAB] Navigation Team Shape and Gravity Models ---------------------------------------(Produced by the navigation team from NLR data) o The files containing the spherical harmonic coefficients for the gravity and shape models were converted from the internal format submitted to flat tables more conducive to PDS handling. No data were changed, added or omitted. o The plate model originally included as part of the shape model file (with the spherical harmonic solution) was pulled out into a separate file. o The triangular plate shape model was reformatted slightly to match the format used in other radar shape models already archived at the SBN. The principal change consisted of adding flags in the first column of each record to indicate which records defined vertices and which facets. Radio Science Team Shape and Gravity Models ------------------------------------------o The Bouguer gravity maps were converted to FITS files and the labels modified accordingly. o The gravity map file was also converted to a FITS file. o The landmarks file was reformatted to collect the position and uncertainty vector for each landmark into a single record. The label was re-written accordingly. These data are available on-line from the Planetary Data System (PDS) at: http://sbn.psi.edu/pds/asteroid/NEAR_A_5_COLLECTED_MODELS_V1_0/

Alternate Names

  • NEAR-A-5-COLLECTED-MODELS-V1.0

Discipline

  • Planetary Science: Small Bodies

Additional Information

Spacecraft

Experiments

Questions and comments about this data collection can be directed to: Dr. David R. Williams

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Brian CarcichData ProviderCornell Universitycarcich@astro.cornell.edu
Dr. Carol NeeseGeneral ContactPlanetary Science Instituteneese@psi.edu
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