Data Set Overview : This file contains a shape model for the asteroid Eros derived from NEAR Laser Rangefinder observations. The NLR measurements were made over the period 30 April 2000 to 27 August 2000 from orbits of 35 and 50 km.  The gravity model (16 x 16 elements) obtained from this shape model is provided as a separate companion file ('GR_101.TXT') to this file.  The shape model (34 x 34) files and information regarding the file formats and contents were kindly supplied by J.K. Miller of the NEAR navigation team, in response to user requests made at the NEAR PDS archive review.   Parameters : SH_101.TXT A multi-part table giving X, Y, and Z vertices of the shape model, the plate model, and parameters.  The shape table lists a serial number and coordinates for each vertex comprising the plate model of the shape of Eros. The vertex numbers are referenced in the following table.  NOTE that the first row of this table contains only a single integer in the first column, giving the total number of vertices in the table.  The index number of the vertex. This number is used in the plate table.  Following rows contain (x,y,z) position of the vertex  The shape table further defines the triangular plates comprising the Eros shape model. For each plate three vertices are listed by vertex number. The positions corresponding to each vertex number are defined in the preceding vertex table.  NOTE: The first row of this table contains only a single integer indicating the total number of plates defined.  Subsequent rows have the index number for the triangular plate defined along with the index numbers of the three vertices defining this plate  Then there is a single-row table contains two constants relating to the table of harmonic coefficients: first the degree of the harmonic solution. The total number of coefficients in the solution is (NDEGREE+1)^2. Second there is a Normalization flag. This value is '1', indicating that the following solution has been fully normalized.  The last part of the table lists several parameters and the harmonic coefficients constituting the shape model solution. The format, an in-house format used by the NAV team, is not tied to logical records, but rather makes use of a repeating, 3-column physical record structure as needed to hold the various parameters. The contents of the rows of the table are as follows:  The first two records contain the volume of the model and the vector offset from the center of the shape model to the true center of gravity:  Record 1: Column 1 Volume in km^3 Column 2 -blank- Column 3 -blank-  Record 2: Column 1 Xcg in km Column 2 Ycg in km Column 3 Zcg in km  The next two record contain the coefficients for the inertia tensor. Note that this is a symmetric matrix, so only the unique elements are specified here:  Record 3: Column 1 Ixx in km^2 Column 2 Iyy in km^2 Column 3 Izz in km^2  Record 4: Column 1 Ixy in km^2 Column 2 Ixz in km^2 Column 3 Iyz in km^2  The subsequent records contain the shape model harmonic coefficients Cij and Sij. All the Si0 are : 0, and are thus omitted from this file. The remaining coefficients are stored three to a record, in this logical sequence:  C00 C10 C11 S11 C20 C21 C22 S21 S22 C30 C31 C32 C33 S31 S32 S33 etc.  which becomes this physical sequence:  Record 5: C00 C10 C11 Record 6: S11 C20 C21 Record 7: C22 S21 S22 Record 8: C30 C31 C32 Record 9: C33 S31 S32 etc.  The total number of coefficients stored is (NDEGREE+1)^2, where NDEGREE is found as the first integer (i.e., COLUMN 1) in the first row of the HDR_TABLE, above,  The last record in the file contains only a single entry in the first column.  GR_101.TXT ASCII coefficients for the gravity model.  The gravity model table starts as one row with three integer parameters: The degree of the harmonic solution presented and two processing flags. The degree of the harmonic solution, i.e., the number of harmonic cooefficient stored in this file is (NDEGREE+1)^2. The first flag indicating that the result has been normalized. It is equal to '1'. A second flag as an internal processing flag, equal to '1'  Next this table lists the various parameters and harmonic coefficients of the gravity solution. The format, an in-house format used by the NAV team, is not based on logical records, but rather makes use of a repeating, 3-number physical record structure as needed to hold the various parameters. The contents of the rows of the table are as follows.  The first two records contain general model parameters:  Record 1: Column 1 Volume in km^3 of the model Column 2 Density in g/cm^3 (assumed constant) Column 3 Mass in kg  Record 2: Column 1 The gravitational potential, GM, in km^2/s^3 Column 2 R0, the average radius used in the model - in this case selected to be the maximum radius Column 3 -blank-  The next two records contain the coefficients for the inertia tensor. Note that this is a symmetric matrix, so only the unique elements are specified here:  Record 3: Column 1 Ixx in km^2 Column 2 Iyy in km^2 Column 3 Izz in km^2  Record 4: Column 1 Ixy in km^2 Column 2 Ixz in km^2 Column 3 Iyz in km^2  The subsequent records contain the gravitational harmonic coefficients Cij and Sij. All the Si0 are : 0, and are thus omitted from this file. The remaining coefficients are stored three to a record, in this logical sequence:  C00 C10 C11 S11 C20 C21 C22 S21 S22 C30 C31 C32 C33 S31 S32 S33 etc.  which becomes this physical sequence:  Record 5: C00 C10 C11 Record 6: S11 C20 C21 Record 7: C22 S21 S22 Record 8: C30 C31 C32 Record 9: C33 S31 S32 etc.  The total number of coefficients stored is (NDEGREE+1)^2, where NDEGREE is found as the first integer in the first row of the file (that is, in column 1 of the INTEGER_TABLE defined above).  The last record in the file contains only a single entry in the first column.  Processing :  The shape model include both a triangular plate model and a set of spherical harmonics. The plate model is comprised of two lists: a list of (x,y,z) vertex positions relative to the center of the model; and a list of the triples of vertices defining each of the triangular plate.  The spherical harmonics are provided as a set of coefficients with corresponding values for volume, center-of-gravity offset and the inertia tensor (KONOPLIVETAL2001, MILLERETAL2002).  The gravity model obtained by integrating this shape model is provided as a separate companion file ('gr_101.dat') to this file in the same form as the shape model.  Ancillary Data : None.  Coordinate System : The Eros coordinate system is defined as follows: prime meridian fixed at 326.06 deg, IAU 1994 right ascension at 11.369 deg, declination at 17.227 degrees, and rotation rate at 1639.38885 deg/day.  Software : None.  Media/Format : CD

Overview : Data in this archive have been reduced as part of mission data analysis activities of the NEAR Navigation Team. Data of questionable validity have been omitted from the solutions.  Review : This archival data set was not reviewed by the NEAR NLR or RSS Teams prior to submission to the Planetary Data System (PDS). It was not one of the data sets included in a comprehensive review by the PDS Small Bodies Node in August 2001. Instead a separate onlinbe review was performed for PDS acceptance.  Data Coverage and Quality : The data included in this archive were collected during the NEAR orbital phase from 2000-04-30 to 2000-08-27.  Limitations : None.