NASA Logo, National Aeronautics and Space Administration
NASA Space Science Data Coordinated Archive Header



Availability: Archived at NSSDC, accessible from elsewhere

Time span: 1991-10-29 to 1991-10-30


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

Data Set Overview ================= This dataset contains the Galileo spacecraft trajectory data sampled every minutes for Oct. 29 and 30, 1991. The spacecraft closest approach to the asteroid was at 22:36:40 at a range of about 1600 km. The trajectory data are provided in two coordinate systems, Gaspra-centric Solar Ecliptic (GaSE) and Heliographic (HG) coordinates. The position of the spacecraft has been extracted from the SPICE kernels provided by the project. The time tags are the exact times for which the S/C position was calculated. The time tag is spacecraft event time (SCET) given in universal time (UT). Primary Dataset Reference: Kivelson, M.G., L.F. Bargatze, K.K. Khurana, D.J. Southwood, R.J. Walker, P.J. Coleman, 'Magnetic Field Signatures Near Galileo's Closest Approach to Gaspra', Science, Vol. 261, p331-334, 16 July, 1993. [KIVELSONETAL1993] Data ==== -----------------------------------------------------------------Table 1. Data record structure -----------------------------------------------------------------Column Description -----------------------------------------------------------------time S/C event time (UT) given in PDS time format YYYY-MM-DDThh:mm:ss.sssZ X S/C distance from Gaspra in the X-direction in GaSE coordinates <km> Y S/C distance from Gaspra in the Y-direction in GaSE coordinates <km> Z S/C distance from Gaspra in the Z-direction in GaSE coordinates <km> R S/C radial distance from the Sun <AU> LAT S/C solar latitude <degrees> LON S/C solar (east) longitude <degrees> Missing data values = 9999999.9 and 99999.999 Fortran Format of the data file: (1X, A24, 3F11.1,3F11.5) Coordinate Systems ================== The data are archived in two coordinate systems, GaSE and IHG (1950). GaSE Gaspracentric Solar Ecliptic (GaSE) is a Gaspra centered coordinate system defined by the primary vector along the instantaneous Gaspra->Sun (GSun) line and the Earth's ecliptic north pole (ENP) as the secondary vector. In this coordinate system: X is the GSun unit vector taken to be positive towards the Sun. Y is the formed by the unitized cross product ENP x GSun Z completes the right handed set (Z = X x Y) such that the X-Z plane contains the ecliptic north pole. The data are also provided in inertial heliographic (epoch 1950) coordinates. The radial direction is taken along the instantaneous Sun->S/C line, positive away from the Sun. Latitude is the angle the radial vector makes with the Sun's equatorial plane at the reference epoch, positive above the equator. Longitude is measured from the longitude of the ascending node. At the reference epoch, the inclination of the Sun's north pole was 7 deg 15 min and the longitude of the ascending node can be computed using the formula: Node = 74 deg 22 min + 0.84 min (year - 1900)

These data are available on-line from the Planetary Data System (PDS) at:

Alternate Names



  • Planetary Science: Fields and Particles

Additional Information


Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II



NameRoleOriginal AffiliationE-mail
Dr. Margaret Galland KivelsonGeneral ContactUniversity of California, Los
[] NASA Logo -