PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2002-09-15 NOTE = "This file describes the various geometry data that are available on this archive volume." END_OBJECT = TEXT END The GEOMETRY directory contains Galileo Orbiter (rotor) attitude (orientation) data and trajectory data for both Galileo and the Galilean moons when the S/C was inside of 30 Rj. The attitude data includes two time varying rotation matrices to facilitate the transformation of data into geophysical coordinates. The rotor attitude data are extracted from the Galileo Attitude and Articulation Control System (AACS) telemetry stream and converted into physical units (radians). Some obviously bad data points have been edited out of the data set. However, the data set is essentially raw data and should be used with caution. The files provided here were requested at the peer review of this volume and are provided as a convenience for the user. The two rotation matrices that are included allow the user to rotate data from the spinning rotor coordinate system to various geophysical coordinate systems. The first transformation matrix provides the rotation from spinning rotor coordinates into inertial Earth Mean Equatorial coordinate system, epoch 1950.0 (EME-50). The second matrix allows a user to perform second transformation (from EME-50) into System III (1965.0) coordinates. Note that this is a left-handed coordinate system. The "moon trajectory" data contains the position of Galileo and the Galilean satellites in System III (1965.0) coordinates, plus the earth and solar phase angles of each body, sampled every 20 seconds. Spacecraft ephemeris data in tabular form can be found in the subdirectories of DATA/TRAJECT. Spacecraft ephemeris tables are available in both Jupiter and Io centered coordinates. These trajectory files are derived from SPICE kernels create by the project navigation team. Lastly, SPICE kernels for the Galileo prime mission are included in ASCII format in the EXTRAS/SPICE directory off the root of this volume. Once again, these files are provided as a convenience to the user. The official archive of the Galileo SPICE products is maintained by the Navigation and Ancillary Information Facility (NAIF) at the Jet Propulsion Laboratory (JPL) in Pasadena CA. SPICE kernels can be obtained from the NAIF Node of the PDS for numerous platforms in addition to those provided here. There may be updates to the various SPICE kernels that will supersede the data provided here. In addition to being the PDS archive site for the SPICE kernels, NAIF provides and maintains a software toolkit (SPICELIB) for accessing the kernels. For more information about NAIF, SPICELIB, or to acquire kernels for platforms not support here, please visit the NAIF website (http://pds.jpl.nasa.gov/naif.html). GEOMETRY | |- [MOON_TRAJECTORIES] Trajectory data of the Jupiter moons | observed by the Galileo spacecraft | |- [ROTOR_ATTITUDE] These files contain an ASCII table of rotor pointing data and a matrix that allows a user to rotate vectors between EME-50 and System III (1965.0) coordinates. The label file describes how to get data from spacecraft coordinates into EME-50 coordinates by using the rotor pointing angles. DATA | |- [TRAJECT] | |- [SATELLITES] Spacecraft Trajectory data at moon encounters | in various coordiante systems. | |- [SURVEY] Whole-orbit spacecraft trajectory data in various coordiante systems. EXTRAS | |- [SPICE] SPICE kernels in transfer form for PC, VAX, and other platforms that use the Carriage Return, Linefeed ASCII line termination characters. SPICE kernels: PDS Name File/Kernel Desc ------------------------------------------------ RTRJ0FIN.TC (.BC) Discrete value rotor pointing C-kernel, Jupiter orbit 0 RTRJAFIN.TC (.BC) Discrete value rotor pointing C-kernel, Jupiter approach NAIF0007.TLS Leap seconds kernel (through Jan 1, 1999) MK98267A.TSC Spacecraft clock kernel PCK00006.TPC Planetary constants kernel S980326B.TSP (.BSP) Spacecraft/Planetary Ephemeris kernel