Log file for SPACIT Version 7.1.1. ******************************************************************************** Comments From File: math9749.bsp Objects In This Ephemeris -------------------------------------------------------- Name Id-code ----------------- ------- Asteroid Mathilde...2000253 Approximate Time Coverage From: February 9, 1996 To : January 24, 2002 Status -------------------------------------------------------- This is the latest official Mathilde ephemeris for use by the NEAR project. It represents the latest knowledge of the position of the asteroid Mathilde as of June 25, 1997. This ephemeris (math9749.bsp) updates and replaces the ephemeris of June 11, 1997 --- math9740.bsp. IF YOU HAVE THE FILE math9740.bsp, YOU SHOULD REMOVE IT FROM YOUR SYSTEM. No updates to this ephemeris are planned. Production/History of this Ephemeris -------------------------------------------------------- This ephemeris was produced by Bill Taber of the Navigation Ancillary Information Facility (NAIF) at the Jet Propulsion Laboratory on June 25, 1997 for use by the NEAR project. It was transformed to SPK format from a numerical integration performed by Don Yeomans of the Solar Systems Dynamics group of the Astrodynamics and Navigation section (section 312) of the Jet Propulsion Laboratory. Yeomans' internal solution number for this ephemeris is solution 49. The ephemeris is based on observations over the interval 1885 Dec. to June 24, 1997. The observations include several recent observations reduced relative to the Hipparchos Star Catalog. The ephemeris was integrated using the JPL developmental ephemeris DE-403 to provide a gravitational force model. Usage -------------------------------------------------------- To determine the state of Mathilde with respect to any object other than the sun, you need at a minimum a planetary ephemeris. Since the planetary ephemeris used for the dynamical force model in the integration of the Mathilde ephemeris was DE-403, it is highly recommended that you use DE403 when computing states of Mathilde with respect to anything other than the sun. DE403 is available via anonymous ftp on NAIF's ftp server: naif-sun (ip address 128.149.126.11) in the directory pub/naif/generic_kernels/spk. Both binary and transfer format ephemerides are available. They are in the files. de403s.bsp ( binary format ) de403s.xsp ( transfer format ) de403s.cmt ( comments about de403s ) To determine the state of Mathilde with respect to the NEAR spacecraft you will need a trajectory file for the NEAR spacecraft. At present NAIF does not possess such a trajectory file. We recommend that you contact the NEAR project for assistance in obtaining a NEAR spacecraft ephemeris. The current estimate for the radius of Mathilde is:30.5 km. The current estimate for the GM of Mathilde is : 0.0198 km**3/sec**2 Accuracy -------------------------------------------------------- The plane of the sky residuals in the position of Mathilde as viewed from earth relative to the Hipparchos catalog are less than 0.5 arcseconds. The current estimated 1-sigma uncertainty in the position of Mathilde at the time of NEAR encounter is approximately 186 km in the direction of Mathilde's velocity, 32 km in the direction orthogonal to the orbital plane of Mathilde and 30 km in the direction radial from the sun. In B-plane coordinates the 1-sigma uncertainty in the position of Mathilde are Radial component --- T : 152 km; Out of plane --- R : 34 km; Time of Flight --- S : 111 km. (See the reference sited below for a more detailed analysis of the accuracy of this ephemeris). References -------------------------------------------------------- JPL IOM 312.1-96-031 dated June 4, 1997. Inquiries If you have any questions regarding this ephemeris contact Bill Taber btaber@spice.jpl.nasa.gov Phone (818) 354-4279 FAX (818) 393-6388 JPL MS 301/125L 4800 Oak Grove Drive Pasadena, CA 91109 ******************************************************************************** ******************************************************************************** Summary for SPK file: math9749.bsp Leapseconds File : /usgs/cpkgs/isis3/data/base/kernels/lsk/naif0010.tls Summary Type : Entire File -------------------------------------------------------------------------------- Segment ID : Asteroid Mathilde Target Body : Body 2000253, MATHILDE Center Body : Body 10, SUN Reference frame: Frame 1, J2000 SPK Data Type : Type 8 Description : Discrete States, Evenly Spaced, Lagrange Interpolation UTC Start Time : 1996 FEB 08 23:58:57.815 UTC Stop Time : 2002 JAN 23 23:58:55.815 ET Start Time : 1996 FEB 09 00:00:00.000 ET Stop time : 2002 JAN 24 00:00:00.000 -------------------------------------------------------------------------------- ********************************************************************************