 
 
Cassini Trajectory Reconstruction: Outer Cruise, Science Cruise and Tour
Pre-Huygens
===========================================================================
 
     Comments added by Lee Elson, NAIF/JPL, June 20, 2005.
 
 
Objects in the Ephemeris
--------------------------------------------------------
 
     This file contains ephemeris data for the Cassini spacecraft as well
     as some planetary barycenters, the sun, the earth and its moon and
     some of the moons of Saturn. The NAIF ID code for Cassini is -82.
 
 
Approximate Time Coverage
--------------------------------------------------------
 
     This file covers the following part of the Cassini mission:
 
                COVERAGE BEGIN TIME (TDB):  2001 MAR 07 12:00:00.000
                COVERAGE END TIME (TDB):    2004 JUL 17 12:00:00.000
 
     Note that not all bodies have complete coverage for this period.
 
 
Status
--------------------------------------------------------
 
     This file was created by the Cassini Nav Team during the
     Outer Cruise, Science Cruise and Tour Pre-Huygens phases of the
     mission. Comments were added by NAIF for archiving with the Planetary
     Data System (PDS).
 
 
Pedigree
--------------------------------------------------------
 
     The original files used to create this SPK file contained only
     reconstructed trajectories. They were officially delivered to the
     Cassini project data base by the Cassini NAV team. The list of the
     original files, from which data have been merged into this file,
     is provided in Appendix 1 of these comments.
 
 
Usage --------------------------------------------------------
 
     The PCK file "cpck14Oct2004.tpc" should be used with this file.
 
 
Contacts
--------------------------------------------------------
 
     If you have questions regarding this data contact:
 
        Lee Elson (818)-354-4223 Lee.Elson@jpl.nasa.gov
 
     or the Cassini IO Lead:
 
        Diane Conner (818)-354-8586 Diane.L.Conner@jpl.nasa.gov
 
 
Appendix 1: Original comments
--------------------------------------------------------
 
     The comments from the SPK files incorporated into this file are
     listed below.
 
; 041014R_SCPSE_01066_04199.BSP LOG FILE
;
; Created 2004-10-14/14:09:40.00.
;
; BEGIN NIOSPK COMMANDS
 
LEAPSECONDS_FILE    = /cnav/software/internal/leapseconds.dat
SPK_FILE            = 041014R_SCPSE_01066_04199.BSP
  SPK_LOG_FILE      = 041014R_SCPSE_01066_04199.log
  INCLUDE_TEXT_FILE = 041014R_COMMENT_01066_04199.TXT
  SOURCE_NIO_FILE   = 041014R_SK_01066_04199.NIO
    BODIES          = -82
    BEGIN_TIME      = CAL-ET 2001 MAR 07 12:00:00.000
    END_TIME        = CAL-ET 2004 JUL 17 12:00:00.000
 SOURCE_NIO_FILE = /cnav/OD/outputs/ops/reconstruction/041013_00Sa/peph_out.nio
    BODIES          = 3 5 6 10 301 399
    BEGIN_TIME      = CAL-ET 2001 MAR 07 12:00:00.000
    END_TIME        = CAL-ET 2004 JUL 17 12:00:00.000
SOURCE_NIO_FILE = /cnav/OD/outputs/ops/reconstruction/041013_00Sa/sateph_out.nio
    BEGIN_TIME      = CAL-ET 2004 JAN 03 00:00:00.000
    END_TIME        = CAL-ET 2004 JUL 17 12:00:00.000
 
; END NIOSPK COMMANDS
 
FILENAME:   041014R_SCPSE_01066_04199.BSP
 
PURPOSE OF DELIVERY:  Post-Jupiter Through Saturn Approach Reconstruction
 
DELIVERED BY:  Joan Pojman
               Reconstruction File Made by Duane Roth
 
DELIVERY DATE:  14 Oct. 2004
 
FILE USAGE RESTRICTIONS:  Use for Post-Jupiter Through Saturn Approach Analysis
 
PLANETARY EPHEMERIS USED:  Based on DE410; updated in OD solution.
 
SATELLITE/ASTEROID/ROCK EPHEMERIS USED:  Based on sat178; updated in OD solution.
 
START EPOCH OF RECONSTRUCTED DATA ARC:  28 February 2001 19:50 ET
 
END EPOCH OF RECONSTRUCTED DATA ARC:  12 August 2004 22:10 ET
 
COMMENTS:
 
041013_00Sa is an update to the previously delivered Saturn approach
reconstruction (040908_00Sa; 040909R_SCPSE_01066_04199.BSP). Spacecraft,
planet, and satellite models were adjusted such that estimates of the Rhea GM,
the Saturn system GM, and spacecraft stochastic non-gravitational accelerations
near the end of the data arc are more reasonable. A refinement to the Iapetus
shape model also resulted in a significantly improved Iapetus ephemeris.
 
Specific modeling changes include:
 
1) used sat178 planet and satellite ephemeris as apriori instead of
sat168 (Bob J. said, in retrospect, sat168 was the worst ephemeris
we could have used for a priori information) and DE410.
Correlations between planet and satellite ephemerides were
maintained in the a priori covariance.
 
2) altered SOI model - fixed duration at AACS' value (DV not
estimated), added RA & Dec rate terms.
 
3) used psf with re-centered Iapetus opnavs near 13 July Iapetus c/a.
 
4) fixed problem with stochastic non-gravs that appeared after SOI in
original reconstruction.
 
5) Added 30 minutes more of 2-way Doppler data right after turn
from DRPC attitude to Earth point.
Brief.  Version: 2.2.0        (SPICE Toolkit N0056)
 
 
Summary for: 041014R_SCPSE_01066_04199.BSP
 
Bodies: CASSINI (-82)           SATURN BARYCENTER (6)   EARTH (399)
        EARTH BARYCENTER (3)    SUN (10)
        JUPITER BARYCENTER (5)  MOON (301)
        Start of Interval (ET)              End of Interval (ET)
        --------------------------------    --------------------------------
        2001 MAR 07 12:00:00.000            2004 JUL 17 12:00:00.000
 
Bodies: MIMAS (601)             RHEA (605)              PHOEBE (609)
        ENCELADUS (602)         TITAN (606)             SATURN (699)
        TETHYS (603)            HYPERION (607)
        DIONE (604)             IAPETUS (608)
        Start of Interval (ET)              End of Interval (ET)
        --------------------------------    --------------------------------
        2004 JAN 03 00:00:00.000            2004 JUL 17 12:00:00.000
 
 
 
 
