KPL/PCK

\beginlabel
PDS_VERSION_ID               = PDS3
RECORD_TYPE                  = STREAM
RECORD_BYTES                 = "N/A"
^SPICE_KERNEL                = "dawn_vesta_v06.tpc"
MISSION_NAME                 = "DAWN MISSION TO VESTA AND CERES"
SPACECRAFT_NAME              = DAWN
DATA_SET_ID                  = "DAWN-M/A-SPICE-6-V1.0"
KERNEL_TYPE_ID               = PCK
PRODUCT_ID                   = "dawn_vesta_v06.tpc"
PRODUCT_CREATION_TIME        = 2012-09-27T14:04:32
PRODUCER_ID                  = "NAIF/JPL"
MISSION_PHASE_NAME           = {
                               "INITIAL CHECKOUT (ICO)",
                               "EARTH-MARS CRUISE (EMC)",
                               "MARS GRAVITY ASSIST (MGA)",
                               "MARS-VESTA CRUISE (MVC)",
                               "VESTA ENCOUNTER",
                               "VESTA-CERES CRUISE (VCC)",
                               "CERES ENCOUNTER",
                               "END OF MISSION"
                               }
PRODUCT_VERSION_TYPE         = ACTUAL
PLATFORM_OR_MOUNTING_NAME    = "N/A"
START_TIME                   = "N/A"
STOP_TIME                    = "N/A"
SPACECRAFT_CLOCK_START_COUNT = "N/A"
SPACECRAFT_CLOCK_STOP_COUNT  = "N/A"
TARGET_NAME                  = {
                               "4 VESTA",
                               "1 CERES"
                               }
INSTRUMENT_NAME              = "N/A"
NAIF_INSTRUMENT_ID           = "N/A"
SOURCE_PRODUCT_ID            = "N/A"
NOTE                         = "See comments in the file for details"
OBJECT                       = SPICE_KERNEL
  INTERCHANGE_FORMAT         = ASCII
  KERNEL_TYPE                = TARGET_CONSTANTS
  DESCRIPTION                = "SPICE PCK file containing constants for
Vesta, created by NAIF, JPL. Vesta rotation constants provided in this PCK
are for the ``Claudia Double-Prime'' coordinate system used in science
products included in the DAWN Vesta mission PDS archives. "
END_OBJECT                   = SPICE_KERNEL
\endlabel


Asteroid Vesta P_constants (PcK) SPICE kernel file
===========================================================================
 
 
Organization
--------------------------------------------------------
 
     The sections of this file are as follows.
 
     Introductory Information:
 
         --   Version description
 
         --   Disclaimer
 
         --   Sources
 
     Pck Data:
 
         --   Orientation constants for asteroid Vesta
 
         --   Radii for asteroid Vesta


Version description
--------------------------------------------------------

     Version 0.6 -- October 20, 2012 -- Dr. Carol Raymond, DAWN Deputy PI,
                                        Boris Semenov, NAIF

        Corrected the Claudia center longitudes provided in the comment
        sections ``Values in the Version 0.5'' (136.7 -> 136.0) and
        ``Values in the Version 0.6'' (146.7 -> 146.0) *WITHOUT*
        changing the file version or file name.

                    September 5, 2012  -- Dr. Carol Raymond, DAWN Deputy PI,
                                  Dr. Steven Joy, Dawn Science Center Manager,
                                  Boris Semenov, NAIF

        Corrected W0 (295.39 -> 285.39). 

     Version 0.5 -- May 2, 2012  -- Dr. Carol Raymond, DAWN Deputy PI,
                                  Dr. Steven Joy, Dawn Science Center Manager,
                                  Boris Semenov, NAIF

        Corrected W0 (75.39 -> 295.39). 
 
     Version 0.4 -- November 2, 2011 -- Dr. Carol Raymond, DAWN Deputy PI,
                                        Boris Semenov, NAIF

        Corrected W0 (76.06 -> 75.39). 

     Version 0.3 -- September 29, 2011 -- Dr. Carol Raymond, DAWN Deputy PI,
                                          Boris Semenov, NAIF

        Per MCR-112436 Vesta pole orientation and prime meridian 
        (Ra, Dec, W0) were changed to (309.031, 42.235, 76.06) degrees 

     Version 0.2 -- February 25, 2011 -- Boris Semenov, NAIF

        Vesta pole orientation (Ra, Dec) was changed to (305.8, 41.4)
        degrees per MCR-111475 and "Dawn Planetary Constants and Models
        Document" Revision 2.0, Feb 16, 2011

     Version 0.1 -- October 12, 2004 -- Boris Semenov, NAIF

        VESTA_FIXED frame definition was removed. It is now in the DAWN
        Frames Kernel file.

     Version 0.0 -- October 6, 2003 -- Boris Semenov, NAIF
     
        This is a preliminary PCK containing draft values for the pole
        direction, prime meridian location, rotation period and shape
        (from [1].)
     
 
Disclaimer
--------------------------------------------------------
 
     This constants file may not contain the parameter values that you
     prefer. Note that this file may be readily modified by you or
     anyone else. NAIF suggests that you inspect this file visually
     before proceeding with any critical or extended data processing.
 
     NAIF requests that you update the ``by line'' and date if you
     modify the file.
 
 
Sources
--------------------------------------------------------
 
     The sources for the constants listed in this and the earlier
     versions of this file are:
 
        1) Thomas, Peter C. et al. ``Vesta: Spin Pole, Size, and Shape
           from HST Images.'' ICARUS 128, 1997. Article NO. IS975736. 
           pp. 93-94.

        2) "Dawn Planetary Constants and Models Document" Revision 2.0, 
           Feb 16, 2011

        3) Analysis of Data from Dawn's Survey Orbit, Sep 23, 2011.
           (IOM attached to MCR-112436).


Orientation constants for asteroid Vesta
--------------------------------------------------------
 
     The inertial reference frame for these constants is J2000; this is
     the default reference frame for PCK orientation data.
 
     The epoch of the constants is J2000; this is Julian ephemeris date
     (JED) 2451545.0.
 
     The NAIF integer code for Vesta is 2000004. See the NAIF_IDs
     required reading for further information on NAIF integer codes.
 

Values in the Versions 0.0 and 0.1

     The pole direction, prime meridian location, and rotation period
     in the versions 0.0 and 0.1 were set to the following values from
     [1]:

       "New data from the 1996 Hubble HST observations of Vesta allow a 
        refinement of the pole solution to: RA = 301 deg, Dec = 41 deg,
        +/- 5 deg. The prime meridian is now given by W = 292 deg +
        1617.332776 deg * d; see Section 3a and Eq. 1. The new data,
        and a scaling correction, change the fit radii to 289, 280,
        229, +/- 5 km."


Values in the Version 0.2

     The pole direction, prime meridian location, and rotation period
     in the version 0.2 were set to the following values from [2]:

       "5.3 Vesta Pole and Prime Meridian

        The Vesta pole and prime meridian values are shown below.

        RA  Vesta = 305.8 +/- 3.1 deg      Right Ascension in EME2000 [25]
        DEC Vesta = 41.4 +/- 1.5 deg       Declination in EME2000 [25]
        W   Vesta = 292 + w * D deg        Prime Meridian
        w   Vesta = 1617.332776 deg/day    Rotation rate


        5.4 Vesta Shape Parameters

        The Vesta shape is described as a triaxial ellipsoid with 
        values 289, 280, 229 km [15] or as a sphere with a radius 
        of 265 km [16]. ... 


        9 References

        ...
        15. "Vesta: Spin Pole, Size, and Shape from HST Images", P. 
            Thomas, et al., Icarus, v128, p88~94 (1997)."
        16. "Impact Excavation on Asteroid 4 Vesta: Hubble Space 
            Telescope Result", P. C. Thomas, et al, Science, 227, 
            1492-1494, 1997.
        ...
        25. "Improved Measurement of Asteroid (4) Vesta's Rotational 
            Axis Orientation", Jian-Yang Li, et al., Icarus, 211, 
            528-534, 2010.."


Values in the Version 0.3

     The pole direction, prime meridian location, rotation period and
     radii in this version are set to the following values from [3]:

       "... 
        The recommended new pole is:
           -  RA: 309.031   Dec: 42.235
           -  Error is estimated as +/-0.03deg 3-sigma

        Data considered:
           -  Konopoliv (Gravity)       309.029    42.225 
           -  Preusker (DLR) Survey     309.031    42.235
           -  OpNav                     309.025    42.245
           -  NAV OD radio              309.025    42.247 

        The rotation rate of Vesta was determined to be .222588677 +/-
        .000000009 days/rev, which agrees very well with the weighted 
        average of all previous determinations.
        ...
        A new prime meridian was chosen as defined by the small crater 
        Claudia that is assigned a longitude of 356 deg East. This new system
        was chosen because the old system was not well-defined and the
        team wanted to make a clear distinction between the old and new
        to avoid confusion. The offset between the old W0 (292) from
        Thomas et al. (1997) and the new W0 (76.06) is about 144.06 deg."

     These values are provided in the keywords below. The W1 was derived 
     from .222588677 days/rev as follows:

        W1 = 1 / 0.222588677 * 360 = 1617.3329428

Values in the Version 0.4

     The pole direction, rotation period, and radii in the version 0.4
     are the same as in the version 0.3.

     The W0 value is 75.39 deg (changed from 76.06 deg to match the
     correct rotation rate while preserving the longitude of Claudia).
     
Values in the Version 0.5

     The pole direction, rotation period, and radii in the version 0.5
     are the same as in the previous version 0.4.

     The W0 value is 295.39 deg (changed from 75.39 deg) so that the
     prime meridian is roughly in the center of the feature originally
     identified as Olbers and the Claudia crater is now defined to be at 
     136.0 deg East.
     
        body2000004_pole_ra    = ( 309.031    0.0              0.0 )
        body2000004_pole_dec   = (  42.235    0.0              0.0 )
        body2000004_pm         = ( 295.39  1617.3329428        0.0 )


Values in the Current Version 0.6

     The pole direction, rotation period, and radii in the version 0.6
     are the same as in the previous versions 0.4 and 0.5.

     The W0 value is 285.39 deg (changed from 295.39 deg) to improve the
     alignment of the prime meridian with the center of the albedo feature
     originally identified as Olbers in the Hubble data, based on the 
     analysis of P. Thomas and J.-Y. Li in July/August 2012. The center 
     of Claudia crater is now defined to be at 146.0 deg East.

     \begindata
 
        BODY2000004_POLE_RA    = ( 309.031    0.0              0.0 )
        BODY2000004_POLE_DEC   = (  42.235    0.0              0.0 )
        BODY2000004_PM         = ( 285.39  1617.3329428        0.0 )

     \begintext



Radii for asteroid Vesta
--------------------------------------------------------
     
     The Vesta radii from [2] are provided in the keyword below.

     \begindata
 
        BODY2000004_RADII      = ( 289.0  280.0  229.0  )
 
     \begintext

End of PCK file.

