Data Set Overview
  =================
    This dataset contains the Galileo spacecraft trajectory data sampled
    every minute for Aug. 28, 1993. The spacecraft closest approach to
    the asteroid was at 16:52:07 at a range of about 2410 km. The
    trajectory data are provided in two coordinate systems, Ida-centric
    Solar Ecliptic (IdaSE) 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., Z. Wang, S. Joy, K.K. Khurana, C. Polanskey,
      D.J. Southwood, and R.J. Walker, 'Solar Wind Interactions with
      Small Bodies: 2.  What Can Galileo's Detection of Magnetic
      Rotations Tell Us About GASPRA and IDA', Advances in Space
      Research, 1995. [KIVELSONETAL1995]


    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 Ida in the X-direction in IdaSE
            coordinates 
    Y       S/C distance from Ida in the Y-direction in IdaSE
            coordinates 
    Z       S/C distance from Ida in the Z-direction in IdaSE
            coordinates 
    R       S/C radial distance from the sun 
    LAT     S/C solar latitude 
    LON     S/C solar (east) longitude 

    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, IdaSE and IHG
    (1950). IdaSE Idacentric Solar Ecliptic (IdaSE) is a Ida centered
    coordinate system defined by the primary vector along the
    instantaneous Ida->Sun (ISun) line and the Earth's ecliptic north
    pole (ENP) as the secondary vector. In this coordinate system:

       X is the ISun unit vector taken to be positive towards the sun.
       Y is the formed by the unitized cross product ENP x ISun
       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)

Confidence Level Overview
  =========================
    These data have been extracted from SPICE kernels that were created
    using post encounter ephemeris data. The data should be of the
    highest possible quality.