Mission Information
MISSION_NAME SATURN SMALL SATELLITE ASTROMETRY
MISSION_ALIAS
MISSION_START_DATE 1994-12-01T12:00:00.000Z
MISSION_STOP_DATE 2005-01-14T12:00:00.000Z
MISSION_DESCRIPTION 
Mission Overview
    ================
 
    Observations made during the 1995-1996 Saturn Ring Plane Crossing
    (RPX) led to the unexpected finding that the positions of both
    Prometheus and Pandora varied significantly from the predictions
    based on the Voyager observations (BOSH&RIVKIN1996,
    NICHOLSONETAL1996, MCGHEEETAL2001, SYNNOTTETAL1983). A long term
    observing campaign was undertaken in order to extend the time line
    of astrometric observations.
 
    The campaign used archival HST data from 1994, previously
    unexamined RPX images, and a large series of targeted WFPC2
    observations between 1996 and 2005. The ultimate goals were to
    refine the ephemerides of both satellites and if possible
    determine the cause or causes of the discrepancies.
 
    Sufficient observations to produce astrometrically meaningful data
    for nine other satellites were obtained incidentally in the
    Prometheus-Pandora observing campaign.
 
    Details of the project can be found in FRENCHETAL2006.
MISSION_OBJECTIVES_SUMMARY 
Mission Objectives Overview
    ===========================
 
    The primary intent of this investigation was to refine orbital
    information for Prometheus and Pandora and if possible to
    determine the cause or causes of the apparent changes in the
    orbits of the two satellites since the Voyager encounters
    (FRENCHETAL2003).
REFERENCE_DESCRIPTION Bosh, A.S. and A.S. Rivkin, Observations of Saturn's inner satellites during the May 1995 ring-plane crossing, Science, 272, 518-521, 1996.

French, R.G., C.A. McGhee, L. Dones, and J.J. Lissauer, Saturn's wayward shepherds: the peregrinations of Prometheus and Pandora, Icarus 162, 143-170, 2003.

French, R.G., C.A. McGhee, M. Frey, R. Hock, S. Rounds, R. Jacobson, and A. Verbiscer, Astrometry of Saturn's Satellites from the Hubble Space Telescope WFPC2, PASP 118, 246-259, 2006.

McGhee, C.A., P.D. Nicholson, R.G. French, and K.J. Hall, HST Observations of Saturnian Satellites during the 1995 Ring Plane Crossing, Icarus, 152, 282-315, 2001

Nicholson, P.D., M.R. Showalter, L. Dones, R.G. French, S.M. Larson, J.J. Lissauer, C.A. McGhee, B. Sicardy, P. Seitzer, and G.E. Danielson, Observations of Saturn's ring-plane crossing in August and November 1995, Science, 272, 509- 516, 1996

Synnott, S.P., R.J. Terrile, R.A. Jacobson, and B.A. Smith, Orbits of Saturn's F ring and its shepherding satellites, Icarus, 53, 156-158, 1983