ACKNOWLEDGEMENTS

We acknowledge Susan K. Fricke (Raytheon ITSS, Greenbelt) for data processing support, Jeffrey Schott (MIT and GSFC) for technical support, John J. McCarthy (Raytheon ITSS, Greenbelt) for aid with SOLVE. Trish Rodan (JPL), and Richard Simpson (Stanford University) provided useful mission and spacecraft information. We are grateful to Boris Semenov (JPL) and the Navigation Ancillary Information Facility for making available the MGS solar array quaternions.