1. S. Nozette, U.S. Air Force Phillips Laboratory, Space Experiments Directorate, 711 North Fayette Street, Alexandria, VA 22314, USA.
2. C. L. Lichtenberg, Naval Research Laboratory, Washington, DC 20375, USA.
3. P. D. Spudis, Lunar and Planetary Institute, Houston, TX 77058, USA.
4. R. Bonner and W. Ort, Protasis Incorporated, Alexandria, VA 22314, USA.
5. E. Malaret, Applied Coherent Technology, Herndon, VA 22070, USA.
6. M. Robinson and E. M. Shoemaker, U.S. Geological Survey, Flagstaff, AZ 86001, USA.