1. H. B. Niemann, J. A. Haberman, D. N. Harpold, R. E. Hartle, W. T. Kasprzak, P. R. Mahaffy, S. H. Way, Goddard Space Flight Center, Greenbelt, MD 20771, USA.
2. S. K. Atreya, G. R. Carignan, T. M. Donahue, Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109, USA.
3. D. M. Hunten, Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA.
4. T. C. Owen, University of Hawaii, Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822, USA.
5. N. W. Spencer, 12013 Remington Drive, Silver Spring, MD 20902, USA.