On the Cover: Looking from Earth, with eyes that see only in a limited spectrum, humans have not been able to determine if deposits of water lie hidden on the Moon. This compound, so abundant on our planet, once seemed absent from Earth's satellite. But the Lunar Prospector spacecraft, carrying instruments that see differently than our eyes, has found evidence of water ice in places near the poles that never feel the Sun's light. In this image of the north pole, compiled from neutron spectrometer data, the places most likely to hold water ice are dark blue and magenta; orange-red marks the places least likely to have it. NASA Ames Research Center
4 Space: You Can't Get There From Here: Neil deGrasse Tysonand Louis Friedman recently had a friendly bout over human versus robotic space exploration. Their arguments are presented here.
8 Lunar Prospector: Receiving Interest in the Moon: Jim Burke, The Planetary Society's resident Moon man, discusses the latest exciting results from this mission.
11 A Lunar Polar Orbiter: A Long Time Coming: Jim Burkegives a personal history of the worldwide, decades-long struggle to send a spacecraft to examine the mysterious poles of the Moon.
12 Scientific Results of the Mars Pathfinder Mission: Project scientist Matt Golombek recalls the thrills of the mission and its water-related discoveries.
3 Member's Dialogue Pioneer's paths; Mars or Moon?
18 News & Reviews "Scientist-speak"; evidence and inference.
19 World Watch Mars Express, the NASA budget, and powering deep space missions.
20 Q&A Could something other than an impact explain Uranus' tilt?