NASA's Mars Global Surveyor and Mars Odyssey missions have provided evidence of a relatively recent ice age on Mars. In contrast to Earth's ice ages, a Martian ice age waxes when the poles warm, and water vapor is transported toward lower latitudes. Martian ice ages wane when the poles cool and lock water into polar icecaps.
The Martian radiation environment experiment on NASA's 2001 Mars Odyssey orbiter has collected data continuously from the start of the Odyssey mapping mission in March 2002 until late last month. The instrument has successfully monitored space radiation to evaluate the risks to future Mars-bound astronauts. Its measurements are the first of their kind to be obtained during an interplanetary cruise and in orbit around another planet.
The first overview analysis of a year's worth of high-resolution infrared data gathered by the Thermal Emission Imaging System (THEMIS) on NASA's Mars Odyssey spacecraft is opening Mars to a new kind of detailed geological analysis and revealing a dynamic planet that has experienced dramatic environmental change.
Images from the visible light camera on NASA's Mars Odyssey spacecraft, combined with images from NASA's Mars Global Surveyor, suggest melting snow is the likely cause of the numerous eroded gullies first documented on Mars in 2000 by Global Surveyor.