2002: Odyssey, the spacecraft NASA placed into orbit around Mars in late 2001, begins its scientific mapping of the red planet.

The Odyssey orbiter was the first of the six current operational vehicles to serve in NASA's Mars Exploration Program.

Flight controllers at the Jet Propulsion Laboratory activated Odyssey's Themis camera apparatus, a thermal-emission?imaging system capable of taking both visible and infrared images. They spent a short period calibrating the camera settings before turning it on the Martian surface.

The first images were transmitted to Earth a few days later and released to a waiting world at a press conference March 1.

The imaging system, designed to measure the distribution of minerals on the Martian surface, is one of three principal instruments carried on board. The others, a gamma ray spectrometer for determining the planet's geological composition, and a sensor for measuring radiation, combined to give scientists the most comprehensive picture yet of one of Earth's nearest neighbors.

Included in the trove of information returned to Earth was new data on the Martian ice fields and a determination that the planet's high levels of radiation pose a manageable risk to future astronaut-explorers. It was also the first spacecraft to detect evidence suggesting that water ice exists beneath the planet's surface away from the polar ice caps ? a fact confirmed last year by the Phoenix Mars Lander.

Odyssey's primary mission concluded in August 2004, following a period when Mars and Earth were closer together than at any time in 73,000 years. Had Odyssey packed it in that August, NASA would have easily gotten its money's worth.

But the spacecraft remains in orbit on an extended mission, and while its role has been diminished as rover vehicles now comb the Martian surface from the ground, it continues transmitting data to Earth. Recently, it sent back evidence that ancient Mars may have had oceans.

Source: NASA, Space.com