Mars Probe Ready to Scan Surface

A year behind schedule but no worse for the wear, NASA's Mars Global Surveyor is finally in position to begin mapping the Red Planet.

The spacecraft, launched in 1996 as a companion spacecraft to Mars Pathfinder, will spend an entire Martian year -- 687 Earth days -- photographing the planet for future expeditions. The survey was delayed so engineers could delicately lower the probe into its proper orbit.

The positioning technique, called aerobraking, involved dipping the spacecraft's solar panel into the thin Martian atmosphere like a paddle to gradually dissipate speed and reshape its orbit. The work was complicated by a structural problem with the solar panel that forced spacecraft operators to aerobrake the spacecraft extremely gently and slowly.

"It has been a long and arduous task that has turned into a valuable learning experience for all of us," says Glenn Cunningham, deputy director of the Mars Exploration Program at NASA's Jet Propulsion Laboratory. "The use of aerobraking has been a pioneering operation for a spacecraft at Mars, and we now know that we can use this technique with confidence for future Mars missions."

Mars Global Surveyor will spend the next two weeks drifting into what's called a sun-synchronous orbit so the spacecraft will cross the Martian equator every day at about 2 a.m. local solar time. In addition to mapping, the satellite will study the planet's topography, magnetic fields, mineral composition and atmosphere. It also will serve as a communications relay for the Mars Polar Lander, which is scheduled to arrive on Mars Dec. 3.

By Irene Brown, Discovery Online News