Three satellites from Earth orbiting Mars are getting moved into position to watch the mission of NASA's latest Mars lander which will descend on the red planet in May, local media reported Saturday. The Phoenix lander, the first robotic spacecraft in the Mars Scout program, was launched on Aug. 4, 2007, and is scheduled to land in the icy northern polar region of Mars on May 25, 2008.
The three orbiters will watch the landing from above and relay radio data to Earth from the Phoenix as the lander hits the Mars air at an initial speed of 12,750 miles (20,514 km) per hour, the U.S. space agency's Jet Propulsion Laboratory (JPL) said.
Longtime Mars planetary scientist Peter Smith at the University of Arizona said the Phoenix lander will use its heat shield, a parachute, and finally a rocket thruster to touch down on the surface of Mars.
Orbiting overhead will be the trio of spacecraft controlled from the JPL in Pasadena, California.
Powerful radio transmitters using dish-shaped antennae will relay telemetry from the Phoenix to ground stations on Earth.
"We will have diagnostic information from the top of the atmosphere to the ground that will give us insight into the landing sequence," said JPL Phoenix deputy project manager David Spencer.
One of the three orbiting satellites would be on the exact wrong side of Mars when the Phoenix lands, were it not for a carefully-measured series of rocket firings commanded from the JPL to alter its orbit, he said. Those firings began this week
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