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Is red planet wet? Mission on way

Published Sep. 28, 2005

A robot lander and two piggy-backed microprobes Sunday embarked on the second of NASA's water missions to Mars, launched atop a Boeing Delta 2 rocket.

After an 11-month journey, the Mars Polar Lander will parachute gently to the surface of the red planet and start scooping up dirt on Dec. 3, minutes after the twin probes it carries have slammed into the ground at speeds up to 500 mph.

Together, the trio of spacecraft will serve as a high-tech divining rod to probe the soil of Mars for water in the form of ice crystals. Water is a key ingredient for life, as well as an important resource for human explorers who may visit Mars in the distant future.

"Liftoff of the Delta 2 rocket carrying the Mars Polar Lander, NASA's first visit to the red planet's southern pole," said a NASA commentator, Lisa Malone, as the engines ignited at 3:21 p.m. to catapult the rocket off a seaside launching pad at Cape Canaveral Air Station. A camera mounted on the side of Delta 2 beamed spectacular views of Earth as the booster sped to space.

About 42 minutes after liftoff, the probe separated from the rocket, revved up an attached motor to escape Earth's gravitational pull, and began spreading its winglike solar power arrays.

"Absolutely clean separation from the launch vehicle third stage has been confirmed," project manager John McNamee said. "We have a completely nominal spacecraft."

The Polar Lander is a companion to the Climate Orbiter, a Martian weather satellite of sorts, now 4-million miles from Earth after its launching last month. The orbiter will slip into orbit around Mars on Sept. 23. Together, it and the lander are the second in a 12-year series of dual missions aimed at returning a Martian soil sample by 2008. The two spacecraft are worth $236-million, including operating costs.

The goal of the program is to understand Mars as a planet, "but I think the most compelling goal in the Mars Surveyor program is basically to understand Mars as a possible abode for life," said Edward Weiler, NASA's associate administrator for space science. "You've got to follow the water if you're looking for life."

Scientists are convinced that Mars was a warmer, wetter planet 4-billion years ago. "There's even a possibility that there was rain on Mars a long, long time ago," Weiler said. "We certainly know water flowed on Mars." The lander and orbiter will try to determine what made it become so cold and seemingly as dry as a desert.

If all goes as planned, the lander will parachute to a touchdown at about 75 degrees south latitude, near the South Pole of Mars, where spring and summer daytime temperatures hover around minus 100 degrees Celsius. No other spacecraft from Earth has landed so close to the pole of a planet, an exciting event to scientists who hope to discover there a vast reservoir of water in the form of layered ice or small ice crystals.

Each of the two saucer-shaped probes is about the size of a basketball and weighs five and a half pounds. Five minutes before the lander enters the Martian atmosphere, the two probes will break away and drop like bombs. The probes are designed to crater on the surface and burrow as deep as three feet, drill into the soil, and heat the soil with lasers to analyze its water and carbon dioxide content.

The lander is expected to come to rest about 60 miles away from the probes' impact point about a minute after they hit. The lander will use a robotic arm to scoop up a small amount of soil and bake it in a tiny oven to release water vapor.

The lander also carries a small microphone provided by the Planetary Society, a space advocacy organization. Scientists will try to eavesdrop on nature, but do not expect to hear much more than the landers gear's turning and maybe windblown dust hitting the microphone. "I don't think _ I hope to be wrong _ that we'll actually hear the wind blowing through the trees and things like that," said the project manager, McNamee.