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Mars Polar Lander Scheduled To Touchdown This Afternoon

By Kathy Sawyer

Ending an 11-month cruise, NASA’s Mars Polar Lander late Thursday was hurtling toward its target landing site in the late spring of the Martian south pole.

By about 3 p.m. (EST) Friday, if all goes well, the Polar Lander will have become the fourth U.S. craft ever to touch down on the surface of the Red Planet and the first to land in the polar region of any extraterrestrial world. Its two passengers, basketball-sized projectiles named Scott and Amundsen after two of Earth’s polar explorers, will have become the first penetrators ever shot into an alien body.

The mission is the second wave of a long-term assault on the planet aimed at learning more about its geology, climate and potential for supporting life, including possibly future visits by humans. The Polar Lander, equipped with a robotic digging arm, will focus on analyzing soil samples for signs of water.

The first signals of arrival could arrive within an hour of the landing, depending on the spacecraft’s health, with an image following soon after. The incoming trove will be piped directly onto the Internet with minimal delay, scientists said.

But first, the Polar Lander has to negotiate a complex entry into the Martian atmosphere, hurtling in at more than 15,400 mph and experiencing heat from friction up to 3,000 degrees Fahrenheit. It must then pop a parachute, and power on retro-rockets to brake its fall. Because it is aimed for an extreme latitude far from the equator, the geometries of the arrival 150 million miles from Earth make it even trickier than most, according to flight operations manager Sam Thurman.

“It’s a very complex process (involving) literally years of effort by hundreds of people” all aimed at that final 5.5 minutes, Thurman said.

This mission has been subjected to unusually exhaustive scrutiny in recent weeks by investigators determined to make sure the Lander does not suffer the fate of a sister ship, the Mars Climate Orbiter, which was destroyed in the Martian atmosphere in September because of a navigation error.