October 24, 2005

Mars Rover Begins Climb Down From Summit

LOS ANGELES -- Spirit, the mountaineering rover that successfully scaled a Martian hill this summer, is searching for flatter ground.

After two months at the summit of Husband Hill, the six-wheeled rover is making its descent toward a basin to the south where it will explore an outcrop dubbed "home plate" that looks like a baseball diamond from orbit.

The solar-powered Spirit's yearlong climb to the peak marked a major feat for the rover, which along with its twin, Opportunity, landed on opposite ends of the Red Planet in 2004 in search of evidence of the past history of water on the cold, dusty planet.

Last month, scientists released the first full-color panoramic photo of the landscape taken by Spirit from the 270-foot-high summit - about the height of the Statue of Liberty. It shows the rover's distinct tracks in the dust, flat plains of the surrounding Gusev Crater region and distant plateaus on the crater rim.

Since reaching the hilltop in late August, Spirit has been busy snapping pictures, studying rocks and using its robotic arm to sift the soil to determine how the hill formed. The leading theory is that Husband Hill became uplifted as a result of crater impact.

Mission scientists say a comparison of the summit rocks reveal similar geologic features to those found on the side of the hill. In both cases, the rock makeup reveal they have been altered by water.

In a twist, Spirit recently uncovered a new set of rocks at the summit that scientists have never seen before. The rocks were made of basalt, a volcanic material, but its composition differs from the basaltic rocks found in the Martian plains, said principal investigator Steve Squyres of Cornell University in Ithaca, N.Y.

It will take about two months for Spirit to completely climb down Husband Hill, which is part of the Columbia Hills range in the Gusev crater region. Husband Hill is named after Rick Husband, the astronaut commander of the space shuttle Columbia that disintegrated as it attempted to return to Earth in 2003.

Scientists poring over elevation maps produced by the rover's panoramic camera indicate the descent should be safe for the robotic geologist. Spirit will traverse across ridge lines toward the inner basin and finally to "home plate."

Meanwhile, Opportunity was in good health again after recovering from a recent computer glitch while surveying the Meridiani Planum region.

Opportunity is exploring the northern rim of Erebus Crater, the largest crater between already-explored Endurance Crater and its next destination, Victoria Crater.

The rovers, operated by NASA's Jet Propulsion Laboratory in Pasadena, have long outlasted their primary, three-month missions.


On the Net:

Mars Rovers: http://marsrovers.jpl.nasa.gov/home/