Red Planet Rovers: Still Stalking Science

DALLAS, Texas – Those peppy Mars rovers, Spirit and Opportunity, continue to make tracks as they wheel about two diverse locales on Mars – far outstripping their original warranties of 90 days of lifetime and a target of roughly 2,000 feet (600 meters) of driving range when they landed on the planet in January 2004.

Both of the mechanized emissaries from Earth remain hard at work, said Steven Squyres, principal investigator for the NASA Mars Exploration Rover Project and  astronomer at Cornell University in Ithaca, New York.

Squyres and other experts discussed past, present and future Mars exploration plans here during the National Space Society's (NSS) 26th annual International Space Development Conference (ISDC).

"Solful" science

After 1,200 sols – a "sol" is one solar day on Mars?Spirit is now surveying a site called "Home Plate," a plateau within Gusev Crater. The robot recently wheeled itself into a remarkable discovery, Squyres reported.

Due to an out-of-commission right front wheel that no longer turns, Spirit is driving backwards dragging that mechanical appendage.

"That's rough ? it's a tough way to drive," Squyres explained. "But what we have discovered is that as you drive it, it digs a wonderful trench as you move along and sometimes interesting things will pop up in that trench."

That was the case a few weeks ago as Spirit investigated a self-dug trench that exposed bright white soil. Utilizing a rover-toted spectrometer, scientists found that the uncovered material was 90 percent pure silica.

Silica Valley

Rover scientists have dubbed the little trench 'Silica Valley'.

"This is the kind of stuff that you need to have water to make that kind of concentration of silica," Squyres said.

What created that pure silica concentration has spurred thought about volcanic fumerals and hot springs on Mars, Squyres added. "Something very, very interesting happened here. And we discovered this after 1,200 days on the martian surface. It really makes me wonder what else is out there."

Indeed, Spirit is presently investigating a rock outcrop, "one of the most beautiful outcrops I have ever laid eyes on," Squyres said.

Furthermore, the rover is engaged in an experiment that combines the overhead imagery from NASA's Mars Reconnaissance Orbiter with Spirit's on-the-surface set of cameras.

The idea is to try and simultaneously catch dust devils in their whirlwind act from two different angles, Squyres noted.

Deep driving into Victoria Crater

Not to be outdone, the Opportunity rover at Meridiani Planum is on duty too.

That robot is studying the "geologic promised land" of Victoria Crater, Squyres explained, a large impact feature some 2,600 feet (800 meters) in diameter and 300 feet (70 meters) deep. "It's just a geologic history book."

Opportunity has completed a partial traverse around Victoria and is now headed back to an alcove dubbed "Duck Bay" – and a site seen as an entrance way down into the crater.

"Our adventure continues and we hope to travel to Duck Bay. And if a careful safety review indicates that it's safe to go in, we're going to go in," Squyres added. "We're going to do a lot of good science ? and then we're going to come out again and keep exploring."

Squyres told ISDC attendees that, in looking into the future, he takes some comfort in the fact that the same agency, NASA, that placed the first humans on the Moon nearly 40 years ago also put Spirit and Opportunity on Mars fewer than four years ago. "And that gives me a lot of hope for the future," he concluded.

Inner truth

Mars is slated to be on the receiving end of another Earth-launched probe next year.

NASA's Phoenix Mars lander is being prepped for an early August liftoff, followed by a cruise through interplanetary space and an alighting on the Red Planet in May 2008.

"It's the truth of Mars ? that's what we're after," said Peter Smith, Phoenix principal investigator at the University of Arizona in Tucson. "What are the treasures that are hidden within Mars?"

Phoenix will use a set of thrusters to slow down and plant itself down upon the Red Planet. That means, this time, no airbags and no bouncing across the planet. Once firmly footed at its arctic landing spot, the craft is to use a robotic arm to dig down and scoop up icy soil for detailed, scientific scrutiny.

Smith said his goal with Phoenix is to get instruments on the surface and obtain "the inner truth of the planet" – to try and make progress on the search for life on planets beyond Earth.

Mars underground

One piece of hardware onboard Phoenix is a microphone, part of the descent imager equipment onboard the Mars lander. "We have the opportunity to be listening during descent," Smith said.

Moreover, once on the surface of Mars, the device could hear the robotic arm plowing into the icy landscape. In doing so, it would add that "extra sense to the touch-and-feel aspects" of the mission, Smith observed.

Smith said that both Mars orbiters and landers will further a deeper understanding of that distant world.

"There are definitely caves on Mars," Smith said. But that raises a key question, he added: Could there be fractures inside those caves that come up from deep underground?

"Maybe water vapor is trapped into the cave and you have the kind of environment where, perhaps, biology could exist," Smith said. This is certainly seen on the Earth, he continued, and many caves on our planet – even those that are sealed from the atmosphere and receive no sunlight – are stocked with forms of life.

Driving force

The armada of prior Mars missions have narrowed down how best to search for life on the Red Planet, said Donna Shirley, president of Managing Creativity and based in Seattle, Washington. She is a retired manager of NASA's Mars Exploration Program.

NASA's ongoing Mars Exploration Program strategy is founded upon the build-up of knowledge from successive missions to the planet, Shirley said.

Shirley also spotlighted that understanding Mars' past – how it changed and why – may well provide clues as to Earth's own future.

"I think the driving force for people exploring Mars," Shirley pointed out, "is going to be the question, can we expand to other planets? Are there places to live? Can we actually live there? Can we afford to go to Mars and live there for a reasonable amount of money?"

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