ShareThisBy BRYAN ROURKE
Friday, October 20, 2006
It's just another day at the office for Michael Wyatt.
Every day for nearly three years, the assistant professor of geological sciences at Brown University participates in a conversation over millions of miles with two Mars rovers that just keep going and going. Spirit and Opportunity, which Wyatt calls "robotic geologists," were supposed to survive 90 days in the planet's dusty and metal-cracking cold climate. They've lasted more than 10 times that.
"There's no doubt the extended lifetime of those rovers has shed new light on the history of Mars," Wyatt says.
Water was once there, and, maybe, life, too. The search is on _ not for Martians, although that would be exciting _ but for rocks.
"Rocks record the geological history," Wyatt says.
The deeper you dig, according to Wyatt, the more history you see. Although maybe you can see the past without digging, which is what scientists may soon discover. Opportunity, which has moved 5.6 miles since it landed in January 2004, is now within meters of a crater that would make the Grand Canyon appear much less so.
"Scientists are extremely excited about this crater," says Greg Mehall, NASA's instrument and mission manager at the Mars Space Flight Facility at Arizona State University.
But scientists haven't decided if the rover should enter the crater.
"Getting in is easier than getting out," Wyatt says.
When Wyatt joined the Brown faculty this school year, he joined the legacy of the university's department of geological sciences, which has long been involved in the exploration of Mars. The late Thomas Mutch, a former professor who died in 1980 while climbing the Himalayas, was involved in NASA's 1976 Viking probe to the planet, which sent back the world's first pictures taken from its surface.
Since then, much of the research and engineering of subsequent Mars projects has involved current Brown faculty members in the geosciences.
"It's the opportunity of a lifetime for me to be joining a group such as the one here," Wyatt says.
Before coming to Brown, Wyatt performed post-doctoral work at Arizona State, where one of the rovers' key instruments, the mini-thermal emission spectrometer, was designed. Every day Wyatt communicates by phone, videoconference or e-mail with scientists at Arizona State who send commands to the two rovers: Analyze soil. Grind rocks. Take pictures.
And every day, by satellite transmission, the rovers send back results, which Wyatt studies.
"When you're doing fieldwork, you don't just like to go to one particular place," Wyatt says. "You like to travel around."
Victoria Crater wasn't on the 90-day travel itinerary.
"It was our wildest dream early on," Wyatt says. "People used to joke how great it would be if we could go there."
This was before the rovers' engineering proved so successful, and before the arrival of a couple of cyclones that completely cleaned the rovers' dust-covered solar panels.
The rovers' longevity, Mehall says, can be attributed to two things: "Engineering and the planet cooperating with us."
Dust is deadly, particularly to solar panels. Most of Mars is covered with dust; after a few months, so were the six-wheeled 1-ton rovers that are roughly 8 feet long, 5 feet wide and 7 feet high.
"Solar power was dropping as the dust was accumulating," Mehall says. "Over one night, the dust we saw on the solar panels was gone. We made it through winter."
At that time, the sun isn't strong, and the temperature is a circuit-killing minus140 degrees Fahrenheit.
But that's not the worst part, according to Mehall. It's the daily change in temperature, from generally 20 above to 100 below.
"Unlike on Earth where temperatures are seasonal, here it's day to day," he says.
The rovers are made of special materials to withstand severe temperature swings. And the rovers use solar energy captured during the day to withstand the night, which it does by charging batteries, which run heaters.
