The strange attraction of Gale crater

It sounds a little odd—a mountain in the middle of an impact crater. Wouldn't the impact have smashed it flat? Some scientists believe the 96 mile wide crater filled in with sediments over time and relentless Martian winds carved a mountain in the center, where it now stands nearly three times higher than the Grand Canyon is deep.

Because of its history, this strangely sculpted mountain is the ideal place for Curiosity to conduct its mission of exploration into the Red Planet's past. Joy Crisp, MSL Deputy Project Scientist from NASA's Jet Propulsion Laboratory, explains:

"This may be one of the thickest exposed sections of layered sedimentary rocks in the solar system. The rock record preserved in those layers holds stories that are billions of years old -- stories about whether, when, and for how long Mars might have been habitable."

Today the Red Planet is a radiation-drenched, bitterly cold, bleak world. Enormous dust storms explode across the barren landscape and darken Martian skies for months at a time. But data from the Mars Reconnaissance Orbiter suggest that Mars once hosted vast lakes and flowing rivers.

"Gale Crater and its mountain will tell this intriguing story," says Matthew Golombek, Mars Exploration Program Landing Site Scientist from JPL. "The layers there chronicle Mars' environmental history."

In the gentle slopes around the mountain, Curiosity will prospect for organic molecules, the chemical building blocks of life. Mars Reconnaissance Orbiter has found an intriguing signature of clay near the bottom of the mountain and sulfate minerals a little higher up. Both minerals are formed in the presence of water, which increases potential for life-friendly environments.

"All the types of aqueous minerals we've detected on Mars to date can be found in this one location," explains Golombek.

Clay settles slowly in water and forms little platelets that conform around things, hardening over time and encasing them in ''casts." Clay could seal organics off from the outside environment much like it preserved dinosaur bones on Earth.

"If organics ever existed on Mars, they could be preserved in the clay."

Even on planet Earth, teeming with life, finding billion year-old well-preserved organics is difficult. But Curiosity will find them if they're present in the samples it takes. The rover is equipped with the most advanced suite of instruments for scientific studies ever sent to the Martian surface1. When these are brought to bear on Gale crater’s mysteriously layered mountain, the odds of a discovery will be at an all-time high.

As seasoned travelers know, however, the journey is just as important as the destination. Curiosity can travel up to 150 meters per Mars day, but will stop often to gather and analyze samples.

"It could take several months to a year to reach the foot of the mountain, depending on how often the rover stops along the way," says Golombek. "There will be plenty to examine before getting to the central mound."

A high-resolution camera on the rover's mast will take pictures and movies of the scenery, taking Earthlings on an extraterrestrial sightseeing tour.

"As Curiosity climbs toward higher layers, you'll see spectacular valleys and canyons like those in the U.S. desert southwest. The walls on either side of the rover will rise over 100 feet. The sights alone will be worth the trip."

Stay tuned for updates from the Red Planet.

Source: Science@NASA