In a case of beginner's luck, a group of international students, who won the chance to image Mars with a NASA spacecraft camera, have stumbled upon a surprising cluster of dark-colored boulders situated in the middle of light-colored terrain.

Mars Global Surveyor image. Photo: NASA/JPL/Malin Space Science Systems

The students' discovery has so far baffled veteran Mars scientists. The mystery boulders, found in images captured by NASA's Mars Global Surveyor spacecraft, managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., cover one of three Martian sites targeted by the young scientists. How the boulders got there and what geological history they represent on Mars are questions scientists still need to answer.

"It's puzzling," said Michael Carr of the U.S. Geological Survey. "I looked at a few pictures around [the area] and couldn't find anything to explain it. Very puzzling! These are huge boulders. There are no indications of any outcrops that could shed such boulders."

"The location and nature of these boulders is unusual, but their shape and distribution -- in respect to the slope upon which they sit -- is consistent with a boulder shattered by weathering. The fall to their present location could also have broken the boulders apart. The mystery is why so much of the rest of the slope is smooth and devoid of blocks," said Dr. Michael Malin, of Malin Space Science Systems, which operates the Mars Orbiter Camera aboard the Global Surveyor spacecraft.

Images of the two other sites chosen by the students revealed an equatorial Martian region with layers of sediment, possibly deposited by flowing water, and layered terrain of a Martian polar cap.

The students, all members of the Planetary Society's week-long Red Rover Goes to Mars Training Mission, range in age from 10 to 16. Under the supervision of scientists at Malin Space Science Systems in San Diego, Calif., they studied imaging data from Global Surveyor and selected interesting areas that coincided with the spacecraft's current orbital position around the red planet. They also selected a candidate landing site for a possible sample return mission, to be imaged sometime in the next five months when Global Surveyor's orbit takes it past the target area.

"This kind of opportunity makes me wish I were a student again," said Michelle Viotti, lead for the Mars Public Engagement Program at JPL. "For those who are still in school, we hope to open up many more opportunities in the near future for students to participate personally in the exploration of Mars."

The fledgling scientists were chosen through an essay contest from more than 10,000 entrants worldwide. The four girls and five boys represent Brazil, Hungary, India, Poland, Taiwan and the United States.

The Planetary Society's Red Rover Goes to Mars project is conducted in cooperation with NASA and JPL. JPL manages NASA's Mars Global Surveyor mission for NASA's Office of Space Science, Washington, D.C., and Malin Space Science Systems built and operates the Mars Orbiter Camera. JPL is a division of the California Institute of Technology in Pasadena.