The Mars Exploration Rovers Spirit and Opportunity have completed their primary requirements, and are receiving straight A's for their ongoing work on the red planet.
The rovers were designed to discover evidence of liquid water in Mars' past, and they did so in dramatic fashion. Opportunity dug into the rocks of Eagle Crater at Meridiani Planum and only two months into its mission, scientists made a stunning announcement.
Image to right: The evidence - Opportunity's microscopic imager showed scientists the layering that took place in Eagle Crater long ago, proving that water affected the rocks in this location. Credit: NASA.
"Liquid water once flowed through these rocks," said Dr. Steve Squyres of Cornell University, principal investigator for the science instruments on the rovers. "It changed their texture, and it changed their chemistry."
Spirit also had its day at the beach, sending home data that convinced scientists that water had once formed crystals in a rock nicknamed "Humphrey."
Now, it's time for extra credit. Both rovers have had their missions officially extended by NASA to at least September of this year, and will continue working for as long as possible after that.
Spirit is blazing a trail to the southeast towards the Columbia Hills, a small group of peaks on the horizon named for the crew of STS-107.
"Within these hills, perhaps we can learn more about the earlier history of Gusev Crater and potentially whether water plays a major role in that early history," explained Dr. Dave Des Marais, rover science team member from NASA's Ames Research Center at Moffett Field, Calif.
Opportunity, after climbing out of the crater it landed in, has begun roving eastward toward Endurance Crater. On the drive so far, the rover has drilled into a rock the spacecraft hit on landing, and looked at a mysterious crack in the Martian surface nicknamed "Anatolia."
Image to left: 2 kilometers away, the Columbia Hills are getting closer with each image taken by Spirit. The team believes the region will open the window to an entirely different period in the Martian past. Credit: NASA
Scientists believe Endurance Crater will expose much of the same type of bedrock as Eagle Crater did, but the new target may hold even greater evidence of Martian water.
Both rovers recently received a software upgrade from Mission Control at NASA's Jet Propulsion Laboratory in Pasadena, Calif. and are prepared for a summer of exploration, although the Martian autumn is quickly approaching.
The rovers will increase use of their heaters as temperatures drop, although the long journeys ahead for both Spirit and Opportunity are sure to keep them hot on the trail of the mysteries Mars has to offer.
NASA's John F. Kennedy Space Center