Spirit is on high ground in the Columbia Hills of the Gusev Crater. It too has found water-altered minerals in the soil and rocks. The rovers, originally designed to last 90 days on the Martian surface, begin their third year of operations on Jan. 3. NASA has approved another round of mission extensions through September.
One of the key challenges facing scientists in 2007 will be to decide how the new evidence of surface water revealed in Global Surveyor’s images should be addressed in future missions. Once Phoenix is on its way, NASA will turn its attention to the Mars Science Laboratory, slated for launch in 2009.
MSL has wide berth because it will be able to land within a target area that is 12.4 miles (20 kilometers) in diameter, as high as 1.2 miles (two kilometers) from the planet's surface and anywhere up to about 60 degrees north or south of the equator.
In comparison, NASA had about 10 options for its 1997 Mars Pathfinder mission and about 150 contenders for Spirit and Opportunity landing sites.
"There are literally billions of potential landing sites," said NASA planetary scientist Matt Golombek.
"For the first time, we are being given the opportunity to really go anywhere on Mars."
