Slideshow: Where on Mars Should NASA Send 'Curiosity' Probe?

Scientists who next year will be searching for signs of ancient life on Mars using NASA’s Curiosity rover (a.k.a. Mars Science Laboratory) are huddling today near the Jet Propulsion Laboratory in Pasadena, California, trying to decide where to land their rover. A 3-day workshop of about 120 scientists ended yesterday without producing a clear favorite, but NASA Associate Administrator Edward Weiler, with advice from Curiosity project leaders, will make a final decision by early July. Here are images of the four finalists, constructed from Mars imaging and data.

  • Mar's Gale crater.

    Mar's Gale crater.

    Gale Crater. The target in Gale would be its 5-kilometer-high pile of sediments--or rather the bottom layers, laden with both clays and sulfates that may record the loss of an early, life-friendly environment on Mars.

  • Eberswalde

    Eberswalde Crater. Hard by the larger Holden Crater, this ancient crater contains a classic river delta, which means a lake must have formed. The easily understood, water-related terrain makes it the favorite of geologists.

  • Mawrth

    Mawrth Vallis. The high ground beyond the crater is the favorite of spectroscopists, who have detected an abundance of water-altered minerals in crustal rocks there. Geologists can’t make heads or tails out of the rocks, however.

  • Holden

    Holden Crater. Water obviously flowed into this impact crater several billion years ago, possibly creating a life-harboring lake. There’s also ancient crust exposed where there may have been microbial life.