John Grant, geologist, Smithsonian National Air and Space Museum in Washington, speaks at a Mars Science Laboratory (MSL) press conference at the Smithsonian's National Air and Space Museum on Friday, July 22, 2011 in Washington. The Mars Science Laboratory (MSL), or Curiosity, is scheduled to launch late this year from NASA's Kennedy Space Center in Florida and land in August 2012. Curiosity is twice as long and more than five times as heavy as previous Mars rovers. The rover will study whether the landing region at Gale crater had favorable environmental conditions for supporting microbial life and for preserving clues about whether life ever existed. Photo Credit: (NASA/Carla Cioffi)