NASA's Mars Science Laboratory has been rescheduled to launch in the fall of 2011, two years later than previously planned. The decision to delay, announced on 4 December, was made following an assessment that more time is needed for testing and to resolve hardware challenges. The length of the delay is because the 2009 launch window ends in October, with the next launch opportunity in 2011.

The mission will study the early environmental history of Mars, exploring a site where there were wet conditions in the past that may have been favorable for supporting microbial life.