NASA's Mars-bound roverMars roverTechnicians monitor movement of the robotic arm of NASA's Mars Science Laboratory rover 'Curiosity', where it is undergoing pre-flight tests, in the 'clean room' of the spacecraft assembly facility at the Jet Propulsion Laboratory in Pasadena, California September 16, 2010. The Mars Science Laboratory rover about the size of a Mini-Cooper automobile, is due to be launched on its mission to Mars late 2011, arriving on Mars in August 2012. REUTERS/Fred Prouser (UNITED STATES - Tags: SCI TECH)Mars roverThe heat shield for NASA's Mars Science Laboratory, the largest ever built for a planetary mission is shown being prepared at Lockheed Martin Space Systems, Denver in this April 2011 photograph released by NASA May 13, 2011. The Mars Science Laboratory mission will launch in late 2011 with the mission's rover, Curiosity, landing on Mars in August 2012. It will study whether an intriguing area of Mars has offered environmental conditions favorable for supporting microbial life and for preserving evidence of whether life existed there. The aeroshell will encapsulate and protect Curiosity from intense heat and friction generated during descent through the Martian atmosphere. REUTERS/NASA/Handout (UNITED STATES - Tags: SCI TECH) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTSMars roverThis computer-generated image depicts part of Mars at the boundary between darkness and daylight, with an area including Gale Crater, beginning to catch morning light in this NASA handout photo released August 24, 2011. Northward is to the left. Gale is the crater with a mound inside it near the center of the image. NASA selected Gale Crater as the landing site for Curiosity, the Mars Science Laboratory. The mission's rover will be placed on the ground in a northern portion of Gale crater in August 2012. The crater is 96 miles (154 kilometers) in diameter and holds a layered mountain rising about 3 miles (5 kilometers) above the crater floor. This view was created using three-dimensional information from the Mars Orbiter Laser Altimeter, which flew on NASA's Mars Global Surveyor orbiter. REUTERS/NASA/JPL-Caltech/Handout (UNITED STATES - Tags: SCI TECH) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTSThe NASA spacecraft nicknamed 'Curiosity' hurtling toward Mars prepared to fire its thrusters Jan. 11 to put itself on course for an August landing.