Curiosity rover explores Mars

This self-portrait of NASA's Mars Curiosity rover is shown in this NASA handout composite image released May 30, 2013. Radiation levels measured by Curiosity show astronauts likely would exceed current U.S. exposure limits during a roundtrip mission to Mars, scientists said on Thursday. The image combines dozens of exposures taken by Curiosity's Mars Hand Lens Imager (MAHLI) on February 3, 2013 and three exposures taken May 10, 2013, to update ... more 

This self-portrait of NASA's Mars Curiosity rover is shown in this NASA handout composite image released May 30, 2013. Radiation levels measured by Curiosity show astronauts likely would exceed current U.S. exposure limits during a roundtrip mission to Mars, scientists said on Thursday. The image combines dozens of exposures taken by Curiosity's Mars Hand Lens Imager (MAHLI) on February 3, 2013 and three exposures taken May 10, 2013, to update the appearance of part of the ground beside the rover. The updated area (bottom, L) shows gray-powder and two holes where Curiosity used its drill on a rock target named "John Klein", displaying how the site where the self-portrait was taken appeared by the time it was ready to drive away from that site in May 2013. REUTERS/NASA/Handout via Reuters (OUTER SPACE - Tags: SCIENCE TECHNOLOGY) ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS less