The twin vehicles-Spirit and Opportunity-are on a four-year mission to look for clues of life on the red planet. It is believed that the latest development will delight space-watchers who have so far been disappointed by the lack of images of little green men captured by the robots. According to Times Online, the alien figure was pictured at the far left of one of the panoramic photographs taken by the exploration rover, Spirit, from the top of a low plateau in late 2007.
The two robots have been roving around on Mars since completing their first successful mission in April 2004. They have been looking for geological evidence of water, which may suggest an environment that might once have been hospitable to life.
After being launched in June and July in 2003 from Cape Canaveral, Florida, they travelled 487 million and 456 million km respectively to opposite ends of the planet, and went on to explore the dusty, rock-strewn landscape.
Both of them are powered by the solar energy, and are a sort of mechanical equivalents of geologists walking the surface of Mars. They are equipped with cameras mounted on masts 1.5 meters (5 feet) high, which provide 360-degree, stereoscopic, humanlike views of the terrain.
Their arms can make almost same movements as human arms, and can place instruments directly up against rock and soil targets of interest.
A microscopic camera installed in the mechanical "fist" of the arm serves the same purpose as a geologist's handheld magnifying lens.
The budget for the project is around 820-million dollars.