III-V solar cells provide power to explore Mars
The Spirit and Opportunity rovers, which landed on Mars on January 4 and January 25, respectively, are powered by Spectrolab’s Improved Triple Junction (ITJ) GaInP/GaAs/Ge solar cells. 
“We’re proud to be part of the NASA mission, in part because it continues Spectrolab’s already solid track record of producing power on interplanetary missions to Mars,” said David Lillington, president of Spectrolab. “Mars Global Surveyor, now entering its third year of conducting critical monitoring of Martian weather patterns, is powered by Spectrolab solar cells.”
The two Mars exploration rovers were launched in mid-2003 to continue NASA’s quest to understand the role of water on Mars. The robots were built by NASA s Jet Propulsion Laboratory at a cost of $800 million.
The solar panels were folded to fit inside the rovers for the trip to Mars. Once on the Martian surface, each rover’s first action was to unfold its solar-array panels to form a total area of 1.3 square meters of triple-junction solar cells. The solar cells will power all the activities and instruments of the spacecraft.
The rovers feature panoramic cameras at human-eye height, and a miniature thermal emission spectrometer with infrared vision to help scientists identify the most interesting rocks. The rovers will extend an arm and a microscopic imager will give scientists a close-up view of the rocks’ texture and composition. Another tool will expose the interior of the rock.
Beagle 2, another Mars exploration spacecraft that landed on Mars on December 25, 2003, was also equipped with Spectrolab solar cells and panels, but contact with the autonomous 60 kg capsule is yet to be established. The spacecraft was designed and built by a consortium of British universities including the Open University and Leicester University, a number of research support teams and industry led by EADS Astrium Ltd as industrial prime contractor.
Spectrolab says that its solar cells have powered more than 500 satellites and interplanetary missions during the last 40 years, and that its multijunction solar cells generate more than 325 kilowatts of power on orbit. Cells representing another 800 kilowatts of power are awaiting launch.
