Summary: What do the Mars Opportunity rover and a bear have in common? They both hibernate during the winter. In the rover’s case, it’s because it needs all the power its solar cells gather during the short days to keep it warm during the bitter nights. The next Mars rover won’t have that problem. Curiosity, which is scheduled to land tomorrow night, will be powered by a small nuclear generator. The radioactive decay of plutonium will generate heat. The generator will convert some of the heat to electricity, while the rest goes directly toward keeping the rover warm. That’ll allow it to keep moving — and working — all year ’round. Nuclear generators have been flying in space for decades. They powered the instruments that Apollo astronauts left on the Moon, and the twin Viking missions to Mars in the 1970s. They’ve also powered every spacecraft that’s visited Jupiter and the other outer planets. Two of those craft are still working after 35 years in space. Curiosity is the largest and most ambitious Mars rover yet. It needs far more power than the earlier rovers to keep its wheels turning and its cameras clicking. The nuclear generator offers one other advantage. Martian dust settles on top of solar cells, blocking some of the sunlight and cutting the amount of power the cells can produce. The nuke won’t have that problem. It should keep Curiosity working through dust storms, darkness — and the long Martian winter. More about Curiosity tomorrow. Script by Damond Benningfield, Copyright 2012 For more skywatching tips, astronomy news, and much more, read StarDate magazine.
