Manned vs. Robotic Exploration

NASA has extended the missions of the rovers on Mars, Spirit and Opportunity, for a fifth time. The two have been roving since January, 2004, and this extension will take the mission into 2009. For missions scheduled to last only 90 days each, the rovers have been incredibly successful. Together, they have beamed back nearly 200,000 images, plus other streams of scientific data. The Rovers of Mars will always have a chapter in any history of early space exploration.

All that said, however, they also tell us about the limitations of robotic exploration. In 45 months, Opportunity has traveled a bit over 7 miles, while Spirit has made about 4.5 miles. A well-equipped human mission-- the only kind worth sending-- could cover that much ground the first day, and curious, educated human scientists on the spot could explore with more insight and efficiency. It's true, more advanced robots could do better than Spirit and Opportunity, but the biggest need is for artificial intelligence,, to allow the robot to act on its own, and developing AI has proven much more difficult than scientists originally believed. Progress is being made, but AI capable of tackling Mars might have to wait for the second half of this century.

So, if we want to study Mars but don't really care how long it takes to get the answers we seek, a continued robot program would be sufficient. If, on the other hand, we want to understand Mars and know whether there has ever been Martian life and leave exciting options to our children, mounting a program to send human explorers is essential.