NASA made history again last month, as the second of two Mars rovers completed its 90-day, original mission. This adventure has already been hugely successful. Aside from finding signs of water, which means Mars might have sustained life, the robots have added understanding to man's fascination with the Red Planet.
The rovers Spirit and Opportunity landed on Mars in January. Their job was to discover whether water could have existed in large enough amounts to make Mars habitable. In March, the Opportunity analyzed a rock and found an "astounding" amount of crystallized salt. Further tests, and findings by the rover Spirit, led scientists to conclude that the ground had been sufficiently soaked to make life possible. Whether life was there is another question.
Beyond furthering the imagination about life beyond us, the rovers have added to what we know about Mars and space exploration. The robots' cameras took more than 20,000 images, many of which are freely available in vivid clarity on the Internet. The rovers set, and broke, records for driving on the Martian surface. Scientists also reported finding a rock with the same chemical makeup as one found in Antarctica in 1979 - a rock "knocked off" of Mars that orbited the sun before falling to Earth.
NASA has extended the rovers' mission, in hopes of learning more about water on Mars and the craft's physical strength. How long the robots can last is unclear - a week, a month, even longer. "Everything we get from the rovers (now) is a bonus," NASA said in a recent statement. "We look forward to continued discoveries by both rovers in the months ahead." This mission is a tribute to NASA and the scientific community and to the value of unmanned flight.
