Robot Rovers Provide a Peek at Mars
Never in his wildest dreams did Jim Bell imagine he would help take pictures of Mars. But in 2004, he did exactly that when he led the photography team for NASAs mobile robot missions to Mars.
Now some of the pictures snapped by the two robot rovers named Spirit and Opportunity can be viewed in Bells new book, "Postcards from Mars." The work includes some 150 pictures of the robots ongoing exploration of Mars desert-like surface.
The two rovers have taken more than 150,000 pictures during their nearly three-year visit to the red planet. For the first time, what came to earth as massive images, some more than 100MB, have been edited, cropped, processed and published in a book for public viewing.
Bell, an associate professor at Cornell University in Ithaca, N.Y., admits he is not a professional photographer. But he has followed his childhood love of the art form all the way to another world.
When it comes to space photography, researchers often take "whatever you can get" because of the difficulties involved, he said. But the technology on Spirit and Opportunity and the duration of the mission gave those involved with the project the chance to think like photographers, he said.
"Once in a while we can think about framing a picture we can make those decisions that landscape photographers make all the time," he said.
The engineers estimated the robots would last 90 days. Bell hoped maybe, with a little luck, they would last 180. But no one, he said, thought the robots would still be there taking pictures more than a thousand days after touching down.
He credits the robots resiliency to good design and luck. For example, Bell said, there was concern Martian dust storms would cake the robots solar panels with dust and make them useless. However, wind has routinely cleaned the panels off.
It was a long journey for Bell to get to this point. About 10 years ago, NASA announced a competition for scientific instruments to be used for an upcoming mission.
Bell and a team of scientists and researchers from around the world submitted a proposal and were rejected twice. The third time however, was the charm, and the group won the right to design a robotic rover. NASA officials later decided they wanted two robots to reduce the risk.
All in all, he said, it took about 39 months to build the machines.
Spirit and Opportunity are far from the first robots to land on Mars. The first in fact, touched down in 1976. But what makes the two robots different is how mobile they are. The previous robots were either stationary or were only able to travel a short distance. Spirit and Opportunity have navigated more than 4 and 6 miles of the planets surface, respectively, he said.
Depending on the position of the planets, it can take as little as four minutes, or as much as 20, for signals sent by the rovers to reach the earth and visa versa.
For that reason, Bell explained, the robots are not given commands in real time. Instead, scientists send them a list of commands in the morning to govern the machines movements for the entire day.
The cameras the robots are equipped with provide a level of resolution equivalent to 20/20 vision in human beings, roughly three times better than the best camera previously used on Mars, he said.
Among the most important things the cameras have turned up is proof of the presence of water on ancient Mars in the form of pictures of marks on rocks on the planets terrain.
"Now we know that there was liquid water on the surface of Mars a long time ago," Bell said.
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