Another U.S. spacecraft is heading for Mars. A spaceship named Opportunity took off from Kennedy Space Center Florida after more than a week's delay because of bad weather and technical problems with the launch rocket. It is the second of two identical craft that are to land on the Red Planet to determine if life could have existed there. The first of the pair, called Spirit, left Earth one month ago.
The twin U.S. spacecraft are to arrive in January and touch down on opposite sides of Mars. Mission scientist Steve Squyers of Cornell University says their job is to gather data to help scientists learn whether the planet was ever habitable.
"It's not a very inviting place today. It's cold -- 60 degrees below zero. This is a desolate, dry, barren world today. Yet, when we look at Mars from orbit, we see these tantalizing clues it was once warmer and wetter," says Mr. Squyers. "So, we want to really find out whether or not Mars had the conditions necessary to support life."
The two landers are to touch down after they deploy parachutes to slow their descent and big airbags to cushion their impact. They will release rovers that are to roam up to one-kilometer over a three-month period, inspecting the Martian terrain.
The spacecraft launched a few weeks ago, Spirit, is heading for a depression in the ground that scientists believe is a dry lake bed. The target of the Opportunity craft is a flat Martian plane that contains the mineral hematite, which forms in the presence of water. Both rovers have stereo panoramic cameras atop masts that will help mission controllers scout for interesting rocks. A scraping tool and microscope will let them see inside them.
The missions take advantage of ideal celestial conditions. Earth and Mars are the closest they have been in nearly 60,000 years. This means NASA can use less fuel to get there. The consequence is that NASA was able to build bigger, heavier, more robust rovers that carry more scientific equipment.
Steve Squyers says there is also another benefit. "Not only is the distance and the amount of mass we can get there good, but at arrival, Earth and Mars are really quite close together," he says. "What that does is enable us to get a lot more data back."
Because Mars is so near, the Japanese and European agencies also have spacecraft on their way to view it.
"Literally, the world is going to Mars," says NASA's chief of space science, Ed Weiler.
The international space flotilla will join two U.S. orbiters already circling the Red Planet. These seven missions represent a total of 17 separate countries conducting scientific investigations on a single planet at the same time -- an unprecedented event in human history."
The European and Japanese spacecraft are due to arrive at Mars in December, about the same time as NASA's Spirit lander.