May 18, 2010
NASA Seeks To Find Martian Life, Yet Again
Scientists say that after the Phoenix spacecraft discovered water on Mars in 2008, it is time the search is put on again for signs of life.
This time, scientists want to bring Martian rock and soil samples back to Earth, where they could be analyzed for fossilized traces of alien bacteria, or chemical and biological clues that could only be explained by something that was alive.
Space policy experts say the timing is right, despite the risks and hefty price.
"We're about out of things to do on Mars other than a sample return," George Washington University space scholar John Logsdon, told the Associated Press (AP). "It is an extremely expensive undertaking, probably the most expensive robotic mission to Mars and clearly the most complex."
The idea of bringing Mars samples back to Earth for study has been brought up for the past 25 years without going anywhere because of the costs and engineering concerns. Many still say it is the best way to answer whether life ever arose on Mars.
NASA Mars researchers said at a town hall meeting near Los Angeles this spring that the next effort would be done in phases. It would be attempted before the mid-2030s, the timetable for astronauts to land on Mars as proposed by President Barack Obama.
A pair of rovers is expected to launch in 2018 to a spot where water once flowed on the red planet. One would drill below the surface and the other would collect rocks and dirt and seal them in containers.
Some cosmic choreography would be used to get the bounty back to Earth several years later. One spacecraft would touch down to collect the samples and launch them into orbit around Mars where a rendezvousing spacecraft would capture the bounty and return it to Earth.
Even if those challenging tag-team missions went according to plan, the first Mars samples would not be returned back to Earth until the 2020s.
Many people criticize the concept. Marine chemist Jeffrey Bada at Scripps Institution of Oceanography believes it makes more sense for NASA to simply look for the molecular building blocks of life by running experiments on Mars before bringing soil back.
He told AP that otherwise it "will be a giant waste of money and likely delay a definitive answer to the life on Mars question for decades."
Mars is a cold, dusty planet that is constantly bombarded by dangerous radiation. However, billions of years ago it was a warmer, wetter planet based on the elaborate mazes of gullies, canyons and other landforms thought to be shaped by flowing water.
People have questioned the chance for life there since the 1900s when amateur astronomer Percival Lowell said he spotted irrigation canals. He theorized that they were built and used by Martians to channel water from the polar caps to the desert and other arid regions.
Later observations made by the Mariner spacecraft in the 1960s and 70s revealed a cratered wasteland similar to our moon. People thought Mars was dead.
Interest was renewed in 1971 when Mariner 9 spied massive extinct volcanoes, riverbeds, dry channels and a network of canyons.
Once the Viking II spacecraft landed in 1976, hopes were high for a discovery of extraterrestrial life.
Viking's experiments found no signs of life, which brought many researchers to believe that planet was hostile to life.
"Viking tried to find life on Mars by hitting a home run," Scott Hubbard, a former NASA Mars czar who now teaches at Stanford University, told AP. "It was one mission betting on having just the right instruments and the right approach. They got a lot of data, but they did not see any of the signs of life that they thought they would."
There has not been another Mars mission since that has pursued the life question directly. Instead, spacecraft circling Mars or landing on it searched for proxies like water and environments that might be suitable for life.
Even the $2.3 billion Mars Science Laboratory, scheduled to launch next year after much delay, is not equipped to look for life. Instead, it will study the planet's habitability.
Despite the successes of the past decade, there is still no answer as to whether life existed on Mars. Life as we know it needs more than just water. It also needs nutrients and energy.
Cornell University astronomer Jim Bell told AP that increased knowledge about the red planet and better technology will make this latest effort to bag Mars samples more realistic than past fits and starts.
Lately, "there's confidence that, 'Hey, maybe we can do this. Maybe it's not all science fiction,'" he said.
Tests on Martian rocks and soil on Earth would be much more useful than the limited ones done by tiny robotic instrument packages like the mars rovers.
Scientists would mainly look for complex organics like carbon compounds that make up the building blocks of life on Earth and other chemical clues potentially left by microbial life.
Planetary scientists David Paige of the University of California, Los Angeles, said the gamble is worth it.
"It's been so long since Viking. Each generation wants to take up the quest," Paige said. "You can't blame people for being interested in this."
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