WEST LAFAYETTE, Ind., June 29 (UPI) --
Evidence of life on Mars could come not from a mission to the Red Planet but from one sent to the martian moon Phobos, U.S. researchers said.
"A sample from the moon Phobos, which is much easier to reach than the Red Planet itself, would almost surely contain martian material blasted off [Mars] from large asteroid impacts," Purdue University Professor Jay Melosh said.
"If life on Mars exists or existed within the last 10 million years, a mission to Phobos could yield our first evidence of life beyond Earth," he said in a university release Friday.
"We are talking little green microbes, not little green men," Melosh said.
Melosh led a team chosen by NASA's Planetary Protection Office to evaluate if a sample from Phobos could contain enough recent material from Mars to include viable martian organisms.
The team concluded a 200-gram sample scooped from the surface of Phobos could contain, on average, about one-tenth of a milligram of Mars surface material launched in the past 10 million years.
"Approximately one ton of martian material lands on Earth every year," Melosh said. "There is a lot more swapping back and forth of material within our solar system than people realize."
There is ongoing international interest in a Phobos mission, he said, and such a possibility will likely be a recurring topic as NASA reformulates its Mars Exploration Program.
A NASA report issued June 26 said the martian moons are "important destinations that may provide much of the value of human surface exploration at reduced cost and risk."
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Observing the sky with the green filter of it panoramic camera, the Mars Exploration Rover Spirit came across a surprise: a streak across the sky. The streak, seen in the middle of this mosaic of images taken by the navigation and panoramic cameras, was probably the brightest object in the sky at the time. Scientists theorize that the mystery line could be either a meteorite or one of seven out-of-commission spacecraft still orbiting Mars. Because the object appeared to move 4 degrees of an arc in 15 seconds it is probably not the Russian probes Mars 2, Mars 3, Mars 5, or Phobos 2; or the American probes Mariner 9 or Viking 1. That leaves Viking 2, which has a polar orbit that would fit with the north-south orientation of the streak. In addition, only Viking 1 and 2 were left in orbits that could produce motion as fast as that seen by Spirit. Said Mark Lemmon, a rover team member from Texas A&M University, Texas, "Is this the first image of a meteor on Mars, or an image of a spacecraft sent from another world during the dawn of our robotic space exploration program? We may never know, but we are still looking for clues." The inset shows only the panoramic image of the streak. (UPI Photo/NASA/JPL/Cornell/Texas A&M)Activity lead Bobak Ferdowsi, who cuts his hair differently for each mission, works inside the Spaceflight Operations Facility for NASA's Mars Science Laboratory Curiosity rover at Jet Propulsion Laboratory (JPL) in Pasadena, California on August 5, 2012. The Curiosity robot is equipped with a nuclear-powered lab capable of vaporizing rocks and ingesting soil, measuring habitability, and potentially paving the way for human exploration, and was designed to assess whether Mars ever had an environment able to support small life forms called microbes. UPI/Brian van der Brug/pool
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