Many questions about new NASA Mars mission
A day after the possible discovery of organic material on the Red Planet, NASA officials announced plans for a news Mars exploration mission in 2020.
The objectives for the planned rover are not set, but it could potentially collect soil or rock samples that could later be sent back to Earth.
Before Curiosity landed on Mars this summer, NASA was unsure of its future direction in exploring the solar system. Big-budget missions to Mars seemed politically unpalatable after Curiosity's $2.5-billion price tag, and no other major missions had been scheduled, even as the next launch window in 2018 approached.
But the rover's dramatic landing and early scientific exploits have rejuvenated enthusiasm for Martian exploration.
It's unclear what the rover would do on the Martian surface, said John Grunsfeld, head of NASA's Science Mission Directorate in Washington. One idea is for the rover to collect and store soil and rock samples. That would only be the first step; a far more complex mission would be to bring them back to Earth.
The Planetary Science Decadal Survey, which publishes long-term goals for exploring the solar system, touted a sample-storing mission as a top priority over the next decade. But this would involve a major technological leap: NASA would have to find a way to protect the samples, launch them from the Martian surface and safely carry them home.
President Obama has set a goal of sending astronauts to Mars orbit sometime in the 2030s. Grunsfeld said a robotic sample-return mission would help provide a road map for a manned mission.
Another option would be to forget the sample cache, and instead outfit the rover with the most advanced tools possible and send it to another tantalizing spot on the Martian surface.
There already are some well-researched options: Curiosity's scientists agonized over which of several tempting landing spots to choose.
If the project goes ahead — it is contingent upon Congress agreeing to fund NASA at the level the Obama administration has requested for the next five years — it would be the seventh NASA mission either being operated or planned.
The announcement of the 2020 proposal electrified many of the roughly 18,000 researchers attending the American Geophysical Union's fall meeting this week in San Francisco, where scientists also discussed the signs of organic compounds in the Martian soil Curiosity has picked up. However, the key ingredient — carbon — may have been a castaway from Earth, scientists said Monday.
After completing an in-depth analysis of dust and sand from a Martian dune at a site called Rocknest, Curiosity's instruments have detected water, sulfur and chlorine compounds, said Paul Mahaffy, a member of the Mars Science Laboratory team based at Goddard Space Flight Center in Greenbelt, Md. Some of the rover's tests produced molecules that appeared to contain chlorine and carbon, but the scientists aren't yet sure what to make of the results.
The chlorinated methane and other molecules were detected by an instrument called Sample Analysis at Mars, which processes and heats soil samples. The measured chlorine levels were far too high to have originated from Earth, but the same can't be said of the carbon in the compounds, said John Grotzinger, lead scientist for the Mars Science Laboratory mission.
It will be a while before they can run another test to look for organic compounds, said Grotzinger, a Caltech geologist. That probably won't happen until after the team has tested the drill at the end of the rover's robotic arm. Even then, it will be a long while before scientists will be able to determine whether any carbon-based compounds are biological in nature.
First, he said, they'll have to see whether they find a similar signal in soils they sample down the road to Mt. Sharp, the 3-mile-high mound in the middle of Gale Crater whose layers could contain clues as to whether Mars was once hospitable to life.
"Curiosity's middle name is patience," Grotzinger said. "We all have to have a healthy dose of that."
-- Amina Khan