Scientists Revisit Mars Sample Return Plans

Scientists Revisit Mars Sample Return Plans
An artist's interpretation of a Mars sample return mission blasting off for the return trip from the red planet.
(Image: © NASA/JPL)

ALBUQUERQUE, N.M. — International planning isunder way to reinvigorate plans for a Mars sample return mission, withresearchers assessing science priorities and strategies to maximize the scientificoutput from such an undertaking.

Over the last severalyears, an armada of orbital and surface missions has revealed Mars to besurprisingly more complex than once thought, imbued with a variety of distinctenvironments — each of value in terms of possible scientific payback given asample return effort.

Mars samples returned tostate-of-the-art Earth laboratories are considered by many to be the only wayto unravel a host of unresolved questions about the red planet. A samplereturn mission also is viewed by many as a key tool to help space agenciesprepare for future human expeditions to Mars.

Mars scientists, spaceengineers and program planners met here April 21-23 to take part in "GroundTruth from Mars: Science Payoff from a Sample Return Mission." Discussionsfocused on what scientific data can be extracted from the return of Marssamples to Earth. Another major topic was the packaging, care and handling ofmartian materials that would be needed to ensure that the specimens offer greatpayoff for their potential to reveal past and present conditions on the redplanet. The meeting was initiated by the Curation and Analysis Planning Teamfor Extraterrestrial Materials, a standing committee of scientists who adviseNASA.

Surprises on Mars

While no nation or groupof nations has committed to fund what is likely to be a multibillion-dollarMars sample return program, scientists feel that groundwork is being laid now,albeit in piecemeal fashion.

The work of Mars rovers Spirit and Opportunity,for example, has been scientifically stellar, said Doug Ming, a space scientistwithin the Astromaterials Research and Exploration Science Office at NASA's Johnson Space Center in Houston. "We were surprised when we got on the ground to see an enormousdiversity of materials. It took us all by surprise," Ming said. The tworobot geologists independently have been exploring Gusev Crater and MeridianiPlanum for more than four years, yielding "an enormous wealth ofinformation that can be fed forward into a Mars sample return mission," hesaid.

Ming and other scientistsat the meeting suggested that a Mars sample return involving either of therover sites could be viewed as the first leg of a two-part mission to bringsamples back to Earth.

Cache and carry

NASA's Mars ScienceLaboratory, which is scheduled to launch in 2009, carries a container forcaching bits and pieces of select martian samples. The cache could be saveduntil it could be transported back to Earth as part of a future Mars samplereturn mission, said John Karcz of the SETI Institute and NASA's Ames Research Center in Mountain View, Calif.

The large nuclear-poweredMars Science Laboratory rover is being designed to wheel across Mars for a fullmartian year, equal to nearly two Earth years. The cache device would be set upto contain from five to 10 or more samples, Karcz said, "if we have thetime, resources and inclination during the traverse."

The samples would be heldin a container designed to allow photo-documentation of the samples over thecourse of the Mars Science Laboratory mission. The hockey puck-sized cachecontainer is designed for easy removal by a future Mars sample return rover,Karcz said, for subsequent transport back to Earth.

Meanwhile, the powerfuleyes of several spacecraft already in orbit around Mars — NASA's Mars Odysseyand the Mars Reconnaissance Orbiter, joined by Europe's Mars Express — areexamining areas that show promise in the search for extinct or extant martianbiology and studies of the planet's evolution.

NASA's Phoenix Marslander, which is set to land May 25, was designed to study the history of waterand the potential uses of the martian arctic's ice-rich soil to provide lifesupport and other needs of future human crews that will explore the planet.

In many ways, Marsresearchers find themselves in a candy store of scientific sweet spots —several candidate sites that seem ideal for a Mars return sample mission.

For example, thehigh-powered zoom lens of the MarsReconnaissance Orbiter was used to identify two possible ancienthydrothermal springs that might have been a cozy niche providing warm, liquidwater to harbor martian life forms as the climate on the red planet becamecolder and drier, said Carlton Allen, the astromaterials curator and manager ofthe Astromaterials Acquisition and Curation Office at NASA's Johnson SpaceCenter (JSC).

Allen and Dorothy Oehler,a JSC research colleague, view these possible springs as an area of potentiallygreat importance to astrobiology. "This may well be the type of site thatwould have high priority for sample return," Allen said. "If this iswhat we claim ? it may well be one of the most significant, bestastrobiological sites on the planet."

Pricey and risky

There is no question thata Mars sample return mission will be a pricey and risky initiative and opinionsat the meeting varied widely when it came time to discuss the best way to getthe greatest scientific returns for the least money.

"We don't want toengineer the [heck] out of this and make it a $10 billion return mission. We'llnever get samples back. Let's be realistic," said Clive Neal, a professorof civil engineering and geological sciences at the University of Notre Dame in Indiana.

"A Mars sample returnwill be much more costly than other Mars missions. That's not actually a thesis? I think that's a given," said David Mittlefehldt of the AstromaterialsResearch Office. "Orbital study is getting increasingly sophisticated.Nevertheless, it doesn't reliably provide an accurate description of thegeology of the surface. And that's really what you need in order to plan a Marssample return mission," he said. "Therefore, I think we should gosome place where wheels-on-the-ground provide that geologic context."

Intelligent decisions

An ambitious mission likeMars sample return needs a lot of push, a lot of energy, and it needs a lot ofpeople explaining why it is important to do, said Carl Agee, a co-convener ofthe meeting and director of the Institute of Meteoritics at the University of New Mexico in Albuquerque.

Agee told Space Newsthat the time to get started on Mars sample return is now so we can "makeintelligent decisions about where to go, rather than just landing blindly."A synergistic Mars program — one that does not pit sample return versus orbitalmission versus on-site study — will "show how all of this fits together toplan the strategy for exploration," he said.

"I think that we'rein danger of trying to over-achieve with our first sample collection andthereby shoot ourselves in the foot," said Derek Sears, director of the Arkansas Center for Space and Planetary Sciences and head of the Cosmochemistry Group at the University of Arkansas in Fayetteville.

The goal should be to getto Mars and obtain the simplest and most obvious rocks from a sensible placeand get them back, Sears advised. "Don't worry if we upset the rocks alittle bit on the way back. Just get them back. Get them in the lab and we'llfigure it all out. Don't over-worry the problem because it'll kill you,"he told Space News.

A Mars sample returnmission that gets under way as early as 2020 is of great interest to both NASAand the European Space Agency, said David Beaty, chief scientist of the MarsExploration Directorate at the Jet Propulsion Laboratory in Pasadena, Calif., and also a co-convener of the meeting. There is a growing desire to create aninternational version of a Mars sample return mission, not only in the United States and Europe, but also in Japan and Canada, Beaty told Space News.

Beaty said there alreadyis a task force, the International Mars Architecture for Return of Samples(IMARS), with representatives from more than a half-dozen countries, along withNASA, the European Space Agency, the Canadian Space Agency and the JapanAerospace Exploration Agency.

"They are trying todevelop a potential plan for Mars sample return that can be separatelypresented to the different countries to generate budget," Beaty said. "Ultimately,we need to have the same plan being presented in multiple places."



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