Sampling the Solar System

After collecting bits of Comet Wild 2, the Stardust spacecraft parachuted its sample return canister into a Utah landing spot in January 2006. CREDIT: NASA

HOUSTON, Texas - In a nation where obsessive collectors bestow value on everything from bean bag animals to baseball cards to anything the marketing department from Disney can pump out, there is one authoritative set of collectibles that is truly one of a kind and out of this world.

The assortment contains bits of comet, samples of solar wind and particles of interstellar dust. Also, toss in loads of meteorites and the collected works of Apollo moonwalkers that lugged back to Earth lunar rock and dirt.

All this and more are under the care of the Astromaterials Acquisition and Curation Office at the NASA Johnson Space Center (JSC). They curate the space agency's current and future holdings of samples from out there.

Samples can guide scientists in unraveling some of the unknowns surrounding the birth and evolution of our solar system and the emergence of life.

Busted up and dirty

But sometimes being on the receiving end of solar system samples can prove unnerving.

That was the case when NASA's Genesis sample container made a high-speed nosedive into a Utah landing zone back in 2004--minus a parachute.

"All the samples came back to Earth. They just busted up and got dirty," said Carlton Allen, Astromaterials Curator and Manager of the Astromaterials Acquisition and Curation Office here at JSC.

However, it has been a painstaking job of extracting Utah mud, salt-filled water and shattered spacecraft from whiffs of solar wind. "We're continuing to clean, analyze and distribute samples. We're getting samples out and people are doing good science with them," he told SPACE.com. "You can learn what the Sun was telling us."

Stardust: prized cargo

On January 15 of this year, after more than 7 years and billions of miles of travel through space, NASA's Stardust spacecraft deposited its return capsule on Earth loaded with prized cargo: pristine samples of comet particles captured during the spacecraft's encounter with Wild 2 in January 2004. This time parachute hardware worked as billed.

Scientists have been busy studying this stash of primo specimens--nothing less than the fundamental building blocks of our Solar System that formed 4.6 billion years ago.

"With Stardust, life's a whole lot easier," Allen said. "Less than a year after mission return, we have high-quality science coming out of the science team."

In addition to discovering stardust, or particles older than the Sun, researcher recently announced they had found material from the hottest part of the solar system in a sample provided by Stardust.

Stardust samples are now available to the worldwide science community at large on request and following a normal peer review process. "Everybody has a shot at Stardust samples," Allen added.

Furthermore, thanks to Stardust@home -- http://stardustathome.ssl.berkeley.edu/index.php -- the public can volunteer to look for minuscule particles of interstellar dust also bagged by Stardust. The intent is to locate the "best hits" in the Stardust collector to be carefully removed next year for study at JSC and other institutions.

Back to the Moon campaign

JSC's Allen said that the need for Apollo lunar samples is on the upswing.

NASA's back to the Moon campaign has meant a 50 percent increase in the number of requests for lunar rocks and dust returned by Apollo moonwalkers.

Researchers are studying everything from potential health hazards through inhalation of lunar dust to using samples for building purposes as well as for processing - particularly to make oxygen from lunar soil.

At present, there are no formal plans within NASA to carry out land, scoop and return duties using robotic spacecraft.

Apollo astronauts brought back to Earth lunar specimens from 1969 through 1972. But given future expeditionary returns to the Moon, Allen said more rocks and soil will surely be transported back to Earth for further scientific scrutiny.

"We understand mostly how to do that. We've been dealing with lunar rocks for 30-plus years," Allen explained. "We know how to take care of rocks."

Red planet plans

Hauling back a suite of samples from Mars by automated means has long been on NASA's red planet plans.

"Mars is a different kind of place," Allen noted. "There are planetary protection considerations with any kind of Mars sample."

A study is now underway--led by the Jet Propulsion Laboratory--to investigate a robotic Mars sample return mission--making use of Ares boosters that are part of NASA's Constellation program, Allen said.

In addition, NASA's Mars Scout program has received sample return proposals, Allen noted.

Unusual phenomenon

The recent revelation that Mars might be home for water-spewing gully action is an exciting prospect, Allen said. Nonetheless, dispatching any spacecraft to such a locale would require adherence to planetary protection regulations - and assuredly a big boost in mission price tag.

"We would have to sterilize the entire spacecraft...something we did for the Viking landers...and not impossible to do," Allen explained.

"The idea that there is liquid that close to the surface is going to make us rethink our ideas about the thermal history of Mars," Allen said. "The thought that there are places on Mars you can go where you can sample liquid, or the remains of a liquid flow that is absolutely modern, is very, very exciting."

Spotting bright material spilling out onto the surface of Mars, perhaps salts of some sort, is a "very unusual phenomenon," Allen observed.

Airless body

Picking up bits of asteroids and toting them homeward are also being considered.

NASA selected in October several prospective Discovery-class missions. One of those now under study is the Origins Spectral Interpretation, Resource Identification and Security (OSIRIS) mission.

OSIRIS would survey an asteroid and provide the first return of asteroid surface material samples to Earth.

How to deal with asteroid specimens and what sort of lab work and personnel would be required is being reviewed.

"We know about asteroid material from our meteorite collection," Allen said. "We know about fine surface material from an airless body...from what we've done on lunar samples. And there's nothing like having two flight missions--Genesis and Stardust--under our belts to give us the confidence to support others."

Ice: warm up act

Yet another specimen to add to the NASA JSC curatorial collection is ice.

"Ice is something that we haven't dealt with before," Allen said. That material might be found in the lunar exploration program--loitering in sunlight shy craters--and is certainly part of a comet's makeup.

"Once you're out past the asteroid belt - there's ice everywhere," Allen pointed out. Sampling the icy face of Jupiter's moon Europa or Saturn's Enceladus would not be easy.

"One of the things underway here over the next year is learning how to do curation in sub-freezing temperatures. We've never had to do that," Allen remarked.

Future work is needed on how best to bring ice back frozen all the way home...or ways to monitor the ice very carefully and understand exactly what changes might be induced by an ice sample warming up on the trek back to Earth.

"That's one of the frontier areas that we want to work," Allen said.

• Image Gallery: Comets
• Image Gallery: Welcome Back: Stardust Returns Home
• Image Gallery: Deep Impact Collides With Tempel 1
• Genesis Special Report: Bringing Solar Wind Down to Earth
• Space Missions: Chasing Comets and Asteroids
• Full Circle: NASA's Stardust Probe Returns Home with Comet Samples