UA scientists set sights on asteroid

Proposed mission could prove biggest yet at the university
2010-08-16T00:00:00Z 2014-07-24T11:11:18Z UA scientists set sights on asteroidTom Beal Arizona Daily Star Arizona Daily Star
August 16, 2010 12:00 am  • 

Mike Drake and Dante Lauretta are tickled that everybody from the president on down seems to be talking about asteroids these days.

Drake, director of the University of Arizona's Lunar and Planetary Lab, and Lauretta, a professor with the lab, head up a mission dubbed OSIRIS-REx, which is competing for a NASA contract that Drake said would produce "the largest project the UA has ever had."

The lab's team proposes to visit Asteroid 99RQ36, circle it, photograph it and bring back samples that Drake and Lauretta believe will be teeming with the ingredients for life.

Their proposal, first submitted for a different NASA competition in 2004, came before a 2009 scientific paper and more recent press reports about their asteroid's potential impact with Earth in the next couple of centuries. And it came long before President Obama announced a switch in the manned space program from the moon to, potentially, an asteroid.

Their rationale for mining RQ36 is still based on the science goals they outlined in 2004, but if the decision-makers at NASA want to add preparing for a manned mission to an asteroid to the list of reasons they should be chosen, well, they're OK with that.

"We've been deliberately fairly quiet," Drake said. "We're in competition."

The UA is a finalist for a NASA New Frontiers space exploration grant of up to $650 million. Its competition is a mission to Venus headed by the University of Colorado in Boulder and a mission to the moon led by Washington University in St. Louis.

NASA has given Drake's team $3.3 million to refine its concept proposal, and Lauretta has dropped his teaching load and moved his desk and his mother's old couch into the building previously used as headquarters for the Lunar and Planetary Lab's Phoenix Mars mission.

Lauretta said the plan is to wait until the asteroid, currently orbiting the sun, is close to Earth in September 2016 to launch a rocket with the UA's spacecraft atop it. When the craft reaches the half-mile-diameter asteroid, it will initially match its velocity and orbit to cruise alongside like two cars each doing 65 mph on a freeway.

Then it will carefully begin circling the asteroid, photographing and mapping it with a variety of instruments. After about six months, it will use a robotic apparatus to extract at least 60 grams of material from the asteroid's surface. Lauretta declined to say exactly how they would do this. He doesn't want the competition to know details of the team's proposal.

In 2023, the spacecraft will approach Earth, fling its collected cargo toward a landing in Utah, and then rocket itself into orbit around the sun.

Then, Lauretta said, "it's like Christmas morning" as scientists open the package at a NASA facility in Houston and begin analysis of what they've found.

It would be the first asteroid sample not contaminated by Earth entry or handling by its finder. He expects labs all over the world will spend decades analyzing the material.

"We're still studying Apollo moon rocks," he said.

Scientists won't find microbes or living organisms, Lauretta said, but they expect to find "the seeds of life" - amino acids and other organic molecules, the kind of material that scientists theorize was transported to a heat-sterilized infant Earth by meteorites. The asteroid is known to be rich in carbon and oxides of water from previous flyby analyses.

Lauretta winces at the more spectacular headlines, but recent stories pointing out that it also has a chance of striking the Earth within the next couple of centuries certainly bolster his team's case for learning more about the orbit of this particular near-Earth object.

Right now, the science that predicts it has a one-in-1,000 chance of striking the Earth in 2186 or thereabouts is based solely on simple physics, Lauretta said.

It does not take into account the Yarkovsky effect - the small force caused by the sun's heating and the asteroid's subsequent cooling. Give a small force a long enough time with a relatively small body, and you'll see a huge deviation in its predicted path, Lauretta said.

Drake said it's no coincidence that Asteroid RQ36 is listed as a danger.

"The thing that is probably not obvious to most people is that, if it's relatively easy for us to get to it with a spacecraft, then it's relatively easy for it to get to us. By definition, it is hazardous."

His mission's careful measurements will help scientists better understand the Yarkovsky effect and more accurately predict the paths of this and other asteroids, he said.

Drake is not a big fan of a manned mission to an asteroid, but he understands the political appeal. It's cheaper than "the unimaginable amount of money it would take to go to Mars," he said. "But there is an interesting question of what exactly you do when you get there."

You can't walk on even the largest asteroids. "It's more like scuba divers on a coral reef," he said.

But if it's going to be done, Drake said, a precursor mission with a robot will be required.

"We have essentially no experience navigating around a small, zero-G (zero gravity) object," Drake said.

He and Lauretta and the OSIRIS-REx team at the University of Arizona would be happy to provide it.

Contact reporter Tom Beal at 573-4158 or tbeal@azstarnet.com

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