[LINK] "Obama's asteroid goal: tougher, riskier than moon"

[rfmcdonald]

One element of Obama's plans for manned space exploration that I quite like is his hope to explore near-Earth asteroids, landing a team on one in 15 years' time. They aren't as visible as the Moon or as sexy as Mars, but they're still of no small worth.

"By 2025, we expect new spacecraft designed for long journeys to allow us to begin the first-ever crewed missions beyond the moon into deep space," he said. "We'll start by sending astronauts to an asteroid for the first time in history."

On the day the president announced the goal, a NASA task force of scientists, engineers and ex-astronauts was meeting in Boston to work on a plan to protect Earth from a cataclysmic collision with an asteroid or a comet.

NASA has tracked nearly 7,000 near-Earth objects that are bigger than several feet across. Of those, 1,111 are "potentially hazardous asteroids." Objects bigger than two-thirds of a mile are major killers and hit Earth every several hundred thousand years. Scientists believe it was a 6-mile-wide asteroid that wiped out the dinosaurs 65 million years ago.

Landing on an asteroid and giving it a well-timed nudge "would demonstrate once and for all that we're smarter than the dinosaurs and can avoid what they didn't," said White House science adviser John Holdren.

Experts don't have a particular asteroid in mind for the deep-space voyage, but there are a few dozen top candidates, most of which pass within about 5 million miles of Earth. That is 20 times more distant than the moon, which is about 239,000 miles from Earth on average.

Most of the top asteroid candidates are less than a quarter-mile across. The moon is about 2,160 miles in diameter.

Going to an asteroid could provide clues about the solar system's formation, because asteroids are essentially fossils from 4.6 billion years ago, when planets first formed, said Don Yeomans, manager of NASA's Near Earth Object program at the Jet Propulsion Lab.

And an asteroid mission would be a Mars training ground, given the distance and alien locale.

"If humans can't make it to near-Earth objects, they can't make it to Mars," said MIT astronautics professor Ed Crawley.