The Million Mile Mission
A small band of believers urges NASA to take its next step—onto an asteroid.
- By Michael Klesius
- Air & Space magazine, July 2008
(Page 4 of 6)
“We really don’t have a ‘best one,’ ” says Abell. “It’s far too early in the time line to select a target.” Besides, scientists find new asteroids all the time. “Hopefully we will have many more [choices], and get to know them a little better than we do now.”
Although Ed Lu has left NASA, he hasn’t gone far, and his Mountain View, California office is just down the road from Korsmeyer’s. Lu took a job last year with an advanced projects group at the headquarters of Google, where the former astronaut is dreaming up technologies that will go beyond Google Maps and Google Earth. He thinks of it as Google’s version of the Lockheed Skunk Works.
Lu says there are two basic ways to reach a NEO. An optimal target would have an orbit similar in breadth to Earth’s, but inclined, so that it would cross the plane of Earth’s orbit at a point not far away. Such an object would come around every six months.
Orion would fly out to meet the asteroid at its first plane crossing, stay with it for half a year, then come home when the asteroid crosses the plane again on the opposite side of the sun.
“You hop on,” says Lu, “and hop off six months later.” The payoff: less fuel required.
The other option—a shorter mission of up to, say, four months—would rendezvous with the asteroid as it approaches Earth, ride it home, then hop off. Or, hop on as it passes Earth, ride it for a few weeks, and hop off in deep space, requiring a return trip of several weeks to a couple months. This type of mission demands more fuel, but would open the field to a greater number of target asteroids.
None of these missions requires more time in space than the six months astronauts typically spend on the space station. A Mars round trip requires three years. Lu’s own return after six months of weightlessness was easy, he says. Having spent two hours on aerobic and strength training every day in orbit—“and we did it religiously”—he was able to stand up on the Kazakh plain immediately after landing there in a Russian Soyuz capsule. “I was 70 percent normal within a few days, and 90 percent within three weeks,” he says.
In other words, one of the big unknowns about a Mars trip—how the human body will react to three years of weightlessness—is no concern at all for an asteroid mission. And once they reach their destination, the astronauts won’t have to adapt to one-third Earth gravity, as they would on the surface of Mars. Amid all the discussion of “hopping on and off,” Lu makes a key point. “People get the misconception that we’ll land on an asteroid,” he says. “We won’t. It’s almost zero-G. You’re not going to walk on that surface.” Working around an asteroid would in some ways be like floating around the space station, which is also the size of a football field. Astronauts would likely perform asteroid “walks” using jet backpacks or tethers, possibly firing small anchors into the surface for leverage.