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Feb. 8, 2012

Vol. 112, No. 7


Fly me to the moon

Princetonians compete for a lunar landing – and the $20 million that comes along with it

By Kenneth Chang ’87
Published in the February 8, 2012, issue

Mike Brown ’87 holds his lunar rover on the roof of Caltech’s historic solar observatory.
Photo: Peter Stember
Mike Brown ’87 holds his lunar rover on the roof of Caltech’s historic solar observatory.

Whittaker was not the only Princeton alum to take up the challenge. Mike Brown ’87 is competing, too. Brown is not a roboticist. He had never designed or built a spacecraft. He is an astronomer at the California Institute of Technology best known — infamous, actually — for discovering Eris, the iceball in the outer solar system bigger than Pluto, which set off the domino of events that culminated with astronomers kicking Pluto out of the planet club.

Two years ago, Fred Bourgeois, the leader of Lunar X team FredNet, visited Brown to recruit him. Brown was skeptical that this group — which bills itself as an “open source” collection of scientists and engineers — could compete against more experienced and well-financed teams. “I had heard about this Google X Prize and I thought, there’s no way you could do this,” Brown recalls. “It’s ridiculous.”

But Brown, who has known Bourgeois since his high school days in Huntsville, warmed up as Bourgeois explained it. Huntsville was where Wernher von Braun and the early rocket scientists built the Saturn V rocket. Brown’s father, an engineer, had worked on those Apollo missions. Bourgeois already had enlisted a small company called Masten for the lander. He wanted Brown to put together the rover.

Brown agreed. He is undaunted by a late start or the fact that other teams can tap into decades of aerospace expertise that he doesn’t have himself. “It’s either going to be a very well-thought-out team,” he says, “or it’s going to be a bunch of really scrappy people with baling wire and bubble gum.”

Brown clearly sees himself as a baling-wire guy.

“It’s a fun experiment in doing things that seem impossible and deciding you’re going to do it,” he says. “It may not work. I would say there’s a good chance it won’t work.” But he also convinced himself that success is not completely impossible: “If it were totally wacko, it’s not worth your time.”

Brown’s attempt to build a rover got under way in a Caltech course, “Roving on the Moon,” which met for the first time at the end of September. The goal for the seven class members — a mix of undergraduates, graduate students, and fellow faculty — was to have a working prototype by the end of the quarter, or in just two months.

Brown wanted to build the smallest, simplest rover to meet the X Prize requirements. “If we sent my cell phone to the moon with wheels, it would satisfy the conditions for winning the X Prize,” Brown says. 

A month into the class, Brown had his design — a closed sphere so no moon dust could get in to foul up the gears. It looked like a hamster exercise ball. It was a hamster ball — more precisely, a hollow, plastic exercise ball, built for a slightly larger rodent, like a chinchilla. 

To get the sphere rolling, the class first used a ­radio-controlled car‚ “not a particularly great solution,” Brown says. Then, the team worked out a more sophisticated design, tearing apart the radio-controlled car and reusing the parts. Members added an axle through the hamster ball, with a motor hanging on a rod from the axle. When the motor turns, it swings itself and the rod upward; gravity then pulls the motor down, and the sphere rolls. To turn left or right, the rod tilts to the side, which tilts the ball. At each end of the axle is a clear bubble to house a camera. 

Brown has been using it to chase around the cats at home.

The class never did build its final prototype by the end of the semester because the students wanted to attempt something more ambitious: an inflatable roving sphere. (Think of a beach ball on the moon.) That would allow the rover to be larger — 3 feet in diameter instead of 8 inches — and more capable of rolling over obstacles while still fitting into the tight confines of the lander. “If we can make it and make it work robustly, it would be a great solution,” Brown says. 

The students will keep working on the prototype, though they no longer will get course credit. Brown said in December that he would argue they should return to the less-ambitious hamster-ball design, so that FredNet would have something to use in the competition. (He was considering invoking his veto power, if needed, over the ­students’ choice: “I also learned not to try to design by democracy.”)

And Brown figures that it will take up to two years and millions of dollars to build a space-worthy version, with radiation-hardy and vibration-tested electronics and structures. “In the end, none of this will happen without any funding,” Brown says. “I’m not that guy to figure out how to do funding. I’m a scientist.”

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