"If NASA really wants to explore space, it has to cut the cost of getting there," Anderson said. "We could set up propellant depots where they need them. The cost of delivering fuel would be slashed by a factor of 100."
But the enterprise would have to be a step at a time. A lot of cutting-edge technology would have to become routinely reliable. And ambitious engineering projects -- whether run by governments or private enterprise -- have a bad habit of growing in cost.
So could it work? So far, there are some veteran doubters who don't sound doubtful. Phil Plait, an astronomer turned writer who keeps an often-skeptical blog called Bad Astronomy, said he did not know the project's details but was impressed: "Let me be frank: I don't think this is a crazy idea."
And physicist Michio Kaku told ABC News he thought Planetary Resources might just have enough resources to pull it off.
"I think they are part crazy and part genius," he said. "But the bottom line is, they're rich."