Receiving money from NASA’s new Commercial Orbital Transportation Services (COTS) program will disqualify a company from winning Robert Bigelow’s America’s Space Prize, Bigelow confirmed for me yesterday.

Under COTS, NASA has allocated $500 million to be spent over five years to help entrepreneurial space companies develop spaceships that can send crew and/or cargo to the International Space Station. The space agency is expected to select companies to receive the first installment of this money by summer’s end.

Robert Bigelow also has a vested interest in helping private enterprise reach orbit; he expects to launch the first commercial space station, now under development in North Las Vegas, by 2012.

But he doesn’t have a way to get people and supplies there, which is why he launched his $50 million America’s Space Prize in 2004 for the first private spaceship capable of docking with an orbital outpost.

America’s Space Prize is not compatible with COTS, however. “One of the conditions of that was that federal money would not be allowed into that program,” Bigelow told me of his prize. And that includes COTS money. “I still think that rule helps to level the playing field.”