That permanent moon base NASA's been talking about for years? Looks like it might not happen.

Acting NASA Administrator Christopher Scolese quietly admitted so on Capitol Hill Wednesday as he testified before a meeting of the House Subcommittee on Commerce, Justice, Science and Related Agencies.

Responding to questions about whether the Obama administration's proposed NASA budget for 2010 would put the space agency on track for construction of a permanent base, Scolese wouldn't commit.

"Do we mean a colony on the moon? That's clearly very expensive," he stated. "It will probably be less than an outpost on the moon, but where it fits between sorties — single trips to the moon to various parts — and an outpost is really going to be dependent on the studies that we're going to be doing."

The permanent moon base was the centerpiece of NASA planning following former President George W. Bush's Vision for Space Exploration speech in 2004, though Bush never specifically called for one.

But NASA, spurred on by then-Administrator Michael Griffin, incorporated a permanent base as part of its grand strategy to get humans back to the moon by 2020.

It was meant to be a research and exploration station, as well as a staging area for missions that would send the first humans to Mars.

Scolese, facing recession-era budget shortfalls and Obama-era budget scrutiny, may be hedging his bets — especially since President Obama hasn't nominated anyone to officially replace Griffin, who handed over the reins temporarily to Scolese when he resigned on Inauguration Day.

A clearer image of NASA budget planning for 2010 is due later this month.

• Click here to read an account at Florida Today.

• Click here to read a longer analysis in New Scientist magazine.

• Click here to visit FOXNews.com's Space Center.