WASHINGTON -- The desolate and cratered shores of nearby Luna beckon, not only as landscape ripe for science and exploration but prime "unreal estate" for hotels, business parks and mining camps.

But at NASA, the call seemingly falls into a vacuum of response. After spending $25 billion to hurl people and payloads across the vast, intervening void, America's costly bridge to the Moon is a busted relic from a Space Age past.

But for a generation of post-Apollo return-to-the-moon revivalist, one question remains: "If we can put a man on the Moon, then why can't we put a man on the Moon?"

For the most part, NASA has left the answer to that question in the dust. Even the prospects for privately financed hops to the Moon are falling short of their mark.

Those attending July's Return to the Moon III symposium held in Las Vegas, Nevada wrestled with scripting a lunar agenda for the 21^st century. The gathering was sponsored by the Space Frontier Foundation, a space activist group.

At the meeting, longtime lunar researcher, NASA's Wendell Mendell of the Johnson Space Center in Houston, Texas served up the straight scoop. "Although concepts for lunar development face formidable technical challenges, equally daunting are hurdles in the financial, institutional, and political arenas," he said.

Mendell said that NASA remains a "dominant entity" associated with future lunar development. The question remains, however, as to the space agency's intentions with respect to the Moon.

Yet another issue looms larger.

The entire state of NASA's human exploration program is problematic until the fate of the International Space Station is resolved, Mendell said. "In any case, human lunar missions are not salient elements in current plans," he said.

Given that the Red Planet is an ultimate target, human missions to the Moon are seen by NASA elite "at best a distraction to that objective and at worst a derailment," Mendell said.

"On the other hand, a significant body of opinion in NASA believes that the jump from a low Earth orbit space station program to a human Mars program is too great in terms of our operational experience and in terms of technological advance," Mendell said.

The Moon as a planetary surface is a great laboratory, Mendell said to test technologies, along with learning how humans cope in partial-gravity environment, as well as the physiological and psychological detachment from Earth.

Buried within the space agency, a small study group -- called the NASA Exploration Team, or simply tagged NExT -- is quietly drafting scenarios for human trips beyond Earth orbit. Some of their ideas may well help defuse the Moon versus Mars issues.

Nevertheless, NASA is stuck in low Earth orbit for now. It needs to untangle itself from the swirl of cost-overruns associated with the International Space Station.

Until then, space agency hopes for long treks from Earth propelled by taxpayers will likely remain on short-circuit.