Former U.S. senator and astronaut John Glenn says placing a base on the moon to facilitate human exploration of outer space may not be such a great idea.

Noting President Bush's idea to return to the moon and use it as a launch pad to further explore space, Glenn told a congressional committee July 30 "it seems to me the moon is questionable as a way station" to Mars.

"If that's what we're doing - which I don't believe it is - but if that's what we're thinking about doing, that is enormously expensive," Glenn told a House Science and Technology Committee hearing on NASA's first 50 years and future challenges. Glenn said packing up thousands of tons of equipment from the Kennedy Space Center and sending it to the moon would be "an enormous order" that might not present a cost savings.

It would be better, Glenn said, to build up a vehicle in Earth orbit and then accelerate out of Earth orbit. "That to me would be the cheapest way to go," added Glenn, who orbited the Earth in a Mercury space capsule and later flew on the space shuttle.

"It's going to take a lot more study to figure out what it's going to take," Maria Zuber, head of MIT's Geophysics Department, told the panel.

Glenn noted that other spacefaring nations are investing heavily in their own space programs, while the U.S. will have to rely on its international partners for the five-year period between the retirement of the space shuttle in 2010 and the development of the Orion Crew Exploration Vehicle in 2015.