Like a car salesman pushing a luxury vehicle that the customer no longer can afford, NASA has pulled out of its back pocket a deal for a cheaper ride to the moon.

It won't be as powerful, and its design is a little dated. Think of it as a base-model Ford station wagon instead of a tricked-out Cadillac Escalade.

Officially, the space agency is still on track with a 4-year-old plan to spend $35 billion to build new rockets and return astronauts to the moon in several years. However, a top NASA manager is floating a cut-rate alternative that costs around $6.6 billion.

This cheaper option is not as powerful as NASA's current design with its fancy new rockets, the people-carrying Ares I and cargo-lifting Ares V. But the cut-rate plan would still get to the moon.

The new model calls for flying lunar vehicles on something very familiar-looking - the old space shuttle system with its gigantic orange fuel tank and twin solid-rocket boosters, minus the shuttle itself. There are two new vehicles this rocket would carry - one generic cargo container, the other an Apollo-like capsule for astronaut travel. Those new vehicles could both go to the moon or the international space station.

What's most remarkable about this idea is who it came from: NASA's shuttle program manager John Shannon. He recently presented it to an independent panel charged with reviewing NASA's costly spaceflight plans. And he was urged to do so by a top NASA administrator.

It shows that top officials in NASA, an agency of engineers who regularly make contingency plans, worry that their preferred moon plan is running into trouble, space experts said.