NASA is preparing to lay out its plans for returning to the moon and plans to send a four-person mission back to our largest satellite in 2018. The astronauts will stay on the lunar surface for a week.

NASA briefed Congress on its plans last Friday, according to the BBC. The agency told elected officials that developing the spacecraft and associated technologies for the mission would cost in the region of $100bn.

The 2018 mission would happen in several stages. First, NASA will have to put a lunar landing module, and a propulsion stage, into orbit around Earth. Next, Shuttle's replacement, the so-called Crew Exploration Vehicle (CEV), and a new launcher would dock with the landing module before heading for the moon.

The agency also proposes building a rudimentary lunar base from which astronauts could begin to exploit lunar resources by mining for water and fuel.

Getting a $100bn project signed off in the current political climate could prove a tough task, however. The US government is already heavily committed to the war in Iraq, and also, post-Katrina, to vast restoration efforts along the Gulf Coast.

Representative Bart Gordon, a Tennessee Democrat on the US House Science Committee, issued a statement saying that "strong presidential leadership will be needed" if there is to be agreement on the mission.

If NASA gets the green light, it will be the first manned mission to the moon since 1972. ®