Nasa's next giant leap: men on Mars and colony on Moon

President George Bush is expected next week to announce proposals for sending humans to Mars when he revives manned lunar missions 35 years after an astronaut first stepped on to the dry, dead surface of the moon.

President Bush intends to reinvigorate the Nasa programme, still reeling from last year's Columbia shuttle disaster, with plans for a permanent human settlement on the moon. "It's going to be a uniter, not a divider," one White House adviser told reporters. "Trying to rally people emotionally around a great national purpose."

Few details have emerged about what the president will actually reveal when he makes his announcement on Wednesday in Washington. But sources say the proposed human settlement - which could take at least a decade to establish - would be part of a broader and much more ambitious plan to send men and women on voyages to Mars. Last week the US robot craft, Spirit, touched down on the surface of Mars and starting sending back images although the British-built craft, Beagle 2, has not been heard from since it landed on the red planet on 25 December.

Mr Bush's announcement should capture the public imagination, just as President John F Kennedy's did in May 1961 when he said he believed that "this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth". White House sources have even admitted that Mr Bush hopes to achieve what he termed "a Kennedy moment".

But critics say the timing of the announcement is carefully designed to boost the President's re-election campaign. Earlier this week, Mr Bush announced an amnesty for illegal Mexican workers in what was widely seen as a feel-good electioneering stunt, and many will see this latest project as little more than rocket-fuelled politicking.

Until now, President Bush has shown little personal interest in space exploration. Ralph Hall, a Republican member of the House Science Committee, said he had been trying to get the President more interested in space travel. "We need to stay in touch with space," he said.

But with America facing its biggest-ever federal deficit, there has been little mention of the cost of the project and reports suggest the proposals have been controversial even inside the White House. One White House adviser said the new initiative was "crazy". The official told The Washington Post: "It costs a lot of money and we don't have the money. This is destructive of any sort of budget restraint."