A new policy recently signed by President George Bush, asserts that his country has the right to conduct whatever research, development and "other activities" in space that it deems necessary for its own national interests.

The new policy further warns that the US will take those actions necessary to protect its space capabilities "and deny, if necessary, adversaries the use of space capabilities hostile" to those interests. The document adds: "Space activities have improved life in the United States and around the world, enhancing security, protecting lives and the environment, speeding information flow serving as an engine for economic growth and revolutionising the way people view their world and the cosmos."

"Freedom of action in space is as important to the United States as air power and sea power."

In some respects the policy represents the space equivalent of the "Bush Doctrine" national security policy initially outlined by Mr Bush in a speech at West Point military academy in June 2002. At that event - and later more formally codified - Mr Bush said the new US policy would place more emphasis on military pre-emption and unilateral actions.

Some experts believe the space directive, discreetly published more than a week ago and barely noticed outside specialist circles, puts the US on a new and dangerous course given that it transports "Bush Doctrine" policy to a new arena and rejects any efforts to limit US behaviour.

"I think that saying we will not have any limits on our actions is quite dangerous," said Theresa Hitchens, director of the Washington-based Centre for Defence Information.

"It claims no one can prohibit our rights but it also denies rights to [others].

"You would think that we would have learnt our lessons about the danger of military pre-emptive action and unilateralism in Iraq yet we are repeating the same policy towards space."

In part the new directive builds on the space policy of the Clinton administration. But some believe its new, hardline rhetoric will increase international suspicions that the US is seeking to develop and deploy weapons in space.

"The Clinton administration opened the door to developing space weapons but that administration never did anything about it. The Bush policy now goes further," Michael Krepon, of the Stimson Centre, told The Washington Post.

Mr Bush's attitude to space has always been more ambitious than that of his predecessor. In 2004 he outlined a vision to restart sending astronauts to the Moon, and even to Mars. In the same year the US Air Force published a highly controversial plan for establishing weapons in space, amid speculation that advanced lasers, spacecraft and space-based weapons firing 100kg tungsten bolts were being developed. And earlier this year it was revealed that the Pentagon was seeking hundreds of millions of dollars from Congress to test and develop space weapons.

In those portions of the new policy document that have been made public, there is no specific mention of the weaponisation of space. It says the US's priorities are to "strengthen the nation's space leadership" and to enable "unhindered US operations in and through space to defend our interests there". But the policy also claims that national security is "critically" dependent upon space capabilities. As a result it calls on the Defence Secretary, Donald Rumsfeld, and the Director of National Intelligence, John Negroponte, to "develop and deploy space capabilities that sustain US advantage and support defence and intelligence transformations".

In a muscular overhaul of policy, the US president outlines the importance of space to the national interest, saying its domination is as crucial to America's defences as air or sea power.

The order also opposes the establishment of arms control treaties that would restrict US access to space, or set limits on its use of space. It calls for the development of space capabilities to support US intelligence and defence initiatives.

The document, first reported in yesterday's Washington Post, amounted to the first overhaul of US space policy in nearly a decade, but it comes two years after the publication of an air force doctrine on protecting US satellites and spacecraft. The defence secretary, Donald Rumsfeld, has also favoured the development of systems to protect satellites and space stations.

"The United States will preserve its rights, capabilities, and freedom of action in space; dissuade or deter others from either impeding those rights or developing capabilities intended to do so; take actions necessary to protect its space capabilities; respond to interference; and deny, if necessary, adversaries the use of space capabilities hostile to US national interests," the strategy says.

It goes on to stress that space activities have improve life in the US and around the world, enhancing security and economic growth and "revolutionising the way people view their world and the cosmos".

Mr Bush has sought to revive the national interest in space by calling for Americans to return to the moon in 15 years, and even use bases there to serve as a launch pad for Mars.

But reports of the space policy raised immediate concerns that America would be seen to be trying to develop a fresh generation of space weapons.

However, the White House spokesman, Tony Snow, insisted there was no change, and that the exploitation of space for defensive purposes did not mean that American was seeking to develop space weapons.

"Protection of space assets does not imply some sort of forceful action," Fredrick Jones, a National Security Council spokesman, told the Associated Press. He said the US faced novel threats since the revision of the last policy declaration on space, and that the document reflected the importance of space in technological advances.

"Technology advances have increased the importance of and use of space," he said. "Now, we depend on space capabilities for things like ATMs, personal navigation, package tracking, radio services, and cell phone use."

The document makes a serious point about our growing dependence on satellites, the military threats to them and ways of protecting them. But America has rejected the desire by 160 other countries to have United Nations talks about banning an arms race in space, an extravagantly unilateral approach whose appeal you might have thought would have been tarnished by its experience in Iraq.

Its vision of the space programme, military more than scientific, is also undermined by its taste for manned missions — and the breathtaking cost.

Bush signed the document on August 31, and the White House released the text this month in the late afternoon of the Friday of a holiday weekend. So the first full revision of space policy for ten years has provoked controversy abroad as much as at home. The eyecatching declaration is that the US asserts the right to deny access to space to anyone “hostile to US interests”, although it gives no basis for that right. It also rejects arms control talks that would limit future US actions in space.

Military, commercial and personal communication has become more dependent on satellites. The US fears that its satellites are vulnerable to attack.

It does not name its potential enemies, but China and Russia clearly have the capability and even Iran has its own satellite and plans for a launch vehicle, while there are about 40 countries with a presence in space.

This focus on defence springs from the American strategy for space, which exchanged President Clinton’s goals of understanding the Universe for ones of security. But in scrapping Clinton’s plans for unmanned probes in favour of manned missions to the Moon and Mars, it drew attacks that it would discover little and spend too much.

When the US last year dismissed other countries’ wish to talk about banning weapons in space (the UN vote was 160-1), it presumably intended to keep its options open, even though it says that it has no intention of putting up space weapons. But instead it may have missed the chance of securing a ban when countries were willing to sign it — at the very least, a cheaper option than eventually putting its own weapons in space.

BODY POLITIC IN REVOLT

How much of Bush’s agenda will stick if the Democrats win one or both Houses of Congress in the elections next month? His new law on the imprisonment, interrogation and trial of terrorist suspects must be a prime contender for attack — by the courts, if not by Congress. Bush signed the Bill just before Congress rose for the home stretch of the campaign, as if that were the last word.

For his own party, it was. Once the opposition by senators John McCain, Lindsay Graham and John Warner folded, the version passed was bound to end up close to the original wishes of the White House. But it now strips away the right to challenge detention without charge from all non-US citizens — not just for those detained outside the US, as in the original. That applies to the 12 million permanent residents who are not citizens.

Legal challenges saying that it is unconstitutional to remove the right of habeas corpus from anyone are already in train. But the potential application to 12 million people within the US will add political heat that was absent when it covered only 500 prisoners at Guantanamo Bay.