The American military is planning a “spaceplane” designed to fly a crack squad of heavily armed marines to trouble spots anywhere in the world within four hours.

At a recent secret meeting at the Pentagon, engineers working on the craft, codenamed Hot Eagle, were told to draw up blueprints for a prototype which generals want to have in the air within 11 years.

Pentagon planners have been encouraged by technical breakthroughs from Burt Rutan, chief designer on Sir Richard Branson’s White Knight spaceship, which is due to begin test flights next year and to carry tourists on suborbital journeys from 2010.

Last week Rutan, 65, who built the first privately funded craft to reach space and won the $10m X prize for his achievement in 2004, gave his blessing to Hot Eagle, which could be based on White Knight’s technology. Rutan said it would be an expensive way to transport troops “but it could be done. It is feasible”.

Will Whitehorn, president of Virgin Galactic, which is funding White Knight, recently predicted that it could be used to airlift emergency supplies into disaster zones.

“It could be like Thunderbirds, like International Rescue,” he said. A passenger version would be capable of flying from London to Sydney in four hours.

The two-stage Hot Eagle would be launched from an aircraft carrier. A large booster rocket would carry a smaller spacecraft containing 13 “space troopers” 50 miles into space, far above hostile radar, before landing in enemy territory.

The marines first called for a spaceplane in 2002 after the US military failed to capture Osama Bin Laden in the mountains of Afghanistan. The project was known as the Small Unit Space Transport and Insertion programme (Sustain). Its advocates said it took too long on foot to reach the caves where Bin Laden was said to be hiding and helicopters were too visible.

General James Mattis, leading the marines’ Central Command at the time, said he wanted the spaceplane in the air by 2019. He was recently promoted to be one of the most senior officers in the US military establishment and Sustain has since become a priority.

Last week Lieutenant Colonel Mark Brown, a US air force spokesman, confirmed that Nasa and Pentagon officers had met for two days of talks to draw up plans for Hot Eagle.

Invitations to the meeting said participants would be discussing a “potential revolutionary step in getting combat power to any point in the world in a time frame unbelievable today”.

Although aided by Rutan’s breakthroughs in ever-lighter composite materials, there are many technological hurdles ahead for Hot Eagle.

Designers have not yet decided whether to build a relatively simple disposable craft, which the space troopers would destroy before being picked up by helicopter, or a vastly more complex vehicle which could fly them home.

Some critics dismiss Hot Eagle as Hollywood-inspired science fiction or an expensive toy. Others question how effective a fighting force of just 13 soldiers could be on the ground.

“That is, if they get there,” said Ivan Oelrich, of the Federation of American Scientists. “It would be wildly vulnerable as you cannot armoura rocket ship.”

Roosevelt Lafontrant, a former marine colonel now employed by the Schafer Corporation, a technology company, said the technology was advancing rapidly. “If we had had the Sustain programme in operation in 2002, Bin Laden would have been captured and history fundamentally changed,” he said recently.

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