NASA is to join forces with Virgin Galactic to study the feasibility of building a hypersonic rocket that could carry passengers from London to New York in less than two hours.

The U.S. space agency will lend expertise and research facilities to Sir Richard Branson’s space tourism company in return for help with testing equipment and training astronauts on board SpaceShipTwo, the Virgin suborbital spacecraft, which is to start flight tests next year.

Virgin plans to carry its first customers into suborbital space, 80 miles above the Earth’s surface, in 2009: 200 people, who will pay roughly $200,000 each for a 2.5 hour flight, have paid deposits. The trip will include 90 seconds of climbing at 2,500 mph in a rocket and five minutes of weightlessness, when passengers will see the Earth’s curvature and the darkness of space.

Virgin is unlikely to recoup the cost of developing SpaceShipTwo and its mother ship — $200 million — from space tourism alone, and is therefore seeking ways of developing the technology “to allow trips from A to B rather than returning to A”.

Alex Tai, of Virgin Galactic, who will pilot SpaceShipTwo’s maiden flight, said that the joint study would investigate types of craft and fuel. Options include an airbreathing scramjet travelling at 60,000 feet and a rocket that reaches 150,000 feet and skips along the top of the Earth’s atmosphere to achieve five times the speed of sound. Developing a hypersonic rocket that could carry passengers between continents would take ten years and cost at least $2 billion, he said.

Dan Coughlin, of NASA, said that the space agency could also use SpaceShipTwo to test spacesuits and other equipment. The two organizations would research hybrid rocket motors, which use both solid and liquid fuel and are safer and more efficient than solid fuel rocket engines.