Nasa to test the 5,000mph surfboard that could lead to hypersonic travel

It will be the world's fastest plane, travelling at seven times the speed of sound ­ and could lead to super-high-speed piloted aircraft in about 20 years.

It will be the world's fastest plane, travelling at seven times the speed of sound ­ and could lead to super-high-speed piloted aircraft in about 20 years.

The US space agency, Nasa, will today send a 12ft (3.6m) surfboard-shaped jet called the X-43A whizzing over the Pacific Ocean, on what it hopes will be a record-breaking flight. Although rockets have reached and exceeded the speeds that the X-43A should achieve, of about Mach 7 (5,320mph), those rely entirely on chemicals stored on board, which are burnt in the engines. The X43-A, by contrast, burns its hydrogen fuel with air scooped in from the atmosphere, in what is known as a "scramjet".

The flight will be a key stage in Nasa's "Hyper-X" programme, which has for decades tried to develop high-speed air-breathing craft to replace rockets. Vince Rausch, Hyper-X programme manager at Nasa's Langley facility in Virginia, said: "The Hyper-X programme takes what we've been doing for the last 40 years in wind tunnel research to flight. Flight is reality. The programme is structured around the scramjet engine and should be a major leap forward in the national capability for access to space. The country is looking for safer, more flexible, less expensive ways to get to space, and that's what the scramjet engine would bring."

However, the British inventor Alan Bond, who in the 1980s designed an air-breathing craft called Hotol, intended to reach space, said: "Scramjets are like Formula 1 cars ­ whereas to get into space, you need the equivalent of a dragster, which will accelerate to top speed very quickly. Scramjets are fine for mixed speeds and cruising ­ say, if you want a Mach 10 cruise missile ­ but they are really not for getting into orbit."

Nasa hopes that future scramjet-based aircraft could take off from the ground and offer a cheaper means of doing most of the tasks now done by the rocket-powered Space Shuttle. It could also provide a path towards high-speed aircraft for the public.

The unmanned X-43A craft, which has a wingspan of 5ft, will be launched from a rocket that itself will be set off from a B-52 bomber this afternoon. Once the rocket reaches an altitude of 100,000ft, the scramjet will ignite and fly for about 10 seconds, during which it should cover roughly 17 miles. The engines will then cut out and the plane will crash into the ocean.

If it succeeds, the X-43A will break the speed record of Mach 6.7 for an atmospheric craft, which was set in 1967 by the rocket-powered X-15 craft. It will also mark the first time that an "air-breathing" plane has flown faster than Mach 5. Nasa is spending $185m (£131m) on the X-43 project, and aims to fly three of the experimental planes in the next 18 months. The next step would be to build planes that could be up to 200ft long ­ and even to develop piloted versions by 2025.