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| Waverider hypersonic jet targets Mach 6 | |
| (about 11 hours later) | |
| The US military has conducted a test flight of its hypersonic jet Waverider, aiming to reach Mach 6 (4,300mph; 6,900km/h) above the Pacific Ocean. | |
| At that speed it could travel from London to New York in about an hour. Results from the test flight have not yet been released. | |
| Pentagon and Nasa hope to use the project to develop faster missiles. | |
| During a test in June 2011, Waverider travelled at Mach 5, but failed to reach the target speed. | |
| It is one of several projects currently under way to create a hypersonic aircraft. | It is one of several projects currently under way to create a hypersonic aircraft. |
| The research could also be used to build a commercial plane, able to reach much higher speeds than today's jets, after Concorde was decommissioned in 2003. | The research could also be used to build a commercial plane, able to reach much higher speeds than today's jets, after Concorde was decommissioned in 2003. |
| Five-minute flight | Five-minute flight |
| The military intended to use a B-52 bomber to lift the wingless unmanned jet from US Edwards Air Force Base in California to 50,000 feet (15,250m). | |
| The craft was then to be dropped and after a free fall of about four seconds, its engine is supposed to ignite. | |
| While it's the prospect of rapid transatlantic flight that has caught the headlines, the technology in the X-51A Waverider could have a potent military application too. | |
| If it works, then this engine technology could power the world's first hypersonic cruise missile. | If it works, then this engine technology could power the world's first hypersonic cruise missile. |
| The Pentagon's ambitious Prompt Global Strike programme has the goal of enabling the US military to strike a target anywhere on Earth within an hour. The Waverider could make such a goal a reality. | |
| X-51A Waverider was then expected to climb to 70,000ft (21,300m) and eventually reach Mach 6. | |
| The Mach number is the ratio of the speed of an object to the speed of sound. Mach 1 is the speed of sound - approximately 768mph, depending on various factors including temperature and altitude. | The Mach number is the ratio of the speed of an object to the speed of sound. Mach 1 is the speed of sound - approximately 768mph, depending on various factors including temperature and altitude. |
| So Mach 6 is six times the speed of sound. Concorde's cruising speed was Mach 2 - it flew from London to New York in just over three hours. | So Mach 6 is six times the speed of sound. Concorde's cruising speed was Mach 2 - it flew from London to New York in just over three hours. |
| The Waverider test flight was expected to last for about five minutes before the craft falls into the Pacific. | |
| The test is essentially a repeat of last summer's attempt, when the hypersonic aircraft reached Mach 5, but the engine failed to attain full power. | The test is essentially a repeat of last summer's attempt, when the hypersonic aircraft reached Mach 5, but the engine failed to attain full power. |
| Military officials said the results would be available later on Wednesday. | |
| Concorde's legacy? | Concorde's legacy? |
| European aerospace and defence giant EADS believes that hypersonic passenger flights are likely to appear in the near future. In 2011, EADS presented its own concept of a commercial high-speed aircraft designed to fly at Mach 4. | European aerospace and defence giant EADS believes that hypersonic passenger flights are likely to appear in the near future. In 2011, EADS presented its own concept of a commercial high-speed aircraft designed to fly at Mach 4. |
| "The business community who wanted to be in New York in three hours made Concorde highly viable, and now there's interest on both sides of the Atlantic to jump a generation and go from supersonic flight to hypersonic flight," EADS' vice-president of business development, Peter Robbie, told the BBC. | "The business community who wanted to be in New York in three hours made Concorde highly viable, and now there's interest on both sides of the Atlantic to jump a generation and go from supersonic flight to hypersonic flight," EADS' vice-president of business development, Peter Robbie, told the BBC. |
| "Such an aircraft will be very expensive, of course, because of the enormous amounts of energy that is required to get to such speeds. | "Such an aircraft will be very expensive, of course, because of the enormous amounts of energy that is required to get to such speeds. |
| "But the idea of going from Tokyo to Paris in two-and-a-half hours is very attractive for the business and political community - and I think that by about 2050, there may be a viable commercial aircraft." | "But the idea of going from Tokyo to Paris in two-and-a-half hours is very attractive for the business and political community - and I think that by about 2050, there may be a viable commercial aircraft." |
| In August 2011, US military scientists attempted to get another unmanned hypersonic experimental aircraft to reach Mach 20 - 20 times the speed of sound. | In August 2011, US military scientists attempted to get another unmanned hypersonic experimental aircraft to reach Mach 20 - 20 times the speed of sound. |
| However, they lost contact with the Falcon Hypersonic Test Vehicle 2 (HTV-2) after it had separated from its rocket. | However, they lost contact with the Falcon Hypersonic Test Vehicle 2 (HTV-2) after it had separated from its rocket. |