US space scientists have unveiled an aviation breakthrough as historic as the Wright Brothers first flight: a plane that would someday streak across America from coast to coast in 30 minutes and scoop oxygen out of the air for its fuel.
Gathered on a wind-swept tarmac in the California desert, NASA scientists displayed the small, black X-43A prototype that they said would fly at seven times the speed of sound - or nearly 8,047 kms per hour - on its maiden flight next month, shattering records for a jet engine that does not require rocket power.
Though the unmanned prototype, a product of NASA's US$185 million "Hyper-X Program," will be carried aloft by a B-52 bomber and launched by a booster rocket, the scientists said the plane will someday take off and land on its own - making way for cheaper and easier space missions, a new generation in commercial travel and military aircraft that fly too fast for an adversary to shoot them down.
The plane's hypersonic concept is so simple that it was first imagined by 17th Century visionaries, and its "scramjet" engine design - which one scientist likened to "keeping a match lit in a hurricane" - is so complicated that it took engineers more than 40 years to achieve.
"I get chills thinking about it," X-43A project manager Joel Sitz said. "This is aviation history."
Scientists have been trying for years to build an "air-breathing" jet that can fly at hypersonic speeds, allowing it to dispense with huge oxygen tanks. That makes the craft considerably lighter and opens up much more room for payloads or passengers.
Currently the fastest "air-breathing" jet is the SR-71 Blackbird, which flies at Mach 3, or three times the speed of sound. Sitz said the X-43A will ultimately be designed to reach speeds of Mach 10. While scientists see the possibilities as nearly limitless for a "scramjet" powered plane, they concede that most of its applications are years away, predicting a prototype space launch 25 years in the future.
"We're doing research for an operating vehicle that will fly 60 years from now," Sitz said. "But we went from the Wright Brothers to the Moon in 60 years. We're doing for hypersonics what the Wright Brothers did for subsonics 100 years ago."
The "scramjet," which has no moving parts and spits out only water, scoops oxygen out of the atmosphere and compresses it into the engine, where it is injected with hydrogen to power the 3.6 metre long prototype.
Eventually, Sitz envisions commercial flights carrying passengers from Los Angeles to New York in 30 minutes or to Tokyo in two hours, or cheap and convenient space travel.
Under that scenario, Sitz said, the plane would allow space agencies to operate regularly between Earth and the moon or a space station, ferrying equipment back and forth.
And Sitz said a "scramjet" powered airplane could be employed in military applications that would be very difficult for an adversary to defeat.
"I wouldn't want to be on the pointy end of one of these things if its got a bomb on it," Sitz said. "We could call someone up and say: 'We're gonna bomb you,' and there would be nothing they could do about it."
The prototype's first flight will take off from the Dryden Flight Research Center at Edwards Air Force base. The X-43A will fly on its own for a matter of seconds before crashing into the Pacific Ocean, where the secrets of its design will be destroyed on impact.
