Supersonic Travel

The A2 plane, designed by engineering company Reaction Engines based in Oxfordshire, southern England, could carry 300 passengers at a top speed of almost 4,000 mph (6,400 kmh), five times the speed of sound, engineers who designed the hypersonic jet said on Tuesday, Feb. 5.

Part of an EU project to expand the boundaries of air travel and partially funded by the European Space Agency, the LAPCAT (Long-Term Advanced Propulsion Concepts and Technologies) project could see the plane operating within 25 years, the firm's boss Alan Bond told the Guardian newspaper.

"The A2 is designed to leave Brussels international airport, fly quietly and subsonically out into the north Atlantic at mach 0.9 before reaching mach 5 across the North Pole and heading over the Pacific to Australia," he said.

The plane, which at 143 meters (469 feet) long would be about twice the size of the biggest current jets, could fly non-stop for up to 12,500 miles (20,000 km). It would be lighter than current intercontinental planes and designed to operate on liquid hydrogen, which is seen as more ecologically friendly than the carbon emitted by today's planes.

"[The A2] produces only water vapor and a little bit of nitrous oxide as exhaust," Richard Varvill, technical director of Reaction Engines. "And although a hypersonic jet loaded with liquid hydrogen might sound dangerous, hydrogen fuel is actually no more explosive than normal jet fuel."

Like carbon dioxide, both water vapor and nitrous oxide contribute to climate change and the greenhouse effect.

Claustrophobe's nightmare

Passengers would, however, have to live without a view of passing over the North Pole and Pacific as heat produced by the jet's high speed makes windows impracticable. Flat screen monitors instead would substitute for an actual look outside the jet.

Bond said he could imagine about 10 percent of air travel taking place on hypersonic jets by 2033. The noise associated with supersonic speeds would prevent the jet from flying over heavily populated areas, though the A2 could fly from Europe to California, across the Atlantic hypersonically then slow down at the US coast.

Fares for the four-hour and 40-miute flight to Australia would be comparable with current first-class tickets on standard flights, of around 3,500 pounds (4,700 euros), researchers said. Flights from Europe to Australia now take about 22 hours.

"It sounds incredible by today's standards but I don't see why future generations can't make day trips to Australasia," he said. "Our work shows that it is possible technically; now it's up to the world to decide if it wants it."