A revolutionary air-breathing rocket engine capable of hitting more than 2,500 miles per hour just past a major milestone

• Reactor Engines, a British aerospace company, says it's successfully tested a rocket engine that could eventually allow for supersonic flight to space.
• The company's engine can cool air from 420 degrees Celsius to room temperature in less than a second, the company said.
• Traditionally, rockets have had to carry massive tanks of fuel to burn, adding to their weight and aerodynamic profile.
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A British company developing a rocket engine that can combust using oxygen from the air, as opposed to carrying liquid oxygen like traditional rockets, says it's passed a "significant milestone" for supersonic flight.

Reaction Engines' SABRE engine, along with technology that can cool air from more than 400 degrees Celsius to room temperature in 1/20th of a second, could allow space-going ships to look more like airplanes than traditional fuel-laden rockets with their ballooning storage tanks.

"This is a hugely significant milestone which has seen Reaction Engines' proprietary precooler technology achieve unparalleled heat transfer performance," Mark Thomas, the company's CEO, said in a press release.

"The HTX test article met all test objectives and the successful initial tests highlight how our precooler delivers world-leading heat transfer capabilities at low weight and compact size. This provides an important validation of our heat exchanger and thermal management technology portfolio which has application across emerging areas such as very high-speed flight, hybrid electric aviation, and integrated vehicle thermal management."

The time milestone reached in testing is equivalent to flight speeds of Mach 3.3, the company said, or more than 2,500 miles-per-hour. That's roughly the speed of the famous SR-71 Blackbird spy plane and more than 50% faster than the Concorde supersonic passenger jet.

Reaction Engines' milestone is the result of twenty years' work by the company's founders Alan Bond, Richard Varvill and John Scott, the Financial Times' reported. To date, the company has raised nearly $100 million from backers including Boeing's HorizonX, Rolls-Royce, Scottish tech investment firm Baillie Gifford, and the Government of the United Kingdom, according to Pitchbook data.

More testing is set to take place this year in the UK.

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