This article was first published in the November 2015 issue of WIRED magazine. Be the first to read WIRED's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.
This big cloud of steam could soon be the secret to sending an aircraft into outer space. The work of Oxfordshire-based Reaction Engines, the Synergetic Air-Breathing Rocket Engine, or SABRE, is a new type of rocket engine that would allow a plane to reach orbit in around 15 minutes, release a payload, return to Earth and land on an airstrip. The company's founding director, Alan Bond, explains that conventional liquid hydrogen rockets are too fuel-thirsty to make a space plane viable.
"Rocket engines alone can't quite hack it," he says. That's why SABRE was designed as a hybrid between a rocket and a jet engine. "If you used jets inside the atmosphere to get to around Mach 5 or Mach 6, and then you transitioned to rockets to get into orbit, you'd stand a good chance of making it." Jetting up to Mach 5 - 1.7kps, or five times the speed of sound - is problematic: the air passing through the engine heats up quickly, slowing down propulsion.
But traditional cooling systems make the engine heavier and slower. That's where SABRE's main technology, the "precooler", comes in. This spiral of one-millimetre-thick micro-tubes is kept cold by the liquid hydrogen that will later fuel the rockets. "It enables the engine to take in air at 1,000°C and cool it down to -150°C," Bond explains. "This happens in one hundredth of a second." The cloud pictured left is what it looks like when it happens on Earth.
One of SABRE's ultimate uses will be in Skylon, a space plane that caught the eye of the European Space Agency. In 2013, the Agency commissioned a €1 million (£728,000) study that concluded that "the Skylon can be realised given today's technology and successful engine development." To see it in the air, though, we'll have to wait for the Skylon's first test flight in 2019. Watch the skies...
This article was originally published by WIRED UK
