What if rockets didn't require those heavy oxidizers to get into orbit? The European Space Agency is daring to dream, awarding a €1 million grant to a British firm that's looking into air-breathing spacecraft.
Thanks to the recent grant from the ESA, British company Reaction Engines is working on the problem of how to make air-breathing engines work on spacecraft, according to New Scientist. Their aim is to create Skylon, a space plane that can take off and land like a conventional plane, yet still achieve orbit, by mixing air-breathing jets for take-off and landing with rockets (fueled by onboard oxygen) past a certain speed:
Skylon's proposed engine would use a heat exchanger to cool incoming air from 1000 °C at Mach 5 to less than -100 °C. Once cooled, the air is mixed with liquid hydrogen and burned... Skylon is designed to run in air-breathing mode directly from launch up to a speed of Mach 5.5. At an altitude of 26 kilometres, the engine would switch to conventional rocket power and use onboard oxygen to propel the plane into space.
"It's a pretty unique concept," says Mark Hempsell, director of future programmes at Reaction Engines. "I think at the moment it's the only realistic way to make aircraft vehicles that go into space."
Mark Lewis, a aerospace engineer from the University of Maryland, disagrees:
I think all approaches are on the table. [Reaction Engines is] looking at one possible combination of engine system, and there's really a much broader range of options we need to explore before we know what to fly up to orbit.
Personally, we're hoping that more affordable space planes come to pass, and sooner rather than later. We're already eight years behind the future Stanley Kubrick promised us in 1968.
Air-breathing planes: the spaceships of the future? [New Scientist]