A true space plane still feels very much like a technology of the future – but one company has just taken an important step to making the dream a reality.

Reaction Engines Ltd (REL), of Oxford, UK, announced this week it has signed a €10 million Development Contract with ESA for its revolutionary Synergistic Air-Breathing Rocket Engine (SABRE). Why is this important? Well, SABRE is a revolutionary technology that can operate both in the atmosphere of Earth and the vacuum of space – a capability that’s crucial to space planes.

This contract finalizes a previous commitment by the UK Government to invest £60 million in SABRE.

“We’ve had valuable support from ESA and UKSA [UK Space Agency] to date, and today’s agreement is a further vote of confidence not only in the revolutionary potential of this technology, but our ability to deliver on it,” said Mark Thomas, CEO of REL, in a statement. “We are now entering an exciting phase where we can accelerate the pace of development to get SABRE up and running.”

The funding will enable REL to begin ground tests of its SABRE engine. First of all, REL simply wants to prove the engine works. It has also seen investment from defence company BAE Systems and the US Air Force.

^{Shown is a cutaway illustration of SABRE. Reaction Engines}

But REL has bigger ambitions. It wants to use SABRE in its own space plane, dubbed Skylon. This vehicle, which could take off and land on a runway, would be able to carry both cargo and humans into orbit. And the SABRE engine would allow it to operate both as a plane in the air and as a rocket in space.

The key breakthrough of SABRE is that it does not need to carry onboard oxygen for its combustion chamber. Instead, it can use atmospheric oxygen, massively reducing the amount of onboard fuel it needs to carry. A major problem has been overcoming frost issues from the atmospheric oxygen, but late last year the company revealed the secret of how it would cope with this, using a methanol injection to function as antifreeze.

There are, of course, other semi-space planes in development at the moment, such as Virgin Galactic’s SpaceShipTwo and XCOR’s Lynx. But both simply make “hops” into space, whereas Skylon could operate as a fully-fledged orbiter. A true space plane, if you will.

There is a still a long way to go in the development of SABRE, let alone Skylon. But this investment shows that there are plenty of interested parties who believe in the technology. If you wanted a reason to get excited about the future of space travel, this is it.