Super Plane Fly's Anywhere In Four Hours 

It almost sounds like a dream: a new kind of hypersonic space-kissing jet that can take you anywhere in the world in just four hours. But the Skylon super plane being developed by UK aerospace firm Reaction Engines is very real.

The UK government has invested £60 million into a next-generation engine that -- its makers claim -- will make low-cost space travel possible for commercial customers.

Oxfordshire-based Reaction Engines got the grant to help it develop its Skylon super-plane, which could eventually make make low-cost space travel possible for commercial customers.

The project took a big step forward this week with Reaction Engines announcing a new partnership with defence and aerospace giant BAE Systems, whose financial backing, along with a considerable investment from the UK government, will help Reaction develop its new class of aerospace engine dubbed SABRE (Synergetic Air-Breathing Rocket Engine) by as early as 2020, with test flights possible just five years later.

'Sabre' engine is a hybrid rocket and jet propulsion system, which theoretically enables travel anywhere on Earth in four hours or less. It could also slash the cost of launching satellites into orbit, once it gets off the ground.

The super-plane will rely on cooling an incoming airstream from 1,000 degrees C to minus 150 C almost instantly, at close to 1/100th of a second.

It will double the technical limits of a jet engine, and allow the craft to reach, up to five times the speed of sound, before switching to a rocket engine to reach orbit.

SABRE operates in two modes to enable aircraft to directly access space in one step, called single stage to orbit. In its air-breathing mode, the engine sucks in oxygen from atmospheric air, to burn with liquid hydrogen fuel in the rocket combustion chamber. Once outside Earth’s atmosphere, the engine transitions to a conventional rocket mode, switching to on-board liquid oxygen.

Based at Culham Science Centre in Oxfordshire, the company has been called a "potential game-changer" by ministers since at least 2012, following a positive appraisal by the UK Space Agency in 2010.