Skylon spaceplane engine

Reaction Engines Ltd (REL) of Culham, Oxfordshire, ran a series of tests on key elements of its Sabre propulsion system under the independent eye of the European Space Agency (Esa).

Esa's experts have confirmed that all the demonstration objectives were met. REL claims the major technical obstacle to its ideas has now been removed. "This is a big moment; it really is quite a big step forward in propulsion," said Alan Bond, the driving force behind the Sabre engine concept.