Audio recordings of a UK Reaction engines presentation are in the NASA Spaceflight forum Reaction Engines is making hypersonic planes and spaceplanes. Their key technology is a precooler.

US Air Forece research lab investigations examined the thermodynamic cycle of the SABRE concept and found no significant barrier to its theoretical viability provided the engine component and integration challenges are met.

In late 2015 / early 2016, BAE Systems invested £20.6 million in Reaction Engines to acquire 20 per cent of its share capital and also enter into a working partner relationship.

BAE Systems will collaborate to accelerate Reaction Engines' development of SABRE – a new aerospace engine class that combines both jet and rocket technologies with the potential to revolutionize hypersonic flight and the economics of space access.