Reaction Engines Ltd ('REL') was founded in 1989 by Alan Bond and the principal two engineers from Rolls Royce behind the RB545 engine programme, John Scott-Scott and Richard Varvill.
Alan Bond had begun work on rocket engines in 1982 with a view to overcoming the inadequate characteristics of existing rocket-based expendable launch vehicles. Within this work Alan realised that the use of heat exchangers within rocket engine cycles can greatly increase their efficiency by allowing them to use atmospheric air to burn in the combustion chambers when flying in the atmosphere like a jet (rather than using heavy liquid oxygen stored in on-board tanks) and extracting heat where it causes a problem whilst using that heat to power the turbo machinery in the engine.
These new Synergetic Air-Breathing Rocket Engines (SABRE) would be suitable for powering modified aircraft directly into Earth orbit and it was subsequently found that in a reconfigured form they would be able to propel aircraft at cruise speeds of up to five times the speed of sound. The key enabling technology that needed to be developed to make these new engines viable was lightweight heat exchangers.
Inspired by the miniaturisation of the silicon chip, and understanding that heat exchangers were far from reaching their physical limit in terms of miniaturisation, developing high power lightweight heat exchangers and understanding the design of the new engines and vehicles that they enable became the focus of Alan Bond and subsequently REL.
From 1989-2000, REL focused on producing a robust technical design for the new SABRE engine and the SKYLON launch vehicle that it could be used to power. This work was supported by a programme of laboratory work to underpin the innovative designs including in the areas of aerothermodynamics, propulsion, structures and control technology.
Subsequently, the company began to attract increasing levels of private investment as well as government support and activities were expanded to undertake an intensive programme of research to demonstrate the full scale light-weight heat exchanger technology as well as the manufacturing techniques needed for commercial lightweight heat exchanger production.
In order to provide independent validation of the technological progress being made and to support continued private investment, experts from the European Space Agency, at the request of the UK government, were assigned to review and report on work undertaken.
The demonstration by REL of the crucial lightweight heat exchanger as well as other SABRE relevant technologies had the objective of removing outstanding technical concerns on the SABRE engine in order to enable its full development:
"ESA are confident that a ground test of a sub-scale [SABRE] engine can be successfully performed to demonstrate the flight regime and cycle and will be a critical milestone in the development of this program and a major breakthrough in propulsion worldwide."