The guys at Reaction Engines are trying to build a jet engine that will operate at very high speeds. In order to make this work the incoming supersonic air has to be slowed to subsonic speeds and compressed. This has the unfortunate effect of also making the air very hot and much less dense than it might otherwise be. This limits the effectiveness of the engine. This cooling technology can be used to cool the hot air before injecting fuel for combustion. This can increase the maximum speed at which the jet engine can operate.
The reason Reaction Engines is working on this type of jet engine is because they want to use it for an airbreathing single-stage-to-orbit re-usable spaceplane. (Technically, the Reaction Engines design is a hybrid that switches to a pure rocket mode at higher speeds.)
My comment was mostly in jest, but to address one point seriously, 'boffins' is fine, if nowadays rare, in British English, and since Reaction Engines is British company, its use would be completely fine here.
At some point in the last twenty years or so. I can perceive the gender of the term. However, my wife is much younger than I, and she and her female friends exclusively use the term "guys" to refer to themselves and cannot comprehend that I can perceive gender in the term. I mean, intellectually, they know it use to connotate gender, but it is silly to them in the same way that it's silly to us that strawberries are berries that grow in straw. In the US, and apparently also depending on your age, "guys" is gender neutral. And as a hobbyist linguist, "we do not prescribe language, we describe it"...
The reason Reaction Engines is working on this type of jet engine is because they want to use it for an airbreathing single-stage-to-orbit re-usable spaceplane. (Technically, the Reaction Engines design is a hybrid that switches to a pure rocket mode at higher speeds.)
Some further reading:
Precooled jet engine: https://en.wikipedia.org/wiki/Precooled_jet_engine
SABRE (rocket engine): https://en.wikipedia.org/wiki/SABRE_%28rocket_engine%29
Single-stage-to-orbit: Airbreathing SSTO: https://en.wikipedia.org/wiki/Single-stage-to-orbit#Airbreat...
Skylon (spacecraft): https://en.wikipedia.org/wiki/Skylon_%28spacecraft%29