COLORADO SPRINGS, Colorado—Boom Supersonic plans to start core tests of its Symphony engine by the end of the year at a Colorado site formerly used by failed hypersonic propulsion company Reaction ...

Pioneering propulsion technologies developed by failed UK firm Reaction Engines could live on, with the sale of its assets to a preferred bidder seemingly in its final stages, the insolvency ...

To be fair it's not solely a Brit thing. Every time anyone else has studied air-breathing rockets they find that the engine is optimized by getting rid of the air-breathing component. And horizontal ...