First major test for world’s first ‘space plane’ passed

Posted on 9 Apr 2019 by Maddy White

Designed to drive space planes to orbit at Mach 5, and also take airliners around the world in just a few hours, the Sabre air-breathing rocket engine has just passed a crucial testing phase.

Sabre is a new type of flexible engine for propelling high speed aircraft and spacecraft - image courtesy of Reaction Engines.
Sabre is a new type of flexible engine for propelling high speed aircraft and spacecraft – image courtesy of Reaction Engines.

Synergetic Air Breathing Rocket Engine, or Sabre, is a new type of flexible engine for propelling both high speed aircraft and spacecraft.

Reaction Engines devised the unique rocket engine to allow aircraft to fly much faster than traditional jets.

However, unlike jet engines, Sabre can also operate in a rocket mode outside of the atmosphere, and this could potentially offer the next generation of reusable space launch vehicles.

Three core elements

There are three core elements to the Sabre engine; the pre-cooler, the engine core that has a a smart thermodynamic cycle to manage heat and fluid flow, and the thrust chamber situated at the rear.

The pre-cooler element of the air-breathing rocket engine successfully passed its first phase of high-temperature testing. The testing was designed to directly replicate supersonic flight conditions.

It showed the ability to handle the simulated conditions of flying at more than three times the speed of sound. It did this by successfully quenching a 420°C stream of gases in less than 1/20th of a second. Future tests are planned at temperatures in excess of the 1,000°C expected during Mach 5 hypersonic flight.

Sabre can be considered a hybrid of a jet engine and a rocket engine. At slow speeds and at low altitude, it would act like a jet, burning its fuel in a stream of air from the atmosphere. At higher speeds and altitude, it would then transition to its rocket mode, combining the fuel with a small supply of oxygen the vehicle had carried in flight.

Flexible travel

The idea of an engine being flexible enough to take passengers to a different continent for a holiday and also into space doesn’t seem like a feasible one. However, the engine could shatter stereotypes of travel if it is successful.

It is a long way off from proving itself, but this, alongside the return of supersonic travel and fully electric planes potentially set to take to the skies, who can predict what the next decade could bring for how we travel in the air?


Mark Thomas, chief executive, Reaction Engines, commented: “This is a hugely significant milestone which has seen Reaction Engines’ proprietary pre-cooler technology achieve unparalleled heat transfer performance.

“This provides an important validation of our heat exchanger and thermal management technology portfolio which has application across emerging areas such as very high-speed flight, hybrid electric aviation and integrated vehicle thermal management.”