Synergetic Air-Breathing Rocket Engine (Sabre) Programme Evaluation Report 2022 (gov.uk)

SABRE is a hybrid combined-cycle air-breathing/rocket engine that, if successful, will enable hypersonic travel within the atmosphere and greatly reduce access-to-space costs. The SABRE concept represents a major breakthrough in propulsion technology, which could enable the realization of a reusable, SSTO launch vehicle (the SKYLON spaceplane). The SABRE is designed to operate in both air-breathing mode (using atmospheric air and on-board liquid hydrogen) and rocket mode (using onboard liquid oxygen and hydrogen).

Features:

    The integration of an air-breathing engine with a rocket engine whilst minimising the duplication of equipment

    Deep pre-cooling of the air used in the engine to enable the operation of a compressor at high Mach numbers

    Use of the energy absorbed from the air to power internal turbomachinery

    Use of the hydrogen fuel as a heatsink for the residual energy prior to combustion