Synergetic Air-Breathing Rocket Engine to burn in 2020

The SABRE engine is designed to use jet propulsion to power an aircraft from standing to five times the speed of sound in the atmosphere. The engine then switches to rocket mode, which could push it to speeds of Mach 25 – nearly 20,000 miles per hour – easily enough to get into orbit. Such systems are technically possible, but the amount of oxygen needed for fuel would make such an aircraft impossibly heavy. Instead, SABRE sucks the oxygen it needs from the atmosphere and uses it on-the-spot, with technology that has so far worked as specified.