The liquid hydrogen and oxygen Sabre engines would make space flight possible. They function similarly to the engines of the current space shuttle. As Fast Company explains, the Sabre engines “also burn liquid hydrogen and oxygen, but they actually breathe in that oxygen from the air itself–cooling it, extracting it from the other gases, and then compressing it before firing it through the engine much as the final stage of the Space Shuttle’s engines do.”
Skylon would provide a cheaper alternative for space flights, at a mere $40 million, which is $20 million cheaper than the current most affordable option provided by Space X’s Falcon 9 rockets.
Now with its approval from the European Space Agency, Reaction Engines, Skylon’s designer, needs to generate interest for the craft and secure money and government backing to develop the engines.