Simple, Fuel-Efficient Rocket Engine for Cheaper, Lighter Spacecraft

Sending NASA’s Space Shuttle into orbit required more than 3.5 million pounds of fuel, which is about 15 times heavier than a blue whale. But a new type of engine — called a rotating detonation engine — promises to make rockets not only more fuel-efficient, but also more lightweight and less complicated to construct. The engine, however, is too unpredictable to be used in an actual rocket.