Georgia Tech researchers have developed a new protoype engine that uses up to 40% less fuel by running on solar power while in space and by fine-tuning exhaust velocity.

The key to the engine improvements is the ability to optimize the use of available power. A traditional chemical rocket engine (attached to a satellite ready for launch) runs at maximum exhaust velocity until it reaches orbit, i.e., first gear.

The new engine allows ground-control units to adjust the engine's operating gear based on the immediate propulsive need of the satellite. The engine operates in first gear to maximize acceleration during orbit transfers and then shifts to fifth gear once in the desired orbit. This allows the engine to burn at full capacity only during key moments and conserve fuel.

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