Beam Propelled Spacecraft

NASA is currently conducting a study looking at the prospects of propelling spacecraft by either laser or microwave beam instead of onboard rocket. The study's report is due out March 11.

The basic idea is simple, and elegant. Instead of carrying rockets, spacecraft would only carry a propellant, like hydrogen. Power in the form of a laser or a microwave beam would be sent from a power plant to the spacecraft. That beam would excite the propellant in the spacecraft, sending it through a nozzle, thus providing thrust. Such a system would allow for simpler, lighter spacecraft with perhaps five times the payload capacity of a ship using onboard chemical rockets.

Power plants capable of producing beams of sufficient energy to be useful in such a project exist now. A mature program might bring on an era of cheap access to orbit and hundreds of launches daily. Longer term, a robust, space-based system could power our first interstellar probe within fifty years.

Such a program would also affect the case for space solar power. If microwave beams could power ships into orbit without environmental damage, the case for beaming solar power to Earth using microwaves would be stronger.