EM Drive

Are we going to have to rewrite the laws of motion?

A group at NASA’s Johnson Space Center has successfully tested an electromagnetic (EM) propulsion drive in a vacuum – a major breakthrough for a multi-year international effort comprising several competing research teams. Thrust measurements of the EM Drive defy classical physics’ expectations that such a closed (microwave) cavity should be unusable for space propulsion because of the law of conservation of momentum.

The concept of an EM Drive as put forth by SPR was that electromagnetic microwave cavities might provide for the direct conversion of electrical energy to thrust without the need to expel any propellant.

Essentially, it converts energy directly into momentum, which shouldn't be possible. Remember that whole "equal and opposite" thing from high school physics? It doesn't apply to this drive, at least not as it relates to mass.

So what's the money shot? This:

If such a similar vehicle were equipped with an EM Drive, it could enable travel from the surface of Earth to the surface of the moon within four hours.

Such a vehicle would be capable of carrying two to six passengers and luggage and would be able to return to Earth in the same four-hour interval using one load of hydrogen and oxygen for fuel cell-derived electrical power, assuming a 500 to 1,000 Newton/kW efficiency EM Drive system.

That's still a long way off from an engineering perspective, as the current models only operate at about 1 N/kw efficiency, but the nuclear reactors required to power such a motor already exist in US Navy submarines.

I will remain skeptical (remember cold fusion?) until I see it work on a real space vessel, but it's definitely intriguing. It wouldn't be the first time physics texts had to be rewritten, but it would certainly be one of the most important revisions in the history of science.