# Electromagnetic accelerator in space

Let's imagine there are already interplanetary spacecrafts and travel. Would it be possible to create electromagnetic accelerator somewhere in the outer space? It would work this way:

There would be a long platform, which would emit electromagnetic waves in specific plates in following scenario:

1. First plate, the nearest to the spacecraft, would emit electromagnetic wave, in order to pull (or maybe push) the spacecraft.
2. First plate would turn off.
3. Second plate, the nearest to the spacecraft, would turn on and pull the spacecraft etc.

As the frequency of turning on/off the plates would be increasing, the speed of the spacecraft would be increasing as well (we are in vacuum).

Could be this approach applicable in reality, could it pull the spacecraft to the desirable speed? I know it would be pretty expensive, but we could avoid burning fuel that can be used e.g. during landing.

Thanks for any constructive advises and explanations.

• A multi-stage coil-gun. One serious roadblock is inductive load has a certain inertia - to switch a magnetic field on or off it takes some time - the stronger the field, the longer, and while in reality it's time of order of tens of milliseconds, a craft moving at mild orbital 8km per second covers 80 meters in 10 milliseconds.
– SF.
Sep 6 '16 at 13:09
• This is in the more general category of mass drivers. More practical on the Moon, where orbital speed is only 1.6 km/s. Sep 6 '16 at 13:58
• It would be nice if you could rephrase your question in order to increase clarity. For me, when I hear about "electromagnetic accelerators in space" i think "Supernova Remnants". They're quite efficient EM accelerators in space and provide us with nice, cosmic radiation. Jun 18 '18 at 23:07

According to Newton, for every action there is an equal and opposite reaction. As the magnets were applied to the craft, it would apply as much force on the accelerator. The accelerator would have to be very massive and/or have rocket engines to generally maintain position and maximize the force imparted on the spacecraft. Of course assembling such an accelerator would require many launches plus maintenance flights etc. The economic advantage in creating such a platform could be quite challenging.

• Let's consider that this platform is very very big, or is placed on some comet or some natural satellite. Sep 7 '16 at 11:52
• This question (space.stackexchange.com/questions/3483/…) discusses mass drivers and should be helpful. Sep 7 '16 at 14:32