A new means of space propulsion... closed loop pulse propulsion... here's the idea

[relayerbob]

57. This is correct

The kinetic energy of the projectile leaving the "gun" will effectively equal the kinetic energy of the impact, leaving zero net energy. In reality, there would be some energy loss as the projectile is turned, so in reality, it would still push you backward, resulting in slightly less energy when hitting, as opposed to firing, so in really the kick back would still send you backwards, albeit very slowly. One could argue that you can just fly backward, but the amount of fuel required to move you at a significant velocity would be FAR more than just any standard propulsion system.

As a physicist with actual objects in space that I've worked on, I pretty much know what I'm talking about. The OP is far off base.