Space – the final frontier?
A mass driver is a device for throwing stuff. If you like, it is a BFG-9000. It uses pure energy or a chemical reaction to throw a lump of whatever. In my opinion it is the best solution to thrust in space at the moment, and with re/supply of ships and colonies.
If you use a nickel-iron piston, you can throw the mass forward using a linear motor, then stop it, so sending the mass of rock/stores on it’s way, and recovering any excess energy from the magnetic field and moving piston to put back in the battery bank. This would use railgun/linear motor technology, and is a few years from perfection.
As for the \”waste\” of Hydrogen and oxygen in a gas powered mass driver, the reaction product is pure water. You get propulsion and drinking water too. This is not wasteful, so long as the driver is a sealed unit. Think of it like a car engine piston. In fact, you could probably modify an engine quite easily. If you wanted to get really clever, you could build in some electrodes so the water was reused forever, being split by electrolysis in situ in the mass driver. The \”charge\” time and current would give you the total power of the \”shot\”, with whatever water, hydrogen and oxygen masses simply all turning back to water after each shot.
Using the mass driver as a weapon might not be terribly effective. Yes, you could throw bits of rock at them. No, the bits of rock probably wouldn’t be fast enough to be non-trivially avoided, nor have enough K.E. to do any real damage. Remember the whole craft in space has no vulnerable intakes like a jet engine, and is designed to survive impacts by flecks of paint at 7km/sec. Of course, it would slow them down and force them to use extra fuel, whilst you moved away from them, due to the reaction forces. Then again, loaded with bits of large gravel, you would have one hell of a shotgun! Ideal for stopping the descending “paratroops” or smaller ships, or incoming warheads. It wouldn’t stop the Death Star though. Remember also that the targeting system would need to be state of the art even assuming the target did not try to change course. The warheads would need a guidance system and some reaction system as aerofoils don’t work. Incidentally, nor do Nukes. With everyone and everything radiation hardened to a fairly high level and airtight with it, and a hard vacuum around the warhead, the incredible heating effects would do very little, except radiate away. No thermal shockwave would occur, as it has little too heat, and nothing to propagate through. The flash heating might cause some ablation, but only to the top layers, which can’t burn without air anyway. The radiation would be absorbed, and the radioative contaminents could be handled fairly easily, as it will just be radioactive dust on the outside of an airtight vessel. However, problems from millions of tiny, high speed particles may destroy satelites due to impact, ripping away solar panels and antennas, as well as the massive EMP (ElectroMagnetic Pulse), which would affect all non-hardened computer systems, as well as any close-by hardened systems. As long as everything has an in-built manual override, few problems would occur, as EMP doesn’t have an effect on biological systems.