well couldn't u put the rocket in like a tube with a lever on it, preventing the rocket from leaving the chamber, and use electro magnetism to build up a magnetic force great enough, then the lever is hit to release the rocket, and the magnetic force "pushes" it out of the launch tube?
just a thought
I did a similar project attracting a nail from 2 feet away using magnetism and some electrical current, u'd do the opposit, more like repulsion, it should be possible, isint that hor electric nail guns work?