Orion was 1950`s Project to study the possibility of a spacecraft powered by nuclear pulse propulsion. The design would have worked by ejecting nuclear weapons from the rear of a vehicle, detonating them, and catching the blast with a shock absorber equipped pusher plate. This sequence would be repeated thousands of times, in effect an atomic pogo stick. The project was scrapped in 1965 amid fear about fallout both political and radiological. Footage shown is of scale testing done using conventional explosives.
Check this video out too.