Orion was a late '50's-early '60's USAF-NASA project to develop a manned spacecraft propelled by the shock waves made by nuclear bombs. Strange as it may sound, the concept was feasible; flight tests were made with a simple high- explosives-propelled device (known as "Putt-Putt" - it's now on display in the National Air and Space Museum). Tests were also carried out using live nuclear weapons tests in the Pacific; these showed that the concept was workable with current technology.
Unfortunately, the project was killed after the signing of the Nuclear Test Ban Treaty, which banned the detonation of nuclear bombs in the atmosphere... but didn't lay out where exactly the atmosphere ended and space began.
The Orion test vehicle shown had a pusher plate diameter of ten meters; it was designed that way so that it could be lofted into orbit (sans bombs) by the Saturn V moon rocket. Orion held high promise, with the chance of early manned exploration and colonization of the solar system; it was killed by bureaucrats.
The Part Time Models kit of the Orion will be of the Basic Orion at 1/144 scale; it will stand (very approxiamately) 1.5 feet tall. It should be out in early '95.