Orion Drive

When you get into space, you're going to need some kind of drive to make moving around easier. If you can't get Artificial Gravity to work your Reactionless Drive, perhaps you need to look at something simpler. Preferably with lots of explosions. You might consider implementing an Orion Drive, an old project that was thought up during the Cold War. Explosive Propulsion meets nuclear weapons, you've got the potential to move much larger ships than normal.

A basic Orion Drive is composed of a Cool Ship, a large armor plate, and enough high yield weapons to set it in motion. They don't necessarily have to be nuclear, but they need to have the equivalent explosive power. A common variant is to have the explosive material be smaller pellets of frozen deuterium-tritium mix, which would then be induced into nuclear fusion by a laser; this is essentially an H-bomb without having to use an A-bomb to set it off.

A common form of harder scifi propulsion systems.

Film

 * Deep Impact: the Messiah has an Orion Pulse Drive.
 * 2001: A Space Odyssey: Early versions had a ship 'Discovery 1' using this drive.

Literature

 * Footfall by Larry Niven and Jerry Pournelle: humanity uses one in a last ditch effort to fight off the invading aliens as it's the only way to get sufficient firepower into the orbitals.
 * Troy Rising by John Ringo: Troy, a massive battle station several kilometers wide made from a hollowed-out and inflated asteroid, adds an Orion Drive so that it can get to the Portal Network and go crush enemy alien fleets. Upon first seeing the Troy come through the gate, the aliens think it's been hit, only to suddenly realize it's actually the drive.
 * Orion Shall Rise, by Poul Anderson: has this as its central premise.
 * The Land Of Crimson Clouds by the Strugatsky Brothers: the scientists build a semi-spherical spaceship whose inner surface is covered with a super-mirror that reflects everything and is somehow able to use the momentum of light, of all things, for propulsion. So basically, when a nuclear explosion takes place under the super-mirror, the spaceship flies forward. Let's leave the physics of it at that.
 * King Davids Spaceship by Jerry Pournelle: inhabitants of a planet that is to be re-admitted to the Empire plot to build the spaceship based on an Orion project concept in order to qualify their planet as a higher-developed, Class One Imperial world. However, this craft uses non-nuclear explosives.
 * The Stone Dogs by S.M. Stirling: Orion spacecraft are created during an arms race between the Domination of the Draka and the Alliance for Democracy, and used by both sides in their explorations of the solar system and as warships. The drive itself features as an improvised weapon in the book, being used to keep other ships at a distance.
 * The Shiva Option: A Starfire novel by David Weber and Steve White: an arachnid homeworld is destroyed by converting several asteroids into Orion-drive starships and launching them at it.
 * Anathem by Neal Stephenson: features a spacecraft that travels between different dimensions and uses an Orion-style propulsion system. This ship, the Daban Urnud, is discovered by observing the nuclear explosions used to modify its orbit.
 * Olympos by Dan Simmons: describes an Orion-style spaceship, designed by the Moravec machine race to emulate 21st century human technology.
 * Tricentennial by Joe Haldeman: featured the Daedelus (or John F. Kennedy, or Leonid Brezhnev - apparently spaceships are also prone to renaming), which was powered by nuclear bombs.
 * Marooned in Realtime by Vernor Vinge: bobble technology makes this method of travel safe.
 * Cepheide the 1981 anthology by Tais Teng describes a ship with Orion propulsion as one of the most primitive and wasteful methods of interstellar flight, still only achieved by a tiny minority of all intelligent races in the universe. The ship is said to be the last relic of an unknown race exterminated by the dominant YiYiki (descendants of the humpback whales).
 * The Golden Globe by John Varley: the wreck of an Orion spaceship is converted to an interstellar starship.
 * Steel Beach by John Varley: sets several scenes near or within the bulk of the "Robert A. Heinlein," an Orion-style ship which was built and then abandoned when humanity lapsed into apathy for stellar exploration.
 * The Hive by Chris Berman: involves the use of a ground launched Orion spacecraft by the People's Republic of China in a gamble to reach an alien artifact in orbit between Jupiter and Saturn before the crew of a spacecraft built by the United States and Russia can reach it first.
 * Ark by Stephen Baxter: a starship Ark One is built to save a small group of people as Earth drowns under a global flood. It launches and performs the first phase of its mission using a version of Orion. This version is ground launched though owing to the situation (the entire planet is about to drown anyway) environmental concerns are set aside.
 * Manifold Space, also by Stephen Baxter, has the main character piloting an Orion craft to a large blue ring situated just outside the Solar system.
 * Project Orion: The Atomic Spaceship 1957-1965 by George Dyson is a non-fiction book about the real research into Orion drives (see the Real Life section below). Dyson is the son of Freeman Dyson, who was involved in the project.

Live Action Television

 * Star Trek: The Original Series episode "For the World is Hollow and I Have Touched the Sky": features a generation ship, constructed out of a hollowed-out iron asteroid, propelled using "Orion class nuclear pulse engines" in which fission bombs were detonated in shafts. It appeared to have been traveling for about 10,000 years, and had traveled about 30 light years on its own power.
 * Virtuality: Phaeton (Earth's first starship) is propelled by an Orion drive.
 * In an episode of Space: 1999 titled "Voyager's Return," there was a nuclear pulse-drive probe called Voyager One.
 * Mentioned in Carl Sagan's Cosmos, as one possible design for a ship capable of crossing interstellar distances, along with the Daedalus (see below).

Video Games

 * Alpha Centauri, the sleeper ship is propelled by an Orion-type drive (probably the laser-fusion variant), the shield of which fails (almost certainly due to sabotage--the ship's captain was also assassinated at the same time) when the ship is almost at its destination, causing the passengers on the colony ship to splinter into factions.

Web Original

 * Cracked.com mentions it in their article about intellectually disabled travel ideas that might actually work.

Western Animation

 * Ben 10: Ultimate Alien. The military calls them into investigate the theft of components to an Orion Drive. Kevin immediately deduces that it's a nuclear bomb.

Real Life

 * Project Orion, of course, which actually happened, although they never went full-scale for obvious reasons. The project eventually got canceled by an international treaty banning nuclear explosions in space.
 * Project Daedalus, which was a conceptual design thought up by the British Interplanetary Society, which wasn't worked upon since it's not yet possible. Instead of bombs, it would use a less hamfisted approach, with lasers being focused on small deuterium-tritium pellets to create small fusion detonations - a process which is indeed being studied as a means of peacefully harnessing fusion energy - but the basic idea of using pulsed explosions remains the same.
 * Project Longshot, which was basically Project Daedalus if it were (A) allowed to decelerate on the way in to Alpha Centauri, and (B) more realistic about the difficulties of using engine power to run its own electrical systems.
 * According to urban legend, a manhole cover was accidently launched into outer space when an explosive device was tested nearby.