A Von Neumann Probe is a small, unmanned, robotic, self-replicating spacecraft. It is sent out into the cosmos to explore and map, but is also programmed to make more of itself. It harvests resources on the planets it explores, and uses those resources to create additional probes. Meanwhile, it broadcasts back to the homeworld all the data it collects.
The benefits to this approach are primarily the low cost per mission. Being small, it doesn't take much fuel to get it out into space. Being unmanned, most of its systems can be dormant while traveling the void between stars. It's capable of replicating itself from resources found on other worlds, so only the initial units deployed cost money or resources from the homeworld.
There are a few potential problems, however. If a unit malfunctioned, it might replicate itself an arbitrarily large number of times. If those "offspring" units have the same defect, it could explode into an unstoppable ever-expanding collection of probes that consume all the resources of the cosmos. Even without such a malfunction, the probe could conceivably provoke an interstellar diplomatic emergency. What would your reaction be if an alien robot landed in your backyard and started mining ore?
- Astrochicken - a genetically engineered cyborg version proposed by Freeman Dyson.
- Berserker Probe - self-replicating warships, hostile attack robots programmed to destroy all life save the species that created it.
- Bracewell Probe - an artificial intelligence probe that searches the cosmos for intelligent life, and initiates peaceful contact. May or may not be self-replicating.
- Embryo Space Colonization - probes sent bearing life. Cheaper and safer than sending people, you just grow them at the remote planet.
Game and Story Use
- Von Neumann Probes carry a big danger in that they could accidentally start interstellar wars, or go rogue and consume civilizations.
- And if they do, the enemy Von Neumann Probes will make great mooks.
- "Hegemonising swarms" - essentially things that are, or act like, a plague of Von Neumann machines seem to be an accepted hazard of intersellar community life in Ian M. Banks' Culture series.
- Consider the problem of a Von Neumann swarm released at sub light speeds as a retributive strike by a dying civilisation - they could appear out of nowhere, centuries later with a distinct air of abusive precursors about them.
- Potentially a powerful and effective terraforming mechanism - you could even design a swarm to clean a world off and then re-form it for settlement. Of course, if anything goes wrong with the programming…