Self-replicating machines are robots or nanobots that are capable of producing copies of themselves, using scavenged materials and energy to do so. These machines have the potential to be used in space exploration, as a single probe could potentially replicate itself endlessly until its descendants have accomplished various goals, such as commercializing space, terraforming planets, or exploring vast distances in multiple directions.

The concept of self-replicating machines was first researched by John von Neumann in the 1940s. Von Neumann was a pioneer in the field of computer science and contributed to the development of the atomic bomb, hydrogen bomb, and intercontinental ballistic missile. He is also credited with coining the term “Mutual Assured Destruction,” or MAD, which refers to the idea that the use of nuclear weapons by one country would result in retaliation from other countries, leading to mutually assured destruction.

Self-replicating machines are often considered an existential risk due to the potential for rapid growth of robot populations. For example, a single bacteria can become 2 million in 7 hours, and if a similar growth rate were to occur with robots, it could lead to 4 trillion robots in 14 hours. This rapid growth could potentially outpace human control and lead to unintended consequences.