Nuclear fusion is the dominant form of power generation and propulsion in the 22nd century, producing vast amounts of non-polluting energy from astronomically-abundant fuel sources. A series of innovations in the late 21st century, including the discovery of room-temperature superconductivity, paved the way for the creation of the first viable fusion reactor, which in turn led to the flight of the first fusion torch engine spacecraft, the Prometheus, in 2093.

The invention of the fusion torch engine in the late 20th century was perhaps the most important in human history: in 2093, the first fusion torch spacecraft, the Prometheus, flew to Mars in twenty-five days. In the thirty years since, the fusion torch engine has engendered the formation of the World Union for Space Policy, put the resources of the entire Inner Solar System within a month’s travel from Earth, and prompted unprecedent prosperity and peace.