Noun
Bussard ramjet (plural Bussard ramjets)
(astronautics) A fusion rocket that gathers fuel from the interstellar medium through attraction via a magnetic field, functioning akin to a regular ramjet.
Because of this fear, humans have placed a Bussard ramjet field generator in close orbit around Down's sun, thus enabling them to destroy the Grog population should they ever take hostile action against any sentient species. Source: Internet
The earlier, Belter period features solar-system colonization and slower-than-light travel with fusion -powered and Bussard ramjet ships. Source: Internet