Reaction drives were a form of spacecraft propulsion used by the Forerunners. Little is known about them other than the fact that they use vacuum energy to expel virtual neutrons from the ship. During their momentary existence, the virtual particles give the ship propulsion, then disappear. They do require a form of on-board fuel and reaction mass to operate, however.
List of appearances
- Halo: Cryptum (First appearance)
- Halo: Cryptum, Chapter 12, page 129
- Halo: Cryptum, Chapter 12, page 124