The Theoretical Propulsion Group was an advanced engineering group working with the Galaxy Class Starship Development Project in drafting room 5, part of Mars Station at the Utopia Planitia Fleet Yards, in the 24th century. The TPG had extensive design input on the engines of the Galaxy-class starship, in particular the matter-antimatter reaction assembly.

Leah Brahms, who worked on the project during the design of the Galaxy-class as a junior member, was the team leader of the project in 2367. (TNG: "Booby Trap", "Galaxy's Child")