The TR-107 was a developmental rocket engine designed in 2002 by Northrop Grumman for NASA and DoD funded Space Launch Initiative. Operating on LOX/RP-1 the engine was throttleable and had a thrust of at a chamber pressure of , making it one of the most powerful engines ever constructed. History The TR-107 was built by TRW following the successful conclusion of the development program for the TR-106 engine, a similar throttleable engine of about half the thrust burning LOX/LH2 instead of LOX / RP-1. Tom Mueller, then VP of Propulsion Development at Northrop, was project manager for both the TR-106 and TR-107 engines. In 2002, Mueller co-founded SpaceX with Elon Musk and became the VP of propulsion after cancellation of SLI program. Status Northrop Grumman development of the TR-107 engine permitted consideration for potential use on next-generation launch and space transportation system. See also Merlin 1D Raptor SLI Prototype engines References External links Booster Engine Prototype Project: TR107 Engine Component Technologies TR-107 Rendering with explanations Rocket engines using kerosene propellant Rocket engines using the staged combustion cycle