SSLC manufactures ablatively cooled engines, characterized by an external layer (structural) of carbon fiber and Sapphire77 resin, and an internal (ablative) layer of silica phenolic. The simple design of the engines enables a very low cost production. These engines have almost no moving parts and do not need expensive components like the turbo pump or the regenerative cooling system. The preferred propellant combination is LOX/Jet A. Engines providing 5k lbf of thrust and 20k lbf of thrust have been built and tested. In particular, the 5k lbf engines have flown on two successful suborbital flights- the SR-S and SR-XM vehicles.