Apollo’s Workhorse: The Service Propulsion System

The Apollo Command and Service Module (CSM) relied on its powerful Service Propulsion System (SPS) engine for critical burns, including lunar orbit insertion and the return trajectory to Earth. This image illustrates the CSM in space as the SPS fires, sending out a burst of exhaust against the black void. With its single, restartable engine, the SPS was one of the most reliable workhorses of the Apollo program—its flawless performance was essential in ensuring astronauts made it safely to and from the Moon.