NASA astronauts listen as elements of an RL10 engine are detailed by an engineer.
NASA astronauts Suni Williams, from left, Eric Boe and Barry “Butch” Wilmore listen as an Aerojet Rocketdyne engineer details the injector plate of an RL10 engine during a tour of Aerojet Rocketdyne’s facility in West Palm Beach, Florida. The engine will be one of two used for the Centaur upper stage during a United Launch Alliance Atlas V mission to launch Boeing’s CST-100 Starliner on a flight test carrying a crew. The engine was test-fired as part of acceptance testing to confirm the engine is ready for flight. Photo credit: NASA/Dimitri Gerondidakis