Carlos Rodriguez, from left, manager of systems development, verification and testing for Aerojet Rocketdyne, talks with NASA astronauts Barry "Butch" Wilmore, Eric Boe and Suni Williams as the group surveys an RL10 engine as it stands in a vacuum chamber at Aerojet Rocketdyne's test stand 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.