Three Pratt & Whitney Rocketdyne Space Shuttle Main Engines (SSME) successfully powered the launch of Space Shuttle Discovery on Mission STS-128 to deliver extra supplies and equipment to support a six-person crew onboard the International Space Station. The SSME is the world’s only fully reusable high performance rocket engine rated for human space flight. Discovery [...] (UTX) Pratt & Whitney Engines on the Space Shuttle Discovery