NASA - Space Launch System Providing Engine 'Brains' With an Upgrade: "America's next heavy-lift rocket needs a strong and reliable engine to launch humans beyond low Earth orbit. That's why engineers with NASA's Space Launch System program, managed at the Marshall Space Flight Center in Huntsville, Ala., will use the proven RS-25, the space shuttle's main engine during its 30-year history, to power the massive rocket's core stage. The RS-25, which was designed and developed with NASA by Pratt & Whitney Rocketdyne of Canoga Park, Calif., is a crucial part to the core stage design, but a few enhancements are planned.
While the RS-25 engines launched 135 missions, it needs a new "brain" to drive the 3.5-ton engine.
"The computer controlling the SSME was manufactured in the early '80s and many parts are now obsolete," said Jeremy Richard, SLS Liquid Engines Office Subsystem manager. "While working on updating the technology, we discovered we could adapt the same controller being used by the new J-2X engine to the RS-25 engine, effectively streamlining the controller and resulting in a cost savings." "
