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How can a rocket engine achieve more than a 100-percent thrust? Well, RS-25 engines were first designed more than 40 years ago, for use with NASA's space shuttle, and the power level they were capable of achieving at the time is the margin known as 100-percent thrust, according to NASA. RS-25 engines are former space shuttle engines that have been modified to perform more powerfully than ever before. "Increased engine performance is crucial for enabling SLS missions to deep space as the rocket evolves to be larger and carry astronauts and heavy cargo on a single flight," NASA officials said...

The newly developed engine controller is a modern version from the RS-25 controller that helped propel all 135 space shuttle missions to space. ... “The controller manages the engine by regulating the thrust and fuel mixture ratio and monitors the engine’s health and status – much like the computer in your car,” say NASA officials. “The controller then communicates the performance specifications programmed into the controller and monitors engine conditions to ensure they are being met, controlling such factors as propellant mixture ratio and thrust level.” A quartet of RS-25 engines, leftover from the space shuttle era and repeatedly reused,...

The contract spans from November 2015 through Sept. 30, 2024. The SLS is the most powerful rocket the world has ever seen and will loft astronauts in the Orion capsule on missions back to the Moon by around 2021, to an asteroid around 2025 and then beyond on a 'Journey to Mars' in the 2030s - NASA's overriding and agency wide goal. The first unmanned SLS test flight is slated for late 2018. The core stage (first stage) of the SLS will initially be powered by four existing RS-25 engines, recycled and upgraded from the shuttle era, and a pair...

(Aug. 13) successful test firing of an RS-25 main stage engine for NASA’s Space Launch System (SLS) monster rocket currently under development, the program passed a key milestone advancing the agency on the path to propel astronauts back to deep space at the turn of the decade. The 535 second long test firing of the RS-25 development engine was conducted on the A-1 test stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi – and ran for the planned full duration of nearly 9 minutes, matching the time they will fire during an actual SLS launch. All indications...