NASA and Aerojet Rocketdyne test SLS core engine

The orange glow of excited hydrogen atoms can be clearly seen at the opening of the nozzle on the RS-25 at the conclusion of the test. Photo credit: Curt Godwin

The orange glow of excited hydrogen atoms can be clearly seen at the opening of the nozzle on the RS-25 at the conclusion of the test. Click to enlarge. Photo credit: Curt Godwin

NASA and Aerojet Rocketdyne recently tested an RS-25 engine at NASA’s Stennis Space Center in coastal Mississippi in an effort to learn more about how the engine may react to the conditions it may encounter on an actual SLS launch.

Engine 0528, a development engine, was active for 420 seconds and was throttled between 80 to 111 percent of original rated power level. Though it may seem unusual to classify levels over 100 percent, it makes more sense to do so than re-write a multitude of pre-existing documentation as refinements come along. With the original design being the 100 percent benchmark, all follow-up enhancements have been measured against that metric.

Initially, SLS is slated to have its four core RS-25 engines operate at up to 109 percent rated thrust, though future mission plans call for it to be boosted to 111 percent. This most recent test ran the engine at that higher level for nearly five seconds. When the engines were used on the Space Shuttle, they would operate at nominal levels of 104.5 percent of rated thrust, though they could peak at 109 percent in an abort scenario.

As with many tests of this type, NASA provided live coverage via their NASA TV outlet. It must be noted, though, that¬†watching the test via broadcast pales in comparison to witnessing the raw power coming from the test stand in-person. Experiencing the test from 1,200 feet (366 meters) away, one can feel every thump and pop from the engine as it is put through its test regime. Read More →