The first Space Launch System (SLS) core stage is on the test stand at Stennis Space Center in Mississippi and is going through tests before its first flight. The SLS is America’s 212-foot-tall, deep-space rocket that will take astronauts to the moon and beyond.
With testing underway, the SLS is approaching its final milestone, the “green run.” The term “green” refers to the new hardware that will work together to power the core stage, and “run” refers to operating all the components together simultaneously for the first time. This includes fueling the rocket as well as pressurizing the core stage, and the test series culminates with firing up all four RS-25 engines.
These tests give NASA the confidence that the engines, tanks, fuel lines, valves, pressurization system, and software can all perform together just as they will on launch day.