Space Launch System Performs a Dramatic Hot Fire Test, Blasting With all 4 Engines at Once - Universe Today

As part of a Green Run Hot Fire Test, all four RS-25 engines on the SLS Core Stage were fired at once as part of the first top-to-bottom integrated test of the stage’s systems.

“All four RS-25 engines ignited successfully, but the test was stopped early after about a minute.

Not only was it the first time that the four RS-25 engines fired together, but the process also validated many key systems and allowed the mission controllers to gather data from the Core stage as its many integrated components worked together.

“In coming days, engineers will continue to analyze data and will inspect the core stage and its four RS-25 engines to determine the next steps.”.

As noted, this was the final step in the Green Run, which is designed to test the new (aka. “Green”) hardware and get the Core Stage ready to enter service.

Steps six and seven involve establishing a timeline for launch and simulating a countdown, followed by a loading test where roughly 2.65 million liters (700,000 gallons) of propellant are loaded and drained from the Core Stage.

The eighth and final test is the Hot Fire Test (aka. “wet dress rehearsal”) where the Core Stage is fully-loaded with propellant and conducts a static fire in place – in this case, on the B-2 Test Stand at Stennis.

The maximum amount of thrust that the four RS-25 engines can generate during launch and ascent is over 900,000 kg (2 million lbs) or around 8,900 kilonewtons (kN) of thrust.

For hot fire tests aboard the B-2 Test Stand, however, the RS-25 engines will peak at 725,750 kg (1.6 million lbs) or 7,117 kN of thrust, which is the maximum amount of thrust they will generate at sea level (on the launch pad).