NASA Marks Milestone in Preparation for Artemis IV Testing
The water is flowing. The data is flowing.
A water system activation at the Thad Cochran Test Stand (B-2) on January 30 at NASA’s Stennis Space Center near Bay St. Louis, Mississippi, captured critical data for testing a new Space Launch System (SLS) stage expected to fly on the Artemis IV mission.
The activation stage allowed testing of new cooling systems that were added for the future Green Run test series of NASA’s Exploration Upper Stage (EUS). The most powerful upper stage is a four-engine liquid hydrogen/liquid oxygen space stage for the advanced Block 1B version of the SLS.
For Green Run, NASA Stennis teams will activate and test all systems to ensure the stage is ready to fly. It will culminate with burning fire from the four RL10 engines on stage, just like a real mission.
As part of the test rig modification, crews added water-cooled diffusers to act as a heat shield to handle the very hot exhaust gases from the four RL10 engines; water-cooled shrouds to direct engine exhaust to align with the diffuser walls; and a purge ring that provides cooling water and nitrogen gas to protect a flexible joint that allows the motors to move, or gimbal, during testing.
These three systems were all integrated by NASA’s Stennis team with the existing flame deflector and acoustic suppression equipment used in previous core stage tests of NASA’s SLS rocket prior to the successful launch of Artemis I.
The exercise also pushed the high-pressure industrial water system to its maximum capacity. While a typical test of the RS-25 engine at NASA Stennis operates a subset of 10 diesel pumps and one electric pump, the Exploration Upper Stage test will require all eleven pumps to operate simultaneously.
The 14 million gallons of water used during the Jan. 30 exercise were recycled throughout the test complex. A 66 million gallon tank supplies water to the test stand via a 96-inch diameter underground pipe, with the water distributed to the various cooling components. The water ultimately flows into the flame deflector and then through a concrete channel to the stand retention basin. When the catchment basin fills, excess water flows into the canal through a drainage ditch, ready to be recycled for future use.
“We will use the data collected to define the final timing of the valve cycle, determine our red pressures and select the operating pressure,” said Nick Nugent, NASA Stennis project engineer. “This exercise also subjected the water system to full load before the final stress test. It is always good to give the system a good test before.”
The Exploration Upper Stage is being built by Boeing at NASA’s Michoud Assembly Facility in New Orleans. The four upper stage RL10 engines are manufactured by L3Harris Technologies. Before everything arrives at NASA Stennis, crews will perform a final 24-hour check, or stress test, on all facilities within the test complex to demonstrate that they are ready for the test series.
