Category: Space Launch System

Engineers have completed tanking for the hot fire test of NASA’s Space Launch System (SLS) rocket core stage at the agency’s Stennis Space Center, and the countdown is proceeding normally.

The liquid hydrogen tank holds 537,000 gallons of liquid hydrogen, cooled to minus 423 degrees Fahrenheit. The liquid oxygen tank holds 196,000 gallons of liquid oxygen, cooled to minus 297 degrees Fahrenheit. After tanking is complete, the team will continue chilling down the liquid oxygen propellant to condition it before the hot fire. While they are conditioning the liquid oxygen, they replenish the liquid hydrogen as it boils off due to temperature fluctuations as the propellant is loaded. The tanks can be loaded up to 22 times for testing and launches.

This part of the test timeline is also important as it pertains to simulating launch. During a launch, many activities will be happening on the pad at this time, such as loading the crew. The hot fire test provides an opportunity to demonstrate that the core stage can remain in a stable configuration and be replenished as needed before engine firing to launch the rocket.

Learn more about Green Run, and check back at this blog for updates on the SLS core stage hot fire test.

NASA is targeting Thursday, March 18 for the second hot fire of the Space Launch System (SLS) rocket’s core stage at NASA’s Stennis Space Center near Bay St. Louis, Mississippi.

After performing tests to demonstrate that a recently repaired liquid oxygen pre-valve was working, the team has continued to prepare the core stage, its four RS-25 engines, and the B-2 test stand for the second hot fire at Stennis. Later this week, the team will power up the core stage again and do a final check of all its systems. Then, on March 16, two days before the test, they will power up the stage, starting the clock for the second hot fire.

This hot fire is the last test before the Artemis I core stage is shipped to the agency’s Kennedy Space Center for assembly and integration with the rest of the rocket’s major elements and the Orion spacecraft. Exploration Ground Systems teams at Kennedy have stacked all parts of the solid rocket boosters for Artemis I in the Vehicle Assembly Building and are finishing up booster assembly. After the core stage arrives, it will be lifted and placed between the two boosters and attached at the core stage engine and intertank sections. Other parts of the rocket and the Orion spacecraft are also at Kennedy and are being prepared for final assembly and integration.

NASA’s SLS rocket is the most powerful rocket in the world, built to send both astronauts aboard Orion and supplies on missions to the Moon and beyond. The Green Run is a comprehensive test of the SLS core stage, a complex new rocket stage that not only includes four RS-25 engines and enormous propellant tanks that hold more than 700,000 gallons of super cold propellant, but also flight computers and avionics that control the first eight minutes of flight. The Green Run test series will help validate that the SLS core stage is ready for its first flight on Artemis I and subsequent missions.

Check back at this blog for an update on core stage power up for the second Green Run hot fire. For more information about SLS Green Run, visit https://www.nasa.gov/artemisprogram/greenrun

NASA and Space Launch System (SLS) core stage prime contractor Boeing are thoroughly examining a liquid oxygen valve inside the stage’s engine section in order to identify repairs needed before a second hot fire with the Artemis I stage.

During preparations for the second hot fire, data indicated the valve was not opening correctly. Technicians installed platforms that allow engineers to access the valve inside the core stage engine section while the stage remains in the B-2 stand at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. After completion of troubleshooting, which will continue over the weekend, NASA will be in a better position to identify a potential date for the second hot fire test.

This valve, called a pre-valve, must be fully operational during hot fire testing. The valve is part of the core stage main propulsion system, and it helps deliver liquid oxygen propellant flowing from the liquid oxygen tank to an RS-25 engine. For the first hot fire on Jan. 16, all four liquid oxygen pre-valves performed as expected as did all four liquid hydrogen pre-valves.

The Green Run is a comprehensive series of tests for the SLS core stage before it launches the Artemis missions to the Moon, and the hot fire is the final and most intensive test. The Green Run tests have provided invaluable information on how the new rocket stage operates before it is used to launch the Artemis I mission.

Check back at this blog for an update on actions needed to resolve the issue, as well as the schedule for the hot fire test. For more information about SLS Green Run, visit https://www.nasa.gov/artemisprogram/greenrun