The NASA Space Launch System (SLS) core stage that will be used for the agency’s Artemis 1 mission has been fitted with its four RS-25 engines.
In a November 8 press release, NASA confirmed that the fourth and final RS-25 engine had been mated to the first SLS core stage at the agency’s Michoud Assembly Facility in New Orleans. Now that the engines are structurally mated with the core stage, engineers and technicians can begin to integrate the electrical and propulsion systems within the structure.
The RS-25 Aerojet Rocketdyne engine was originally used to power the space shuttle orbiter. Each engine produces 1,860 kilonewtons of thrust. The initial flights of the SLS rocket will make use of refurbished Block II RS-25D engines that had previously launched orbiters during the space shuttle program. As the SLS core stage is expendable, it is unclear what the agency plans to use once the current stock of RS-25D engines is exhausted.
Once the Artemis 1 core stage is completed, it will be shipped to the Stennis Space Center in Mississippi to undergo a static-fire test referred to by NASA as the “Green Run.” This test will be the team’s toughest challenge yet and is designed to ensure that any problem in the system is caught before launch day.
NASA hopes to launch Artemis 1 by 2020. However, critics of the work being done by prime contractors Boeing have cast doubt on the likelihood of the agency being able to hit this ambitious target. In October, NASA’s acting associate administrator for human exploration and operations, Ken Bowersox seemed to confirm the date was unlikely.
“We have a chance to actually have a rocket on the pad and launch by the end of next year,” said Bowersox. “But when you start throwing all those different uncertainties, it’s more likely that we will move out into 2021.”
The admission was the first time a NASA official had deviated from the agency’s insistence that it would launch Artemis 1 by 2020.