With SLS rocket future uncertain, L3Harris still cranking out engines

Yahoo

25-06-2025

While NASA's Artemis program may ultimately abandon the Space Launch System rocket, for now, Melbourne-based L3Harris is pushing forward with the manufacture of the powerful rocket's core stage engines.
The SLS core stage gets 2 million pounds of thrust from four RS-25 engines that for the first four Artemis missions are engines from the Space Shuttle Program refurbished by Aerojet Rocketdyne, which L3Harris acquired in 2023.
The first engine produced for the fifth mission, which was built from scratch after the depletion of the space shuttle supply, is now in NASA's hands. On Friday, the engine, dubbed No. 20001, underwent an 8 1/2-minute hot fire on a test stand at NASA's Stennis Space Center in Mississippi.
That duration equals the time the engine would burn on launch if and when Artemis V gets off the ground. The engine was also cranked up to 111% power.
'This successful acceptance test shows that we've been able to replicate the RS-25's performance and reliability, while incorporating modern manufacturing techniques and upgraded components such as the main combustion chamber, nozzle and pogo accumulator assembly,' said Kristin Houston, president of the company's space propulsion and power systems division.
So far NASA has flown the SLS once on the Artemis I mission in 2022. The four RS-25 engines powered the core stage that paired with two solid rocket boosters from Northrop Grumman, combined to create 8.8 million pounds of thrust on liftoff. It remains the most powerful rocket ever to make it to orbit. SpaceX's Starship and Super Heavy nearly doubles that thrust, but has only performed suborbital test launches so far.
Artemis II, the first crewed flight of the Orion spacecraft, is set to launch atop SLS on its second flight no later than April 2026 on a mission to fly around, but not land on, the moon. A lunar landing mission is supposed to come with Artemis III, slated to fly by summer 2027, but it still needs a working version of Starship to act as the human landing system.
Artemis IV and V are on the roadmap for 2028 and 2029, but the use of SLS was targeted for elimination in President Trump's proposed NASA budget for fiscal year 2026. The budget seeks to switch to a commercial provider to achieve the Artemis program goals of a sustained lunar presence and push on to send the first humans to Mars.
Sen. Ted Cruz, though, countered the budget proposal with a call to restore funding at least through Artemis V, including saving the Gateway lunar space station that was also targeted for demise by the Trump budget proposal.
So while the future of Artemis may shift, L3Harris will continue to build engines for which it has contracts. Manufacturing of the RS-25s happens in California.
The newly manufactured engines cost 30% less than those produced and refurbished for the shuttle program, according to L3Harris, using updated processes such as 3D printing. A test version of the new engine design went through a 12-step certification series completed last year to pave the way for operational engine production.
NASA has already ordered up to 24 of the new engines on top of the 16 refurbished shuttle-era engines that would support flights through the ninth Artemis. The order totals $3.5 billion, which is about $145 million per engine.
Each engine will get tested at NASA's Stennis before it gets sent to the Michoud Assembly Facility in New Orleans where the core stage is manufactured by Boeing. Starting with Artemis III, the core stage parts will be shipped to Kennedy Space Center for final assembly.
'The second Artemis V engine is slated to hot-fire later this year, with the other two engines set to be hot-fired next year,' said an L3Harris spokesperson.
L3Harris also produces the single RL-10 engines used on both the upper stages of Artemis I-III, but also the proposed more powerful European Upper Stage, which would use four RL-10 engines for Artemis IV and beyond.
Those engines are manufactured at the company's West Palm Beach facilities, which have been building and testing rocket engines for more than 60 years.
'Our propulsion technology is key to ensuring the United States leads in lunar exploration, creates a sustained presence on the moon and does not cede this strategic frontier to other nations,' Houston said.