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RS-25 Engines are Ready for Artemis IV

Aerojet Rocketdyne
Jul 8, 2024 | 2 MINUTE Read

CANOGA PARK, Calif., July 8, 2024 — Aerojet Rocketdyne, an L3Harris Technologies (NYSE:LHX) company, has completed modernizing the four flight-proven RS-25 engines that will help power NASA’s Space Launch System (SLS) rocket on the Artemis IV mission. Artemis IV will be the first flight of the enhanced Block 1B configuration of the super-heavy-lift rocket and the last to use engines remaining in inventory from the space shuttle program.

Aerojet Rocketdyne has upgraded the Artemis IV engines with modern flight computers that will allow them to withstand the higher temperatures due to being located next to the SLS solid rocket motors.  NASA and Aerojet Rocketdyne completed testing of the flight computers and former space shuttle main engines for the first four Artemis missions at the Stennis Space Center in Mississippi.

Artemis IV marks the debut of the upgraded SLS Block 1B rocket featuring the exploration upper stage powered by four Aerojet Rocketdyne RL10 engines. The first three Artemis missions are using the SLS Block 1 configuration that uses the interim cryogenic propulsion stage powered by a single RL10. 

“The SLS Block 1B upgrade is a game changer that will enable the most ambitious missions ever attempted,” said Kristin Houston, President, Space Propulsion and Power Systems, Aerojet Rocketdyne, L3Harris. “The new universal stage adapter above the exploration upper stage provides 24% more volume for a co-manifested payload than an industry-standard five-meter-class payload fairing.”

Crewed versions of the SLS Block 1B with the exploration upper stage will be capable of delivering 38 metric tons of payload to cislunar space in a single mission, versus 27 metric tons for the SLS Block 1. This means more than 10 metric tons of additional cargo can fly with every crewed mission. Cargo-only versions of the enhanced vehicle will be able to deliver 42 metric tons to cislunar space.

Beginning with Artemis V, the SLS deep space exploration rocket will use newly manufactured versions of the RS-25 engines that take advantage of production efficiencies and advances in manufacturing to reduce unit costs by more than 30% from the shuttle versions, while also flying at a higher thrust level.

Artemis IV info graphic

Click the graphic to view a full size pdf

About L3Harris Technologies

L3Harris Technologies is the Trusted Disruptor in the defense industry. With customers’ mission-critical needs always in mind, our employees deliver end-to-end technology solutions connecting the space, air, land, sea and cyber domains in the interest of national security. Visit for more information. 

Forward-Looking Statements 
This press release contains forward-looking statements that reflect management’s current expectations, assumptions and estimates of future performance and economic conditions. Such statements are made in reliance upon the safe harbor provisions of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. The company cautions investors that any forward-looking statements are subject to risks and uncertainties that may cause actual results and future trends to differ materially from those matters expressed in or implied by such forward-looking statements. Statements about rocket capabilities are forward-looking and involve risks and uncertainties. L3Harris disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise.

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Media Contacts

Mary Engola

Aerojet Rocketdyne, Space Propulsion & Power Systems
C: 571-289-1371

Sara Banda

Corporate Media Relations
C: 321-306-8927

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