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.