ESM-3

ESM-3 is the third European Service Module built by Airbus Defence and Space in Bremen under ESA contract, intended to power Orion on Artemis III. It arrived at Kennedy Space Center in August 2024 and is inside the Neil A. Armstrong Operations and Checkout Building, where it has joined the crew module adapter and completed initial power-up and functional testing.

The critical question for ESM-3 is whether its pressurisation valves incorporate a corrected design relative to ESM-2, which leaked at 10 times the ground-test prediction throughout the Artemis II mission. A redesigned valve is described by NASA as non-negotiable before Artemis IV lunar-orbit operations, and ESM-3 sits in the production sequence directly before that redesign must be available. Neither ESA nor Airbus has publicly confirmed whether ESM-3 uses the existing or a corrected valve design. ESA deferred technical review to the June 2026 ministerial council.

ESM-3 is a single point of dependency for the Artemis III 2027 target. Its physical presence at KSC is a sign of programme momentum, but the valve disclosure gap means the hardware sitting in the Armstrong building carries an unresolved engineering question that only ESA can close.