NASA has delayed the launch of its Artemis II mission, pushing the first crewed flight of the Space Launch System (SLS) and Orion spacecraft to March 2026 at the earliest. The delay stems from issues encountered during a critical pre-launch test, a “wet dress rehearsal,” at the Kennedy Space Center in Florida. Engineers detected hydrogen leaks near the base of the SLS rocket, forcing a halt to the simulated launch countdown with just minutes remaining.
The wet dress rehearsal, conducted on , is a standard procedure designed to validate the performance and readiness of the rocket and its systems before astronauts are onboard. During the test, the rocket was loaded with over 700,000 gallons of cryogenic propellant. Automated systems ultimately stopped the countdown after sensors recorded increasing leak rates, according to NASA.
This delay means NASA will forgo the February launch window, which had been scheduled to close on . Potential launch opportunities are now being targeted between and , with an additional window on , and further options available in April if needed.
The Artemis II mission is a significant milestone for NASA, representing the first crewed flight of the Artemis program. It will send four astronauts on a 10-day journey around the Moon and back to Earth. The mission aims to test the SLS rocket and Orion capsule with humans onboard, paving the way for future lunar landings, including the Artemis III mission planned for 2027.
The issues encountered during the wet dress rehearsal were described by John Honeycutt, the Artemis II mission management team chair, as providing a valuable opportunity for the rocket to “talk to us.” He emphasized the importance of these practice runs in assessing the rocket’s performance before risking the safety of the crew.
Interestingly, the delay in the Artemis II launch could potentially clear the way for another NASA mission: sending a new group of astronauts to the International Space Station (ISS) via a SpaceX rocket. The timing of the Artemis II launch directly impacts the scheduling of other NASA missions.
As a result of the delay, the four astronauts who had entered quarantine on to ensure optimal health conditions have been released. They will re-enter quarantine two weeks before a new launch date is finalized.
The Space Launch System (SLS) booster and Orion spacecraft haven’t flown since late 2022, and this is the first time they will launch with astronauts onboard. NASA’s first uncrewed test flight of the Artemis program occurred in November 2022, serving as a crucial test of the Orion spacecraft, which includes a European-built module, and the SLS rocket. That launch was also preceded by various challenges.
The United States aims to use the Artemis program to prepare astronauts for long-term missions on the Moon and, journeys to Mars, with a target of reaching the red planet by 2030. The program is designed to “test systems and equipment” for the Artemis III mission, which will attempt to land astronauts on the lunar surface.
The issues with hydrogen leaks during the wet dress rehearsal are not entirely new to NASA. Similar problems were observed during the Artemis 1 mission in 2022, suggesting a recurring challenge in managing cryogenic propellant systems.
