“Engineers have identified a helium check valve that is not functioning as expected, requiring these changes to ensure safety of the flight hardware,” the agency said. Engineers at the Kennedy Space Center will evaluate the valve and replace it if needed, the agency added.
The critical prelaunch test is known as a “wet dress rehearsal” and simulates every stage of launch without the rocket actually leaving the launchpad. The Space Launch System (SLS) rocket and Orion spacecraft will be powered on, supercold propellant will be loaded into the rocket’s tanks (the “wet” in wet dress rehearsal), and NASA’s team will go through a full countdown simulating the launch.
NASA has said that it plans to launch the mission in June or July, depending on the results of the wet dress rehearsal. The first step will be an uncrewed mission — Artemis I. Then, Artemis II will take astronauts on a crewed flyby of the moon, and Artemis III will bring NASA astronauts to land on the lunar surface for the first time in fifty years.
The agency hopes to land the first woman and the first person of color on the lunar surface by 2025.