NASA has returned its Space Launch System (SLS) rocket to the Vehicle Assembly Building (VAB) at the Kennedy Space Center, delaying the launch of the Artemis II mission to no earlier than April 2026. The rollback, initiated on Wednesday, is a result of a detected issue during routine checks of the rocket’s helium system.
The decision to return the SLS to the VAB was made to allow technical teams to address the problem, which NASA Administrator Jared Isaacman described as requiring access and resolution only possible within the assembly building. “Whatever the potential failure is, access and resolution of those issues can only be done inside the VAB,” Isaacman stated on Saturday, according to reports.
The 98-meter-tall SLS had been installed on Launch Complex 39B in January. The rollback involves a slow, deliberate movement of the rocket on its transporter platform back to the VAB, a process that could take considerable time.
Artemis II is planned as the first crewed mission of the Orion spacecraft and the second flight of the SLS. The mission will carry a crew of four – NASA astronauts Reid Wiseman, Victor Glover, and Christina Koch, along with Canadian Space Agency astronaut Jeremy Hansen – on a trajectory around the Moon and back to Earth. The ten-day mission is intended to test critical systems for future lunar surface missions and longer-duration space travel.
The delay impacts the original launch schedule. NASA is currently targeting April 2026 for the launch, but this date remains subject to change depending on the duration of the repairs and subsequent retesting before a return to the launchpad. Victor Glover is slated to turn into the first person of color, Christina Koch the first woman, and Jeremy Hansen the first person not from the United States to travel around the Moon.
The Artemis II mission builds upon the success of the uncrewed Artemis I flight in 2022, which demonstrated the capabilities of the SLS and Orion spacecraft. Artemis II will further validate these systems and pave the way for future missions aimed at establishing a sustained human presence on the Moon and eventually, Mars.