NASA will roll Artemis 2 moon rocket back to the launch pad on March 20

NASA needs to wait one more day to roll its moon rocket back to the launchpad, but that shouldn't affect when it launches.

The Artemis 2 Space Launch System (SLS) rocket has been inside NASA's Vehicle Assembly Building (VAB) at the Kennedy Space Center (KSC) in Florida since its rollback from its launchpad last month. The agency had been gearing up for a March flight around the moon, but prelaunch tests revealed maintenance requirements engineers could only address back in the hangar.

Now, the agency is planning to roll SLS back to the pad at Launch Complex-39B (LC-39B) on March 20 — a one-day delay from its previous March 19 target. The culprit this time can be traced to an electrical harness for the flight termination system in need of a quick replacement. The work on said harness is already complete, but added just enough work to NASA engineers' pre-rollout checklist to push the rocket's transportation back to LC-39B by 24 hours. It won't, however, delay the April 1 target date for Artemis 2's launch, according to a NASA update.

NASA is still aiming to launch SLS during an Artemis 2 window that lasts from April 1-6. The mission is the first crewed installment of NASA's Artemis program, and the first flight of the Orion spacecraft with astronauts onboard.

The shakedown cruise will fly NASA astronauts Reid Wiseman, Victor Glover and Christina Koch, as well as Canadian Space Agency astronaut Jeremy Hansen on a 10-day trip around the moon on the first crewed mission to lunar space in more than half a century. It's designed as a stepping stone to later Artemis missions planned over the next few years that will test and mature technologies like deep space life support systems and new lunar landers for NASA's ultimate goal for the program: establishing a permanent human presence on the lunar surface.

It's a similar concept to how NASA has maintained the International Space Station's continual occupancy for the past 25 years, through crew rotations and cargo supply missions to sustain crews in space while they conduct scientific research in low Earth orbit. NASA wants a similar framework for missions to the surface of the moon, but must first perfect the technologies needed to enable such long-term excursions so far from Earth, where an emergency evacuation would take days instead of hours.

If all goes according to plan during Orion's debut astronaut mission around the moon on Artemis 2, NASA plans to launch Artemis 3 to low Earth orbit (LEO) to rehearse rendezvous and docking maneuvers with either or both of the two lunar landers contracted for the Artemis program. Those include SpaceX's Starship and Blue Origin's Blue Moon lander. Both have experienced development delays, however, and are part of the reason the current Artemis mission architecture is outlined the way it is.

Artemis 3 had originally been slated as the program's first moon landing, with a target launch in 2028. A recent programmatic shuffle, though, rearranged that roadmap to reshape Artemis 3 with the goal of launching to LEO in 2027, and designated Artemis 4 as the first mission to return astronauts to the lunar surface, which is still targeted for 2028. And, if NASA's timeline holds, the agency has indicated the possibility of a second 2028 moon landing on Artemis 5.

For that schedule to stick, Artemis 2 needs to go perfectly right, and soon. The March 20 VAB rollout for SLS will be the rocket's second journey to LC-39B, on a launch campaign NASA had originally hoped to have been wrapped by now.

The Artemis 2 SLS rolled to the pad for the first time on Jan. 17, and had targeted an early February liftoff. Issues during two subsequent "wet dress rehearsal" fueling test countdown simulations prompted the rocket's subsequent VAB rollback, leapfrogging the mission's possibility for a March launch to its available dates in April. NASA officials have stated the existence of launch windows for Artemis 2 beyond its April opportunities, which include April 30, but have not provided dates past next month.

NASA is planning to livestream the March 20 SLS rollout, which typically takes about 12 hours from first motion inside the VAB to its dropoff at LC-39B. The four-mile journey is made possible thanks to NASA's crawler-transporter vehicle, which carries the massive 322-foot (98-meter) tall rocket and mobile launch platform at an average speed of 1 mph (1.6 kph).