KENNEDY SPACE CENTER, FLORIDA — NASA rolled the Artemis II Space Launch System rocket and Orion spacecraft to Launch Pad 39B at Kennedy Space Center for the second time this month. The 322-foot-tall rocket and its launch platform made a four-mile journey from the Vehicle Assembly Building to the launch pad, carried by the Crawler-Transporter-2.

The rocket and launch platform weigh approximately 11 million pounds and were transported by the tank-like vehicle on caterpillar tracks built in 1965 that moves at a maximum speed of about 1 mile per hour. The four-mile journey can take up to 12 hours, with the slow motion designed to reduce stresses on the rocket and launch tower.

In March, a problem with the rocket's helium system detected during a fueling test forced NASA to roll the rocket back to the Vehicle Assembly Building for repairs. The helium issue was uncovered after an hours-long fueling test and launch-day walkthrough known as a wet dress rehearsal. Engineers replaced suspect components, swapped batteries in critical systems, and repeated tests to confirm that the helium fault had been cleared. NASA fixed the helium flow issue by replacing a seal in a line that feeds helium from ground systems into the rocket.

NASA officials held a two-day flight readiness review meeting with mission managers, the four-astronaut crew, and other agency representatives. After reviewing the repair data, NASA managers signed off on a second rollout to the launch pad. NASA formally certified the rocket and spacecraft for flight and decided to press ahead with an April launch attempt.

At the launch pad, engineers will plug the launch tower back into the vehicle and run pressure tests on the helium system. Controllers will rehearse parts of the countdown by sending commands through the same computers and networks used on launch day, without filling the fuel tanks. NASA's mission management team will meet a few days before the earliest launch opportunity on April 1 to review data and decide whether to proceed.

NASA is targeting launch opportunities in the first week of April, with the first launch opportunity set for 6:24 p.m. Eastern Daylight Time on April 1. If the April 1 launch attempt is delayed, additional launch windows are available on April 2, 3, 4, 5, and 6. If those launch windows are missed, a final opportunity is available on April 30.

Artemis II will be the first crewed mission in the Artemis program, carrying astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen. The ten-day mission will loop around the far side of the Moon before returning to Earth. The crew have entered pre-flight quarantine and will travel to Florida closer to launch to take part in rehearsals.