Artemis II launch time is set for a 6:24 p.m. Eastern window on Wednesday, and NASA has said the window will remain open for two hours.
Crew and launch teams began fueling the rocket shortly before 9 a.m. Eastern after NASA gave clearance to prepare the vehicle for liftoff, as reported by agency officials.
The mission is the first crewed flight test of the Space Launch System deep space rocket and the Orion spacecraft, and NASA described it as a test mission with the overall goal of returning astronauts to the moon.
NASA said the crew will spend the first two days testing Orion's systems relatively close to Earth before the spacecraft begins its outbound journey toward the moon.
The outbound transit is expected to take about four days to reach roughly 230,000 miles from Earth, and the trajectory will carry the crew to about 4,600 miles beyond the moon at the mission's maximum distance.
NASA described the return as a fuel efficient free return trajectory, which uses the Earth Moon gravity field so Orion will be pulled back naturally for reentry and a splashdown planned in the Pacific Ocean near San Diego, California.
The four astronauts assigned to Artemis II were announced by NASA, and the crew includes commander Reid Wiseman, pilot Victor J. Glover, mission specialist Christina Koch, and Canadian Space Agency astronaut Jeremy Hansen.
Reid Wiseman is a former U.S. Navy captain with extensive experience as an astronaut, including a long-duration International Space Station mission where his crew completed more than 300 scientific experiments and he spent roughly 13 hours as lead spacewalker.
Victor J. Glover served as pilot on a previous ISS crew and has accumulated long-duration flight experience including multiple spacewalks, while Christina Koch holds the record for the longest single spaceflight by a woman and has participated in the first all-female spacewalk.
Jeremy Hansen will fly his first space mission with Artemis II, and NASA said backup launch dates have been selected should the attempt be delayed or scrubbed.
NASA Goals And Leadership Remarks
NASA Administrator Jared Isaacman described Artemis II as the opening act for a broader plan, saying it is time to start believing again and calling the mission a step toward an enduring lunar presence.
Isaacman said NASA should be sending uncrewed rockets to the moon on a cadence measured in months, and he portrayed Artemis II as a test that sets up later crewed lunar surface operations and a moon base.
He compared the agency's next phase to past lunar efforts, noting how missions were launched more routinely in an earlier era, and he cited the Apollo program's rapid mission cadence as an example.
Isaacman said the moon will serve as a proving ground for mobility, habitability, and technology needed for more distant exploration, and he added that when Americans step from a lander on the lunar surface, the capability to send astronauts to Mars will have been demonstrated.
The administrator also described a desired operational tempo, saying the agency knows how to get into this kind of cadence and that Artemis II will inform the next steps for lunar surface and deep space planning.
