ISTANBUL

Astronauts assigned to NASA's Artemis II mission said Sunday they are prepared for launch as the final countdown toward a planned crewed flight around the moon gets underway this week.

The four-member crew, commander Reid Wiseman, pilot Victor Glover, mission specialist Christina Koch, and Canadian astronaut Jeremy Hansen, arrived at Kennedy Space Center in Florida ahead of the scheduled April 1 launch, pending favorable weather conditions.

Speaking during a virtual news conference while in quarantine, the astronauts said they were ready for the mission but acknowledged the uncertainties typical of a test flight.

"This is the first time we're loading humans on board," Wiseman said, noting that both the crew and the vehicle are prepared but that launch will proceed only when all systems are confirmed ready.

The 49-hour, 40-minute countdown is set to begin Monday afternoon, targeting liftoff at 6.24 pm ET (2224 GMT) Wednesday. The astronauts will fly aboard an Orion spacecraft mounted on NASA's Space Launch System rocket, marking the first time both vehicles carry a crew.

The mission had initially been planned for early February but was delayed due to hydrogen fuel leaks and issues with pressurizing the rocket's upper-stage propulsion system. Weather forecasts currently indicate an 80% chance of acceptable launch conditions, though high winds and cloud cover remain potential risks.

Ground systems manager Shawn Quinn said the final pre-launch review was among the smoothest conducted, with no major outstanding technical issues.

Artemis II will be NASA's first crewed mission to the moon since 1972. The spacecraft will not land but instead perform a flyby of the moon's far side, using lunar gravity to return to Earth for a planned splashdown in the Pacific Ocean on April 10.

If launched as scheduled, the crew is expected to travel farther from Earth than any humans in history, surpassing the record set during the Apollo 13 mission. NASA says the mission will test critical systems including propulsion, navigation, communications, and life support, ahead of future missions involving lunar orbit operations and planned moon landings later in the decade.