(FOX NEWS) — The historic moment has arrived as the four Artemis II astronauts have begun the process of boarding the Orion spacecraft.

One by one, the closeout crew is assisting Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen through the side hatch and into their seats, where they are being meticulously strapped into their five-point harnesses.

Suspended 252 feet above Launch Pad 39B, the crew is now performing the critical comm check, verifying their audio links with the Launch Control Center and Mission Control in Houston.