The crew of NASA’s Artemis II mission will have the rare opportunity to observe previously unseen regions of the Moon during Monday’s lunar flyby, according to NASA.

During a six-hour observation period, the astronauts will reach their closest approach to the Moon as they pass around its far side—an area largely hidden from Earth.

Kelsey Young, a science lead at NASA’s Science Mission Directorate, said that significant portions of the Moon’s far side remain unseen by human eyes. She explained that Apollo missions were carefully timed to land when the near side was illuminated, leaving the far side comparatively unexplored by astronauts.

“As they get closer, they’ll be able to see features that human eyes have never before seen,” Young said during a news conference.

John Honeycutt, an official with NASA’s Space Launch System (SLS) Program, noted that regions previously observed only by robotic spacecraft are now becoming visible to humans, pointing to a recent image captured by the Orion spacecraft.

In addition to the flyby, the crew is expected to witness a solar eclipse lasting approximately 53 minutes, occurring about an hour after Earthrise.

The Artemis II mission is part of NASA’s broader effort to return humans to the Moon and lay the groundwork for a sustained human presence, including the eventual establishment of a permanent lunar base.