NASA’s Orion spacecraft made its closest approach to the moon on Monday morning during day five of the Artemis 1 mission.

The uncrewed capsule flew about 81 miles above the lunar surface, the agency said.

Artemis I launched from Florida on Wednesday, with NASA’s most powerful rocket ever – the Space Launch System (SLS) – successfully carrying Orion into space. While no astronauts are onboard, the nearly month-long journey around the moon is a critical demonstration for NASA’s lunar program.

Orion will use the moon’s gravity to assist it in setting a trajectory back to Earth. Over the course of the mission, Orion is expected to travel about 1.3 million miles.

The mission represents a crucial inflection point in NASA’s moon plans, with the program delayed for years and running billions of dollars over budget. The Artemis program represents a series of missions with escalating goals. The third – tentatively scheduled for 2025 – is expected to return astronauts to the lunar surface for the first time since the Apollo era.