The astronauts on the Artemis II mission have reached the moon's gravitational sphere, meaning the spacecraft is more strongly affected by the moon's gravity than Earth's, NASA said on Monday.
While entering the moon's gravitational influence, the Orion capsule was about 63,000 kilometers (39,000 miles) from the moon and about 232,000 miles from Earth, a NASA official said.
In the next few hours, the spacecraft is expected to come closest to the moon, about 7,500 kilometres beyond the far side.
The flight trajectory of the Artemis 2 flight resembles a figure of eight around Earth and the moon.
Why is the Artemis II mission historic?
When the spacecraft comes closest to the moon, the astronauts will be able to see Earth and the moon at the same time — and even a solar eclipse in which the Sun disappears behind the moon from Orion's perspective.
The astronauts entered what NASA calls the lunar sphere of influence at 0442 GMT Monday and will soon record the first lunar flyby since 1972, during which the crew will travel farther from our home planet than any human before.
Artemis II moon flight making history
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This is the first time in more than 50 years that a crew, consisting of US astronauts Victor Glover, Christina Koch and Reid Wiseman and Canadian astronaut Jeremy Hansen, is traveling to the moon.
Victor Glover will become the first person of color to ever fly around the moon, and Christina Koch will be the first woman.
What have the astronauts observed so far?
The astronauts are tasked with documenting the moon during the lunar flyby.
They have already started seeing features of the moon never before viewed with a naked human eye.
In the early hours of Sunday, NASA published an image taken by the Artemis crew that showed a distant moon with the Orientale basin visible.
"This mission marks the first time the entire basin has been seen with human eyes," the US space agency said.
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