The sun rises behind Artemis I, NASA's heavy-lift lunar rocket system, as it sits temporarily grounded at pad 39-B at Kennedy Space Center, Florida, on Sept. 6, 2022. 

ORLANDO, Fla. — NASA was riding a high after the overall success of Artemis I when the uncrewed rocket made a test run to the moon and back in 2022, so the message remained full steam ahead to push for a crewed Artemis II flight in 2024 and the return of humans to the moon in 2025.

But under the surface were issues, and the sheen of success hit reality, prompting NASA to delay Artemis’ first human spaceflight until no earlier than September 2025, and then pushing the moon landing until at least one year later.