NASA is delaying putting astronauts back on the moon until 2025 at the earliest, missing the deadline set by the Trump administration.
The space agency had been aiming for 2024 for the first moon landing by astronauts in a half-century.
Announcing the delay Tuesday, NASA Administrator Bill Nelson said Congress did not provide enough money to develop a landing system for its Artemis moon programme.
In addition, a legal challenge by Jeff Bezos' rocket company, Blue Origin, stalled work on the Starship lunar lander under development by Elon Musk's SpaceX.
A federal judge last Thursday rejected a lawsuit by Blue Origin against the US government challenging Nasa's decision to award a $2.9 billion lunar lander contract to SpaceX.
NASA is still targeting next February for the first test flight of its moon rocket, the Space Launch System, or SLS, with an Orion capsule. No one will be on board. Instead, astronauts will strap in for the second Artemis flight, flying beyond the moon but not landing in 2024, a year later than planned. That would bump the moon landing to at least 2025, according to Nelson.
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"The human landing system is a crucial part of our work to get the first woman and the first person of colour to the lunar surface, and we are getting geared up to go," Nelson told reporters.
Officials said technology for new spacesuits also needs to ramp up before astronauts can return to the moon.
NASA's last lunar landing by astronauts occurred during Apollo 17 in 1972. Altogether, 12 men explored the moon's surface.