The US space agency NASA on Saturday announced that an issue with the flow of helium to the upper stages of its SLS rocket has left engineers with no option but to again postpone the launch of the agency's first manned moon mission in 50 years.

NASA Administrator Jared Isaacman said that a bad filter, valve or connector plate could have stalled helium flow, explaining that the 322-foot-tall (98-meter) rocket would have to be rolled back into the Vehicle Assembly Building at Kennedy Space Center in Florida to allow specialists to track down the source of the problem.

"We will begin preparations for rollback, and this will take the March launch window out of consideration," Isaacman said via X. NASA's next opportunity will likely come in April.

Artemis moon mission delayed after rocket issue

The Artemis 2 mission had been most recently scheduled for launch on March 6. It was intended to send three US and one Canadian astronaut into lunar orbit during a 10-day flight.

"I understand people are disappointed by this development," said Isaacman. "That disappointment is felt most by the team at NASA, who have been working tirelessly to prepare for this great endeavor."

NASA says this latest issue is not related to hydrogen fuel leaks that marred a countdown dress rehearsal of the Space Launch System (SLS) rocket earlier this month.

The Artemis program has completed one unmanned lunar orbiting mission to date and has been plagued by similar technical issues.

Between 1968 and 1972, NASA's Apollo program flew no less than 24 humans to the moon.

It is expected that NASA will need several years to put a person on the moon's surface again — a declared goal of US President Donald Trump.

The push comes as China pledges to match the US with a crewed mission by 2030.

The US hopes to use the moon as a launching pad for future flights to Mars.

Edited by: Roshni Majumdar