Mankind’s leap back to the moon will have to wait at least a month more after a final Artemis II launch rehearsal revealed critical fuel leaks in the mission’s giant rocket.

The Artemis II launch won’t happen until at least March after Monday’s “wet dress rehearsal” found the Space Launch System rocket was leaking liquid hydrogen as the fuel was pumped through its systems.

Artemis – due to carry four astronauts around the moon for the first time in over 50 years – could have launched as early as Sunday if everything went well with Monday’s rehearsal, which was scheduled to carry out the entire launch sequence to ignition-minus 30 seconds.

But the fuel problem quickly emerged, with technicians unable to find any workarounds and finally calling the rehearsal off early Tuesday with about five minutes left on the countdown.

“As always, safety remains our top priority,” NASA Administrator Jared Isaacman said on X after the rehearsal was called off. “We will only launch when we believe we are ready to undertake this historic mission.”

The four astronauts – three Americans and one Canadian – were not aboard the rocket for the rehearsal, and have since been released from the pre-launch quarantine they entered nearly two weeks ago.

Monday’s dress rehearsal problems mean Artemis II will miss its first launch window – Feb. 8 to 11 – as the rocket’s problems are addressed, and will have to wait until March 6 through 11.

And if problems persist through then, the next launch would be a month later between April 1 and 6.

Those launch windows were chosen so the far side of the moon – which the mission will closely study for the first time in history – will be in sunlight as the astronauts pass by.

The return to the moon will be similar to man’s first crewed trip — 1968’s Apollo 8 — which flew a figure eight from earth to the moon and back over six days. Artemis II will last 10 days.

And it’s the first time humans will have seen the moon up close since Apollo 17 astronaut Gene Cernan stepped off the lunar surface in 1972, and blasted home with astronauts Jack Schmidt and Ronald Evans.

Artemis II’s will be commanded by engineer and naval aviator Reid Wiseman, be piloted by engineer and naval aviator Victor Glover, and will include scientist and astronaut Christina Koch along with Canadian aviator and scientist Jeremy Hensen.

Glover will be the first black person to go to the moon, and Koch will be the first woman.

Monday’s leaks were similar to the problems which delayed the unmanned Artemis I launch in 2022, but were later resolved.

Artemis II will fly just over 4,000 miles from the lunar surface, and the mission will test life-support and module systems crucial to the landing missions expected in coming years.