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The full Artemis II stack at launchpad 39B.
CAPE CANAVERAL—NASA will skip its February launch opportunity to send four astronauts on a flight test around the Moon to review data from a launchpad fueling test that ended early due to a hydrogen leak.
The Artemis II first wet dress rehearsal was scrubbed early Feb. 3 with 5 min. 15 sec. remaining on the countdown clock. The two-day simulated launch countdown began at 8:13 p.m. EST Jan. 31.
NASA plans to conduct a second wet dress rehearsal, the agency noted in a Feb. 3 mission status update.
“Engineers pushed through several challenges during the two-day test and met many of the planned objectives. To allow teams to review data and conduct a second wet dress rehearsal, NASA now will target March as the earliest possible launch opportunity for the flight test,” the agency said.
Artemis II, which is expected to become the first crewed flight into deep space since Apollo 17 in 1972, has launch opportunities March 6-9 and March 11.
During the practice countdown, the launch team twice wrestled with leaks on Feb. 2 as liquid hydrogen flowed through an interface that connects a fuel line to the base of the Space Launch System rocket’s core stage. Using techniques developed after a series of tanking tests for Artemis I in 2022, the concentrations of liquid hydrogen returned to acceptable levels, allowing the Artemis II wet dress rehearsal to proceed.
“Attempts to resolve the issue involved stopping the flow of liquid hydrogen into the core stage, allowing the interface to warm up for the seals to reseat and adjusting the flow of the propellant,” NASA said.
NASA reported at about 4:45 p.m. Feb. 2 that core stage fueling was complete. The team then switched over to topping mode to replenish the cryogenics’ boil-off. “Engineers continue to watch the leak at the interface of the tail service mast umbilical, but the liquid hydrogen concentration in the umbilical remains within acceptable limits,” NASA noted.
The dress rehearsal also included sending a five-member team to Launch Complex 39B to practice closing out the Orion crew module for flight. A valve that had recently been replaced required retorquing, further delaying the test, which had been slated to end at 9 p.m. EST Feb. 2 with a simulated launch.
Instead, the countdown ended with 5 min. 15 sec. left on the clock when the ground launch sequencer automatically halted operations due to a spike in the liquid hydrogen leak rate.
NASA said cold weather, which had delayed the wet dress rehearsal two days, affected several cameras and other equipment. The launch team also spent time troubleshooting ground team audio communications dropouts.
The Artemis II crew been prepared to fly from Houston to the Kennedy Space Center on Feb. 3, pending results of the wet dress rehearsal. NASA had been targeting their launch as early as Feb. 8.
Instead, the astronauts were released from their routine preflight medical quarantine while NASA reviews the tanking test data and makes plans for a second test. They will return to quarantine about two weeks before their next targeted launch opportunity.
“As always, safety remains our top priority, for our astronauts, our workforce, our systems and the public,” NASA Administrator Jared Isaacman said in a statement. “We will only launch when we believe we are ready to undertake this historic mission.”
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