For NASA’s Artemis 1 moon rocket, the fourth time may be the charm. On Monday, the rocket completed two days of tests, including simulated countdowns and fueling—the first practice run after three attempted trials earlier this year. The recent dress rehearsal nearly prepared the Space Launch System rocket and NASA’s Orion capsule, designed to take humans on missions to the moon and Mars, for launch.
Around 8:45 a.m. Eastern time on Monday at NASA’s Kennedy Space Center in Florida, the crew filled the rocket with 700,000 pounds of cryogenic fuel. But not everything went according to plan: The Artemis 1 team discovered a hydrogen leak after the rocket was fully fueled. In an actual countdown, the leak would have set off alarms. But in Monday’s test, known as a wet dress rehearsal, the mission management team chose to have the computer ignore the alarm.
The countdown proceeded with only a slight change—stopping at T-minus 29 seconds before liftoff, instead of the planned T-minus 9 seconds. Despite the fuel leak, NASA officials say the wet dress rehearsal provided important data and an opportunity to troubleshoot issues.
“It was a long day for the team, but it was a very successful day,” NASA Artemis launch director Charlie Blackwell-Thompson told reporters Tuesday during a press conference. Loading the liquid oxygen and hydrogen propellant, and reaching the final seconds of the terminal countdown, were “amazing milestones,” she said.
During NASA’s three previous practice runs in April, multiple hardware issues surfaced and forced the rocket to undergo repairs for six weeks.
It’s not uncommon for a new rocket to face technical problems. The purpose of wet dress rehearsals is to expose those issues while preparing for the harsh conditions the spacecraft will face during a launch. “It’s a violent, violent atmosphere for those components to be in,” Kevin Miller, an engineer at NASA’s Kennedy Space Center, told Popular Science in April. “It’s an interesting environment unlike anything else in the world, and we have to make sure it operates flawlessly.”
Monday’s practice run was the final test that NASA planned for Artemis 1 before its launch. But there is a possibility that the space agency may add a fifth wet dress rehearsal or delay the launch, considering Monday’s leak.
Jim Free, NASA’s associate administrator for Exploration Systems Development Mission Directorate, told reporters that Artemis 1 is expected to launch between August 23 to September 6, according to FOX Weather. When the rocket finally blasts off, it will be a key step to bring astronauts back to the moon, potentially reigniting a new chapter in lunar exploration.