NASA is finalizing plans for the historic Artemis moon rocket launch on Monday morning, but there is one detail that won’t be known until just a few hours before the 8:33 a.m. launch.

Did engineers truly find a solution to the troublesome hydrogen leak that hampered earlier test runs?

When they begin fueling the enormous orange fuel tank that serves as the Space Launch System’s backbone on Sunday night, the Artemis I mission managers will be on the lookout for that.

Derrol Nail, a NASA analyst, stated, “Our team here — the exploratory ground crew — has worked so hard and so carefully to get that hydrogen leak rectified.”

The leak, which presented a flammability concern during a wet dress rehearsal in April, led to the cancellation of the test.

When super-chilled to minus 423 degrees Fahrenheit, it has a reputation for being an extremely slippery propellant. It’s difficult to contain this stuff. “Keeping it confined and unleashing all of that energy is incredibly challenging since it’s the tiniest molecule known to humans,” Nail added.

On the SLS, the issue was a 4-inch disconnect at the point where the rocket and mobile launcher were connected. Although NASA has now replaced the seals, it won’t be until the last hours before launch when technicians force liquid hydrogen through that connection point that space experts will know whether the remedy is effective.

We did the best job we could to fix this leak. So, with tremendous confidence, we’re going to launch this rocket, and when we do, it will hold, ” Nail added. “But you know, as you mentioned, it’ll be the first time we’ve got it on the pad ready to go since we had that leak, and we’re hoping it will hold. This will be launched by us.