After months of testing, troubleshooting and repairs, NASA ran into trouble early Monday refueling the Space Launch System moon rocket, forcing the agency tofrom its Artemis 1 test flight — to send an unmanned Orion crew pod on a 42-day mission beyond the moon and back.
The launch was originally scheduled for 8:33 a.m. EDT, opening a two-hour window. The next launch opportunity will be on Friday, September 2 at 12:48 PM EDT, if issues are resolved by then.
The countdown was paused overnight due to stormy weather and troubleshooting to fix an apparent hydrogen leak, 750,000 gallons of super-cold liquid oxygen and hydrogen fuel were loaded into the SLS core trap, paving the way for another 22,000 gallons to enter the top to be pumped phase.
The Artemis 1 test flight is intended to:to propel Orion capsules into Earth orbit and then to the Moon. Engineers will also test the crewship’s myriad systems in deep space and ensure the heat shield can protect returning astronauts from the 5,000-degree heat of reentry.
NASA plans to track the unmanned Artemis 1 mission by launching four astronauts on a round-the-moon flight in 2024. the period 2025-2026.
But first, NASA must prove that the rocket and capsule will work as planned — and that starts with the launch of Artemis 1.
Refueling was delayed 55 minutes by an approaching storm and lightning within about 6 miles of launch pad 39B. The six-hour refueling procedure began at about 1:13 a.m. but was interrupted by evidence of a hydrogen leak near the area where the propellant lines enter the missile’s base.
During a transition from “slow fill” to a speed 10 times faster, sensors detected higher than allowable concentrations of hydrogen, indicating a leak somewhere in the system. After returning to slow filling and equalizing the temperature in the pipes, fast filling was restarted and this time there were no problems.
Still to be determined: the status of a 4-inch quick coupler used to feed hydrogen to the core stage engines to cool them before igniting. NASA reported that three of the engines were properly conditioned, but engine No. 3 did not initially “see” the desired flow rates. That led to additional troubleshooting.
And if that wasn’t enough, an unusual row of frost was observed on the outside of the rocket’s core stage — a possible indicator of some kind of leak, thermal insulation crack, or some other problem.
Backup launch options will be available on September 2 and 5. But if the missile is not off the pad by then, the SLS will have to be transported to the Vehicle Assembly Building for maintenance.