NASA halted the launch attempt — although it later found that the sensor was probably faulty and the engine was as cold as it needed. On the second try, on 3 September, a large hydrogen leak appeared in one of the previous leaky locations, a ‘quick disconnect’ seal on a fuel line.
On NASA’s first try, on August 29, lightning near the launch pad delayed work to fill the rocket’s fuel tanks. Then two hydrogen leaks appeared. Finally, a sensor indicated that one of the SLS’s four main engines was not chilled to the temperature necessary to receive fuel before lift-off. This leak was much larger than the previous one, so the gas, which is flammable, built up to dangerous levels.
At a news briefing after the launch was scrubbed, Jim Free, NASA’s associate administrator for exploration-systems development, said “Hydrogen is difficult to work with. “I’m not saying that’s an excuse, it’s just a fact.”
Why does NASA need to use hydrogen even though it leaks too much?
As a rocket fuel, liquid hydrogen is lightweight and powerful. When combined with liquid oxygen, it produces the highest specific impulse—a measure of the thrust it can generate—of any rocket fuel. So, NASA has continued using it even though it can be extremely finicky and prone to leaks.
At a September 8 media briefing, John Blevins, the SLS chief engineer with NASA, said, “Hydrogen is a challenging molecule, but it’s worth it.” “If you look at the mission we’re doing, this mission bugs to use this fuel.”
When will NASA try to launch again?
For the moment, engineers are working to fix the hydrogen leaks while the SLS is still on the launch pad at the Kennedy Space Center in Florida. But there are many constantly changing factors that dictate when and how NASA might next try to launch. All this boils down to the next launch attempt probably not coming before mid-October. However, the launch pad is reserved on September 23 and September 27 in case it is able to resolve the hydrogen leak and battery reset by then.
