NASA’s new large moon rocket is headed back to the garage for some minor repairs, potentially delaying its first launch until late summer or later.
That means NASA will stop for now from trying to complete what it calls a wet dress rehearsal for the rocket — a detailed countdown exercise called “wet” because it involves loading more than 700,000 gallons of ultra-cold liquid hydrogen and liquid oxygen into the rocket’s fuel tanks.
For the past month, the rocket, called the Space Launch System, has been sitting on the launch pad at the Kennedy Space Center in Florida to test its ground systems. The tests were to culminate in the wet dress rehearsal.
However, three attempts at that drill all ended early due to a variety of technical issues during the countdown. The goal of the rehearsal with a new missile system is to identify and solve such problems.
Technicians also found that a valve on the top stage was malfunctioning, and for the third rehearsal last Thursday, the test was modified so that only the fuel tanks on the booster stage had to be filled. But then a hydrogen leak was discovered in what’s called the tail service mast’s umbilical cord attached to the underside of the rocket, and the rehearsal was scrubbed. The oxygen tank was not yet half full and the hydrogen refueling had just begun.
Last week, NASA officials said they hoped to fix the hydrogen leak while the rocket was still on the launch pad. But on Monday they said they had changed their mind. Next week, the rocket will be rolled back to the Vehicle Assembly Building, where technicians can more easily access parts of the rocket. That will allow replacement of the balky top kick valve.
At the same time, a third-party supplier that supplies nitrogen gas – which is used to remove hazardous gases – will upgrade its systems. During two of the rehearsals, nitrogen supply failures delayed the countdown.
“The mega-moon rocket is doing very well,” Tom Whitmeyer, deputy associate administrator for common exploration systems development at NASA, said at a news conference Monday. “I think we’re getting really smart with this rocket. But we still have some more work to do.”
The Space Launch System, a key part of NASA’s Artemis program to send astronauts back to the moon, is years behind schedule and billions of dollars over budget. With the latter issues, getting the rocket ready in time for a two-week launch in early June would be a challenge, Whitmeyer said. There are additional options of two weeks from the end of June and the end of August.
“We are currently working on a number of different scheduling options that we will discuss with the management team over the course of the week,” said Charlie Blackwell-Thompson, the launch director.
One would be to make the minimum amount of repairs needed — the top stage valve and the hydrogen leak — and return to the launch pad for the wet dress rehearsal as soon as possible. A second option would involve some extra work needed to get the rocket ready for launch. Both options require a trip back to the Vehicle Assembly Building.
A third option would be to get the rocket all ready for launch and then do both the rehearsal and launch without going back to the building again.