NASA has shared more information about its ongoing work on its new Space Launch System rocket and the issues that arose during three previous tests. The problems, which NASA called a nuisance rather than a major problem, arose during attempts to conduct a wet dress rehearsal during which fuel is loaded into the rocket.
The first problem to fix was a liquid hydrogen fuel leak, which was a relatively simple fix of tightening some bolts that had come loose in the umbilical that carries fuel from the mobile launch pad to the rocket. NASA says its engineers are confident the bolts now stay properly tightened and should maintain their tightness during refueling operations. To be on the safe side, engineers also moved a filter that removes any contaminants from the fuel to another location. This filter had not previously caused a leak, but moving it ensures that it will not contribute to a future leak.
Another issue the team worked on was a helium check valve that had been left open due to an errant piece of rubber. Engineers weren’t sure where that rubber came from, but they’ve since found a damaged O-ring that came loose and got stuck in the valve. While engineers were able to replace any mounting hardware that might have been affected, it’s still unclear what caused the o-ring to come loose in the first place. The team will continue to investigate the root cause of the issue and test their solution by repressurizing the system.
Other work done is to check if the rocket was damaged by the lightning and thunderstorm that occurred during one of the tests – but it wasn’t, as there are towers on the launch pad that directs lightning away from the rocket to prevent damage in this type of situation. NASA also asked its supplier of nitrogen gas used in the test to upgrade its facilities in time for the next attempt.
NASA has previously said it does not plan to try the wet dress rehearsal again until June at the earliest. In the update, the agency clarified that “NASA will announce pad deployment dates and the next wet dress rehearsal attempt once work inside the [Vehicle Assembly Building] and testing of the nitrogen system is nearing completion.