WASHINGTON — NASA will try to repair on the pad a liquid hydrogen seal that induced a House Launch System scrub, protecting open the choice to proceed with a brand new launch try later this month.
In a press release late Sept. 6, NASA mentioned that technicians will proceed with plans to switch the seal for the interface referred to as the short disconnect between a liquid hydrogen feed line and the core stage of the SLS. That work will likely be accomplished on the pad reasonably than rolling the car again to the Car Meeting Constructing (VAB) on the Kennedy House Middle.
An issue with that seal resulted in what officers referred to as a big leak of liquid hydrogen throughout fueling of the core stage throughout the Sept. 3 launch try. A number of efforts to reseat the short disconnect, by warming after which cooling it and by making use of helium gasoline strain on the becoming, did not cease the leak, and NASA referred to as off the Artemis 1 launch try three hours earlier than the two-hour launch window opened.
At a briefing after the Sept. 3 scrub, NASA officers mentioned that they had been contemplating choices to restore the short disconnect seal whereas remaining at Launch Complicated 39B versus rolling again to the VAB. Staying on the pad has “a few professionals and cons related to it,” mentioned Mike Sarafin, Artemis mission supervisor. “The cons occur just about each afternoon round right here whenever you get a bathe or thunderstorm coming by.”
NASA mentioned in its newest assertion that, earlier than beginning work changing the seal, technicians would place an enclosure across the interface “to guard the {hardware} from the climate and different environmental circumstances.” The company didn’t state how lengthy both that preparatory work, or the substitute of the seal itself, would take.
One benefit of doing the work on the pad is that employees can then check the becoming utilizing liquid hydrogen there, which isn’t an choice if the work is finished again on the VAB. “That’s the solely place we will get a full cryo check and ensure we wouldn’t have an extra difficulty with respect to leaks on the temperatures we have to fill the car on the day of launch,” Sarafin mentioned.
Doing the work on the pad would additionally protect the choice of continuing with one other launch try with out rolling again to the VAB. That’s solely attainable, although, if the U.S. House Drive’s House Launch Delta 45, which operates the Jap Vary, extends the certification of the flight termination system (FTS) on the rocket. That certification expired Sept. 6, and NASA must roll again to the VAB to reset the FTS, which is in part of the rocket that may’t be accessed on the pad.
“We don’t have an FTS waiver proper now past 25 days. Till we have now that, we have now to roll again,” Jim Free, NASA affiliate administrator for exploration techniques improvement, mentioned on the Sept. 3 briefing. He mentioned the company would think about searching for an extension, however would wish to find out how lengthy of an extension it wanted versus how a lot the Jap Vary would grant. “That negotiation hasn’t occurred, so so far as I’m involved we have now to roll again.”
If, nevertheless, the Jap Vary does prolong the FTS certification, it could possibly be attainable to try one other SLS launch throughout the subsequent launch interval, which opens Sept. 20 and runs by Oct. 4. “I believe it’s too early to inform” if a late September launch is possible, Sarafin mentioned. “It actually comes right down to what the fault tree evaluation tells us and what are the mandatory adjustments and mitigations required so as have the arrogance that we’ve resolved this.”
Free mentioned different components may weigh into a choice to stay on the pad, together with any constraints for the Orion spacecraft remaining on the pad. “Finally we’re pushed by the FTS.”
If NASA decides to roll again to the VAB, which could possibly be to carry out different work on the car or due to climate as Florida enters the height of the hurricane season, it might delay the launch by a number of weeks, Sarafin mentioned. That will push the launch again to at the very least the following launch interval, which runs from Oct. 17 by 31.
The Sept. 6 replace from NASA didn’t present further particulars on what induced the short disconnect seal to leak. Company officers speculated after the scrub that an “inadvertent overpressurization” of the liquid hydrogen line throughout preparations for fueling may have broken the seal, however mentioned they wanted extra time to analyze the difficulty.
