PARIS — NASA officers say they’re able to attempt a brand new method to fueling the Area Launch System to forestall the return of leaks that scrubbed an earlier launch try although they don’t seem to be sure what brought on that leak.
Preparations are underway for the Sept. 21 tanking take a look at of the SLS at Launch Complicated 39B, with loading of liquid hydrogen and liquid oxygen propellants into the core stage starting at round 7 a.m. Japanese. After filling the tanks of the core stage and higher stage, controllers will conduct assessments of a “kickstart bleed” of hydrogen into the core stage engines and a pre-pressurization take a look at earlier than wrapping up at about 3 p.m. Japanese.
The primary goal of the take a look at is to verify that repairs to seals in liquid hydrogen strains into the core stage, in addition to different adjustments in procedures, eradicate a big leak seen within the second try and launch the rocket on the Artemis 1 mission Sept. 3. Controllers noticed concentrations of hydrogen within the enclosure across the connection at the least two occasions a restrict of 4%.
Employees changed the seals for 2 liquid hydrogen quick-disconnect fittings. The bigger one, 20 centimeters in diameter, has a “witness mark” or indentation related to overseas object particles, stated Mike Sarafin, NASA Artemis mission supervisor. The scale of the indentation was about 0.25 millimeters. “An indentation of that measurement does present a possibility for a pressurized gasoline to leak via that,” particularly hydrogen, he stated.
Nonetheless, later within the name company officers backed away from the speculation that the overseas object particles brought on the indentation, noting that no particles was recovered. They even hesitated to conclude the indentation was the supply of the leak.
“There are simply so many issues that might have created the indentation. We consider that indentation is according to the leak, however we don’t absolutely know that, both,” stated John Blevins, NASA SLS chief engineer.
Tom Whitmeyer, deputy affiliate administrator for frequent exploration methods improvement at NASA Headquarters, famous the leak didn’t seem throughout the first SLS launch try Aug. 29. He prompt that a number of elements could have performed a task within the leak.
“There’s definitely multiple side for this situation that we don’t actually absolutely perceive,” he stated. “We’ve checked out each path doable that may very well be associated to it and ensuring that we’ve performed every little thing we are able to.”
That features a new “kinder, gentler” loading method for liquid hydrogen, utilizing much less stress to push liquid hydrogen via the strains into the core stage. “We’re attempting to attenuate each stress spikes and thermal spikes,” stated Jeremy Parsons, deputy supervisor of the Exploration Floor Techniques program. “The group feels this helps mitigate a number of the dangers.”
Company officers stated they need to know fairly shortly after the take a look at if the brand new seals and fueling course of have been profitable in stopping a reoccurrence of the leak. Nonetheless, that alone is not going to be sufficient to clear the best way for a Sept. 27 launch try, the subsequent out there alternative. NASA continues to be working with the U.S. Area Pressure, which operates the Japanese Vary, to acquire a waiver for the SLS flight termination system (FTS). That system’s certification expired after the final SLS launch try.
“Proper now, we’re nonetheless within the course of of getting technical discussions with the vary. It’s been very productive and collaborative. We simply must see the place these dialogue take us,” Whitmeyer stated.
A choice on an FTS waiver will not be anticipated till after the tanking take a look at, Jim Free, NASA affiliate administrator for exploration methods improvement, stated in a Sept. 18 presentation on the Worldwide Astronautical Congress right here.
Approval of the FTS waiver, and of a Sept. 27 launch, might come all the way down to the wire. A mission administration group assembly is scheduled for Sept. 25, stated Sarafin, a “formal resolution gate the place we are going to determine on whether or not we wish to proceed that individual try.”
A choice might come sooner, he added. “It will depend on what the end result of Wednesday is and what, if something, we have to change or be taught between from time to time.”