NASA set for “kinder, gentler” SLS tanking test

PARIS — NASA officers say they’re able to attempt a brand new strategy to fueling the House Launch System to stop the return of leaks that scrubbed an earlier launch try although they aren’t sure what induced 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 traces into the core stage, in addition to different adjustments in procedures, get rid of a big leak seen within the second try to launch the rocket on the Artemis 1 mission Sept. 3. Controllers noticed concentrations of hydrogen within the enclosure across the connection no less than 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 international object particles, mentioned Mike Sarafin, NASA Artemis mission supervisor. The scale of the indentation was about 0.25 millimeters. “An indentation of that measurement does present a chance for a pressurized fuel to leak by that,” particularly hydrogen, he mentioned.

Nevertheless, later within the name company officers backed away from the speculation that the international object particles induced 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 would have created the indentation. We consider that indentation is in line with the leak, however we don’t absolutely know that, both,” mentioned John Blevins, NASA SLS chief engineer.

Tom Whitmeyer, deputy affiliate administrator for widespread exploration techniques 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 actually a couple of facet for this situation that we don’t actually absolutely perceive,” he mentioned. “We’ve checked out each path potential that could possibly be associated to it and ensuring that we’ve accomplished every part we will.”

That features a new “kinder, gentler” loading strategy for liquid hydrogen, utilizing much less stress to push liquid hydrogen by the traces into the core stage. “We’re attempting to reduce each stress spikes and thermal spikes,” mentioned Jeremy Parsons, deputy supervisor of the Exploration Floor Methods program. “The crew feels this helps mitigate a number of the dangers.”

Company officers mentioned they need to know fairly rapidly 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. Nevertheless, that alone won’t be sufficient to clear the way in which for a Sept. 27 launch try, the following out there alternative. NASA continues to be working with the U.S. House Drive, 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 mentioned.

A call on an FTS waiver is just not anticipated till after the tanking take a look at, Jim Free, NASA affiliate administrator for exploration techniques improvement, mentioned 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 right down to the wire. A mission administration crew assembly is scheduled for Sept. 25, mentioned Sarafin, a “formal choice gate the place we’ll resolve on whether or not we wish to proceed that exact try.”

A call might come sooner, he added. “It relies on what the result of Wednesday is and what, if something, we have to change or study between every now and then.”


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