NASA halts third attempt at SLS practice countdown

WASHINGTON — NASA lower quick a 3rd try and load propellants onto the Area Launch System for a countdown rehearsal April 14 after encountering a number of issues, together with a hydrogen leak.

NASA began loading liquid oxygen into the core stage of the SLS at Launch Complicated 39B round 9:30 a.m. Jap after a delay brought on by points with the availability of nitrogen fuel on the pad used to help tanking operations. Nevertheless, controllers stopped liquid oxygen loading shortly after starting preliminary “gradual fill” operations when a temperature restrict was exceeded.

NASA developed an answer to the problem, which the company didn’t instantly describe, and restarted liquid oxygen loading shortly earlier than 12 p.m. Jap. A few half-hour later, liquid hydrogen began flowing into the core stage, in accordance with updates offered by a NASA Twitter account.

Nevertheless, NASA mentioned shortly after 1 p.m. Jap that it halted loading of liquid hydrogen when engineers detected a surge in stress when transferring from the preliminary gradual fill of the propellant to quick fill. Controllers halted liquid oxygen loading to repair that drawback and go into what NASA known as a “modified” quick fill.

Controllers, although, stopped liquid hydrogen loading once more after detecting a leak in an umbilical line connecting the core stage to the tail service mast on the launch platform. At that time the core stage’s liquid oxygen tank was 49% full however the liquid hydrogen tank solely 5% full.

NASA successfully scrubbed the check round 4 p.m. Jap when it introduced it will not proceed filling the core stage tanks and as an alternative deal with chilling down propellant traces within the SLS’s higher stage. NASA managers beforehand determined to not fill the tanks on that higher stage on this check due to a defective helium examine valve within the stage.

It was not instantly clear when NASA would strive once more to finish the moist costume rehearsal of the SLS. NASA mentioned solely it will not proceed with the terminal stage of the countdown and as an alternative “will assess subsequent steps after at present’s operations.”

NASA scrubbed two earlier moist costume rehearsals of the SLS, though neither received fairly so far as this check. The primary, April 3, stopped earlier than propellant loading may start. The second, the subsequent day, additionally crammed the liquid oxygen tank within the core stage to about 50% however stopped earlier than liquid hydrogen loading may start due to a misconfigured valve on the cell launcher.

After the second try, technicians found the malfunctioning helium examine valve within the higher stage, main them to proceed with a modified plan for the moist costume rehearsal that didn’t contain filling that stage’s tanks with propellants. “We consider that we’ll be capable of meet the vast majority of our check targets and supply us with a fairly good set of knowledge previous to rollback” to the Car Meeting Constructing, mentioned Charlie Blackwell-Thompson, NASA Artemis launch director, throughout an April 11 name with reporters.

As with the primary two tanking assessments, the circulation of data was usually as irregular because the circulation of liquid hydrogen and liquid oxygen. NASA offered restricted updates through Twitter and a weblog. NASA beforehand claimed it couldn’t present extra detailed info, resembling launch commentary, due to issues it may launch info that’s topic to export controls.

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