Link here. The article provides more information on the temperature issue that caused the seventh of eight fueling tests of the core stage to abort early.
The temperature issue arose when NASA transferred superchilled liquid oxygen, to fuel the rocket, from a holding facility to the core stage of the SLS. This procedure has been modeled and verified before, Julie Bassler, SLS stages manager at Marshall, told reporters during the same teleconference. But this was the first time the transfer actually took place.
“We were actually just a few degrees different than what we wanted to see coming in,” she continued, but said the temperature must be precise during the initial phases of filling the tank. The requirement is minus 290.57 degrees Fahrenheit (minus 179.21 degrees Celsius.) But the liquid oxygen was slightly cooler, at minus 296.67 degrees Fahrenheit (minus 182.59 degrees Celsius).
“We filled up [the tank] just enough to pass the phase where we knew we weren’t going to be able to get the temperature to a level that was going to be acceptable to meet the requirement, and that’s when they caught us … in the testing,” Bassler continued.
Despite this issue, NASA still hopes to do the last core stage test, dubbed the Green Run, in the last week in December. During that static fire test they will fuel the core stage entirely and then fire its engines for the full duration of an actual launch — almost ten minutes. If all goes well they will then pack up the stage and ship it to Florida for the planned November unmanned test mission sending Orion around the Moon.
They have no schedule margins, however, because all the components of this very expensive and complex rocket need a lot of time to get anything done. The two solid rocket boosters that will be attached to the sides of the core stage only have a twelve month lifespan once assembled, and they are holding off assembling them pending this test. The core stage itself needs two months to be disassembled, and then two months to be reassembled in Florida. And there remain the issue of a failed power unit in the Orion capsule that could take four to twelve months to repair.
The article however had this telling quote, based on comments from a NASA official, about future launch procedures, that sent a chill up my spine:
Future missions of Artemis will not need a wet dress rehearsal or hot fire test as the SLS will already be certified for flight.
Future Artemis missions will also have people on them. This attitude, similar to NASA’s attitude during the shuttle era, makes too many risky assumptions about the reliability and safety of this new rocket. Just because they have run a single static fire test does not mean they have worked out all the kinks. SpaceX for example does such tests routinely on all engines being built, as well as full dress rehearsal countdowns and engine ignitions prior to every launch, just to make sure there isn’t something they might have missed.
During the shuttle era NASA had the same “No need for further tests” attitude, and this led to the loss of two shuttles, because NASA assumed that once they had achieved one launch they had solved all their engineering issues, and could stop looking. Thus, Challenger was lost during launch because of o-ring problems in the solid rocket boosters, and Columbia was lost on its way back to Earth because of damage sustained during launch by falling foam from the external tank. In both cases the problems had been seen in previous launches, but no one at NASA saw any reason to address them. The shuttle was “certified!” Only after people were killed did NASA fix these engineering faults.
If the Artemis missions do fly as NASA hopes, I will not be surprised if this continuing nonchalant approach causes more launch failures and the lose of more lives.
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