Artemis

[Dakota Tebaldi]

Yesterday the Artemis launch team carried out a bunch of tests to assess the repairs done to the seals on the hydrogen fill-line quick-disconnect fitting, the one that's been having the leak problems. The engineers had in fact discover an imperfection in the seal they removed, which they believe could have been responsible for the leak. So yesterday the SLS rocket went through a complete tanking - the same sequence that would be used to fuel the rocket for actual launch - so the pre-chill, the slow-fill, the fast-fill, the topping, and finally the replenish phase (where an exact amount of hydrogen is continuously added to replace the cryogenic hydrogen as it boils off, to keep the level the same). Everything worked great, with all seepage well below the constraints. They also did a kick-start engine bleed, where the liquid oxygen and hydrogen fuel lines through, around, and into the engine are primed and the engine chilled for ignition - if you remember during the first launch attempt, one of the engines' sensor readings indicated that engine wasn't bleeding correctly, which turned out to be a bad sensor rather than an actual problem with the engine. Well, this engine bleed test went great too, with no problems. On their conference call today, the launch team said that they are completely satisfied with all of the data from yesterday's testing and as far as they are concerned, the SLS rocket is totally in launch condition and ready to go for the next window, which is actually this coming Tuesday, the 27th.

There's an entirely new problem though.


This storm is currently forecast to become a hurricane and while the forecast is very uncertain at the moment, severe weather conditions COULD be impacting or at least coming uncomfortably close to the Space Coast late Tuesday or Wednesday. The launch window itself would MOST LIKELY come and go before the weather becomes an actual problem, but here's the thing - what if there's another scrub? Now the rocket might have to sit out in an actual hurricane.

So, even though engineers were successfully able to repair the seal problems at the launch pad, it may turn out that Artemis 1 has to be rolled back to the VAB anyway. The ground team is waiting for a major detailed weather report later this evening, and they may end up making the decision either tonight or early tomorrow on whether to roll back. The ground manager says he needs three days to roll back a launch-ready vehicle, so they will be getting it back to the VAB just in the nick of time, really, if they start late tomorrow.

 

[Govi]

Clearly, the NASA team should call in The Count of Mucho Crisco to use his Sharpie to change the course of the hurricane.

 

[Dakota Tebaldi]

NASA has decided they will not try for a September 27th launch. They have begun preparations for rolling Artemis 1 back to the VAB; however, the latest forecasts for now-Tropical Storm Ivan are pulling it west, further away from the Space Coast, and the forecast track may change even more in near-future forecasts, and the Cape may not experience any severe effects after all. Because of this, the ground team at Kennedy has adopted a modified rollback procedure, in which "non-interference" steps - in simplified terms, the parts of the preparations that don't involve disconnecting and unbolting the rocket and its tower from the launchpad - are all being done first as much as they can be, just in case an upcoming forecast solidifies that it's safe to leave Artemis at the pad. There will come a time tomorrow morning through when all that business HAS to go forward, so the final decision to roll or not to roll will have to be made by then.

 

[Dakota Tebaldi]

 

[Dakota Tebaldi]

Kennedy seemed to make it through the hurricane okay, although assessments are ongoing. One assessment that has been finished is of Artemis, and it looks like it was kept safe and sound inside the UAB.


In other news, Artemis 2's four engines have been delivered to New Orleans for installation!

 

[Argent Stonecutter]

UNBOXING VIDEO!

 

[Caete]

 

[Dakota Tebaldi]

 

[Dakota Tebaldi]

 

[Dakota Tebaldi]

Shortly after midnight this morning, Artemis 1's launch team arrived on station and the countdown for the next launch attempt began!

NASA is aiming for the launch window beginning at 1:04am EST on Wednesday, November 16, with full coverage starting at 10:30pm EST Tuesday night. Before that, lightly-commentated coverage of tanking procedures will begin at 3:30pm EST.

Artemis weathered Hurricane Nicole without any serious issues. Tomorrow, teams plan to replace an electrical data connector between the mast and the rocket, as there's some intermittent data transfer through it - but, this isn't a crucial repair and it won't stop the launch if the replacement doesn't fix the problem because there are redundant channels for that data and the others are working fine.

The only other problem is some "delaminated caulk" where the bottom of the launch abort system skirt meets the surface of the rocket. Tomorrow engineers are going to analyze whether there's any risk to anything important on the rocket should any of that caulk come loose and fall during the launch. My first instinct says no, as unlike with say the Space Shuttle, everything south of the crew module itself (which is covered by the abort system skirt and is above the caulk anyway) on the outside of the rocket is expended during the launch. Unlike the Service Module on Apollo which was exposed at the top of the rocket during launch, the European Service Module on Artemis is smaller in diameter than the crew module, and is completely enclosed within the shell of the crew module adapter segment. But, like, I'm not a NASA engineer, so my instinct isn't really connected with reality, lol.

At any rate, if neither of these problems is a showstopper, the weather for launch is looking 80% go right now.

 

[Dakota Tebaldi]

The launch countdown is currently in a planned hold at -6:40:00, and tanking has begun!

First up, the liquid oxygen and hydrogen transfer lines are being chilled. They're doing this VERY slowly, and it is a changed procedure from the one that was initially used. Engineers analyzing the leaks from the first couple launch attempts believe that some thermal imbalances during tanking were causing the leaky seals, so they've created this new procedure that lets just enough liquid propellant into the lines for it to quickly boil into gas, but that gas is still STUPID cold, and they're using it to do the main work of chilling all the lines and fittings. This should ensure that once the liquid starts actually flowing through the lines there will be very little further thermal compression.

The analysis team has concluded that the torn silicone caulking I mentioned last night, won't be a problem and the rocket is cleared for launch. The caulking was not there to seal any joints, but rather to fair a surface ridge (i.e., make it a bit smoother for the air that will be flowing over it while the rocket is flying); but it's more like just a little extra touch of gravy, not anything that's going to negatively affect the flight dynamics of the rocket.

Weather forecast is 90% go for the launch window.

 

[Dakota Tebaldi]

Chill complete! Liquid HYDROGEN slow-fill has begun...

ETA: Liquid OXYGEN slow-fill has now also started.

Remember that this is the filling of the core stage. Filling of the ICPS (the second stage) is separate and begins later, after fast-fill in the core stage is underway.

Fill 'er up!

 

[Dakota Tebaldi]

Liquid hydrogen transition from slow-fill to fast-fill is coming up soon. That is the point at which fittings in the fill line began to show leaks in previous launch attempts...

 

[Dakota Tebaldi]

Looks like everything is good so far!

According to the launch director just a few minutes ago, there is a very small but expected amount of hydrogen gas seeping from the fittings, but this time it's far within the constraint, and getting lower as tanking goes on which is also expected.

The leak was the big show-stopper the last couple of times. Has it been fixed?

 

[Dakota Tebaldi]

The planned hold has ended! T - 6:33:00 and counting!

Back in a couple of hours. But so far, everything is going fine with no issues to speak of. Engine bleed completed.

 

[Dakota Tebaldi]

Core stage liquid H2 and O2 tanks are now full and in "replenish" mode, where fuel is being added at the same rate it is boiling off, to keep the level at 100%. No known issues, AFAIK!

Upper stage H2 and O2 are currently in fast-fill.

-4:10:00 on the clock, although remember that at 10 minutes to launch there is a built-in 30-minute hold, which is to give the launch team a little extra time to resolve any outstanding issues. The hold happens no matter what, but the good news is that SO FAR there aren't any issues to work on.

 

[Dakota Tebaldi]

Nooooooo! ICPS liquid hydrogen fill has stopped, due to a detected leak!

This is a completely different leak from any of the previous ones, somewhere around a valve on the replenish line, located inside the mobile launcher - i.e., the big grey base the rocket and tower are sitting on. The launch director is sending a "red team" - a team specially trained to visit the pad while a fueled rocket is sitting on it - to have a look and see what's up. Right now they're thinking that just some bolts need to be tightened on the valve, but we'll see.

Still three and a half hours to go!

 

[Dakota Tebaldi]

The "red team" is on the way to the launchpad now. Once they arrive at the area of the valve, the task should take no more than 15 or 20 minutes. The team consists of two technicians and a safety lead. Let's see how it goes...

 

[Casey Pelous]

JFC.....

What kind of courage does it take to be on the Red Team? Those folks are just amazing.

Also, I volunteer for the Green Team.

 

[Dakota Tebaldi]

The red team has finished their work and is leaving the pad. It did take a little longer than they were expecting, but it SOUNDS like they got done what they wanted to get done. So we'll see if this fixed the problem or not, when they re-top the liquid H2 and start replenishing again.