Updates SLS Updates

[DaveS]

Up until now, all of the major problems encountered has been on the ground side, not the vehicle the side. The two hydrogen leaks were with the QDs on the hydrogen Tail Service Mast Umbilical (TSMU) which are GSE on the ML itself, so ML problems. The ICPS helium checkvalve issue turned out to be FOD and not a valve problem at all, once the FOD had been removed, the valve worked normally again and has been ever since, it was never replaced. It is however unknown where the FOD came from, but it is highly suspected that the ICPSU on the ML might be the source, so again an ML problem.

Today was the first time that they encountered significant vehicle problems, the Engine 3 bleed issue and the vent valve issue. The vent valve however has been checked out multiple times including during the last WDR and it always worked fine so it will be interesting to see the root cause of that one. The Engine 3 bleed issue seems to be not in the engine itself but rather the egine bleed plumbing in the Engine Section as the other three engines were also off but still within their LCCs. A forward plan will be presented to the MMT tomorrow after the team had some time to rest and study the data more closely.

 

[GLS]

https://twitter.com/i/web/status/1564737323094384641

https://twitter.com/i/web/status/1564754146212937728

https://twitter.com/i/web/status/1564754386139717632

https://twitter.com/i/web/status/1564755662516764674

https://twitter.com/i/web/status/1564755755038801921

https://twitter.com/cbs_spacenews/status/1564755851818287104

 

[Thunder Chicken]

https://twitter.com/i/web/status/1564737323094384641

https://twitter.com/i/web/status/1564754146212937728

https://twitter.com/i/web/status/1564754386139717632

https://twitter.com/i/web/status/1564755662516764674

https://twitter.com/i/web/status/1564755755038801921

https://twitter.com/cbs_spacenews/status/1564755851818287104

What everyone forgets is that temperature sensors indicate the temperature of the sensor, which may be derived from some unholy combination of steady and transient heat conduction and convection and even radiation from different sources and sinks of heat in the system surrounding the sensor. Just because it is poked into a H2 line doesn't necessarily mean it is giving an unbiased real-time H2 temperature, even if it isn't faulty.

But again, this is something that should have been worked out during a wet dress rehearsal, not a launch attempt. They even mention that they they changed their operating parameters from the Green Run testing where these temperatures were apparently nominal. This testing and fault-correcting is a very necessary activity, but it damages NASA public relations when they say they are ready for flight but really don't quite have everything sorted out.

 

[GLS]

https://twitter.com/i/web/status/1565168302095302657

 

[DaveS]

 

[GLS]

Turns out the famous sensor isn't one that the engine controller uses to verify that the engine is ready for ignition, but one just used to confirm that the turbopump bearings are at temperature that reduces bearing wear during ignition.

https://twitter.com/i/web/status/1565470274761392128

 

[Thunder Chicken]

https://twitter.com/i/web/status/1566072010316333062

Gah..

 

[clipper]

Looks like the journey back to VAB is likely at this point:

https://twitter.com/i/web/status/1566088891395883009

 

[APDAF]

Can't wait for all the Elon fanboys to demand all Artemis funding be given to Starship.

 

[steph]

Looks like the journey back to VAB is likely at this point:

https://twitter.com/i/web/status/1566088891395883009

Nope. They try again on Tuesday

 

[clipper]

Nope. They try again on Tuesday

We'll find out soon enough

https://twitter.com/i/web/status/1566104350635835393

 

[Thunder Chicken]

NASA Live

NASA launches, landings, and events. Watch live broadcasts from NASA Television and NASA's social media channels, and a schedule of upcoming live events including news briefings, launches and landings.

www.nasa.gov

Now saying 1630 ET for briefing.

The music makes me feel like I am on hold with an insurance company.

 

[Thunder Chicken]

It seems that there was some improper command sequence to open a series of valves, leading to an over-pressurization, which may or may not have been associated with the hydrogen leak.

It seems they are going to stay on the pad for the time being, but a rollback is still on the table. Looks like they have a lot to sort out yet.

 

[Thunder Chicken]

Ooof...

https://twitter.com/i/web/status/1566135021823528960

 

[Thunder Chicken]

I'm seeing tweets about a NET October 17 launch attempt, but nothing official.

 

[DaveS]

I'm seeing tweets about a NET October 17 launch attempt, but nothing official.

That is based on the need to return to the VAB to re-certify the FTS as the Eastern Range have only certified it for 25 days on SLS. And that clock started when they did the End-To-End (ETE) test in the VAB prior to rollout. It was the last pre-rollout test done. And that test was done pretty much a month ago right now, so the clock is about to expire. So the two options right now are:
A)Get the ER to agree to an extension on the FTS beyond the 25 days, this would allow a stay at the pad
B)Rollback to the VAB, changeout the FTS batteries and re-do the FTS ETE test to get another 25 days from the start of the new ETE test for the mid-October launch period

 

[jarmonik]

I almost can't believe this, are we actually going back to the Moon during my lifetime. Seeing a rocket on a launchpad ready to launch and capable of bringing mankind back to the moon really brings my hopes up.

 

[Matias Saibene]

I almost can't believe this, are we actually going back to the Moon during my lifetime. Seeing a rocket on a launchpad ready to launch and capable of bringing mankind back to the moon really brings my hopes up.

I think the same, here is my list of things to see in this life.
SLS and return to the Moon.
ITER and the success of nuclear fusion in the fight against climate change.
*GNU Hurd 1.

*Dreaming costs nothing.

 

[richfororbit]

May be a Monday launch.

There is the talk of next month.

I was thinking had this been a meet with life from another world, the Astronauts would be late. So much for being to travel a few million miles.



Well for the next mission, obviously a bit of delay with this mission being slow to get going.

 

[Thunder Chicken]

That is based on the need to return to the VAB to re-certify the FTS as the Eastern Range have only certified it for 25 days on SLS. And that clock started when they did the End-To-End (ETE) test in the VAB prior to rollout. It was the last pre-rollout test done. And that test was done pretty much a month ago right now, so the clock is about to expire. So the two options right now are:
A)Get the ER to agree to an extension on the FTS beyond the 25 days, this would allow a stay at the pad
B)Rollback to the VAB, changeout the FTS batteries and re-do the FTS ETE test to get another 25 days from the start of the new ETE test for the mid-October launch period

Wait...they already have extended the certification window for the FTS from 20 to 25 days:

NASA, Space Force resolve SLS flight termination system issue - SpaceNews

NASA and the U.S. Space Force have resolved an issue with the flight termination system on the SLS that could have cut short the vehicle’s launch window.

spacenews.com

I'm presuming that there are some very valid engineering reasons on why the FTS needs to be retested and recertified, that it's not some bureaucratic paper-shuffling nonsense. I mean, if SLS decides it really wants to head to Miami, that's bad, right? And we'd like that FTS to be reliable in that instance?

I haven't been very excited by SLS as the whole mission for it seems ill-defined, but now I absolutely dread it flying. They are struggling with H2 leaks in an engine and propellant system forced on them by Congress, the project is well over-budget, and now the margins are getting squeezed. What a mess. I'm hoping it blows up on the pad now so it doesn't kill anybody. I am getting pre-Challenger vibes from this whole thing.