Artemis 1 going to the Moon (launched Nov 16)

[mfb]

NASA wants to fix the hydrogen issue with the rocket on the pad. That could allow a launch in the second half of September, and it will mean more time for tests with the rocket and the launch tower. Downside: The certification for the flight termination system runs out and they can't access it, so this plan only works if they get an extension. This is not a new constraint - I would expect that NASA applied for it long ago. Would be a strange coincidence if the normal process was almost done just at the time they need it, so I'm not sure what's going on.
If they don't get that extension the vehicle needs to roll back.

 

[.Scott]

NASA wants to fix the hydrogen issue with the rocket on the pad. That could allow a launch in the second half of September, and it will mean more time for tests with the rocket and the launch tower. Downside: The certification for the flight termination system runs out and they can't access it, so this plan only works if they get an extension. This is not a new constraint - I would expect that NASA applied for it long ago. Would be a strange coincidence if the normal process was almost done just at the time they need it, so I'm not sure what's going on.
If they don't get that extension the vehicle needs to roll back.

From what I have read, the purpose in doing the work at the pad is to actually work the problem with the plumbing attached.

The last I read about the schedule was like this one from livesciences:

After the launch was called off, NASA Administrator Bill Nelson said the rocket's next launch window will open in early October, but because other missions will be prioritized over Artemis 1, the third launch attempt likely will fall in the middle of the month.

The recertification relates to the flight termination system. It expires because there are batteries that need to be replaced. Those batteries can only be replaced with SLS in the VAB. At this point, it seems as though a visit to the VAB is unavoidable.

However! :
We should be getting additional details 75 minutes from now.
Nasa has scheduled a livestream report on this at 11am ET.

 

[.Scott]

Per the 11am call:

They need to comply with test range requirements.
They are asking for a waiver to extend their FTS batteries retest requirements (to avoid the VAB visit).
(batteries are mostly on the core stage - one for each "command receiver/decoder")
Need to deconflict with DART mission's use of Deep Space Network.
Need to avoid Crew-5 with regards to replenishing issues at the range.

They need to remove and replace 4" and 8" seals on the quick disconnect lines. (at pad)
They reconnect and retest - all at pad.
Cryo event expected at 9/17 at pad.
Tanking process will now involve more smooth-flow fueling.

They have asked for the launch test range for Sept 23 and 27.

Also: There was an inadvertent Saturday pressure rise of the H2 lines over the interface spec. This was the result of late changes to the fuel loading procedure. Unknown if that was a cause of the leak.

 

[mfb]

Launch dates in late September / early October

Crew-5 is planned for October 3. Moving that back a few days would be possible - the weather might do that anyway - but moving it more would need more changes to the ISS schedule.

There is another certification limit: It can only go back to the VAB two more times. Of course, as with all other certifications, this might get extended if necessary.

 

[.Scott]

The FTS battery limit could be a problem. The original limit was 20 days based on the device spec. It was already waived to 25 days based on actual observed battery performance. Bumping it to 40+ days could be a non-starter. A visit to the VAB may be unavoidable.

 

[mfb]

NASA wouldn't keep the rocket on the pad if they were not pretty confident to get that extension.

Repair work is ongoing and they want to a test tanking next Saturday.

 

[.Scott]

NASA wouldn't keep the rocket on the pad if they were not pretty confident to get that extension.

Repair work is ongoing and they want to a test tanking next Saturday.

Up until Sept. 17, it's been on the pad because the leak is at the Rapid Disconnect seals. They have needed at the pad to see the problem and repair it. It needs to remain there until the repair is tested (now scheduled for the 17th).

If they get the FTS battery extension, it raises this question: When the 20-day to 25-day extension was granted, why didn't the analysis support an extension to 40+ days? Or, if it did, why was it not immediately extended to 40+ days?

 

[.Scott]

According to "Florida Today", the cryo test will be No Earlier Than (NET) 9/21 and the launch will be NET 9/27.

In that same article:

But avoiding a rollback is dependent on the Space Force: the military branch is responsible for public safety and requires the rocket's flight termination system, or FTS, be recertified every 25 days. The current certification for the FTS, which is designed to destroy the rocket in the event of an emergency, expired Sept. 6.

Officials said they submitted FTS extension requests with the range and are waiting for a response.

9/27 would put the battery period at 46 days. Space Force needs to start with the assumption that there is no FTS until demonstrated otherwise. So they could clear the launch without a VAB visit if it can be safely done with no FTS (not a prayer) or if there is solid reason to believe that the FTS would work (sound like a stretch to me).
The only reasons I see for hope is that 1) An extension was submitted - so they must have come up with some argument; and 2) Space Force hasn't already ended this conversation.

 

[mfb]

So they could clear the launch without a VAB visit if it can be safely done with no FTS (not a prayer)

I don't see that happening. The rocket is big and you can't shut down the SRBs. If the system breaks apart and can't be destroyed they could end up anywhere.

or if there is solid reason to believe that the FTS would work

NASA wouldn't plan with an extension without good arguments for that. But I don't understand why they weren't pushing for a longer certification period earlier.

 

[.Scott]

NASA wouldn't plan with an extension without good arguments for that. But I don't understand why they weren't pushing for a longer certification period earlier.

I don't either. And I'm wondering whether the reason that Space Force hasn't put a quick kibosh to a 45-day extension is that after the next cryo test it could become a 65-day extension. NASA's been struggling with LH2 leaks for decades.

 

[mfb]

No official word yet, but I have heard that there are two ways forward:

* They get the FTS extension, launch September 27 or October 2, if that doesn't work back to VAB for a launch not before the November 12-27 launch window.
* They don't get the FTS extension, back to VAB immediately and maybe catch the launch window October 17-31.

Crew-5 is planned for October 3, so the October 2 launch date needs some extra coordination to prepare both rockets in parallel.

 

[.Scott]

No official word yet, but I have heard that there are two ways forward ...

Perhaps NASA's history with LH2 might steer you toward a more pessimistic launch date.

 

[mfb]

More delays are always possible, but these are time ranges where we can expect launch attempts at least.

 

[.Scott]

The fueling test is tomorrow: space.com
According to another website, work starts at 7:15am tomorrow.

 

[mfb]

Tanking test has started

The first components are being chilled down now.

 

[.Scott]

Tanking began at 9:09am ET. Hydrogen "Fast fill" is expected at about 10:30am. Completion at about 3:30pm.
So far, so good.

Hydrogen "Fast Fill" will start sooner. NASA reports that the Hydrogen temperature inlet sensor was not working - and that has affected the Liquid Hydrogen (LH) "Fast Fill" time. Apparently it was expected to start at 10:30am based on that faulty sensor. It is now expected to start earlier.

The LH Fast Fill is where the failure occurred during the last launch attempt - a couple of weeks ago. However, at this moment (10:02am), they are at LH "stop flow".

The LH "stop flow" was triggered by a hydrogen leak. The leak ended on "stop flow".

 

[mfb]

The LH "stop flow" was triggered by a hydrogen leak.

6 attempts to fill the rocket on the pad, 6 hydrogen leaks despite repairs between the attempts.

 

[.Scott]

6 attempts to fill the rocket on the pad, 6 hydrogen leaks despite repairs between the attempts.

At 10:13: The "leak team" has just reported to the launch director that the leak profile is identical to the leaks during those previous attempts. They will attempt to cycle temperatures in an attempt to better seat the connection. Next attempt around 10:45am.

 

[PeroK]

At 10:13: The "leak team" has just reported to the launch director that the leak profile is identical to the leaks during those previous attempts. They will attempt to cycle temperatures in an attempt to better seat the connection. Next attempt around 10:45am.

Why do things not work these days? Perhaps that's an unfair assessment?

 

[.Scott]

Why do things not work these days? Perhaps that's an unfair assessment?

NASA has never "mastered" LH fueling - in the sense that they can created results that matched the design intent on the first try.
In this case, the NASA live coverage is reporting that today's fault is identical to the Quick Disconnect fault that happened on Sept 3rd.

 

[fresh_42]

Why do things not work these days? Perhaps that's an unfair assessment?

I have heard today about regulations here concerning fire prevention after a major fire at an airport years ago. Someone commented on them as overregulation that hinders efficiency too restrictively. I could imagine that NASA suffers similar problems after the shuttle disasters.

 

[.Scott]

I have heard today about regulations here concerning fire prevention after a major fire at an airport years ago. Someone commented on them as overregulation that hinders efficiency too restrictively. I could imagine that NASA suffers similar problems after the shuttle disasters.

It doesn't sound "too restrictive" to me. The LH leak limit is 4%, they are seeing "7% concentration". I have not been able to find an exact and explicit description of what the numerator and denominator are in that 4% limit. However, this LH leak is into an environment rich in O2 - because the LOX also leaks and because there is O2 condensation.

Also, the temperature cycling procedure they are using now was tried twice on Sept 3rd to no advantage.

 

[.Scott]

11:08am: Temperature cycling complete. New plan: when refueling (LH) this time with a pressure reduction in the storage tank to only 5psi and then a very slow LH pressure build-up.

They have also repeated that the leak stopped immediately after the flow stopped.

 

[.Scott]

11:35am NASA Announcement: They are in LH Fast Fill - and apparently no important leak yet.
11:45am NASA Announcement: As the pressure increased, an 0.5% leak has developed.
The % measurement is the concentration of hydrogen in a cavity near the Quick Disconnect.
They are going to continue to increase pressure until the pressure reaches 10% (or the LH tank is full). So it will be allowed to pass the 4% limit.
11:51am: Pressure is up to the minimum required for tanking. H2 concentration in QD Cavity is still about 0.5%.

 

[mfb]

Hydrogen tanks are 27% full, now going up at a good rate.
If this were a launch attempt at the 27th the delay would have been too long for the launch window.

 

[.Scott]

The new concentration limit is actually "10% for 5 minutes" - with no further explanation. Not clear to me whether the 5 minutes starts at 4% or 10%.

12:07: 35% LH full, leak concentration is "under 1%" (no longer "about 0.5%").
12:12: Engine kick start bleed has started and is nominal. Leak rate now over 1%.
12:15: Leak concentration topped out at 3.4% with pressure sufficient for the kick start bleed.

 

[russ_watters]

It doesn't sound "too restrictive" to me. The LH leak limit is 4%, they are seeing "7% concentration". I have not been able to find an exact and explicit description of what the numerator and denominator are in that 4% limit.

That's the Lower Explosive Limit(LEL) volumetric (and molar) concentration for hydrogen. That they exceeded it means they had an explosive mixture. Really dangerous.

 

[.Scott]

That's the Lower Explosive Limit(LEL) volumetric (and molar) concentration for hydrogen. That they exceeded it means they had an explosive mixture. Really dangerous.

It's the H2 concentration in the LH QD Cavity. There are two mitigating issues regarding an explosion: 1) That cavity has no ignition sources. 2) The equipment in that region is pretty rugged - a moderate H2 "explosion" could be taken in stride.

But clearly, they are not being overly conservative.

12:25: 50% LH Full. LOX tank full.

 

[mfb]

2/3 full

A bit under 1% per minute, slower than nominal but likely enough for an actual launch attempt. They'll try filling with a higher pressure now to see how the leak behaves.

 

[.Scott]

12:43am NASA Announcement: LH 67% tank. NASA has decided to increase the storage tank pressure to nominal.

With the process based on the procedure up to this point, it would take about 2 hours to fill the LH tank.
The 10%, 5 minute limit would stop the fill at either 10% H2 concentration or 5 minutes past 4% concentration.

Also, that QD cavity is apparently pretty small - in the ball park of a few cubic feet.

 

[.Scott]

1:11pm NASA Announcement: They just reached "replenish" on the LH tank - so "Fast Fill" has completed successfully.

1:19pm: NASA decided earlier not to start the upper stage fueling on schedule. They are now deciding whether to go for that part of the test or not.

1:35pm: No news on the upper stage test - but NASA will be moving forward on the "prepres" test - bringing the tanks up to the flight pressure and and down to flight temperature levels.

Also, NASA has moved on to the upper stage fueling.

 

[.Scott]

2:07pm: Upper stage QD Boot Containment was lost. Has happened before. Doesn't sound very important.
2:11pm: Fast fill for both LOX and LH in upper stage.

(meanwhile - Elon says Starship flight very likely in November)

3:15pm NASA Announcement: Upper stage LH in the "Topping" stage.

The Prepress test is still expected today.

3:27pm: LH upper stage fill is complete.
3:32pm NASA Announcement: Go for the LH2 Prepress test. Replenish and fill and drain valves are closed. Tank vent valve close. Engine bleed with high flow. Simulates flight conditions.
3:36pm NASA Announcement: LH2 Pre-press test started. Upper stage LOX tank is continuing to load.

The Pre-press is the last item on the original checklist for a launch attempt. This doesn't mean that 9/27 launch attempt is go, but its one less item that could stop it.

3:44pm NASA Announcement: LH Leaking crossed the 4% concentration limit - and is holding at about 4%. But this was the 4-inch LH bleed quick-disconnect - not the 8-inch LH feed one that was causing the problem earlier.
3:45pm NASA Announcement: Upper stage LOX fill has completed.
3:48pm NASA Announcement: The pressure test target pressure has been reached. The Pre-press test is complete.

3:56pm NASA Announcement: Core tank is in replenish.
4:12pm NASA Announcement: Pre-press test was successful - and the pressure control was good enough to complete the test in only 15 minutes.
The 4-inch bleed QD reached a little over 5% - but it lowered on its own. In an actual launch, it would have stopped the launch.
4:15pm: LOX Upper stage is nearing completion.

4:31pm: A final replenish test was just completed. That was the last test. They are go for "cutoff" (the simulated countdown) and detanking.

- - -

 

[.Scott]

There was actually more information about how the testing was progressing than you commonly get with a SpaceX test.

There was more information about that FTS battery issue. It's sounding to me like the 25-day limit is tied a lot more to guaranteeing regular FTS equipment access to the Range (Space Force) than it is to what might reasonably cause an FTS equipment malfunction. -- So I am a lot more optimistic about NASA getting an extension on the FTS waiver.

I wouldn't guess about whether they will want to do another test before the launch. Sounds like a close call to me.

And .. https://www.nasaspaceflight.com/ announced that they will now have a 24/7 video feed of the NASA Florida launch complex.

 

[mfb]

Artemis Cryogenic Demonstration Test Concludes, All Objectives Met

No commitment to the September 27 date yet, but this seems to be the goal.

 

[.Scott]

NASA announced that this test went well enough to go for a 9/27 launch.
This topic will be discussed on NASA Live in 2 hours (12:30pm ET 9/23/2022).

The press release is at: https://www.nasa.gov/press-release/...pdate-on-demonstration-test-artemis-i-mission

"Based on data from the test, teams are fine-tuning procedures for the next launch opportunity, targeted for no earlier than Sept. 27. The rocket remains in a safe and flight-ready configuration at the launch pad."