Boeing's Starliner (CST-100) - Discussion Thread 6

#940 by Vettedrmr on 31 Jul, 2023 23:27
Quote from: Vahe231991 on 31 Jul, 2023 23:18
I can't be sure why flammable tape was used as protective cover for the wiring harnesses throughout the Starliner capsule during construction of the spacecraft.

AIUI the part number for the flame-proof (resistant?) tape only has one different digit. A simple mistake, for sure, compounded at every inspection point along the way. That's my biggest takeaway from this; a huge QC error for a vehicle/program that has already had way too many black eyes in the QC department.
#941 by mn on 01 Aug, 2023 00:31
Quote from: Vettedrmr on 31 Jul, 2023 23:27
Quote from: Vahe231991 on 31 Jul, 2023 23:18
I can't be sure why flammable tape was used as protective cover for the wiring harnesses throughout the Starliner capsule during construction of the spacecraft.

AIUI the part number for the flame-proof (resistant?) tape only has one different digit. A simple mistake, for sure, compounded at every inspection point along the way. That's my biggest takeaway from this; a huge QC error for a vehicle/program that has already had way too many black eyes in the QC department.

I can't imagine they did this kind of mistake and missed it in every checkpoint.

I was under the impression that it was more like this tape is flammable over x temperature, original analysis showed that they would never exceed that temperature, further analysis showed that some spots could reach that temperature.

(I don't remember if I read that somewhere as a fact or just someone guessing)
#942 by Vettedrmr on 01 Aug, 2023 02:19
Quote from: mn on 01 Aug, 2023 00:31
I can't imagine they did this kind of mistake and missed it in every checkpoint.

I was under the impression that it was more like this tape is flammable over x temperature, original analysis showed that they would never exceed that temperature, further analysis showed that some spots could reach that temperature.

(I don't remember if I read that somewhere as a fact or just someone guessing)

It took some digging, but I found the discussion that I was thinking of, a well-written comment on one of Eric Burger's articles on Ars Technica. It's comment #322:

https://arstechnica.com/civis/threads/boeing-stands-down-from-starliner-launch-to-address-recently-found-problems.1492401/page-9

Then there's this post earlier on this thread about the two types of tape (#791 on page 40).

For whatever reason, it's still a mess.
#943 by Steven Pietrobon on 02 Aug, 2023 08:14
The two tapes in question. Seems like P213 was used instead of P212.

P212. Silicon adhesive with up to 200 C insulation.
https://www.nitto.com/au/en/products/e_parts/heat_resistant020/

P213. Acrylic adhesive with up to 155 C insulation.
https://www.nitto.com/au/en/products/e_parts/heat_resistant022/

212.pdf

213.pdf
#944 by clongton on 02 Aug, 2023 11:58
If P212 was specified but P213 was used instead, then that is pure incompetence.
#945 by 24Launch on 02 Aug, 2023 19:55
It begs the question, with the higher heat resistance of P212, is there a higher cost? Could this have been a "155 C should be sufficient" cost cutting measure?
#946 by mn on 02 Aug, 2023 20:10
Quote from: 24Launch on 02 Aug, 2023 19:55
It begs the question, with the higher heat resistance of P212, is there a higher cost? Could this have been a "155 C should be sufficient" cost cutting measure?

Everything has tradeoffs, apparently the P213 is better for some other reasons, so preferable if you don't expect to get anywhere near 155C

(Going back to what I read somewhere regarding the current starliner issue, but can't remember where - likely somewhere on NSF but not sure)
#947 by whitelancer64 on 02 Aug, 2023 20:19
Quote from: Vahe231991 on 31 Jul, 2023 23:18
Quote from: SteveU on 31 Jul, 2023 22:42
Question for those with more experience and insight. Is it possible that Boing and NASA are now being extra careful and slow walking to the manned launch because 1) they cannot survive the PR s. storm that would hit if there was a problem, and 2) with SpaceX doing manned launches there’s no need to rush?

The latest delay for the CFT mission was announced due to the flammable nature of the tape covering the wiring harnesses throughout the Starliner capsule and botched parachute lines. I can't be sure why flammable tape was used as protective cover for the wiring harnesses throughout the Starliner capsule during construction of the spacecraft.

The tape in question, P-213 acrylic glass cloth tape, is used throughout the aerospace industry, its primary use is as anti-chafing protective wrap around wires. AIUI, the tape was found to ignite under high voltage conditions if the insulation on wires are broken within it, which is exactly what the tape is there to prevent. As a precaution, Boeing is removing most of the tape from Starliner, they are already in the process of doing this.

The soft link design is fine for 3 good parachutes. Again AIUI, recent modeling showed that in certain off nominal scenarios with one parachute failing, the soft links can be stressed beyond their rated strength. It should be noted that Starliner's parachutes went through multiple parachute-out tests, including the pad abort test (where a parachute out was not intended), and was fine. However, a replacement soft link joint has already been identified and is in testing.

My understanding is that both issues are edge cases that passed all of the engineering design reviews and testing, but were only found recently.
#948 by Nomadd on 02 Aug, 2023 20:24
I'm starting to think the roots of "root cause" are getting a little too deep on this one.
#949 by whitelancer64 on 02 Aug, 2023 20:42
Quote from: Nomadd on 02 Aug, 2023 20:24
I'm starting to think the roots of "root cause" are getting a little too deep on this one.

Root causes are always (if you've done the fault tree correctly) high level management / engineering decisions. It's worth remembering that such decisions might have been correct at the time, but were later found to be insufficient for one reason or another.
#950 by ccdengr on 02 Aug, 2023 20:44
Quote from: mn on 02 Aug, 2023 20:10
Everything has tradeoffs, apparently the P213 is better for some other reasons
Like low outgassing, the P212 datasheet says nothing about this.

One wonders what kind of tape they used on Dragon.
#951 by whitelancer64 on 02 Aug, 2023 20:53
Quote from: ccdengr on 02 Aug, 2023 20:44
Quote from: mn on 02 Aug, 2023 20:10
Everything has tradeoffs, apparently the P213 is better for some other reasons
Like low outgassing, the P212 datasheet says nothing about this.

One wonders what kind of tape they used on Dragon.

I don't know for sure, but I think we can say with some confidence that Dragon has P-213 tape in it. Its use as an anti-chafing overwrap is standard practice in the aerospace industry.
#952 by Nomadd on 02 Aug, 2023 21:01
Quote from: ccdengr on 02 Aug, 2023 20:44
Quote from: mn on 02 Aug, 2023 20:10
Everything has tradeoffs, apparently the P213 is better for some other reasons
Like low outgassing, the P212 datasheet says nothing about this.

One wonders what kind of tape they used on Dragon.

I'd think outgassing specs would be an extremely basic part of flammability.
#953 by ccdengr on 02 Aug, 2023 21:07
Quote from: Nomadd on 02 Aug, 2023 21:01
I'd think outgassing specs would be an extremely basic part of flammability.
No, I'm talking about outgassing in vacuum. From https://www.nitto.com/us/en/others/products/file/datasheet/PDS_NA_Glass_Cloth_Tape_P-213LW_012020_EN.pdf

Quote
experiences minimal out gassing under high vacuum conditions,
making P-213LW ideal for use in outer space applications

The P-212 datasheet says nothing like this.
#954 by SWGlassPit on 03 Aug, 2023 16:05
Quote from: ccdengr on 02 Aug, 2023 21:07

The P-212 datasheet says nothing like this.

Yeah, in general, silicone (which P212 uses) is a pretty terrible material to use if you are concerned about outgassing. If you look on the exterior of ISS, you can see all sorts of brown stains in the areas where silicone was used heavily.
#955 by Vahe231991 on 07 Aug, 2023 14:51
Since Boeing now wants to have the CFT take place in March 2024, I'm curious as to why the parachute lines for the Starliner capsule to be used in the CFT mission got botched during the process of manufacturing.

I might feel tempted to expect NASA to notify Boeing later this year that no more Starliner flights will be contracted once the CFT and all six operational Starliner missions are completed because Boeing has proven time and time again the true underdog in getting a new-generation manned spacecraft into orbit.
#956 by whitelancer64 on 07 Aug, 2023 15:25
Quote from: Vahe231991 on 07 Aug, 2023 14:51
Since Boeing now wants to have the CFT take place in March 2024, I'm curious as to why the parachute lines for the Starliner capsule to be used in the CFT mission got botched during the process of manufacturing.

I might feel tempted to expect NASA to notify Boeing later this year that no more Starliner flights will be contracted once the CFT and all six operational Starliner missions are completed because Boeing has proven time and time again the true underdog in getting a new-generation manned spacecraft into orbit.

They were not botched during manufacturing.

A new analysis found that the soft links (the loop of cord which connect a riser to the parachute lines), under certain parachute-out conditions, could exceed their rated strength. Boeing has already identified a replacement soft link and it is in testing. There will be a parachute test in a few months to validate the new part.

NASA is very unlikely to tell Boeing that with that reasoning, however, Boeing likely will not get any further flights to the ISS. One Starliner flight per year will fulfil their contractual requirements to the planned end of the ISS's life.
#957 by DanClemmensen on 07 Aug, 2023 15:38
Quote from: Vahe231991 on 07 Aug, 2023 14:51
Since Boeing now wants to have the CFT take place in March 2024, I'm curious as to why the parachute lines for the Starliner capsule to be used in the CFT mission got botched during the process of manufacturing.

I might feel tempted to expect NASA to notify Boeing later this year that no more Starliner flights will be contracted once the CFT and all six operational Starliner missions are completed because Boeing has proven time and time again the true underdog in getting a new-generation manned spacecraft into orbit.
There is no requirement for a formal notification from NASA about a hypothetical follow-on contract.

As far as we know, the plan is still for alternating CCP between Crew Dragon and Starliner, so each gets one flight a year. If Boeing manages to fly Starliner-1 in 2025, Starliner-6 would be in 2030, the last year of ISS.

The only way Boeing can fly more than six operational missions is to get a non-CCP customer, and beyond six also requires getting crew-certified for Starliner on Vulcan (or some other launcher) because there are only enough remaining Altas V for CFT and six operational flights.

I speculate that the cost to ULA to keep Atlas V operational until 2030 to support only a single customer will be high. Boeing owns 50% of ULA, so this cost will hurt Boeing also. The Starliner 2014 contract was fixed price, IDIQ (indefinite delivery, indefinite quantity), originally for from two to six flights, but in 2018 Boeing forced a change committing NASA to buy all six, so it's now "IDFQ". Boeing is stuck with this and NASA has no particular reason to be nice to them.

SpaceX claims that each Crew Dragon capsule is now good for 15 uses. If NASA agrees, there is no further need for Starliner, and NASA and Boeing would be in better shape if they simply agreed to cancel Starliner now.
#958 by whitelancer64 on 07 Aug, 2023 15:45
Quote from: DanClemmensen on 07 Aug, 2023 15:38
*snip*

I speculate that the cost to ULA to keep Atlas V operational until 2030 to support only a single customer will be high. Boeing owns 50% of ULA, so this cost will hurt Boeing also. The Starliner 2014 contract was fixed price, IDIQ (indefinite delivery, indefinite quantity), originally for from two to six flights, but in 2018 Boeing forced a change committing NASA to buy all six, so it's now "IDFQ". Boeing is stuck with this and NASA has no particular reason to be nice to them.

SpaceX claims that each Crew Dragon capsule is now good for 15 uses. If NASA agrees, there is no further need for Starliner, and NASA and Boeing would be in better shape if they simply agreed to cancel Starliner now.

Cost for ULA continuing to support Atlas is not high. The high bay at LC-41 is already configured for dual-use.

Boeing wouldn't be in better shape, they'd be missing out on all the milestone-based payments they haven't achieved yet. They want to claw back as much of their losses as they can.
#959 by Jim on 07 Aug, 2023 15:45
Quote from: DanClemmensen on 07 Aug, 2023 15:38
If NASA agrees, there is no further need for Starliner, and NASA and Boeing would be in better shape if they simply agreed to cancel Starliner now.

not true