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#880
by
Surfdaddy
on 25 Jul, 2024 17:29
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I have a broader question. While other vehicles have had thruster problems in the past, are this vehicle's issues just being blown out of proportion from a news perspective, since it's Boeing/Starliner/and manned?
Or are these issues uncharacteristically bad for what we should expect from a capsule on its third flight using thruster technology that has been in use for decades?
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#881
by
OTV Booster
on 25 Jul, 2024 17:39
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I really don't want to get into egregious and uninformed Boeing bashing, so help me out here.
Were the thrusters not tested to the standard of 'test it like you fly it'?
The T in CFT stands for "test".
You cannot test everything on the ground, or analyze any possible combination of factors to arbitrary resolution. Otherwise, test flights would be superfluous.
To be fair, this sounds like an unexpected (but maneageable) situation that could conceivably have been considered during design, and tested analytically in a more thorough manner pre-flight. Yet it's also conceivable there were other more pressing issues at hand that weren't just "unexpected while manageable", but rather would constitute a more severe problem to the mission if they happened in flight.
It's not like this is an unforeseen use or a rare combination of random interactions. Using the thrusters within the expected operational envelope is where the failure occurred.
I have to quote my mentor and role model. "Duh!"
No wonder Boeing isn't persuing reusability. The MBA team hasn't figured out usability yet. I could go on and on about MBAs screwing up industries but that veers too far OT.
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#882
by
JayWee
on 25 Jul, 2024 17:51
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I really don't want to get into egregious and uninformed Boeing bashing, so help me out here.
Were the thrusters not tested to the standard of 'test it like you fly it'?
The T in CFT stands for "test".
You cannot test everything on the ground, or analyze any possible combination of factors to arbitrary resolution. Otherwise, test flights would be superfluous.
To be fair, this sounds like an unexpected (but maneageable) situation that could conceivably have been considered during design, and tested analytically in a more thorough manner pre-flight. Yet it's also conceivable there were other more pressing issues at hand that weren't just "unexpected while manageable", but rather would constitute a more severe problem to the mission if they happened in flight.
CFT can potentially run into a QA issue, but shouldn't run into what appears a design problem that should have been tested on the unmanned flight before.
Was the OFT-2 flight profile (which included docking) somehow different?
Also, didn't the original OFT-1 have crazy thruster firings, something where they could have seen the elevated temperatures too?
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#883
by
Targeteer
on 25 Jul, 2024 17:58
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There were other problems that no one asked about, and NASA and Boeing didn't mention. The journalists allow the agency to set the narrative by not bringing them up.
The unnecessary, in my humble opinion, questions about the thruster corrosion problems from 2021 wasted limited question time. The second question on the subject was just asinine. I think Steve Stich hinted at the CO2 sensor issue, maybe, when he briefly mentioned "erratic sensors".
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#884
by
eeergo
on 25 Jul, 2024 18:08
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There were other problems that no one asked about, and NASA and Boeing didn't mention. The journalists allow the agency to set the narrative by not bringing them up.
Care to elaborate what the other problems the narrative is being set up on are?
The crewed *test* flight should be a shakedown cruise to bolster already verified end to end performance, procedures, mission timelines, etc.
Im with OTV on this, the types of tests conducted at White Sands are what the qualification testing should have encompassed.
Arm waving that this is a "test" flight to justify a failed RCS system is not accurate.
As far as I'm concerned, there's indeed a grand amount of handwaving with this flight, but towards issues which were treated as routine IFAs during STS flights out of proportion, based on poor arguments that get disproven with every news release or study result, to then resurface anew unperturbed in spite of no evidence to their favor. The negative handwaving IMO includes having the RCS system described as "failed" when only 1 out of 28 RCS thrusters is conservatively kept offline and full functionality maintained even in the heat of the RCS issues during docking, by the way.
To both your and OTV's posts: Do you know that the conditions this thruster issue popped up in are NOT related to this being a crewed mission with hand-flown profiles requiring lingering in particular orientations? How would you go about testing that integrated regime on the ground? Why would you favor full-up testing of that regime as opposed to other extreme cases where problems might in principle also lurk, when you might be damaging entire SMs in the process, and your analyses are providing good enough results to ensure no major failure modes will occur? Unless you know the answers to those questions, it seems this is another acute case of "I know better than the engineers from the comfort of my couch" kind of strong statement.
Again, hindsight is 20/20 and I agree in principle that these issues could conceivably have been caught pre-flight in an ideal world - but engineering is never fully perfect, especially in tests, plus it will be bound by earthly constraints like time, effort and cost that limit studies of potential issues with complex degradation (not failure) modes when skirting some redundant limits just below impeccable performance.
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#885
by
eeergo
on 25 Jul, 2024 18:15
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CFT can potentially run into a QA issue, but shouldn't run into what appears a design problem that should have been tested on the unmanned flight before.
Was the OFT-2 flight profile (which included docking) somehow different?
Also, didn't the original OFT-1 have crazy thruster firings, something where they could have seen the elevated temperatures too?
OFT-1 was probably in a much different orientation still in battery power (hence with the rear solar panel not pointed at the Sun), and just off the LV when the firing craze happened. Also, I seem to recall it was in orbital night. So conditions would have been totally different.
Regarding OFT-2's profile and why this wasn't observed then, that's a question I missed someone asking at the press event (rather than having no less than 3 reporters push and prod the speakers to say the D word and state the obvious fact that, was the root cause of Starliner's issues not fully signed off in the coming days and some other problem discovered making it unsuitable for nominal return, there is evidently a backup plan to use a Dragon, as if it was taboo). Personally, I have no idea, and indeed I'm also curious about it.
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#886
by
OTV Booster
on 25 Jul, 2024 18:18
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I have a broader question. While other vehicles have had thruster problems in the past, are this vehicle's issues just being blown out of proportion from a news perspective, since it's Boeing/Starliner/and manned?
Or are these issues uncharacteristically bad for what we should expect from a capsule on its third flight using thruster technology that has been in use for decades?
You had me up until you included "manned". This calls for a higher standard. Substitute "Surfdaddy" for "manned" and think on it.
You do make a good point about this thruster technology being in use for decades, but it also raises a further question. Has this exact design and combination of materials and propellant ever been used before? If so, why did it behave differently? If not, why was it not tested to duplicate the expected operating envelope?
SpaceX unexpectedly blew the crap out of a Crew Dragon on the test stand by the happenstance firing of thrusters in a sequence never expected in actual use and, IIRC, before a human rode in it. That was a GOOD thing. I expect that by the time they asked that the FAA recertify Dragon for crewed use they had tested the system every way they could think of.
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#887
by
FutureSpaceTourist
on 25 Jul, 2024 18:24
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#888
by
dglow
on 25 Jul, 2024 18:27
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To both your and OTV's posts: Do you know that the conditions this thruster issue popped up in are NOT related to this being a crewed mission with hand-flown profiles requiring lingering in particular orientations? How would you go about testing that integrated regime on the ground? Why would you favor full-up testing of that regime as opposed to other extreme cases where problems might in principle also lurk, when you might be damaging entire SMs in the process, and your analyses are providing good enough results to ensure no major failure modes will occur? Unless you know the answers to those questions, it seems this is another acute case of "I know better than the engineers from the comfort of my couch" kind of strong statement.
Care to get a bit more pointed and personal?
The majority of this forum is armchair quarterbacking. Sharing hot takes and testing out ideas here does *not* imply any claim of superiority over the engineers doing actual hard work. Geesh, what a horrible accusation.
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#889
by
Surfdaddy
on 25 Jul, 2024 18:36
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I have a broader question. While other vehicles have had thruster problems in the past, are this vehicle's issues just being blown out of proportion from a news perspective, since it's Boeing/Starliner/and manned?
Or are these issues uncharacteristically bad for what we should expect from a capsule on its third flight using thruster technology that has been in use for decades?
You had me up until you included "manned". This calls for a higher standard. Substitute "Surfdaddy" for "manned" and think on it.
You do make a good point about this thruster technology being in use for decades, but it also raises a further question. Has this exact design and combination of materials and propellant ever been used before? If so, why did it behave differently? If not, why was it not tested to duplicate the expected operating envelope?
SpaceX unexpectedly blew the crap out of a Crew Dragon on the test stand by the happenstance firing of thrusters in a sequence never expected in actual use and, IIRC, before a human rode in it. That was a GOOD thing. I expect that by the time they asked that the FAA recertify Dragon for crewed use they had tested the system every way they could think of.
I'm still not really hearing an answer to my question. In short, is the press overblowing the magnitude of these problems and they aren't unusual on a third test flight, or is this in fact really quite poor performance given that the thruster technology has been in use for decades? What's the bottom line here?
I hear some people saying essentially "oh it's a test flight, no big deal" and others saying essentially "The Starliner's performance is piss-poor and shoddy". Which is it? (I do realize that there are in-betweens here).
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#890
by
Targeteer
on 25 Jul, 2024 18:44
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Sunny and Butch have been in Starliner all afternoon charging computers, batteries, and having to constantly reset comm settings as the ground does various commanding. CAPCOM just called up that a caution/warning for cooling pump 2A earlier in the day was in fact valid and that it is now considered suspect. Pump 2B was activated and a recovery attempt plan for 2A will be ready next week. The audio quality from Starliner has been consistently poor/spotty with the ground having to have the crew repeat their calls frequently. The recurring comm config resets caused unrelated ground commanding have lead to many missed calls to the ground that have to be repeated.
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#891
by
gaballard
on 25 Jul, 2024 18:45
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Are they saying the SM for the next mission has been sitting for 3 years with NTO aboard? Why wouldn’t they de-tank it? Or was the logic something along the lines of, ICBMs sit fueled for years, why not the SM?
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#892
by
eeergo
on 25 Jul, 2024 18:51
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Are they saying the SM for the next mission has been sitting for 3 years with NTO aboard? Why wouldn’t they de-tank it? Or was the logic something along the lines of, ICBMs sit fueled for years, why not the SM?
No, it was supposed to fly with CFT (then with OFT-2 after OFT-1's debacle) but suffered an issue whose specifics I can't recall right now, but they were widely discussed back in the day. The one earmarked for the third flight was bumped forward in the manifest (part of the cause for OFT-2's delays) and this one has become what I believe is safe to describe as a ground test article. It was unloaded of propellants, but the fumes remain and they're still capable of degrading the seals.
EDIT:
Here's some info about the swap in SMs from two years ago, and why SM-2 ended up being in White Sands.
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#893
by
haywoodfloyd
on 25 Jul, 2024 19:07
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Care to get a bit more pointed and personal?
The majority of this forum is armchair quarterbacking. Sharing hot takes and testing out ideas here does *not* imply any claim of superiority over the engineers doing actual hard work. Geesh, what a horrible accusation.
I agree. If people aren't permitted their personal musings then what would be their incentive to visit this forum?
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#894
by
Jim
on 25 Jul, 2024 19:13
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I really don't want to get into egregious and uninformed Boeing bashing, so help me out here.
Were the thrusters not originally tested to the standard of 'test it like you fly it'?
Because you can't setup test conditions like flight.
Most spacecraft have just the thrusters tested. Full up spacecraft propulsion systems are not tested in thermo-vac with propellant. The first time most spacecraft propulsion systems see propellant is at the launch site.
I don't know where the CST-100 thermo-vac was done and if the propellant tanks were just filled with gas or a referee fluid. Either way, no fluid goes through the plumbing. The referee fluid is just for thermal mass.
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#895
by
Jim
on 25 Jul, 2024 19:16
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Im with OTV on this, the types of tests conducted at White Sands are what the qualification testing should have encompassed.
Arm waving that this is a "test" flight to justify a failed RCS system is not accurate.
Can't be done. White Sands testing is done at 1 atm.
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#896
by
OTV Booster
on 25 Jul, 2024 19:21
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CFT can potentially run into a QA issue, but shouldn't run into what appears a design problem that should have been tested on the unmanned flight before.
Was the OFT-2 flight profile (which included docking) somehow different?
Also, didn't the original OFT-1 have crazy thruster firings, something where they could have seen the elevated temperatures too?
OFT-1 was probably in a much different orientation still in battery power (hence with the rear solar panel not pointed at the Sun), and just off the LV when the firing craze happened. Also, I seem to recall it was in orbital night. So conditions would have been totally different.
Regarding OFT-2's profile and why this wasn't observed then, that's a question I missed someone asking at the press event (rather than having no less than 3 reporters push and prod the speakers to say the D word and state the obvious fact that, was the root cause of Starliner's issues not fully signed off in the coming days and some other problem discovered making it unsuitable for nominal return, there is evidently a backup plan to use a Dragon, as if it was taboo). Personally, I have no idea, and indeed I'm also curious about it.
Like you, I feel that much of the response to OFT-2 has been overblown and would still feel that way if ground testing had not been able to duplicate the thruster overheating problem. That would mean the root cause is from a totally unexpected direction that reasonable testing might not reveal. Test like you fly. Fly like you test.
The manual control did move thruster use off the automated nominal but in a way that could reasonably be foreseen. AIUI the ground testing very reasonably duplicated the sequence of burns used on the flight. I find it hard to believe that only this exact burn sequence was at fault. I would expect that it was the general case of heavier manual thruster use than that expected of automated. This last is admittedly conjecture, but not unreasonable conjecture. Why have a manual system if you don't intend to use it (or test it)?
And no, I do not believe I can do the Boeing engineers job better than the engineers themselves can. What circumstantial evidence leads me to believe is that the Boeing MBAs think that they can do better engineering than the engineers.
In a move I do not understand, the Boeing purchase of a dying McDonnell Douglas backfired and the bean counter leadership of McDonnell Douglas ousted the engineering oriented leadership of Boeing. The bean counters were killing McD D and they're now doing it to Boeing. Their commercial aircraft quality is going dangerously down and they're loosing a lot of money on this Firm Fixed Price space capsule.
This is what underlies my opinion on insufficient testing. I offer it up as background only. It's sufficiently off topic that we shouldn't pursue it here. PM me if you'd like to discuss it further.
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#897
by
OTV Booster
on 25 Jul, 2024 19:26
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I have a broader question. While other vehicles have had thruster problems in the past, are this vehicle's issues just being blown out of proportion from a news perspective, since it's Boeing/Starliner/and manned?
Or are these issues uncharacteristically bad for what we should expect from a capsule on its third flight using thruster technology that has been in use for decades?
You had me up until you included "manned". This calls for a higher standard. Substitute "Surfdaddy" for "manned" and think on it.
You do make a good point about this thruster technology being in use for decades, but it also raises a further question. Has this exact design and combination of materials and propellant ever been used before? If so, why did it behave differently? If not, why was it not tested to duplicate the expected operating envelope?
SpaceX unexpectedly blew the crap out of a Crew Dragon on the test stand by the happenstance firing of thrusters in a sequence never expected in actual use and, IIRC, before a human rode in it. That was a GOOD thing. I expect that by the time they asked that the FAA recertify Dragon for crewed use they had tested the system every way they could think of.
I'm still not really hearing an answer to my question. In short, is the press overblowing the magnitude of these problems and they aren't unusual on a third test flight, or is this in fact really quite poor performance given that the thruster technology has been in use for decades? What's the bottom line here?
I hear some people saying essentially "oh it's a test flight, no big deal" and others saying essentially "The Starliner's performance is piss-poor and shoddy". Which is it? (I do realize that there are in-betweens here).
See my post above for a more detailed opinion. Some things can only be tested on orbit. Some things, like the current thruster problems, obviously can be tested on the ground.
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#898
by
edzieba
on 25 Jul, 2024 20:07
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If heavy manual thruster use was the cause of the overtemp situation, then surely the prolonged and excessive thruster firings of OFT-1 should have triggered the same effects and instigated further investigation half a decade ago?
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#899
by
SoftwareDude
on 25 Jul, 2024 20:40
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There were other problems that no one asked about, and NASA and Boeing didn't mention. The journalists allow the agency to set the narrative by not bringing them up.
The unnecessary, in my humble opinion, questions about the thruster corrosion problems from 2021 wasted limited question time. The second question on the subject was just asinine. I think Steve Stich hinted at the CO2 sensor issue, maybe, when he briefly mentioned "erratic sensors".
Someone could have asked a simple question like, are there any other unresolved issues on this flight such as the power glitches, valve that did not fully close, CO2 sensor, etc.