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#160
by
TJL
on 03 Jun, 2024 18:35
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Please refresh my memory, would you know the last time an Atlas 5 launch was scrubbed twice, not weather related, in the final hours of the countdown? Thank you.
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#161
by
meekGee
on 03 Jun, 2024 20:05
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How is the competitor launching a more complex rocket from multiple pads at 100/yr with so much less drama?
You're making it sound like these issues are inevitable.
When you launch only a few times per year, these occasional hiccups will not change your annual total and therefore the incentive to nail down every potential hiccup is not as strong (and management thinks, rightly or wrongly, that it's not worth the cost).
Wrongly. Very very wrongly. And I know management thinks that way, which is exactly the problem. These are not coincidences, it's a pattern, which is a direct result of being used to being an irreplaceable vendor.
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#162
by
Ben
on 03 Jun, 2024 20:14
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Does seem a bit like CST-100 is contagious.
Thanks jimvela for the link to the DAQ press release. I hadn't seen any specific mention of what the hardware actually was, and was wondering if it was NI. Similar, but different; looks expensive. I've automated an orbital launch site and the more industrial, less 200khz aerospace-specific DAQ you can use, the better.
On the mission itself, does anyone know if they upload a last minute trajectory before deorbit that includes landing wind forecast, or does it open mains low enough to keep the CEP under 2km or whatever even with a pre-baked trajectory?
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#163
by
Remes
on 03 Jun, 2024 20:53
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From what I understand, that comes close to the self regulating pressure valve, p. 59.
https://ntrs.nasa.gov/citations/19750007924The cavity with the reference pressure I talked about here
https://forum.nasaspaceflight.com/index.php?topic=47978.msg2591463#msg2591463is at A_Be
Tory said, they have a valve to switch that regulating valve off. So as said, perhaps its a two pilot valves configuration, one for increasing, one for reducing the pilot pressure.
And now the question: What is the fail safe for a tank pressure regulating valve in a configuration as in Centaur? Fail open, and it collapses. Fail close, and it will exceed structural limits. Are there 2x2 valve configurations or other override mechanisms? I know, those who know can't talk, but perhaps someone has a public source.
(edit: Was the chattering valve the tank pressurization valve or am I mixing up different things? :/ )
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#164
by
meekGee
on 03 Jun, 2024 21:56
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How is the competitor launching a more complex rocket from multiple pads at 100/yr with so much less drama?
You're making it sound like these issues are inevitable.
When you launch only a few times per year, these occasional hiccups will not change your annual total and therefore the incentive to nail down every potential hiccup is not as strong (and management thinks, rightly or wrongly, that it's not worth the cost).
And you know what? Here's another thing.
In a parallel thread there was a separate discussion about how some work wasn't costing anything because there's a standing army that's employed at a fixed cost and the extra work just gets absorbed into it. This is true at both NASA and the contractors.
So if this standing army is just, well, standing there, and if there's a problem with the valve or electronics or whatever, why don't they just fix it? For zero cost?
The answer is that unless they can bill even more for the fix, the company won't get out of its proverbial bed to do it. Because, again, the "customer" doesn't have a choice.
That's why the competitor is kicking their ass - not because of the flight rate. The flight rate is a symptom, not a cause.
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#165
by
DanClemmensen
on 03 Jun, 2024 23:10
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Please refresh my memory, would you know the last time an Atlas 5 launch was scrubbed twice, not weather related, in the final hours of the countdown? Thank you.
It's not completely clear, but I think this is because this is a crewed launch and scrub criteria are more rigorous. For earlier uncrewed launches, the valve buzz was fixed by manually cycling the valve. For the CLS, earlier uncrewed missions launched with one of the three redundant computers off line.
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#166
by
SoftwareDude
on 04 Jun, 2024 00:45
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I am still unsure why we discuss ULA's valves and ground support computers on a CFT mission discussion thread, but I digress.
Regarding the ground support computer that failed, can someone please explain to me what a rack of cards with no redundant power supply architecture is? It sounds pre-year 2000 to me.
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#167
by
DanClemmensen
on 04 Jun, 2024 01:10
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I am still unsure why we discuss ULA's valves and ground support computers on a CFT mission discussion thread,
It's in the thread title. It's about the entire mission, not just the Starliner.
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#168
by
cohberg
on 04 Jun, 2024 02:49
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Regarding the ground support computer that failed, can someone please explain to me what a rack of cards with no redundant power supply architecture is?
The power supplies are redundant
x.com/torybruno/status/1797331024529043914
Power supply failed and was still offline when we got in. The redundant PS did not activate. Unit going back to vendor for FA
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#169
by
SoftwareDude
on 04 Jun, 2024 02:52
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Regarding the ground support computer that failed, can someone please explain to me what a rack of cards with no redundant power supply architecture is?
The power supplies are redundant
x.com/torybruno/status/1797331024529043914
Power supply failed and was still offline when we got in. The redundant PS did not activate. Unit going back to vendor for FA
Yes, I missed that, thank you.
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#170
by
SoftwareDude
on 04 Jun, 2024 03:02
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Regarding the ground support computer that failed, can someone please explain to me what a rack of cards with no redundant power supply architecture is?
The power supplies are redundant
x.com/torybruno/status/1797331024529043914
Power supply failed and was still offline when we got in. The redundant PS did not activate. Unit going back to vendor for FA
Yes, I missed that, thank you.
Tony Bruno mentioned the cards which I assume are something like DCS input-output for controlling the ground equipment and collecting data during the countdown and launch. I used to work on telephony applications for Sprint and saw massive racks of similar cards.
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#171
by
Lee Jay
on 04 Jun, 2024 13:58
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The power supplies are redundant
x.com/torybruno/status/1797331024529043914
Power supply failed and was still offline when we got in. The redundant PS did not activate. Unit going back to vendor for FA
So, one failed, the other didn't activate and the card "came up slowly"? How did it come up at all?
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#172
by
AnalogMan
on 04 Jun, 2024 14:49
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The power supplies are redundant
x.com/torybruno/status/1797331024529043914
Power supply failed and was still offline when we got in. The redundant PS did not activate. Unit going back to vendor for FA
So, one failed, the other didn't activate and the card "came up slowly"? How did it come up at all?
Phantom powering (sneak circuit) via I/O lines linked to other external active interfaces (through over-voltage clamp diodes to power rails on un-powered card )?
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#173
by
litton4
on 04 Jun, 2024 16:03
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Please refresh my memory, would you know the last time an Atlas 5 launch was scrubbed twice, not weather related, in the final hours of the countdown? Thank you.
It's not completely clear, but I think this is because this is a crewed launch and scrub criteria are more rigorous. For earlier uncrewed launches, the valve buzz was fixed by manually cycling the valve. For the CLS, earlier uncrewed missions launched with one of the three redundant computers off line.
I mentioned this a couple of days back....
https://forum.nasaspaceflight.com/index.php?topic=60593.msg2596585#msg2596585
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#174
by
1
on 04 Jun, 2024 17:08
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The power supplies are redundant
x.com/torybruno/status/1797331024529043914
Power supply failed and was still offline when we got in. The redundant PS did not activate. Unit going back to vendor for FA
So, one failed, the other didn't activate and the card "came up slowly"? How did it come up at all?
Phantom powering (sneak circuit) via I/O lines linked to other external active interfaces (through over-voltage clamp diodes to power rails on un-powered card )?
Sneak circuits are always a good guess, but I doubt IO would be the culprit. You usually wait for a power good signal to come back from the receiving circuitry before enabling IO, and it's common to default to high-Z in the interim.
I can't do anything more than guess, but in a system where you need to operate through a failure, you generally need to hot swap the parts rather than cold swap. In other words, both power supplies should nominally turn on from the get go. Your primary actively supplies power and the backup sits in a quasi-quiescent state is but otherwise ready to immediately take over in the event of failure of the primary. Ideally before your rails droop too far. And hot swapping is prime sneak circuit territory, because sneak circuits only tend to appear during failure events, and anticipating and testing for all failure modes is always a challenge.
A hotswap issue could easily cause a brownout condition where your system does get power, but not enough, or too slowly, or below nominal voltages, etc. Taking Torys words 10 degrees off of face value, I could interpret "The redundant PS did not activate" as the redundant PS not taking over properly rather than not activating at all, which, IMO is more reasonable. Just a guess.
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#175
by
cpushack
on 04 Jun, 2024 17:49
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Suppose the question is, what's to stop it from happening again in the middle of a launch sequence?
The redundant nature failed, and they do not know why (they are sending the unit back to the vendor to find out why). in the mean time, they will launch with a sequencer that has shown redundancy problems.
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#176
by
punder
on 04 Jun, 2024 18:00
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Suppose the question is, what's to stop it from happening again in the middle of a launch sequence?
The redundant nature failed, and they do not know why (they are sending the unit back to the vendor to find out why). in the mean time, they will launch with a sequencer that has shown redundancy problems.
Zooming out a bit... they are highly motivated professionals trying to do their best in an imperfect world. They will test everything to ensure it
should work properly, do the statistical analysis, then pray/cross fingers like the rest of us.
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#177
by
wings_no_capsules
on 05 Jun, 2024 11:50
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username not withstanding, Go starliner! Go Sunni and Butch!
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#178
by
Ken the Bin
on 05 Jun, 2024 11:57
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For the return from the ISS from the USCG District 11 weekly Local Notice to Mariners that came out today.
ARIZONA -OFF SHORE CALIFORNIA-LAUNCH REENTRY-HAZARDOUS OPERATION
Hazardous operations will be conducted by Boeing CST-100 Starliner Crewed Flight Test (CFT) starting at 5 June, 2024 from Kennedy Space Center, Florida. The expected landing is to take place at White Sands Space Harbor or Range Road 26, New Mexico with a landing on 14 June, 2024 at 13:39 GMT with a backup landing opportunity at 20:59 GMT on 15 June at WSSH or RR26. If the mission duration onboard the International Space Station (ISS) is extended, the next landing opportunity is at WSSH or RR26 on 18 June, 2024 at 12:04 GMT with a backup landing opportunity at 19:52 GMT on 19 June, 2024 at WSSH or RR26. Mariners operating offshore are advised of potential of falling debris that may present a hazard to vessels in the Pacific Ocean due to space operations. Mariners are advised to avoid the below bounded area and operate in a heightened state of awareness.
Hazard Area A:
12:58Z 14 June, 2024 until 13:59Z 14 June, 2024
SOUTHEASTERN PACIFIC & SOUTH PACIFIC
21-16-00N 122-22-00W
18-25-00N 118-33-00W
05-04-00S 136-09-00W
02-22-00S 139-54-00W
Hazard Area B:
20:18Z 15 June, 2024 until 21:19Z 15 June, 2024
NORTH EASTERN PACIFIC & NORTH PACIFIC
49-12-00N 132-49-00W
47-00-00N 134-15-00W
50-41-00N 170-48-00W
52-03-00N 170-59-00W
53-10-00N 166-40-00W
Hazard Area C:
11:23Z 18 June, 2024 until 12:24Z 18 June, 2024
SOUTHEASTERN PACIFIC & SOUTH PACIFIC
21-16-00N 122-22-00W
18-25-00N 118-33-00W
05-04-00S 136-09-00W
02-22-00S 139-54-00W
Hazard Area D:
19:11Z 19 June, 2024 until 20:12Z 19 June, 2024
NORTH EASTERN PACIFIC & NORTH PACIFIC
49-12-00N 132-49-00W
47-00-00N 134-15-00W
50-41-00N 170-48-00W
52-03-00N 170-59-00W
53-10-00N 166-40-00W
Mariners are advised to remain clear of these areas for the duration of operations. For more details or comments contact Matt Dulski at 281-483-9112 or [email protected].
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#179
by
ClayJar
on 05 Jun, 2024 13:40
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So, I was just asked a question that I could not answer, so I'm going to forward the question here:
What does "41Ø1" on the pad camera mean? Obviously, the "41" would be SLC-41, but the "Ø1"? I had logical-sounding guesses, but I figure someone here would know the answer.