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#180
by
rcoppola
on 01 Sep, 2015 15:22
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I think it's all fairly straightforward.
Yes the struts failed but so did the QA process. And that process, unlike the strut, touches every part of the rocket. So while they are down, they'll cross check everything including putting in a buddy system for workmanship double checks.
And recall, adding more pressure, is the fact that they are returning to flight with a version that has never flown before. Now that will keep you up at night.
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#181
by
the_other_Doug
on 01 Sep, 2015 15:48
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I think it's also possible that SpaceX discovered that, while the strut likely failed and began what ended up being the sequence of events leading to the RUD, the fault tree says that either something else likely happened to precipitate the strut failure, or that the strut failure itself was unlikely (though potentially capable of being) the single-point fault source. In other words, they're pretty certain of the strut failure, but less certain that the strut failure alone caused the accident.
At some point, they have to decide at what point they say "We fixed the strut issue, let's go fly" and stop saying "But, but, but -- I'm not done checking each and every branch of the fault tree! It's not elegant to go fly until I'm done! And no -- I have no idea how many more months, or years, it will take for me to be done."
At some point, you've just got to trust the basic design and go fly.
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#182
by
rcoppola
on 01 Sep, 2015 16:03
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It's not just about fault tree.
Why would they fly after fixing the strut if the very thing that allowed the strut to fail, porous QA, potentially effects many other components the rocket depends on to have a successful RTF?
There is no but, but, but. Only check, check, check. There's a finite parts count. Therefore a finite amount of time it will take to ensure they are manufactured properly and integrated properly. With 50 launches and contracts exceeding $7-Billion, the difference between 2 more months and 3 more months for RTF, is insignificant.
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#183
by
savuporo
on 01 Sep, 2015 17:41
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Yes the struts failed but so did the QA process. And that process, unlike the strut, touches every part of the rocket. So while they are down, they'll cross check everything including putting in a buddy system for workmanship double checks.
The side effect of this is higher mountain of paperwork ( or whatever the modern digital equivalent is .. bytework ? ) and growing costs.
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#184
by
rcoppola
on 01 Sep, 2015 18:15
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Yes the struts failed but so did the QA process. And that process, unlike the strut, touches every part of the rocket. So while they are down, they'll cross check everything including putting in a buddy system for workmanship double checks.
The side effect of this is higher mountain of paperwork ( or whatever the modern digital equivalent is .. bytework ? ) and growing costs.
While I agree in the short term, the long term value of this exercise will actually reduce cost and increase reliability and competitiveness. They grew fast, ripped through 3 versions of the F9 in almost as many years. This entire incident will prove to be an important enabling function of balancing rapid iterations and reliability. The holy grail of their business model. So they'll take a short-term hit but medium to long term, they'll be an even better competitive position.
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#185
by
Chris Bergin
on 01 Sep, 2015 18:30
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Dan Leone noting the ISS Advisory committee says CRS-8 is Nov. 15. We had that one as November 16 a week or so ago, so that's all aligning.
Nothing set yet, of course.
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#186
by
woods170
on 02 Sep, 2015 06:58
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Parabolicarc reporting that he's hearing the failure cause was "something more than the strut." Yes, this is rather nebulous, but his sources are usually reliable.
http://www.parabolicarc.com/2015/08/31/shotwell-couple-months-falcon-9-return-flight
Editor’s Note: I’ve been hearing reliable reports that something more than the strut was the cause of the accident in June. The last I heard, they were still trying to figure out exactly what happened.
Doug also was the one claiming the engine had exploded on the SS2 accident, while in fact that was not what had happened. It wasn't until images released by the NTSB and press, showing an intact engine, that he reversed himself.
Personally, I'm not too keen on putting faith in Doug's reports, particularly when his sources are as nebulous as the example provided above. Basically they are heresay. The same applies to the Lurio reports.
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#187
by
yg1968
on 02 Sep, 2015 13:35
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L2 has more reliable information.
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#188
by
woods170
on 02 Sep, 2015 14:18
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L2 has more reliable information.
Affirmative and it fits nicely with my opinion on Doug's reporting.
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#189
by
koshvv
on 02 Sep, 2015 23:46
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I saw this video and now have a question:
Does a steel which struts made of change its mechanical properties under cryogenic temperatures?
And if it changes, will SpaceX test all new struts cooled to cryo temps, or not?
Do anyone have an idea?
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#190
by
cscott
on 03 Sep, 2015 00:12
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#191
by
cscott
on 03 Sep, 2015 04:17
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USA today is reporting the US Senate committee wants a complete review of the Commercial cargo program (who knows). They also are calling for a complete review of Commercial Crew. They are putting the review under the "changes since the shuttle", looks like the IG has been called up.
http://www.usatoday.com/story/news/politics/2015/09/02/gardner-vitter-seek-gao-review--nasa-program/71599958/It looks like cheap lobbyist service until/unless the GAO actually decides to grant the request.
And as has been noted for a previous stunt of this sort, almost all the information the article lists from their request is already available and public.
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#192
by
Elmar Moelzer
on 03 Sep, 2015 06:13
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USA today is reporting the US Senate committee wants a complete review of the Commercial cargo program (who knows). They also are calling for a complete review of Commercial Crew. They are putting the review under the "changes since the shuttle", looks like the IG has been called up.
http://www.usatoday.com/story/news/politics/2015/09/02/gardner-vitter-seek-gao-review--nasa-program/71599958/
It looks like cheap lobbyist service until/unless the GAO actually decides to grant the request.
And as has been noted for a previous stunt of this sort, almost all the information the article lists from their request is already available and public.
I hope it ends in nothingness.
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#193
by
Gordon C
on 03 Sep, 2015 11:33
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It's coming from CO and Louisiana. ULA and SLS. Then, spacex did file suit against the US air force screaming about ULA. Goose and gander something or other.
Orbital will come out looking responsible. Some tantrum action with Aerojet, but buying he Atlas flight for the good of their contact is totally righteous.
The GAO can brush off the request, but even if they do the big guys will come back at them from another direction.
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#194
by
sublimemarsupial
on 03 Sep, 2015 15:37
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It's coming from CO and Louisiana. ULA and SLS. Then, spacex did file suit against the US air force screaming about ULA. Goose and gander something or other.
The fact that ULA and the Air Force's repeated request to dismiss the suit were all denied, and that it was settled quietly under seal tells you that the suit had very valid claims ....
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#195
by
oldAtlas_Eguy
on 03 Sep, 2015 17:59
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It's coming from CO and Louisiana. ULA and SLS. Then, spacex did file suit against the US air force screaming about ULA. Goose and gander something or other.
Orbital will come out looking responsible. Some tantrum action with Aerojet, but buying he Atlas flight for the good of their contact is totally righteous.
The GAO can brush off the request, but even if they do the big guys will come back at them from another direction.
What's the connection with SLS? I can understand Orion but SLS & Cargo? We got to be careful this isn't too far off topic 
But congress could affect a RTF my (who knows).
Considering how fast Congress acts, RTF will occur way before any action is taken by Congress.
This is a non problem for RTF but could have implications for CRS-2 but that is still unlikely. Its more of congressmen showing constituents and "contributors" that they are looking out for their interests. Without a reply date cited for a report, GAO is likely to answer in a long letter in a couple of months the information requested (after CRS-2 has been awarded).
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#196
by
rcoppola
on 04 Sep, 2015 00:58
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#197
by
Coastal Ron
on 04 Sep, 2015 01:45
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Something has the Senate and House CO delegations spooked. Definitely a coordinated effort. The timings are not accidental.
Well, if we ascribe their actions to somehow benefiting ULA, then they would be wanting to slow down SpaceX as much as possible, especially if it means delaying when SpaceX can win any future Air Force launch contracts (i.e. ULA's monopoly right now).
But that's only if we ascribe their actions to somehow benefiting ULA...
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#198
by
WHAP
on 04 Sep, 2015 02:32
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Something has the Senate and House CO delegations spooked. Definitely a coordinated effort. The timings are not accidental.
Well, if we ascribe their actions to somehow benefiting ULA, then they would be wanting to slow down SpaceX as much as possible, especially if it means delaying when SpaceX can win any future Air Force launch contracts (i.e. ULA's monopoly right now).
But that's only if we ascribe their actions to somehow benefiting ULA...
Yeah, and McCain's rants about the RD-180 are
really about sending money to Russia and were not influenced in any way by any supporters of SpaceX.
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#199
by
science_business
on 04 Sep, 2015 02:42
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Fortunately, Elon Musk and SpaceX have reached critical mass....too little way too late for ULA...the wall is coming down!
But congress could affect a RTF my (who knows).