SpaceX News

[kunkmiester]

You generally have a lot of tracking of materials and parts even outside of space travel. There will be no trouble knowing which rockets need to be checked. The helium and lox tanks I imagine are things that get checked a lot, so the strut is probably accessible. This isn't something to scrap the whole rocket over, just something to fix and improve quality assurance for later.

[ladajo]

Given what we know, maybe they will just need to remove all the existing struts and test/replace or just replace them.
Either way, not fun.
I certainly hope they don't have to scrap the current builds.

[krenshala]

Are the He tanks inside the LOX tanks, or just next to them? My understanding is the struts are holding the He tanks in place, and when the strut failed the He tank ruptured the LOX tank. I had gotten the impression the He tanks were inside the LOX tank so the LOX kept the He cold, and if so that would mean they would effectively have to replace the LOX tanks that use the struts -- lots of work, even if just to 'check' the strut, followed by recertification of the tank, reinstallation, et cetera.

For their sake I'm hoping I have bad information and the He tanks are outside teh LOX tanks. Still lots of work to replace the struts, but better than having to pull and reinstall the (bigger) LOX tank.

[hanelyp]

The helium tanks are inside the oxygen tanks. So when the strut failed, the helium tank moving damaged the plumbing, the helium leak bursting the oxygen tank.

[mvanwink5]

Regulating valves are also inside the tank. I find it hard to believe there is no access.

[Skipjack]

It cant be a huge problem since SpaceX says they will return to flight in fall.

[ladajo]

Maybe they are going to fly new builds, and that is the delay. I am not sure how long it takes them to put together a booster package.

[mvanwink5]

I thought the delay was to do the engineering, make decisions, acquire material, etc. and certification, plus a complete review of all possible items that should be tested and not just count on paper certs, and do the tests. Also, I still find it hard to believe valves would not be accessible. Moreover, I thought there were pictures of the struts on the bird that was launched. And in addition, I find the assembly would be impossible to build a LOX tank around the He bottles and plumbing. I mean really, that would be ridiculous. Further, the size of the He tanks look like what one would choose to fit through an access. Finally, if all the boosters in inventory were to be trashed, wouldn't you think that point would have been made especially since Musk has been upfront on the big hits?

The concern to my mind is really far fetched, sorry.

[mvanwink5]

From SpaceX:

Several hundred struts fly on every Falcon 9 vehicle, with a cumulative flight history of several thousand. The strut that we believe failed was designed and material certified to handle 10,000 lbs of force, but failed at 2,000 lbs, a five-fold difference. Detailed close-out photos of stage construction show no visible flaws or damage of any kind…

Despite the fact that these struts have been used on all previous Falcon 9 flights and are certified to withstand well beyond the expected loads during flight, SpaceX will no longer use these particular struts for flight applications.  In addition, SpaceX will implement additional hardware quality audits throughout the vehicle to further ensure all parts received perform as expected per their certification documentation.

As noted above, these conclusions are preliminary.  Our investigation is ongoing until we exonerate all other aspects of the vehicle, but at this time, we expect to return to flight this fall and fly all the customers we intended to fly in 2015 by end of year. 

[ladajo]

As you noted, and as I also saw;

Several hundred struts fly on every Falcon 9 vehicle

SpaceX will no longer use these particular struts for flight applications

Which makes one wonder how they will either remove "several hundred struts on every vehicle", or just not fly vehicles that are already built, and how many of which currently exist right now, I do not know.

Either way, those two statements combined are significant.

[mvanwink5]

Customer trust I would suppose is paramount. I thought somewhere bolting was mentioned in reference to the strut attachments, but hard to say. Anyway, a serious amount of work per inventoried booster. 'Chop - Chop!' we used to say. Then there are other components passed just with cert paper that need a functional bona fide redo.

[Tom Ligon]

Chopping up an O2 tank could open its own can of worms. If this is a welded tank with no access hatch, I'd be paranoid of introducing new potential catastrophic failure mechanisms if I tried to cut and weld. There should be new tanks "in the pipeline", and I'd get those into service for the next launch if I had that kind of chop job to do. You could send the old tanks back for some sort of certified remanufacture later, but I'd want them tested pretty thoroughly.

If they're designed to come apart, well, splendid. Get out the wrenches. There's probably a disassembly process specified already.

They certainly intend the first stages to be fully overhauled and reused, assuming they can ever get past the toppling over and exploding problem, so I presume those components are designed for inspection and repair. I have difficulty believing these tanks don't at least have an inspection access.

Musk is not looking to shut down the program to do the sort of investigations NASA does after a manned spaceflight accident, but it also wouldn't pay to have the next launch fail, especially due to an ill-thought-out repair. Imagine, you replace struts in a tank ... those struts were OK, but could have been bad. Then the tank fails due to a faulty repair. Now THAT would be a setback.

[mvanwink5]

https://en.wikipedia.org/wiki/Chop_chop_(phrase)

"Chop chop" is a phrase rooted in Cantonese. It spread through Chinese workers at sea and was adopted by English seamen.[1] "Chop chop" means "hurry, hurry" and suggests that something should be done now and without any delay. The word "chopsticks" likely originates from this root.[2]

[Skipjack]

Chopping up an O2 tank could open its own can of worms. If this is a welded tank with no access hatch, I'd be paranoid of introducing new potential catastrophic failure mechanisms if I tried to cut and weld. There should be new tanks "in the pipeline", and I'd get those into service for the next launch if I had that kind of chop job to do. You could send the old tanks back for some sort of certified remanufacture later, but I'd want them tested pretty thoroughly.

If they're designed to come apart, well, splendid. Get out the wrenches. There's probably a disassembly process specified already.

They certainly intend the first stages to be fully overhauled and reused, assuming they can ever get past the toppling over and exploding problem, so I presume those components are designed for inspection and repair. I have difficulty believing these tanks don't at least have an inspection access.

Musk is not looking to shut down the program to do the sort of investigations NASA does after a manned spaceflight accident, but it also wouldn't pay to have the next launch fail, especially due to an ill-thought-out repair. Imagine, you replace struts in a tank ... those struts were OK, but could have been bad. Then the tank fails due to a faulty repair. Now THAT would be a setback.

They had problems with the helium tanks in the past (different kind of problem) and were able to fix them within a few weeks. So I am very confident that they have a way to get into the tank and replace vital equipment. The fact that they are planning to reuse their first stages, makes it also very likely that they have way to replace parts for maintenance.

[ladajo]

Skip,
A few tanks is significantly less than all internal struts sourced from the vendor in question. They have no way of knowing if the struts are good or bad without testing, and from the sounds of it, destructive testing.
Pulling each one out and stressing it to 10,000lbs, which from and engineering perspective is not that much, but enough to take some time per strut, seems like more than a couple of weeks work. And that is not counting rebuild and certs and closeouts...