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L'Affaire Siloxane

mceglowski.substack.com

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Re: L'Affaire Siloxane

#51

Post by mannykannot »

lugoues wrote: post #28
mannykannot wrote: post #16

Earlier quoted context omitted.

A two meter cubed volume would be sufficient to hold that much. I would guess that cruise ships store more urine than that, though presumably not separated from everything else humans dump into toilets. With the qualification 'in orbit', I imagine it is.

I thought they just dumped it overboard but maybe there are some ethical cruises... maybe.

It seems that in most ports they are required to hold and treat it (and, perhaps to a lesser extent, in inshore waters.) Fouling the places they take their customers to is ultimately bad for business.

Re: L'Affaire Siloxane

#52

Post by krunck »

No mention was made of eliminating the siloxane use by astronauts: leave-in hair conditioner, deodorant, etc.

I wonder if they track PFAS/PFOS contamination also?

Re: L'Affaire Siloxane

#55

Post by Centigonal »

s0rce wrote: post #9
RobotToaster wrote: post #6

I'm sceptical of the claim that they couldn't eliminate the majority of them from stuff that's shipped up to the ISS. Even if it meant making special space certified hair conditioner.

I don't see why not either, just get "organic"/plant or mineral based cosmetics, deodorants and hair products.

It's really, really complicated. Even "organic" or "all natural" products often contain synthetic contaminants as a result of manufacturing, packaging, or shipping processes. Unless NASA were to set up separate factories and supply chains for manufacturing all known sources of siloxane contamination (either on their own or in partnership with manufacturers), it would be very difficult to actually get a siloxane-free product with any kind of certainty or consistency.

An example with a different contaminant: We can't seem to keep carcinogenic plasticizers out of our RXBars and our baby formula[1]. Those products are already way more regulated than something like wet wipes, and the companies that make them have a strong interest in keeping them free of contamination.

[1] https://www.plasticlist.org/

Re: L'Affaire Siloxane

#56

Post by RetroTechie »

idlewords wrote: post #11
RobotToaster wrote: post #6

I'm sceptical of the claim that they couldn't eliminate the majority of them from stuff that's shipped up to the ISS. Even if it meant making special space certified hair conditioner.

There's a nice paper on this, ICES-2018-123 "Dimethylsilanediol (DMSD) Source Assessment and Mitigation on ISS: Estimated Contributions from Personal Hygiene Products Containing Volatile Methyl Siloxanes (VMS)". The upshot is more than half of the siloxane burden on ISS comes from God knows where (packaging, plastics, machinery, you name it). https://ttu-ir.tdl.org/items/ff1a240e-1fb1-4b04-acb2-42e9c45...

Got it. Time to introduce a "certified siloxane free" programme for the space station building & supply industry.

Just joking here, but reading between the lines it might not be such a bad idea? (if doable)

Re: L'Affaire Siloxane

#58

Post by shmeeed »

s0rce wrote: post #21
duskwuff wrote: post #14

Earlier quoted context omitted.

Especially if the real change is a couple levels separated from the problem. For instance, I can imagine a situation where the manufacturer of that "special cloth" didn't even change anything themselves, but their lubricant supplier silently changed the formula of their sewing machine oil. (Or maybe even that one of the suppliers to the lubricant company changed something - it's turtles all the way down.)

Yes, you would also audit the quality system for your suppliers to confirm they are sufficiently controlling for upstream changes. In theory you can have all your ducks in a row.

"In theory" is doing a lot of heavy lifting there. ;)

Depending on the product and quantity, you can factor your purchase price level times 2-10 for every level of sub- and sub-sub-supplier you want to have audited to your "wacky spec" - which may even still sound kinda reasonable, until you realize your attack surface is basically fractal to the n-th degree. The amount of process steps and auxiliaries used in manufacturing is absolutely staggering.

Edit: I need to add this depends a lot on the sector. There's useful certificates for a lot of industries, if you choose to believe them.

Re: L'Affaire Siloxane

#59

Post by adolph »

pjc50 wrote: post #47
adolph wrote: post #7

An interesting substory that is simultaneously reminiscent of the Fogbank story and how Hayek's "curious task" is much more broadly applicable: There is a good cautionary tale here from the Space Shuttle era. That vehicle had heat resistant tiles that had to be attached to the aluminum belly of the orbiter. A special cloth had been certified for wiping the aluminum clean before applying the primer that securely bonde…

The "curious task" full reference from Hayek: “The curious task of economics is to demonstrate to men how little they really know about what they imagine they can design.” Intended as a warning against command economies and centralized structures more generally, because the information-processing requirements are much larger than one might expect. But of course there are few things more central-planning than a space…

In this case a broader reading is an exhortation to guard against intellectual hubris. Through its various trials NASA seems like a good organization for learning from error and not accepting easy answers (except when they have to terrible results), and in this siloxane story I'm glad to see evidence of institutional curiosity that I could not have drempt up.
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