Part of my job is to keep siloxanes out of a complex, multi-step, multi-sub-contracted manufacturing process. A supplier change that should have been a simple affair has cost us several kilobucks in analyses in the past months. I hate the stuff.
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).
Indeed. "Grease peaks" we called them, they were always there in basically all NMR or MS spectra I took as an organic chemist. Like PFAS or microplastics, you just can't get rid of them.
I hope to see these seemingly mundane unknown unknowns raised in space travel centered hard science fiction. I think The Martian and Seveneves almost captured these but not quite.
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 bonded the tiles to the metal. After
years of uneventful use, tile engineers discovered that new replacement tiles
were no longer curing properly.
A careful investigation revealed that the supplier of that special cloth had
changed the lubricant used in the machine that sews its hem. Minute amounts
of the lubricant were being deposited on the stitching, and enough of that
residue was getting on the aluminum skin to prevent the tile adhesive from
curing properly.
In medical device manufacturing you have systems in place that your vendors have to disclose changes to their manufacturing process that hopefully can catch stuff like this before people die. I can see how minute stuff gets easily passed off as not an important change.
https://ttu-ir.tdl.org/items/ff1a240e-1fb1-4b04-acb2-42e9c45...
Is that a record for the biggest piss bottle ever made?