https://ifixit.org/blog/11986/iphones-are-allergic-to-helium/

Hiding out in a gas giant could get a fair bit of helium into the
ship. It's "mostly harmless" and seals to keep it out are not easy.

And scrubbers to get it out of the air are a *real* pain (since it's
non-reactive the only way is to cool the air below LH2 temps, then
pump out the remaining gases (which will be just helium). Not
something you want to do to all the air in the ship. Yes, the stuff
in the storage tanks too!

It might also be possible to get rid of it by using a membrane
that'll pass helium, but not anything else (fairly easy to do, though
you may not have anything on the ship that'll work) and have ship's
air on one side and a vacuum on the other.

Hydrogen could get into the ship's air lots of ways (you've got
*literally* tonnes of it onboard).

The explosive limits for an air/hydrogen mix are from 18-60%.

So if you keep the ratio of air to hydrogen outside those limits,
your ship won't become a flying bomb.

But the falammability limts are rather broader. For air/hydrogen it
is 4-75%

An oxygen hydrogen mix has flammability limits from 4-95%. Ouch.

Mind you, given how old space travel is in the TU, most equipment
will fare better than the iPones do. :-)

And hydrogen can be dealt with by catalysts (if the level is below
that 4% lower limit. They'll turn the hydrogen (and some oxygen from
the air) to water. Heck, several possible air treatment systems will
do this more or less automaticaly (they'd flash heat air passing thru
to temps high enough to make any trace gases react with oxygen)

But PCs are always picking up odd gear here and there. Some of it may
not be space rated. Especially if it's from a lower TL world.

Might take them quite a while to figure out why thee frammistat quit
working. And if they don't figure out why, won't they be surprised
when it starts working again a week or so *after* the helium/hydrogen
leak has beeen dealt with.

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com