When I finally treated myself to my rather expensive Fisher 'Space Pen' a few years back I tested all the claims made for it.

Yes, it writes underwater.
Yes it writes on various greasy surfaces.
Yes it writes upside down.
Yes, it writes on wet paper.  (Truly useful if your writer's notebook gets damp.)

I tried all these things and more, but I could never bring myself to deliberately put it through the washing machine.  I wondered if it could survive.  I said at the time this test would probably happen sooner or later in the natural order of things.

Yesterday it did, and I didn't even notice until I was pegging out the laundry and realised the tiny pen was securely in my shirt pocket.

No leaks, no problems, no damage.  And unasked for proof that the clip  holds well despite washing and spinning.

The only outstanding 'normal' question is would it survive a 90 degree 'boil wash'.  I think it would, but, once again, I can't bring myself to do it deliberately,  But if it happens, I'll let you know.

I must admit I'm tempted to fire it from a crossbow, just to see what happens.  Even the makers never tried that ;-)

Gyppo

The more you know ...

glad your pen didn't break and leak ink all over everything
you would have lost more than a pen

Of course, the Russian space program achieved the same results with a pencil...

True,

But now I find myself wondering if a boil wash or a lengthy agitation in hot soapy water would separate the two halves of a wooden pencil, letting the lead fall out and break.

Probably depends in the  quality of the pencil.  Some cheap ones from the pound shops fall apart if you look at them too hard.

When I was at infant school we did our first scribblings and letters on slates with a wooden frame, with a slate pencil.  When I mention this some people laugh and say 'You're not that bloody old."

To which I reply, "There's been a lot of changes in seventy years, but slates still work and they don't go blobby or leak like cheap pens.  An electronic tablet and a stylus is just an electric slate which is useless when the power runs out."

Do you know, I think the one contingency the Russian space program didn't consider was what the outcome would be if one of their cosmonauts tried to boil his pencil.

I don't think most space vehicles are fitted with a washing machine either, so that would be a reasonable oversight  ;-)