Side note -- I hate that anecdote. There was a good reason
by BigBadBrewer (2017-09-12 17:25:02)

In reply to: X marks the spot.  posted by The Holtz Room

for the pen and not the pencil at that time. The mechanical pencils the US used had tips that would break, leaving debris and graphite dust floating around the cabin which could potentially interfere with operation (get in eyes, graphite is flammable, etc). The US ended up allowing the pressurized pens to be sold to the Soviets IIRC as well.