This is a myth, using a pencil in space isn't clever or thrifty, it's a disaster waiting to happen. The graphite from pencils breaks off in small fragments while writing and the fragments can create shorts in electronics and to top it off they're also flammable. None of those are properties you want to bring into a spacecraft.
I wonder how graphite can create shorts, when all electronics board and components on them can be easily covered with protective nonconducting PCB varnish.
dumb question but how well do sharpies work in space? the ink diffuses through the felt tip - that doesn't require gravity. wouldn't that work pretty well?
also crayons seem like a better bet than pencils - they're still flammable and prone to flaking but at least they're not conductive.
Your question piqued my curiosity, so I did some googling... Apparently sharpies do work in space, though NASA seems to prefer the Duro brand of marker.
Sharpies and markers generally run out waaay quicker than pens or pencils. They also dry out if you're not careful, and dry out temporarily if you use them for more than a few minutes at a time.
Crayons just aren't dark enough, and are too wide. Accurately reading numbers and symbols written in crayon at a normal handwritten size is not something I want to do. Not to mention the constant sharpening.
