When Nasa.......

[excelsior-1]

.... first started sending up astronauts, they quickly discovered that ballpoint pens would not work in zero gravity.

To combat the problem, NASA scientists spent a decade and $12 billion to develop a pen that writes in zero gravity, upside down, underwater, on almost any surface including glass and at temperatures ranging from below freezing to 300 degrees Celsius.

The Russians used a pencil.

[baza]

damned commies.

[Old_Geezer]

They should have used a wax crayon and avoided the graphite dust !

[frugalfred]

I knew a constipated mathematician who worked it out with a pencil.

[heathfield]

Oh well. NASA had the advantage. The Russians pencil wouldn't write on glass

[dizmouk2009]

Unless I'm mistaken a non graphite pencil will actually write on glass. Well it does because I have just tried it. That kind of ruins the additional joke, sorry.