[peterbraden]

or just paint behind the robot

[rayiner]

And use a pencil instead of inventing a pen that works in zero gravity.

[happymellon]

The pencil introduced graphite dust into the air that caused electrical problems.

This is why astronauts use a pen. Sometimes the "cheap and simple" way has side effects that are more harmful than the original problem.

[matkoniecz]

And Russian space station (while they had one) was notorious for repeated fires.

Probably that approach to safety was cause for it.

[jakear]

Oil pencils and wax pencils are a thing too.

[happymellon]

They are, and the Soviets stopped using them because

- The paper peeled away is a fire hazard

- The oil and wax writing smudges and is a terrible way of writing

- The floating bits of paper from sharpening the pencils was a mess and since they float, got in people's faces.

Generally those are terrible ideas too, especially compared to a $100 for a pen. It's really not that much compared to every other cost.

[jakear]

What about mechanically advancing wax rods? The question isn’t whether the unit price of a super-pen is less than that of a consumer-waxpencil, but rather the R&D cost of the super-pen vs that of a supposed super-waxpencil.

[happymellon]

NASA didn't spend any R&D on it as it was developed by a third party, so that point is moot as the answer is $0.

https://www.scientificamerican.com/article/fact-or-fiction-n...