Fisher Space Pen is What NASA Astronauts Use to Write Aboard the ISS, Here’s How it Works and is Made

The Fisher Space Pen Company manufactures the Space Pen, which is a specially designed writing utensil that uses pressurized ink cartridges capable of writing in zero gravity, underwater, over wet greasy paper, at any angle, and in various temperatures. They are used by astronauts aboard the ISS as well.

How does it work in zero gravity? Well, the ballpoint itself is made from tungsten carbide and is precisely fitted in order to avoid leaks. There’s a sliding float separating the thixotropic visco-elastic ink from the pressurized gas. The ink in the hermetically sealed and pressurized reservoir is capable of writing for three times longer than a standard ballpoint pen. That’s right, it can write at altitudes up to 12,500 feet, thanks to the ink being forced out by compressed nitrogen at a pressure of nearly 45 psi. Operating temperatures can range from −30 to 250 °F, even without the help of gravity, at any angle to boot.