The secret behind the unique capabilities of our pens lies in the ink cartridge itself. Our refills contain thixotropic ink and are hermetically sealed, pressurized with nitrogen gas, and feature a tungsten carbide ballpoint tip. To prevent leaks, Fisher ink is actually more of a gel than a liquid when it is at rest, but when pressure is applied to the ballpoint, the ink becomes spreadable, while still retaining the stickiness required to adhere to nearly any material. | Fisher Space Pens' popularity is due to their use by NASA during Debuting the Apollo 7 mission in 1968. Normal ballpoint pens expose the ink to air and rely on gravity – which wouldn’t work in space at zero-gravity – while our specialized ink cartridges rely on pressurized gas that won’t leak or dry up. This allows the pen to write at any angle (including upside down), in extreme temperatures (-30F to +250F), on almost any surface, underwater, through grease, and, of course, in space! | When it comes to pens, if you’re anything like us you can’t settle with just any old plastic ballpoint. You expect and deserve more from your pens - much more. To ensure the highest quality, our products are both hand- and machine-tested, so you can write confidently with the knowledge that your Fisher Space Pen will never let you down. |