The story Behind the Fisher Space Pen
The Fisher Space Pen with its sealed pressurized ink cartridge was selected by NASA after rigorous testing for use on all manned space flights because it is the only type of pen that will write satisfactorily in the gravity-free void, freezing cold (-50°F) and extreme heat (+250°F) of space. Since 1967, Fisher Space Pens have been used by Astronauts on all manned space flights - even those on the Moon. They are also purchased by the Russian Government and used by the Cosmonauts on all Soyuz flights.
Nitrogen-powered, the ink in the replaceable Space Pen cartridge is positively fed to the tungsten carbide ball by gas pressurized at about 40 pounds per square inch. The Fisher Space Pen will write at any angle, even upside down. We believe it to be our world's smoothest and most dependable pen.
Pressurization required the development of a new special viscoelastic ink (like thick rubber cement). It is also highly thixotropic, which prevents oozing through it's highly precision stainless steel point.
The revolving tungsten carbide ball liquefies the thixotropic ink, allowing the Fisher Space Pen to write smoothly and dependably on most surfaces, even under water.
Paul Fisher invested more than $2 Million Dollars in perfecting these pens.
Ordinary ball pens rely on gravity to feed the ink and need a small hole in the top of the refill through wich the ink can evaporate or leak. There is no hole in the hermetically sealed Space Pens. Evaporation, wasted ink and back leakage are eliminated and shelf-life increased from a normal two years to an estimated 100 years.
Your Fisher Space Pen is unconditionally guaranteed to give you good, satisfactoy service both here on earth and in sapce.