Space Pen

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The Space Pen, which term generally refers to those marketed by Fisher Space Pen Co., is a particular type of pen. It uses pressurised ink cartridges to allow for features in addition to those offered by a standard ballpoint pen. The Fisher Space Pen was invented by American industrialist and pen manufacturer Paul C. Fisher and is manufactured in Boulder City, Nevada, USA. Pens claiming some or all of the same abilities have also appeared on the market from other manufacturers. There are two prominent styles of the pen: the AG7 "Astronaut pen", a long thin version shaped like a common ballpoint, and the "Bullet pen" which is considerably smaller.

1 Claims and specifications
2 Uses in the U.S. and Russian space programs
3 References in popular culture
4 External links

[edit] Claims and specifications

The Space Pen is claimed to write in zero gravity, upside down, underwater, over wet paper, at any angle, and in extreme temperature ranges. Several of the Fisher Space Pen models (the "Millennium" is one) are claimed to write for a lifetime of 'average' use, however the product literature states that the pen will write approximately 30 miles (approximately 48 kilometers).

The ballpoint is made from tungsten carbide and is precisely fitted in order to avoid leaks. A sliding float separates the ink from the pressurized gas. The thixotropic ink in the hermetically sealed and pressurised reservoir is claimed to write for three times longer than a standard ballpoint pen. The pen can write at altitudes up to 12,500 feet. The ink is forced out by compressed air at a pressure of nearly 35 pounds per square inch (340 kPa). Operating temperatures range from -50 to 250 degrees Fahrenheit (-45 to 120 degrees Celsius). The pen has an estimated shelf life of 100 years.

[edit] Uses in the U.S. and Russian space programs

At the end of the Apollo 11 moon landing, while discarding some of the equipment from the LEM, the switch used to ignite the motors was broken off. To improvise, the astronauts used the casing from one of their space pens to turn the switch and start the motor. This wouldn't have been possible if they had been using pencils.

There exists a common rumor claiming that because a standard ballpoint pen would not work in zero gravity (which is false ^[1]), NASA spent millions of dollars developing the zero-g capable Space Pen, with the humorous note that the Russian space agency opted to simply use pencils.^[2] This has been debunked several times, with reasons such as the danger that a broken-off pencil tip poses in zero gravity and the high flammability of both the graphite and wood present in pencils. In fact NASA never approached Paul Fisher to develop a pen, nor did Fisher receive any government funding for the pen's development. Fisher himself invented it, and then asked NASA to try it. After the introduction of the AG7 Space Pen, both the American and Soviet (later Russian) space agencies adopted it. (Previously both the Russian and American astronauts used grease pencils and plastic slates.)

[edit] References in popular culture

A bullet-style Space Pen is on permanent display at the New York Museum of Modern Art (MOMA).
The Space Pen was featured on an episode of the American television show Seinfeld.
The Discworld story The Last Hero by Terry Pratchett describes a spaceflight undergone with Renaissance technology. Amongst the items Leonard of Quirm invents for the flight is a quill pen with a pressurised ink reservoir "to write Upside Down during sojourns in the Void". In reference to the above urban legend, a note on the diagram says "Or invent better pencil".
In Diane Duane's young adult fantasy novel So You Want to be a Wizard, the main character, Nita Callahan, owns a space pen that becomes not only the catalyst for the central conflict, but also the tool for solving the conflict.
In one of the characteristic flashbacks in episode 3, series 3 of Scrubs, JD begs his brother Dan not to write on his face, claiming it is "a Space Pen and prom is in two weeks".