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File:AG-7 Space Pen.JPG
An AG-7 Astronaut Space Pen in presentation case.
File:SpacePen.jpg
Bullet pen.

The Space Pen (also known as the Zero Gravity Pen), marketed by Fisher Space Pen Company, is a pen that uses pressurized ink cartridges and is able to write in zero gravity, underwater, over wet and greasy paper, at any angle, and in a very wide range of temperatures.

File:AS07-4-1586.jpg
Astronaut Walter Cunningham, Apollo 7 lunar module pilot, writes with space pen as he is photographed performing flight tasks on the ninth day of the Apollo 7 mission.

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InventorsEdit

The Fisher Space Pen was created by Austrian Friedrich Schächter and expanded by Erwin Rath. Paul C. Fisher invented the "thixotropic special ink". The pens are manufactured in Boulder City, Nevada. Paul C. Fisher first patented the AG7 "anti-gravity" pen in 1965.<ref>Template:Cite patent</ref>

ModelsEdit

There are two prominent styles of the pen: the AG7 "Astronaut pen", a long thin retractable pen shaped like a common ballpoint, and the "Bullet pen" which is non-retractable, shorter than standard ballpoints when capped, but full size when the cap is posted on the rear for writing.

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 exactly 30.7Template:Nbsmiles (Template:Cvt). In contrast, the standard PR (Pressurized Refill) cartridge is rated to write for over 12,000Template:Nbsfeet (Template:Convert or Template:Cvt).

Standard Space Pen refills can be used in any pen able to take a standard Parker-type ballpoint refill, using the small plastic adapter that is supplied with each refill. Fisher also makes a Space Pen-type refill that fits Cross pens, one that fits 1950s-style Paper Mate pens (or any pen that uses that type of refill), and a "universal" refill that fits some other ballpoint pens.

TechnologyEdit

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 visco-elastic ink in the hermetically sealed and pressurized reservoir is able to write for three times longer than a standard ballpoint pen. The ink is forced out by compressed nitrogen at a pressure of nearly Template:Cvt. Operating temperatures range from Template:Convert. The pen can write without the help of gravity, at any angle. The pen has an estimated shelf life of 100 years.

One of the first Space Pen patents is US3285228, which was filed on 19 May 1965.<ref>Sakpal, Nilesh J Space pen | Zero gravity pen | Astronaut's pen AG7 - Fisher Space Pen Co.</ref>

Uses in the U.S. and Soviet space programsEdit

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} An urban legend states that NASA spent a large amount of money to develop a pen that would write in space (the result purportedly being the Fisher Space Pen), while the Soviets just used pencils.<ref name="physics1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="snopes1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In reality, NASA began to develop a space pen, but when development costs skyrocketed the project was abandoned and astronauts went back to using pencils, along with the Soviets.<ref name="physics1"/><ref name="snopes1"/> However, the claim that NASA spent millions on the Space Pen is incorrect, as the Fisher pen was developed using private capital, not government funding. The development of the thixotropic ink cost Paul Fisher around $1 million (equivalent to $Template:Inflation million in Template:Inflation/year).<ref>Template:Cite news</ref> NASA, and the Soviets,<ref name="snopes1"/><ref name="thewritersedge">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> eventually began purchasing such pens.

NASA programs previously used pencils<ref name="spacepen1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> (as demonstrated by an order in 1965 for mechanical pencils)<ref name="sciam">Template:Cite news</ref> but because of the substantial dangers that broken pencil tips and graphite dust pose to electronics in zero gravity, the flammable nature of wood present in pencils,<ref name="sciam"/> and the inadequate quality documentation produced by non-permanent or smeared recordkeeping, a better solution was needed. Soviet cosmonauts used pencils, and grease pencils on plastic slates until also adopting a space pen in 1969 with a purchase of 100 units for use on all future missions.<ref name="NASA">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> NASA never approached Paul Fisher to develop a pen, nor did Fisher receive any government funding for the pen's development.<ref name="sciam"/> Fisher invented it independently and then, in 1965, asked NASA to try it. After extensive testing, NASA decided to use the pens in future Apollo missions.<ref name="spacepen1"/><ref name="NASA"/><ref name="thewritersedge"/> Subsequently, in 1967 it was reported that NASA purchased approximately 400 pens for $2.95 apiece (equivalent to $Template:Inflation each in Template:Inflation year).<ref name="NASA"/><ref>You can see the original 1967 purchase order between NASA and Fisher Space Pen {{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

In 2008, Gene Cernan's Apollo 17-flown space pen sold in a Heritage auction for US$23,900.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

As of 2021, Fisher space pens were still being used on the International Space Station.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

In popular cultureEdit

  • The 20th episode of season 3 of the comedy television show Seinfeld is called "The Pen" with a Space Pen featured as a major plot point.<ref>{{#invoke:citation/CS1|citation

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  • The Space Pen is featured in the 2009 Bollywood film 3 Idiots, presented by the director of an engineering college to his students.<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

See alsoEdit

ReferencesEdit

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External linksEdit