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Spaceworthy: The Cartridge Inside the Fisher Space Pen

By Wesley Fenlon

Contrary to popular belief, the US government didn't develop a pen for spaceflight. The most famous pen in history was the independent creation of Paul Fisher.

Thanks to Seinfeld's classic "Take the pen" bit and an old-as-the-Internet meme about Soviet astronauts using pencils, most people know that NASA astronauts of the 1960s used the Fisher Space Pen to take notes in a weightless environment. As the story goes, NASA spent millions of dollars to invent a pen that would work in space, while Soviet cosmonauts simply used pencils. Turns out that's not true. Both American and Soviet astronauts used pencils for early trips to space, and the Soviets eventually adopted the space pen, too. And all the R&D money that went into creating the coolest pen of all time? The government had nothing to do with it.

Smithsonian's Design Decoded blog has a great post up about the history of the Fisher Space Pen, busting the myth of NASA's R&D efforts with some research into when the pen was actually created. Paul C. Fisher, who actually ran against John F. Kennedy for the Democratic primary in 1960, was reportedly working on the pen before ever talking to NASA. He wasn't thinking about astronauts--he just wanted to build the perfect pen that would work upside down, in freezing temperatures, or underwater. He wanted to isolate the ink from air that it wouldn't dry up. So it's actually true that a million bucks went into developing the Space Pen--it just came out of Fisher's pocket, not NASA's.

Fisher's invention of the ink cartridge actually opened the door to the Space Pen. As the blog details:

"The secret to the space pen is in the cartridge. It is a hermetically sealed tube containing thixotropic ink, pressurized nitrogen gas, and a tungsten carbide ballpoint tip. During development, Fisher found that while the pressurized cartridge successfully pushed ink out the tip of the pen, it also successfully leaked uncontrollably. Rather than redesign the cartridge, Fisher redesigned the ink. He developed a thixotropic ink that is a gel at rest, but turns into a liquid under pressure. Sort of like toothpaste. With this new, thicker ink, the pen didn’t leak and would only write when pressure was applied to the ballpoint. Success."

Fisher filed for a patent in May 1965, but NASA had to spend a couple years testing the pen to make sure it would be safe before green-lighting it for space flight. Pencils posed their own hazards--they'd easily catch on fire in a 100 percent oxygen atmosphere, and broken tips could float into equipment or the eyes of the astronauts--and the Space Pen passed NASA's tests with flying colors, earning it a trip to space with Apollo.

The Fisher Pen company sold NASA 400 perfect pens for $2.95 a pop. They cost a bit more these days. But on the bright side, there are a ton of choices.