There's a famous legend that America spent millions on the development of a "Space Pen" that writes upside down, while the Russians used a pencil. Here's the truth behind the legend.


In fact, the Space Pen was developed by a private company and sold quite cheaply to NASA for space flights as part of a marketing gimmick. The Soviets, by the way, used them too.

The real kicker of the whole flap about the million-dollar Space Pen was it came on the heels of another overpriced writing implement. The early Apollo mission was embroiled in scandal when the public found out that astronauts were using pencils priced at $128.89. People were outraged to find that NASA ordered over four thousand dollars worth of pencils, and an inquiry was opened into the matter. At the inquiry the NASA representative, probably the guy who'd drawn the short straw that day, wearily explained that the pencils were made of special fibers, but were a bargain at $1.75 each. The extra money came from the fact that they had to be modified so that they could be attached to the inside of the space ship and be used by someone wearing a space suit.


In actuality, pencils were a terrible implement to use inside a space ship. The tips could break, sending debris into instruments. Even if the tips were tough, the pencils eventually required sharpening. And pencils burn, which is never good in space. A pen was a more practical instrument, but after the price fiasco, they weren't about to develop something new.

Fortunately, they were spared the expense by Paul Fisher of the Fisher Pen Company, had spent a million of his own dollars developing another pen. The Fisher Space Pen was a marked improvement over conventional ballpoints. At the time, the ink in a ballpoint was rarely kept in a sealed container. Exposed to air, it would dry and clog the pen. It would also run at inconvenient times. Fisher stopped this by developing a sealed ink cartridge for the pen. But there was a problem. The regular pens had open cartridges had ink that would flow freely. If the cartridge was sealed, when the ink flowed down around the ball, it created a vacuum at the top of the cartridge as the ink tried to empty out leaving nothing behind. The ink stopped flowing down and the pen stopped working.

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To combat this, Fisher pressurized the cartridge with nitrogen. The ink now had about 40 pound per square inch of nitrogen shoving it down towards the ball and out of the pen. This proved to be too much. The ink was forced out of the pen, making it leak. Fisher had to stop the leakage, without easing up on the pressure. There was no structural solution in the pen, so he used the structure of the ink. Instead of a regular liquid, Fisher developed a thixotropic liquid. Another thixotropic liquid is ketchup. Hold the bottle upside down, and nothing happens. Shake it, and enough ketchup will pour out to douse a plate. Fisher developed an ink that was more gel-like. When the ball of the pen moved, the ink would be agitated - like ketchup in a shaken bottle - and flow freely. When it was left in peace, it stayed in the pen, even under pressure.


Fisher offered the Space Pen to NASA for a low price of $1.98, and soon it was flying on missions with astronauts. Which is exactly the kind of marketing that Fisher wanted. The Space Pen caught on, and is still sold, although other companies make other pens based and marketed on the same principle. The Space Pen was so popular, that the Soviets took notice, and carried the design on their missions. However, the idea that America likes its shiny toys and its wasteful bureaucracy, while the Soviet Union was a model of lean efficiency was popular, and the Space Pen/Pencil story caught on.

The real kicker? Although the Space Pen was eventually used on missions, and although NASA did happily buy from the Fisher Pen Company, the first pens bought were not Space Pens, but regular ballpoints. Why? Because although only the Space Pen writes upside down, ballpoint pens do work in space.


Top Image: atomicjeep, via Wikimedia Commons CC BY-SA 2.0

Second Image: NASA

Via Scientific American, How Stuff Works, and ITOTD.

This io9 Flashback originally appeared in September, 2011