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Writing in space: Space pen

Picture of Rodrigo Valdivieso

Rodrigo Valdivieso

Unmanned Aerial Systems Expert


You have probably heard the story that describes how during the early days of the space race NASA engineers started to think about how their astronauts needed to be able to make notes and do calculations by hand, and how they spent millions of taxpayer’s dollars to develop a pen that could write in space.

According to the story, when the Cold War ended, a delegation of Russian cosmonauts (a cosmonaut is the eastern bloc equivalent to an astronaut in the western bloc) visited Cape Canaveral. During their visit, an American engineer proudly told them about all the work they had carried out and all the investment that had been required to develop their space pen. The engineer then asked (in a sarcastic tone) how they had solved the problem of writing in space. The Russian cosmonaut didn’t even answer. He took out his pencil, which had been casually resting behind his ear, and showed it to the American engineer, with a gesture that made everyone laugh.

In the early days of the space race, there were no portable calculators. Using slide rules required making notes by hand. Writing in space was therefore a necessity.

And so this story gets passed around on social media, with its corresponding array of more or less amusing variations.

But the story is actually a myth… NASA did not develop space writing, and the Russians did not use graphite pencils.

The truth is that today’s space writing solutions are due to technical problems that have been well known by all space agencies in the world since the very beginning. Indeed, Americans also began by using graphite pencils early in their space careers, but they quickly realised that not only do pencils not work in space, but they are actually also a huge hazard. The graphite tips of pencils are very brittle. When broken, fragments of carbon and wood, which are highly flammable, disperse in all directions due to the effect of microgravity, and usually end up inside electrical panels. This can cause elements to short-circuit, as they act as incandescent resistors in an oxygen saturated environment, or can simply block connection ports or inputs of any kind. Graphite pencils were banned almost from the outset in all space activities. The ban was reinforced after the Apollo 1 accident, where all three crew members were killed as a result of a fire in the cockpit, which was due to the ignition of highly flammable materials. Another mission that highlighted the problem was Gemini 3, when an astronaut smuggled a sandwich into the space capsule and witnessed for himself the chaos that breadcrumbs can produce by spreading in zero gravity conditions.

Of course, people soon realised that ink pens and felt-tip pens would not work either. They require gravity to exert its action in order to supply and deposit ink on the writing surface. Just as they do not work upside down, they do not work in microgravity environments either. There were also other problems in addition to that of microgravity: extremely high temperatures denatured the ink, turning it into colourful clumps, whereas extremely low temperatures froze the ink into crystals, rendering the pen unusable.

However, writing in space was still a necessity. Keep in mind that in the 1960s there were no portable calculators, and slide rules were used to carry out simple calculations. These were plastic rulers that slid together to align the operands in one area of the ruler and show the result in another area. This process required handwritten annotations of subtotals in order to arrive at the final calculations. Therefore, the need to write in space was absolute.

But it wasn’t NASA that ended up providing a solution for writing in space by investing millions of taxpayer dollars; instead, it was an American company that did so, using private capital.

In 1965, the Fisher Pen Company invested a million dollars (at the time) in designing and patenting a pen that could write face up, underwater and at temperatures between -35 °C and +120 °C. To allow writing in any orientation and in microgravity conditions, they developed an ink cartridge that contained compressed nitrogen at a pressure of 2.5 atmospheres. The pressure in the cartridge pushes the ink against the tungsten carbide ball at the pen’s tip, causing it to release ink like a normal ballpoint pen. All of this was enveloped in a strong metal body that included an internal vacuum insulation (like a coffee thermos) to mitigate the effect of the extreme temperatures it would be subjected to.

They also developed the necessary ink from exotic elements that allowed the ink to maintain its fluidity, durability and grip in the working conditions of space. The ink remains in the pressurised cartridge in a gel state until friction with the ink-dispensing ball turns it into a less viscous fluid, allowing it to escape. The inert gas in the cartridge also prevents the ink from coming into contact with oxygen in the air, preventing it from oxidising or drying out.

After numerous tests, NASA finally decided to adopt the “Space Pen” in its space programmes, starting in 1967. In 1968, they purchased 400 units exclusively customised for the Apollo programme.

In 1969, even the Soviet Union stopped using its grease pencils on plastic blackboards, and bought 100 units and 1,000 ink cartridges from the Fisher Pen Company for the Soyuz missions (and they got the same commercial discount NASA received for large purchases!).

As a curious anecdote, the Space Pen has not only been used for writing. It has also had a very different application that likely changed the course of history. It occurred during the Apollo 11 mission (the first time a human stepped on the Moon), when the Eagle landing module was resting on the moon’s surface and astronauts Neil Armstrong and Buzz Aldrin were carrying out their programmed activities. On one of his walks, Aldrin saw a strange artefact lying in the lunar dust. When he picked it up, he immediately identified it as the Eagle’s mechanical switch, which had to be activated before the take-off procedure could take place on their return to meet Collins, who was waiting for them in orbit around the Moon. And indeed, only a hole remained where the switch, now useless, had once been. Clearly it must have inadvertently been broken at some point while entering or exiting the module, going unnoticed due to their bulky space suits. It was instantly an emergency situation, as without the switch they would not be able to reunite with the module currently in orbit, and they would die on the lunar surface when they ran out of compressed air to breathe. Such was the desperation and sense of impending disaster that President Nixon’s cabinet prepared a speech announcing the death of the astronauts and the failure of the Apollo mission. But creativity thrives when crisis hits. At the last second before the take-off countdown procedure, Aldrin stuck his Space Pen into the switch hole, and managed to operate it successfully and in time. Thus, he saved both their lives and the mission.

A lot of time has passed since Space Pens were first used. Since then, several different Space Pen models have emerged, which have been used by both U.S. astronauts and Russian cosmonauts. These include exclusive product lines, such as the Shuttle Pen (for crew members on missions carried out on the U.S. orbital shuttle) and the Mir Pen (for crew members on the Russian space station).

Nowadays, anyone can have access to this space technology, as you can buy a custom Space Pen for a very affordable price from many different online stores.

Escritura espacial


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