Most of us have never heard of the space pen. But if you have one, it may be through listening/reading. NASA has spent billions of dollars to develop a special ballpoint pen that can work in space, but savvy Russians just use pencils.

Well, yes, space pens do exist, but in fact, when they say billions of dollars, they mean $2.39.

Space travel is dangerous. A spacecraft, like a submarine operating underwater, is a closed environment-but with additional dangers.

In space, the lack of effective gravity means that everything stays where you left off.

Warm gas (such as the air you exhale) does not spread quickly in all directions. Solid objects will not automatically fall to the floor. With a pencil, if the tip of the graphite tip breaks, it just floats in the air. If you sharpen a pencil, sawdust or graphite powder will also sharpen.

These floating debris may fall in your lungs or eyes. But the situation may get worse. If the debris is conductive (just like graphite), it is the main threat to electronic components and electrical switches. Graphite is also flammable.

The Russians have a pencil problem. Astronaut Anatoly Solovyev said, "The pencil lead is broken... and it's not good in the space capsule: metal lead particles are very dangerous in zero gravity."

In 1965, Paul C. Fisher from the California Fisher Pen Company independently developed the AG-7 pen and applied for a patent. (AG means anti-gravity.)

It looks like an ordinary ballpoint pen.

But the first difference is that the ink is a thixotropic gel-pressure changes it from a semi-solid gel to a liquid. Secondly, the ink is pressurized to two atmospheres (similar to the pressure in a car tire) by compressed nitrogen to continuously press it on the ball of the pen tip.

When you start writing, the tungsten carbide balls rolling on the paper rub against the gel ink and shear the chemical polymer bonds in the gel. The gel becomes liquid, spreads on the roller ball and quickly deposits on the paper.

Gravity has no effect in this case-the pen will work in the microgravity of space.

It is said that the total cost of developing this technology is approximately US$1 million. It is not paid by NASA. The cost is entirely borne by the private company Fisher Pen Company. (This is completely different from NASA spending billions of dollars.)

By 1967, NASA ordered 400 Fisher Space Pens for their Apollo program.

The Russians followed suit and ordered 100 pens and 1,000 ink cartridges for their Soyuz space mission. In other words, once Russians can stop using pencils, they did it.

And because both NASA and the Soviet Space Agency are buying in bulk-they obviously both get the same 40% discount. Instead of paying $3.98, they paid $2.39.

But when is the truth enough to hinder a good story?

"Interview with Paul Fisher, the inventor of NASA's space pen", April 12, 2004, Audiology Online

"Fact or fiction?: NASA spent millions of dollars to develop a pen that can write in space, while Soviet astronauts use pencils", by Clara Kotin, December 20, 2006, "Scientific American"

"Fisher Space Pen boldly write places that no one has ever written", Jimmy Stamp, January 11, 2013

"Legend of Space Writing", Caleb Wong, June 9, 2017, National Air and Space Museum