Why need pens that can be used in space?

In ballpoint pens, the ink flows through gravity and reaches the ball at the end of the pen. With the help of this rotating ball, the ink flows to the tip of the pen in a controlled manner. However, since ink does not flow on its own in weightless environment, special pens that can be used in space have been developed.

Many people have heard the story that while the Americans spent millions of dollars developing ballpoint pens that could be used in space, the Russians thought to use pencils. In fact, NASA also used pencils on its first space missions, for example, Gemini. However, because graphite is a highly flammable substance and is easily broken, graphite dust is a danger of damaging electronic systems in spacecraft in a weightless environment, so instead of pencils, ballpoint pens are suitable for use in a weightless environment for the first time, Paul C., An entrepreneur from the United States, has been It was developed by Fisher. A pressure ink cartridge, this pen can be used in weightless environments, underwater and in a wide temperature range of about -50 to 200°C.

These pens contain a system of pressurized gas and a buoy that can move. The float separates the gas from the ink. Compressed gas pushes the ink to reach the tip of the pen. Since the force exerted by the pressurized gas does not depend on the direction of the pen-as in weightless environments - it is possible to write with these pens by holding the pen at any angle. In addition, these items are used with inks whose fluidity varies depending on the strain applied on them. When needed, the inks become fluid and the Pens can be used for longer periods of time without leakage.