You all might have heard a story that during the height of the space race in the 1960s, NASA scientists figured out that pens cannot be used in space, so they developed a pen that could write in space, and this cost NASA millions of dollars. The Soviets on the other hand just used a pencil. This story is just a myth.

According to historians, NASA astronauts used pencils. In 1965, NASA ordered mechanical pencils from Houston’s Tycam Engineering Manufacturing, Inc. But the cost of one pencil was $128.89 and when this news reached the public they were not thrilled. Because of a public outcry, NASA had to find out something much cheaper.

See the pencils also have one peculiar fault. The tip could shave off or break, it then might drift due to microgravity. This could cause serious damage to the astronauts and to all life support equipment which might create some serious problems. Apart from this, a pencil is flammable and NASA wanted to avoid anything flammable on the spacecraft.

What about ordinary pens then. Why can astronauts use pens just like we use them on earth? See regular pens that we use rely on earth's gravity, the ink flows downwards when we hold the pen in our hand. As we go up in space the earth’s gravity decreases and that is the reason why astronauts float around in space. This is also the reason why a regular pen won't work in microgravity.

So how are astronauts writing in space? Well, when NASA was busy with mechanical pencil controversy one individual named Paul C. Fisher designed a ballpoint pen that could work in space. His company Fisher Pen Co. invested one million dollars of its own funds to design and patent this pen.

The pen can be used efficiently not just in space, but it can be used in various other conditions such as a weightless environment, underwater, in different liquids, at heights of 12,500 feet, and also in the temperature range of -34°C to 121°C.

After a few years of testing, NASA approved these pens to be used in space missions. It was first used in the Apollo 7 mission and since then it is being used in various space missions. The Russian space agency has also used it for various space missions.  

If you would like to buy one you can do so by ordering it online. They are not cheap and may cost upwards of ₹ 2,000.