Why Can't We Write with a Normal Pen on the Moon?

Why Can't We Write with a Normal Pen on the Moon?

Have you ever wondered why you can't write something on the moon using a regular pen? It's food for thought, though.

Well, in this post, we are going to look at some possible and plausible answers to this question.

Which Pens Can We Use on the Moon?

On the moon, you can write things down using a normal ballpoint or a Fisher Space Pen. The latter is the more practical and recommended option since it is made particularly for this use. Fisher pens are also more compact, which makes them easy to carry around clipped inside a pocket or in some compartment in a heavy duty web belt.

You could be thinking, since you can use normal ballpoints up there, what's up with the title of this post?

Well, the non-functionality applies to fountain and gel pens. Incidentally, it also applies to lead pencils (we'll explain this one a bit further on as well).

Why Can't We Use Fountain and Gel Pens?

Ink Cartridges

Usually, these instruments use simple cartridges. In the cartridges, the ink is stored without any pressure or propulsion acting on it. When you hold the pen with the nib downwards, the stuff comes trickling down and ta-da! You can write with it.

Picture this. You're writing something on a flat surface while standing underneath it. This position is such that the nib is facing up and the body (cartridge) is below it. After some time, the point will run dry since there is no ink coming down on it.

The same thing happens in zero-g. There is a far lesser pull of gravity when you're up on the moon. While in space, the gravity is nil. It goes up to 1.62 m/s² on the moon. This force is one-sixth of what we experience here on Earth.

Due to the reduced down-pull, you will have trouble writing with gel and fountain pens. However, with pressurized cartridges, as are found in our Trayvax Bullet Space Pen (which, by the way, you can get as part of the pack if you buy our leather slim minimalist wallet: the Summit Notebook), the flow is not much affected.

Blots and Floats

What is blotting? Blotting is when the ink comes out in quantity more than it is supposed to. That usually results in the writer getting an ugly blob on the paper.

Now imagine. If some gel pens were to blot up there on the moon, the ink would come out, and since no force is acting on bringing it down, it will start floating. Yep, that can happen.

So, this is another reason why these instruments cannot be used in zero-g. Think about it. Some poor astronauts are bouncing here and there with inky blots floating all around. If it was water or some edible stuff, he could have some fun catching it in his mouth, but what can you do with ink?

And this floating is the exact point that one individual mentioned as the reason why lead pencils cannot be used in zero-g. What happens if the tip breaks? And what about all those pencil shavings?

bullet space pen

Trayvax Bullet Space Pen

Even if you don't want to go the outer space anytime soon, it's nice to have something that is not as likely to blot and has a good ink pumping system. If you're looking for something that falls in this criterion, try out the Trayvax Bullet Pen.

You can check out our product page or other posts on our blog to learn more about this product. In brevity, the Trayvax Bullet Pen is an awesome product that you can buy individually and part of the deal if you opt for the Summit Notebook front pocket wallet. The former can be a good choice if you already have a minimalist leather wallet and are just looking for something to help you take notes during your day.


Normal ballpoints can work just fine on the moon. The rumor's bunkum. However, fountain and gel pens cannot be used in low or zero gravity. We discussed some reasons above for that as well.

If you want to buy something that will bring with it the assurance of working in different unusual situations, try the Trayvax Bullet Space. This thing won't leave your side anywhere, whether you're on high altitudes, in deep waters, or outer space. The looks are an added benefit that you can get to enjoy.

Reading next

Why Don't Ballpoint Pens Work Underwater?
The Best Pens That Write On Any Surface

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