You might have heard me refer to Earth as "Sol C" before. This comes from my system for referring to spaceports by short codes! First of all, here are some example codes:

Planet	Spaceport	Code
Earth	Baikonur	Sol C1
Earth	KSC + CCAFS	Sol C2
Mars	First human mars landing site	Sol D1
Moon	First human moon landing site	Sol Ca1

The star name (Sol in this case) is optional, but I put it in there for good measure.

As you can see, the code is short (although case-sensitive) and refers to a spaceport. Notably, it lacks support for referring to space stations, as I haven't thought about them when I came up with the code.

Structure of the code

The code is made up of the planet number and spaceport number, like this:

So this code refers to the first spaceport on the Moon, which is the first natural satellite of Earth, the third planet from the sun.

The characters are basically base26 - AA1 is a spaceport on the 27th planet. This is why the code is case-sensitive - CA1 is not on the moon, but is on the 79th body from the star!

The spaceport number can be omitted like the star name: Sol E is Jupiter.

The system can also be extended to include moons of moons. If you consider Proxima Centauri to be the innermost planet of Alpha Centauri AB, Alpha-Centauri AcA is the innermost moon of Proxima Centauri c.

How numbers are assigned

Planet and moon numbers are given by increasing average distance to its host body. This means that the code with star name functions like the systematic planet name, but the two refer to completely different planets. The planet called Proxima Centauri c has the code Proxima-Centauri B.

Naturally, new planets might be discovered that are in between two known planets, which means that the systematic name will have to change. Two solutions: either change the code too, or just assign the next available number to the new planet. I don't know which is better.

Spaceports get numbers if they have launched a human into low orbit or beyond, and plan to do so consistently. They are sorted by the date of the first successful orbital flight with a human on board. Because only three countries have launched humans into space so far, only three spaceports have numbers - 1 for Baikonur, 2 for KSC (and Cape Canaveral, which is effectively part of the same facility), and 3 for Jiuquan. I think C4 will be either Satish Dhawan or Boca Chica.

Extensions

It is possible to add extra information after the code. The formatting of this area has a bit more leeway because it's less clear what information will be needed.

For worldbuilding purposes, I use this space to store a bunch of key-value pairs with capital-letter-only keys and number-and-lowercase-letter values. Here are the defined keys so far:

• P: Launch pad
• T: Tower frequency (used for "tuning the radio")
• C: Center frequency (also used for tuning the radio. Controllers on this frequency make sure launching and reentering spacecraft don't have intersecting trajectories)

This means that you can refer to the Apollo launch pad, Pad 39A at KSC, as C1P39a.

What is this for?

Honestly, it's just something I came up with and have fun using. Feel free to take this and use it in your own projects, either in fiction or in real life!