The year and number designator is for known man made object launches. All satellites get a COSPAR ID It's done in sequential order. https://en.wikipedia.org/w

The year and number designator is for known man made object launches. All satellites get a COSPAR ID It's done in sequential order. https://en.wikipedia.org/wiki/International_Designator https://en.wikipedia.org/wiki/International_Designator Even top secret NRO launches get a designator, since it's impossible to hide the launch itself, but its orbital activity and TLE might not be obvious once in space.