I made a home ages ago, probably over a year back. No updates have broken it, and I can teleport to it just fine – I have three different teleport "bookmarks" there, and they each work. I recently started playing again and learned that you can make space stations.
I wanted to put one in orbit above the existing base, so I went about trying to find it. Obviously just fumbling around the map looking for the name was out of the question, and there's no way to search for it by name. So I tried two other methods:
First, I cracked open the universe folder and looked at the filenames of recently visited planets. I'm sure I was doing this somewhat wrong, since some of those co-ordinates didn't even go to systems. I tried different permutations on negative and positive co-ordinates, and still couldn't find the system – although I did visit a few of the ones I checked.
Second, I obtained a quest on the planet. Looking at the GUI for the starmap, I noticed you could move to whatever your active quest location was. So I plopped down a couple colony deeds, did a lap around the world looking for active NPCs to no avail, went downstairs and accepted a quest to kill a dark knight in the abandoned cabin next door. However, when I went back to my ship excited to have a bookmark, it wasn't there. The fact that the automatic planet-marking that the quests do has me concerned that this planet plain isn't reachable by space.
As a followup, I beamed down to a nearby planet, got a quest, and verified that the quest tracker did work for quests I accepted… today.
The tl;dr is – is it possible that an update or error removed my planet from the universe, but not from existence, allowing me to reach it by bookmark but not by spaceship?
Best Answer
Starbound generates the universe procedurally. Whenever you look at the map, what you see is actually the game generating nearby systems based on some "universe seed" value. I don't know where that value is drawn from, but it doesn't change - that means that even if you erase all the worlds and characters in your save data, you could still possibly visit a planet that you've seen before. Every time you view the interstellar map, the game regenerates the system info using this universe seed, and since the seed never changes, the layout of all the stars appears the same as well.
When you visit a planet, that planet is procedurally generated using a combination of the universe seed and the planet seed (which is based on your current coordinates in space). However, in this case, it doesn't make sense to regenerate the entire planet every time you visit, otherwise all your construction and destruction would be erased. Therefore, when visiting a planet, a "planet save file" is created that stores all the changes you make to the planet. IIRC, the name of the file contains the planet's coordinates.
Sometimes the devs make changes to the procedural generation code. As a result, even though the universe seed is the same, the new code will generate a different universe than it used to. When you view your interstellar map, it's possible that according to the new universe, your planet does not exist, and therefore it won't show up on the map.
But you can still get to the planet by teleporting. This is because when you teleport to a planet, the game tries to load whatever planet file is associated with the coordinates stored in the teleporter. Since you've been on the planet before and saved its location, that's how you're able to teleport to the now-nonexistent planet.