The Outer Worlds Tartarus planet is just sitting there on your map. You can visit a ton of planets after the first few hours but not that one. But why not? How do you get to Tartarus in The Outer Worlds? It is alluring as it sits next other planets you can visit. But just be warned that this isn’t the Greek dungeon of torment.
The Outer Worlds Tartarus | How to get to Tartarus
Even though it seems like a regular planet, you can’t get to Tartarus until the end of the game. This is the final level, after all. It’s part of the story so you can’t prematurely go there and start killing raptidons.
To unlock Tartarus, you need the Tartarus navkey. You’ll get this navkey from Phineas Welles, the eccentric scientist that woke you out of your slumber, after you get the Dimethyl Sulfoxide from Byzantium. Once you go back to him on his secret lab, he will tell you to go the Hope ship. Once you go there and come back, Phineas won’t be there. Instead, he will be gone.
Follow that mission by searching the cystipig for the key, which opens up the terminal that opens up his secret room. Once you get to the secret room, the objective marker will be over the Tartarus navkey, as you can see in the above picture. Once you pick it up, you can go to Tartarus. This is all part of the main plot, so if you’re worrying, you haven’t missed it.
That’s how most people will get to Tartarus. Given how open the game is, there are other possible ways to get there. For example, turning in Phineas yields a different way to get there. In that timeline, she has you skip the Hope to Tartarus by directive of the Board. Regardless, this is again part of the main plot.