[cjslep]

You can warp through planets. You can also create bookmarks while warping. Create a bookmark as you warp through a planet, and now you can warp to that bookmark inside the planet.

Edit: I think in an update you no longer warp inside the planet though (and get launched out of it), just to its edge or its designated warp point in lieu of landing inside. Its been forever since I played.

[stcredzero]

You can also create bookmarks while warping.

I think that's what I did. I discovered a pocket of near-stability in the center of planets. I had some sort of plan to try and anchor containers and things there, which I never finished.