I flew to the space (on Asteroids) and i am just floating in space, i can't land, i can't do anything. I tried this on second world and it was good, but in my main world it is broken. Can somebody help me what to do ?

Does the client log show anything?

No, it isn't bug in client, just bug in game, i can't land because i am flying down a then up.

So you are stuck? Delete your player file then.