Two questions

I put two questions in one to avoid fatigue, (hahaha).
First: I have pending the Sidor mission to get an artifact, (Night Star). I have the artifact but I suppose it is something "special" because there is not option to give Sidor the Nigth Star I have.
Second: What mission should I do to get access to the Red Forest, (Jupiter, Zaton, etc)

Hi DanielMSAR.

The Night Star that Sidorovich wants is a unique item and you must follow his clue to find it. I don't think he will accept a different Night Star. When you return to him, Sid does not always have the Night Star dialogue immediately- especially if you have other things to talk about. Try again a bit later. If he still doesn't have the necessary dialogue, try removing the Night Star from the container (or replacing it in the container) and talk to him again. He should accept it eventually, but it might take a few tries.

From your first question I assume that you are still fairly early in your game. You will be sent to the Red Forest after you reach Recon, which happens after you have visited both parts of the Sarcophagus. Jupiter and other maps in the north will not become available until you reach Level 1 (Collector), which comes much later. Don’t worry, just follow the main story and you will reach all areas eventually.