I have been going back over the side quests to help level up a bit before the bigger story missions. I have been able to do side quests on all of the planets except for Sargasso as the quest is unavailable. Why is this?
The side quest in Sargasso requires you to complete a major story event before it becomes available. I won’t spoil what exactly it is but eventually, the story will take you back to this planet and once you complete this, the side quest will become available for you. If you need some more help with this quest, you can check out the help trudi quest guide.