Introducing the SF world - getting the balance right

As an SF writer, I face a classic tension at the start of every story.  Because everything in my world is invented, I need to provide enough description of everything to show the reader where they are.  But on the other hand, I don't want to slow the action of the story down and bore my readers.

This balancing act is one that every science fiction and fantasy writer faces.  We have to sketch in enough of our setting to show the reader the city, space station, starship, or monarch's throne room.  And we have to establish our setting on the run.  Whilst the Iron Throne has an interesting design, it's the actions of the characters scheming against each other to gain it that readers want to see.

I've just finished rewriting Auroradawn, and that novel presented me with a particular challenge in chapter one. I had to get across the idea that my heroine Arrien is newly bereaved.  She is now the Captain  of a Great Family, one of several powerful wealthy landowners on Vedrana.  I had to explain that each Family had a bioengineered soulship.  The ships had intelligent biomechanical AIs, which have the capacity to reach full sentence through absorbing the memories of their dead Captains,  which is why Arrien is in the Transfer Loft at the start of the novel, transferring her just-dead mother's memories to a crystal to give to Auruoradawn, her soulship.

In 1600 words I've introduced the idea of soulships, memory crystals, and the Starrider Great Family.  Then Arrien's younger brother Baak appears, and he has to be introduced.  I have to explain that he ran away from home two years ago, and that he's now trying to steal the memory crystal.  

I thought all that information was essential for the reader to make sense of the scene I was showing them.  But there were a lot more things that I decided couldn't fit into chapter one. I have Arrien hoping the soulship will Awaken, but I don't explain what that process involves, or the changes it will make to the soulship.  At the top of the chapter I've labelled the location as Mithras, Starrider Great Family compound, Vedrana, but I haven't explained any of those names. 

Those are the sort of choices we have to make when setting the balance of action and description.  And this week I read the finished chapter to Havant and District Writers' Circle.  Most of them are not SF readers, and they didn't get confused by my start, so I guess I've got the balance right.