|Ok. I'll admit I'm not at all up on the environment from which this story starts. So, take my comments as a newbie to your world.
The overall thing is I'm lost almost from the beginning of this story. Clearly, you are working in a world with very different parameters. So, if you do want to bring in readers who do not know your world, I suggest something that orients them to what is going on here.
I'm also unclear about the inner lives of your many characters. For me, at least, that's what I find interesting. For example, you start with Joan traveling to Marc but her trip, at the beginning is mostly logistics. But as soon as she sees Marc she's emotionally undone to the point of trembling. I'm not sure why we don't see that throughout the trip. And for all the characters you then introduce, I'm lost as what's going on with them. What are they feeling and thinking about their various interactions?
You also present so many characters that I have trouble keeping them all straight. If you're going to create such a complex social interaction, I would suggest you help your reader by being very careful about laying out those relationships and their complexities. Maybe work on POV and being clear in your narration whose POV we're seeing. This might also help to get us emotionally invested in one or two of your main characters.
Don't know if this helps or not.