Cutty's ship is named RMS Essex, although "ESSEX" is just what's painted on the side. The original Essex was scrapped; its LH2 tank was converted into the crew compartment of Cutty's ship.
So, LH2 tank engineering is not trivial. If you want it to launch from Earth, then you have to confront icing and insulation. For various reasons, this works best with a single layer of structural tank, with insulation foam applied outside that and optional paint outside that.
But this becomes a problem if you have dreams of using these big LH2 tanks for a space habitat. Bits of foam breaking off becomes space debris - a hazard in LEO.
Thus, Essex was not allowed to operate in LEO, severely limiting its ability to bring in revenue. Besides, its avionics and various systems degraded and became obsolete, so Essex was scrapped.
Cutty's ship would be built around its LH2 tank, repurposed into a crew compartment. Spraying the outside with large cellulose bubbles both solved the problem of space debris and provided Whipple shield-like impact protection.
Postcards From Cutty is about a woman who has gone on a one way trip to explore an Oort cloud system 550AU away. It's set in the 2170s, at a time when humanity's off-world population is in decline - from a peak of several hundred, to some dozens.
In the back-history of PFC, there hasn't been any "true" space colonization. ...
It's been years since I actively wrote anything for Postcards from Cutty and I think I basically can't do it. At least, I can't write anything anyone would want to read, in a traditional form.
However, I can info-dump random technical and world-building details, and maybe I should just do that and not worry about telling a traditional story.