I started a book many years ago (probably about 30!) and I have never been able to remember the title.
All I do remember is a student navigator on a winter (icy) planet who climbs into his spaceship which I seem to remember is called Tycho Brahe - or not, but the name stayed in my head as being connected to the novel.
This young student is at a college for spacefarers or similar . I remember him going into a cafe and getting hot chocolate after ice skating. He was prematurely asked to pilot a ship (the Tycho Brahe, I believe) which involved a very cramped compartment and some sort of symbiosis with the ship itself - and then its a blank. Sorry its not much to go on. I will look at the suggestions made.