|SR-72 closely resembles spaceplane Percival in the novel|
My inspiration at the start was filker Leslie Fish's song "Ballad of Transport 57" (actually, I don't remember the number). This song is about a cargo ship in space attacked by pirates. The space navy chases away the pirates, but the transport has to limp to a starbase using its cargo--beer--as propellant.
I started Percival's Descent with a pirate attack underway. (I always find it easier to write openings by bombing into action underway.) In a nod to Leslie Fish, I decided to call the my cargo ship the Fisher King.
Immediately after picking the name, I knew I was onto something, because it made the name of the protagonist obvious to me: Percival, the fool and would-be knight of the Holy Grail legends. I decided to call him Percy, instead of Percival (although he prefers Perce), and have him, like both Percival and Perseus, raised by his mother in a community of women, away from the ways of men, until just before the age of eleven.
Also, the mythology made clear to me certain things that had to be true of the Fisher King. It is a wounded ship that has seen better days. It is also a barren ship, crewed entirely by men. The myths gave me the overall plot of the entire Fisher King series: Can Perce heal the Fisher King?
The Fisher King carries spaceplanes used to shuttle cargo between the freighter and planetary surfaces. By manufactured coincidence, one of these spaceplanes that figure prominently in the story is named Percival. That decision inspired the other part of the title: Percival's Descent.
From the time that Perce boards the Fisher King, he begins to have strange dreams that often involve a lance and a cup. That is, he begins to have a vision quest for The Grail.
I'm saving more mythology for the second novel, tentatively called Fisher King: Dancing Lance, where we will learn that Perce, again like both Percival and Perseus, is (figuratively) the son of a king.
You can read more about the book at https://cololitnet.com/node/71.