What happened was that Hilary was writing a straight future disaster story -- collapse of society stuff -- but didn't get that far with it. I
borrowed that for the scenes on Earth and rewrote it fairly heavily.
All the scenes in the ship are mine. Many of the scenes back on Earth are Hilary's. That's why it was never presented as a regular collaboration.
She didn't want it done that way. So I worked in acknowledgements in the dedication.
Ironically, the stuff Calvert liked to read out at Hawkwind gigs was cut from the US edition by the editor, Terry Carr, who thought it too
So it goes.