More book information

I've remembered more information about the book I'm looking for.

• It cannot have been printed after 1999.
• It was in hardback.
  
• The cover was green.
  
• It was not part of an anthology.
  
• There is a sequence where the heroine's private spacecraft is launched into escape velocity by a massdriver. I further suspect this is at a spaceport in or near the Canary Islands.
  
• The heroine is an immortal, just like the hero.
  
• It was fairly hard sci-fi.
  
• It is categorically NOT "Holy Fire", by Bruce Sterling.
  
• It was not, to the best of my knowledge, written by any of the "big guns" of science fiction.