I'd ditto the question ;) Semi-recent thread with some interesting-looking suggestions, not sure of 'hard' scifi label though: http://www.reddit.com/r/printSF/

I'd ditto the question ;) Semi-recent thread with some interesting-looking suggestions, not sure of 'hard' scifi label though: http://www.reddit.com/r/printSF/comments/1eyt3b/is_there_any_sf_book_that_gets_orbital_mechanics/ http://www.reddit.com/r/printSF/comments/1eyt3b/is_there_any... I'd recommend other books by Greg Egan, though. Permutation City (http://en.wikipedia.org/wiki/Permutation_City http://en.wikipedia.org/wiki/Permutation_City) is particularly interesting and makes some very interesting conjectures dealing with computation, cognition, 'quantum ontology', etc. Character development is somewhat poor, but eh! (there's also a FAQ on the author's website: http://gregegan.customer.netspace.net.au/PERMUTATION/FAQ/FAQ.html http://gregegan.customer.netspace.net.au/PERMUTATION/FAQ/FAQ...)