The sky road - Ken MacLeod

Centuries after its catastrophic Deliverance, humanity is again reaching into space. And one young scholar working in the space ship yard, Clovis colha Gree, could make the difference between success and failure. For his mysterious lover, Merrial, has seduced him into the idea of extrapolating the ship's future from the dark archives of the past.

A past in which, centuries before, Myra Godwin faced the end of a different space age - her rockets redundant, her people rebellious, and her borders defenceless against the Sino-Soviet Union. As Myra appealed to the falling empires if the West for help, she found history turning on her own dubious past - and on her present decisions.

Decisions which, centuries later, will determine the future of the new space age. Merrial's people, the itinerant computer engineers, know this. And they know that the truth they seek lies within the secret files left by Myra Godwin.