The Ophiuchi Hotline: John Varley

An Eight Worlds novel. Following the effortless capture of Earth by vastly superior aliens, humanity was left to fight for existence of the Moon and other chunks of airless rock. Then the Hotline was intercepted off Pluto: a constant stream of data from the direction of star 70 Ophiuchi, facilitating the development of amazing new technologies. Someone really should have sent a response. Perhaps the mysterious senders would have appreciated a show of thanks. For now, four hundred years later, the latest Hotline transmission is a bill for services rendered. It should hardly matter to Lilo, since she's been caught experimenting with human DNA and sentenced to permanent death for crimes against humanity. But Lilo is rescued by the maverick Boss Tweed, ex-President of Luna - only to find herself and several illegal clones of herself - hurtling from different directions towards a long-delayed confrontation with humanity's alien conquerors.