Starfarers — Vonda N. McIntyre

SPACE PIRATES

They were idealists, scientists, and pioneers. Their ship was more than a mere spacecraft:
Star farer was both a habitat and an experiment, unfurling its solar sails toward a rendezvous with the unknown, from which its predecessor never returned. Yet for Victoria MacKenzie, scientist and leader of the ship's revolutionary command structure, the first and greatest danger came not from space ...but from Earth itself.

A shifting political landscape has turned the government against the voyage, and now the mission's controllers are demanding a new regime of martial law. To MacKenzie it is clear that Starfarer is being co-opted for a military purpose. To save the mission she must do the unthinkable: hijack the ship and continue the peaceful search for extraterrestrial life--even at the risk of nuclear suicide!