Meanwhile, the colony's political leader, Malcolm Eberly, a Machiavellian bastard, is intent on maintaining power at all costs. But he faces a formidable opponent in upcoming elections in the form of Holly Lane, the colony's human resources director. She's campaigning on an emotion-packed proposal to reverse the ship's Zero Population Growth rules.

Meanwhile, scientist Nadia Wunderly is convinced that Saturn's rings harbor actual living organisms that are historically responsible for maintaining these unlikely constructions. She needs a sample from the rings to prove her thesis, but Eberly is against her plans, since if it's proven the rings harbor living organisms, he won't be able to mine the structures for valuable water ice.

Lastly among the main threads, we follow the troubles of Ilya Timoshenko, who's not only in charge of life support for the colony but battling suicidal depression. It's not enough that the blind forces of the universe seem to want the colony dead, but the man in charge of the Goddard's survival appears to agree with their goal.

Making the solar system safe for humanity

It occurs to me after reading this latest installment in Bova's Grand Tour series that he has successfully imported a narrative model from mainstream fiction into SF. That model extends back at least as far as Arthur Hailey's Hotel (1964). Pick a fascinating venue, assemble a cast that's representational of a variety of types, then chart the daily activities of the protagonists and antagonists, with an occasional crisis tossed in for good measure. It's a sturdy formula, and Bova has it down pat by now.

His cast of characters represent all the major vices, virtues, emotions and drives. By jumping among them in short chapters, he keeps a refreshing variety of reactions going in the reader. Amazingly enough—or maybe not so amazingly, given that this is pure SF, despite the mainstream template—the most interesting sections here revolve around the low-level AI inside the Titan probe. As the spirited machine makes its way across the weird, sensuously described landscape of the moon, we are likewise transported to a fascinating environment. Like Poul Anderson and Stephen Baxter, Bova has the knack for making the exotic comprehensible by use of concrete metaphors and sharp description.

Back on board the Goddard, Bova keeps all his plates spinning deftly as well. Bova's scientists are intriguing in both their commitment to research and their flawed personalities. Both Urbain and Wunderly are concerned with their public images almost as much as with incrementing the treasury of human knowledge. As for the political aspects of his plot, Bova conveys a certain cynicism about the invariant nature of human ambition, even under the changed circumstances of the year 2096.

Eschewing space opera, limiting himself strictly to probable scientific developments already on the horizon, Bova is intent on carrying forward the core mandate of SF: showing us a likely future we can actually attain. His innate optimism shines through, such as when he observes that the Greenhouse Crisis that almost killed Earth was also responsible for goosing space exploration. How's that for seeing a silver lining? In Bova's future history, the only limits to mankind's destiny are those inherent within us—and these can always be overcome, as witness the pivotal choices made by Timoshenko in the novel's multiple climax.