The dream begins with a disaster. Given the task of dismantling NASA's aging shuttle program after a horrifying re-entry crash, Paula Benecerraf comes up with a bold plan to keep America in space using existing technology.

Possible signs of organic life have been found on Titan, Saturn's largest moon. Inspired by this, Benecerraf assembles an unlikely group of visionaries for a dinner party in Houston, and presents them with a mission proposal so preposterous, yet so plausible, that it renders them speechless - then sets them arguing far into the night. And so begins a new era in space exploration.

The crew includes an aging NASA flyboy; a JPL "double-dome" genius obsessed with extraterrestrial life; a pair of Skylab astronauts who became secret lovers in orbit; and Paula herself, the first grandmother to leave the inner solar system.

The ship is patched together from the remnants of fifty years of spaceflight: Mercury and Gemini hardware, a stripped-down Columbia-class shuttle, a Skylab hab module, a couple of Apollo capsules, and a battery of refurbished F-1 engines - plus some surplus Soviet Topaz nuclears.

The destination is Titan. The billion-mile voyage, the most stupendous in human history, takes most of a decade, and includes a "slingshot" transit of Venus, a catastrophic solar storm, and a constant struggle to keep the ailing systems up and the tiny crew together.

Back home, it is a decade that will see the USA dismantled, the Earth engulfed in environmental collapse, and the Chinese conquering space with disastrous results for the human race. But it is on the icy surface of Titan itself that the true adventure begins. For it is here, in the orange methane slush, under the awesome rings of Saturn, that the Tartarus astronauts are to discover the secret of life's origins, and reach for a human destiny beyond their wildest dreams.