Titan by Stephen Baxter

Possible signs of organic life have been found on Titan, Saturn's largest moon. A group of visionaries led by NASA's Paula Benacerraf plan a daring one-way mission that will cost them everything. Taking nearly a decade, the billion-mile voyage includes a "slingshot" transit of Venus, a catastrophic solar storm, and a constant struggle to keep the ship and crew functioning. But it is on the icy surface of Titan itself that the true adventure begins. In the orange methane slush the astronauts will discover the secret of life's origins and reach for a human destiny beyond their wildest dreams.