July/August 2007

Saturn Is Ready for Its Close-Up

John Horvath '81 discusses the complexity of the Cassini-Huygens voyage in her book showcasing 150 of the mission's best photographs of Saturn.

By Jennifer Chu

SATURN: A NEW VIEW By Laura Lovett, Joan Horvath ’81, and Jeff Cuzzi Abrams, 2006, $40.00

In January 2005, about three weeks after separating from the Cassini orbiter, the Huygens probe touched down at its final destination: the surface of Saturn's largest moon, Titan. The first packets of data from the probe streamed back to Earth, and NASA scientists beheld a landscape: in the foreground, a dry riverbed strewn with ice chunks, and in the distance, beds of sand, gravel, and rock.

Amid the 150 images of the ringed planet and its moons in the book Saturn: A New View, the one captured in those first minutes serves in a very real sense as a vantage point. It may be easy to view Saturn's signature rings with some detachment, as a confirmation of an image remembered from childhood. But the tight, focused shot of Titan's terrain gives us the feeling of standing on its surface, its rocks at our feet.

Joan Horvath '81, coauthor of this new collection, was one of thousands of people from 17 countries who helped launch the Cassini-­Huygens mission. In the book, she outlines the team's ambitious objective: to build an unmanned spacecraft, the size of a school bus, armed with cameras and instruments and able to survive a seven-year flight before entering its orbit around Saturn and ultimately sending a probe to Titan. Planning the mission was an arduous feat. As Horvath explains in one of the book's few essays, "It's similar to a mountain-climbing expedition--there is no food to be found on the icy upper slopes, so mountaineers need to carry everything they eat. The longer the expedition, the more food needed and the heavier the load. By comparison, getting into Earth orbit is car camping!"

That planning process took 15 years. To maximize fuel efficiency, engineers calculated how to use the gravitational forces of the solar system to swing the spacecraft around Venus and Earth, each planet providing a "gravity assist" that propelled the craft in the right direction at the right speed.

Most of the photographs in this book were taken by Cassini's two cameras: one wide-angle and the other narrow-angle, for close-up shots. Horvath and her collaborators, Laura Lovett and Jeff Cuzzi, sifted through some 34,000 images taken in the first year in orbit to assemble 150 of the best. Some pictures are sequential, overlapping frames that form a composite image of the planet. Others are close-ups of lunar craters and images of Saturn's icy rings.

As Cassini orbits Saturn over the last years of its mission, scientists hope to deepen their understanding of the planet and its moons. They also hope to answer important questions like whether the atmospheres of Saturn and its moons harbor organic chemicals that may offer clues about Earth's beginnings. Meanwhile, the photos in this book may renew our awe at our own small but remarkable outpost in the universe.