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The Planetary Report

Volume XXV, Number 4, July/August 2005

Credit: NASA / JPL-Caltech / University of Maryland

On the Cover

On July 3, 2005, 67 seconds after its impactor smashed into the nucleus of comet Tempel 1, Deep Impact’s flyby spacecraft took this picture. Scattered light from the collision saturated the high-resolution camera’s light detector on the flyby craft, creating the bright splash and rays seen here. It’s reflected sunlight, however, that illuminates the comet’s nucleus.

From The Editor

"Dream no small dreams for they have no power to move the hearts of men.”

Goethe said it first, but Thomas O. Paine was fond of quoting it, and I’ve taken it as my personal motto for The Planetary Society. Tom was the administrator of NASA during the first Apollo landings and a director of The Planetary Society until his death in 1992. When we face setbacks—as with the loss of Cosmos 1—I conjure up Tom’s voice saying those words and resolve not to give up.

In my book, there are three types of dreams: the unconscious at its nightly play, ideas that will never become reality, and blueprints for an achievable future. The solar sail belongs in the last category. We lost Cosmos 1 at the very beginning of its journey, when the Volna rocket failed to lift it to its intended orbit. But as far as we are concerned, our attempt to achieve the first solar sail flight is not a failure, it is merely a dream deferred. We will try again.

Meanwhile, we still have a full roster of other projects. In this issue, we cover the threat to Earth from errant asteroids and what can be done about it—work we are sponsoring. We also have a report on Huygens’ discoveries on Titan by longtime Society friend Toby Owen.

Exploration goes on, as does the dream of new worlds to explore, and we are still part of it.

— Charlene M. Anderson

Features

Approaching Xanadu: Cassini-Huygens Examines Titan
Huygens’ January 14 landing on the surface of Titan was a great accomplishment, showing us never-before-seen views of the mysterious moon. But the in-depth examination of the intriguing moon has only just begun. Scientists are still studying Huygens’ data, and the Cassini orbiter is completing the first year of its 4-year tour of the Saturnian system. As it dances through a complex series of orbits, Cassini repeatedly turns a close eye to Saturn’s haze-shrouded moon Titan. Here, longtime Society friend Toby Owen—a planetary scientist and one of the architects of the Cassini-Huygens mission—explains what Cassini-Huygens has taught us so far about Titan and its tantalizing atmosphere, which resembles that of early Earth.

We Must Decide to Do It! The Saga of Asteroid 2004MN4
We watch for asteroids and track these space rocks orbiting around our Sun, hoping we never find one on a collision course with Earth, but history tells us one eventually will come our way. When we do find that near-Earth object on a dangerous path toward Earth, will we be ready to protect ourselves? How will we do it? We could send explosives to space in an attempt to destroy the threat. Or, as Apollo 9 astronaut Rusty Schweickart suggests and explains here, we could send a craft to gently nudge it into a new orbital path. The discussion of exactly how to handle an NEO headed for Earth continues, and there are many differing opinions. The Planetary Society is part of this discussion, working with Rusty and others to help come up with a solution.

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