TheThe PLANETARYPLANETARY REPORT REPORT Volume XXV Number 1 January/February 2005 Nature’s Canvas Volume XXV Table of Number 1 Contents January/February 2005 A PUBLICATION OF From Features The Exploring the Unknown: Huygens’ 6 Plunge Through Titan’s Atmosphere Editor On December 25, 2004, the European Space Agency’s Huygens probe success- fully detached from the Cassini spacecraft and headed off to fulfill its destiny— arl Sagan, cofounder of The Plane- a 3-week coast to Saturn’s fascinating moon Titan, ending in a 2.5-hour dive C tary Society, dated our existence as through the moon’s thick, hazy atmosphere and a rough landing on the never- an organization from the publication of the before-seen surface. Titan, still enshrouded in mystery even after two close first Planetary Report in December 1980. Cassini flybys, intrigues scientists because of its similarity to early Earth. Here, If you do the math, you’ll see that this Huygens Mission Manager and Project Scientist Jean-Pierre Lebreton describes year marks the silver anniversary of The what we know so far about the unusual moon and details the probe’s harrowing Planetary Society. mission of exploration. And so . it’s time to party! Right now, we are scheduling an array of A Suborbital Search for Vulcanoids 25th anniversary events that will take place 14 Scientists are often detectives trying to solve a mystery. In the case of around the world and will range in size from Vulcanoids, an intriguing idea about a theoretical population of small asteroids gatherings in coffeehouses to a gala dinner orbiting near the Sun awakened the detective skills of planetary scientist Dan and beyond. Our goal is to involve every Durda. Dan and his colleagues developed a plan to prove or disprove the exis- Society member in the celebrations. After tence of the elusive asteroids by using a special camera aboard a sounding all, The Planetary Society is nothing but its rocket. Planetary Society members joined the investigative team by funding the members—combined into a strong force to innovative test. Here, Dan provides a personal account of what happened during achieve our ultimate goals of exploring the suborbital search and explains why Vulcanoids remain a mystery. other worlds and seeking other life. We do have a lot to celebrate. From the searching for putative Vulcanoids inside Mercury’s orbit to saving a spacecraft bound Departments for Pluto, The Planetary Society has come through time and time again. We’ve focused 3 Members’ Dialogue our efforts on projects that can make almost unimaginable differences to life on Earth, 4 We Make It Happen! from seeking possibly life-destroying aster- oids to searching for civilizations among 19 World Watch the stars. What other group can you think of that has set such lofty goals and achieved 20 Questions and Answers so much in pursuing them? We celebrate each other, joined together, 22 Society News as The Planetary Society. Let’s start the party now. —Charlene M. Anderson On the Cover: Contact Us In a portrait created by light and gravity, lonely Mimas is visible Mailing Address: The Planetary Society, 65 North Catalina Avenue, Pasadena, CA 91106-2301 against the cool, blue-streaked backdrop of Saturn’s northern hemi- General Calls: 626-793-5100 Sales Calls Only: 626-793-1675 sphere. Delicate shadows cast by the rings arc gracefully across E-mail: [email protected] World Wide Web: http://planetary.org the planet, fading into darkness on Saturn’s night side. Images taken with red, green, and blue filters were combined to create this color The Planetary Report (ISSN 0736-3680) is published bimonthly at the editorial offices of The Planetary Society, 65 North Catalina Avenue, Pasadena, CA 91106-2301, 626-793-5100. It is available to members of The Planetary Society. Annual dues in the US are $30 (US dollars); in Canada, $40 (Canadian dollars). Dues in view. The images were taken with Cassini’s Narrow-Angle Camera other countries are $45 (US dollars). Printed in USA. Third-class postage at Pasadena, California, and at an additional mailing office. on November 7, 2004 from a distance of 3.7 million kilometers Canada Post Agreement Number 87424. Editor, CHARLENE M. ANDERSON Copy Editor, A. J. SOBCZAK (2.3 million miles) from Saturn. The image scale is 22 kilometers Associate Editor, DONNA ESCANDON STEVENS Proofreader, LOIS SMITH Managing Editor, JENNIFER VAUGHN Art Director, BARBARA S. SMITH (14 miles) per pixel. Image: NASA/JPL/Space Science Institute Technical Editor, JAMES D. BURKE Science Editor, BRUCE BETTS Viewpoints expressed in columns and editorials are those of the authors and do not necessarily represent positions of The Planetary Society, its officers, or its advisers. ©2005 by The Planetary Society. Cofounder CARL SAGAN 1934–1996 Board of Directors Chairman of the Board NEIL DE GRASSE TYSON Members’ Astrophysicist and Director, Hayden Planetarium, American Museum of Natural History President Dialogue WESLEY T. HUNTRESS JR. Director, Geophysical Laboratory, Carnegie Institution of Washington Vice President BILL NYE science educator More Sound Off Wars” military programs has going into space, and that Executive Director As the debate continues, I would continued to have vast beneficial window will not remain open LOUIS D. FRIEDMAN ANN DRUYAN hope that colonization is left out fallout such as global position- indefinitely. Somewhere along author and producer DANIEL GERACI as a reason to send people to other ing system navigation, and the line, going back to the Executive Vice President, Phoenix Companies LAURIE LESHIN planets. One recent letter cited satellite monitoring of weather Moon will become so costly planetary scientist JOHN M. LOGSDON “massive climate change” as a and natural resources. So I am in money and resources that Director, Space Policy Institute, reason to colonize Mars. A mas- in favor of the government it will become effectively George Washington University Advisory Council Chair CHRISTOPHER P. McKAY sive disruptive climate change on supporting an active space impossible. If and when that planetary scientist, NASA Ames Research Center Earth amounts to a few degrees program, but let’s argue for it day comes, we will have lost BRUCE MURRAY Professor of Planetary Science and Geology, Celsius, or a latitude shift of a from a foundation that makes the last and greatest frontier California Institute of Technology ELON MUSK few hundred miles. And to es- sense. In the risk-to-reward and, quite possibly, the future Chairman, CEO, SpaceX JOSEPH RYAN cape that we would make a trip ratio, [putting] people on Mars of our civilization as well. Executive Vice President and of several months to live in a is off the charts. —JAMES S. VELDMAN, General Counsel, Marriott International ROALD Z. SAGDEEV former Director, Institute for Space Research, frozen vacuum with no tolera- —DAN LeMAY, Joliet, Illinois Russian Academy of Sciences ble climate other than what Fallbrook, California STEVEN SPIELBERG director and producer could be artificially created? And the debate goes on. It is MARIA T. ZUBER It’s easier to do that here. As a Planetary Society mem- moot to argue over which is Professor, Massachusetts Institute of Technology And the arguments that ber for several years, I am best. In some cases, robotic Advisory Council JIHEI AKITA humans must be there to really disturbed by what seems to be exploration will seem advan- Executive Director, The Planetary Society, Japan BUZZ ALDRIN observe and explore don’t a lack of vision (imagination, tageous for the purpose or Apollo 11 astronaut NORTON BELKNAP wash. Humans are not very if you prefer) on the part of place. At other times human President, Paul Taylor Dance Company RICHARD BERENDZEN good observers. They can’t see some members. Lack of vision expeditions will seem more educator and astrophysicist anything outside their limited in an organization such as The logical. We can’t afford to JACQUES BLAMONT Chief Scientist, Centre National d'Etudes Spatiales, France visual spectrum, they can’t see Planetary Society is, indeed, write off either case. Let’s have RAY BRADBURY microscopic items, they can’t almost chilling. our logic come into play, but poet and author DAVID BRIN ascertain chemical composi- Of course robotic explo- let’s not simply take sides for author FRANKLIN CHANG-DIAZ tion, and they have no means ration has to come first and, mere opinion’s sake. NASA, Astronaut Office ARTHUR C. CLARKE to make other key observations in some cases, is all that’s pos- —MIKE MARTINEZ, author FRANK DRAKE except with special instru- sible at the moment, as in the Lakeland, Minnesota President, SETI Institute; Professor of Astronomy and As- ments and tools. These tools New Horizons mission to trophysics, University of California,Santa Cruz OWEN GARRIOTT former astronaut; Professor, can just as well be carried by Pluto and the Kuiper belt— Editors’ Note: University of Alabama, Huntsville robots that don’t have the which I fully support. The A handful of our members tell GARRY E. HUNT space scientist, United Kingdom weight and maintenance penal- current robotic missions to us their November/December BRUCE JAKOSKY ties of human caddies. Mars are highly worthwhile issues of The Planetary Report planetary scientist THOMAS D. JONES The International Space and necessary. But to suggest arrived with pages missing. planetary scientist, former astronaut, and author SERGEI KAPITSA Station (ISS) has shown us that our exploration should be If your copy is missing pages, Institute for Physical Problems, Russian Academy of Sciences that many of the technical limited to robot probes is to please call or e-mail us for CHARLES E. KOHLHASE JR. arguments for the usefulness sell the future short. Numbers a replacement copy at (626) mission designer, author, and digital artist JON LOMBERG of a facility with microgravity of studies have indicated that 793-5100, extension 219, or artist HANS MARK and a good vacuum just aren’t a group of trained men and [email protected] University of Texas at Austin YASUNORI MATOGAWA worth the expense.