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On the Cover: Volume XIX Not all ice is water. Not all water is on Earth. These are the first Table of Number 2 I. insights to come from studying th e various 'ices in our solar system. Comets, such as Hale-Bopp ~nset), are made primarily of Contents March/April1999 water ice, but frozen carbon dioxide often makes up a substantial part of a comet nu cleus . The Martian north polar cap (3~ back ground image, exaggerated vertically to show detail) is primarily frozen water, but the southern cap on Mars is mostly frozen carbon dioxide. The larg est of Jupiter's moo ns, Ganymede (full disk) , is Features bigger than the planet Mercury. Still, in composition, it is roughly half water ice, making it a truly giant snowball in space. 4 Grand Challenges for Space Exploration It's not often that a government official gets to layout a vision for the future that goes Hale-8opp image: Jerzy Giergielewicz Mars: MSSSlNASA beyond the next election cycle. But Wes Huntress, who recently stepped down as NASA's Ganymede: JPUNASA Associate Administrator for Space Science, did just that in a speech accepting the Carl Sagan Medal of the American Astronomical Society. Wes' text was far-ranging and detailed, and we had space in the printed magazine for only highlights of his talk. But the beauty of digital media is th at you can squeeze a lot of text into a little space. The full text is available Froln at the Planetary Society's World Wide Web site. S "Ices" Throughout the Solar Systenl: The A Tour of Condensable Species Editor Water is abundant throughout our solar system and probably in other solar systems as well. Most of it is in the form of ice. However, the word ice does not necessarily denote frozen water. Frozen carbon dioxide, frozen methane, and frozen nitrogen coat some of the small t's very hard to explore planets. The worlds of the outer solar system. To get a true feel for the planetary system we live in, we I distances between worlds are nearly have to understand a bit about ices and how they behave. Wendy Calvin of the United States impossible for humans to comprehend, Geological Survey takes us on a tour through a garden of alien ices. used as we are to this small, solid world. Space beyond our protective atmosphere '4 Building TOlNard Mars: A Vision for the Future is a hostile place, a near vacuum through NASA has made a major commitment to exploring that most Earth-like of nearby which huge blasts of radiation-----deadly worlds, Mars. Every two years, the US space agency will launch two spacecraft to the Red to humans and their robotic surrogates Planet. The European and Japanese space agencies are also reaching out for Mars. In an regularly flow. effort to coordinate all this energy and activity, NASA recently formed a Mars Architecture Many, many of our robot explorers group. Their charge is to study and suggest ways to get the most out of robotic exploration have crashed, blown up, or simply disap perhaps leading to a human presence on Mars. Charles Elachi, Director for Space and Earth peared while attempting to complete Science Programs 'at the Jet Propulsion Laboratory, leads the group, Lou Friedman, Planetary their missions. Mars Observer seems to Society Executive Director, also serves on the panel. Here they summarize their findings have blown up while maneuvering into for Society members, Mars orbit. Galileo, exploring the Jupiter system, carries on despite being crippled. Nozomi, on its way to Mars, and the Departlnents NEAR spacecraft, bound for Eros, have had to scramble to new trajectories. (You 3 Menlbers' Dialogue can read the details in Lou Friedman's World Watch World Watch on page 7.) 7 It's easy for people to cluck their '9 NelNs and RevielNs tongues and ask, whyc an't those "rocket scientists" do it right? Planetary Society 20 Questions and AnslNers members know better. We know how great the challenges are. And we know 22 Society NelNs how great the potential payoffs can be. So we'll cheer the resourceful engineers and scientists who find ways to over come adversity and keep us on our Contact Us journey outward. We choose the journey in part because it is hard- and worth Mailing Address: The Planetary Society, 65 North Catalina Avenue, Pasaden a, CA 91106-2301 the effort. General Calls: 626-793-5100 Sales Calls Only: 626-793-1675 -Charlene MAnderson E- mail: [email protected] Wo rld Wide Web: http ://planetary.org ~~:~~~e~~ZAR~~~g~~~~~?7:~~j'gg!~~6~_blt~~~e~v~!~~~~htlb ~~~b~~~o~~atlh~ff~I~~~~~~: ~~c~~~~~YA~~~:~Yd~~sNi~r~~~5t~I~~ ~v2e;ue, (US doll ars); in Cana~a, $35 (Canadian dollars), pues in other countries are $40 (US dollars). Printed in USA. Th ird·class postage at Pasadena, California, and at an additional mailing office. Canada Post Agreement Number 87424. A Publication of Editor, CHARLENE M. ANDERSON Technical Editor, JAMES D. BURKE Associate Editor, DONNA ESCANDON STEVENS Copy Editor, KARL STULL THE-PL.A~TfRY SOCIETY Assistant Editor. JENNIFER VAUGHN Proofreader. LOIS SMITH Production Editor, WILLIAM MCGOVERN Art Director. BARBARA S. SMITH o .~ -e- cp -& 0 Viewpoints expressed in columns or editorials are those of the authors and do not necessarily represent positions of the Planetary Society, it~ officers, or advisors. © 1999 by the Planetary Society. o ----------------------~=========m----------~~._--------------==--------~~~~--======------====_, Co-founder CARL SAGAN Members' 1934·1996 Board of Directors BRUCE MURRAY Dialogue President Professor of Planetary Science and Geology, Galifornia Institute of Technology LAUREL L. WILKENING Vice President Chancelfor, University of California, Irvine LOUIS D. fRI EO MAN Executive Director NORMAN R. AUGUSTINE Space: Getting There round instead of flat. ity of human Mars exploration Chairman and CEO. Lockheed Martin Corporation ANN DRUYAN FroID Here We should reach for the inner could be brought down to a level author and producer My friend Neil Tyson is a worthy planets as soon as possible, and that could be funded within a frac DONALD J. KUTYNA opponent; however, I put my necessity will be the mother of tion of the current NASA budget former Commander, US Space Command JOSEPH RYAN money on Louis Friedman's side invention to bring the technology spread out over about a decade. Executive Vice President and General Counsel, Marriott International of the bet. I am sure Neil will for to go to outer space. Participation by other spacefar ROALD Z. SAGDEEV former Director, {nst/lute for Space Research, give me! (See "Space: You Can't - JAMES F. PINKHAM, ing nations, private industry, univer Russian Academy of Sciences Get There From Here" in the Hudson, New York sities, and nonprofit organizations STEVEN SPIELBERG JanuarylFebruary 1999 Planetary would make the enterprise even director and producer KATHRYN D. SULLIVAN Report.) I look back on my days I just finished reading "Space: more affordable. Furthermore, Pres/dent and CEO. Ohio'S Center of Science and Industry at Cape Canaveral (1957 to 1960) You Can't Get There From Here." unlike the Apollo project, these and former astronaut NEIL DE GRASSE TY SO N and realize that things I never What an outstanding article! It new architectures lend themselves Director, Hayden Planetarium, dreamt possible have happened should be required reading for to long-duration, wide-ranging American Museum of Natura/ History over four decades. every appropriations officer in surface exploration instead of bare Advisory Council For example, Arthur C. Clarke's our government. Thank you, Neil, bones, flag and footprints missions. JOHN M. LOGSDON Chairman Director, S08ce Policy Institute, geosynchronous-orbital communi for verbalizing what I and others - PAUL CONTURSI, George Washington University cations satellite was denied a have known for years: that most Brooklyn, New York DIANE ACKERMAN patent in 1946 because the United of space beyond Mars is indeed poet and author BUZZ ALDRIN States patent office claimed the science fiction. Stories from Star Ice on the Moon Apollo 11 astronaut theoretical orbital rocket to test Trek and Star Wars sound exciting Another perceptive individual, RICHARD BERENDZEN educator and astrophysicist his hypothesis did not then exist. to those of us plugging along in besides Arthur C. Clarke and JACQUES BLAMONT Chif]fScif]ntist, Ten years later his patent was once our eat1hly Jives, but there are more Bruce Murray, proposed the Centre National d'Etudes Spatia/es, France again denied because he had pub important (and realistic) projects existence of ice on the Moon (see RAY BRAOBURY lished his works in the 1940s so here on Eat·th to spend our precious the January/February issue of poet and author DAVID BR IN the idea was "eminent domain." billions on. The Planetary Report, page 10). author ARTHUR C. CLARKE Last week the international dis - BRIAN SULLIVAN, Although I no longer possess author tress signal SOS was officially Springfield, Virginia V A. Firsoff's SUijace of the CORNEUS DE JAGER Professor of Space Research, The Astronomical discontinued because satellite Moon (published in 1961, I Institute at Utrecht, the Netherlands locator systems are so much supe Given the cost and complexity of believe), I recall my astonislunent fRANK DRAKE PreSident, SETllnslitute; rior that SOS is no longer needed. traditional human Mars mission at his suggestion of ice being a Professor of Astronomy and Astrophysics, University of Callfomia, Santa Cruz In World War II, we built rock plamling, which really didn't possibility on the Moon. STEPHEN JAY GOULD Alexander Agassiz Professor of Zoology, ets, but Wernher von Braun was change much from Wernher von - WILLIAM REYNOLDS, Harvard University already envisioning what became Braun's Collier s.