A Publication of THEPLANE~ SOCIETY

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Board of Directors FROIVI THE CARL SAGAN BRUCE MURRAY EDITOR President Vice President Director. Laboratory for Planetary Professor of Planetary Studies, Cornell University Science, California InsUtute of Technology LOUIS FRIEDMAN Executive Director HENRY TANNER California Institute THOMAS O. PAINE of Technology s we go to press, the Phobos 2 space­ proach to Earth provided opportunities to Former Administrator; NASA Chairman, National JOSEPH RYAN A craft is orbiting Mars, preparing to ren­ re-examine its familiar face, and to recall Commission on Space O'Mefveny & Myers dezvous with the moon Phobos. This com­ the work of earlier observers. Board of Advisors plex craft will send two landers to Phobos' Page 13 -The Concept of Extraterres­ DIANE ACKERMAN JOHN M. LOGSDON surface, irradiate it with a laser to measure trial Intelligence: An Emerging Cosmol­ poet and author Director. Space Policy Institute George Washington University its composition and conduct many other ogy?-Is the search for extraterrestrial in­ ISAAC ASIMOV author HANS MARK experiments that should greatly expand our telligence a truly scientifIc endeavor or an Chancellor. RICHARD BERENDZEN University of Texas System understanding of this strange, asteroid-like exercise in metaphysics? A new cosmology, President, American University JAMES MICHENER satellite. JACQUES BLAMONT aurhor based on centuries of thinking about the Scientific Consultant, Centre National dEludes Spa/isles, MARVIN MINSKY As our readers know, Phobos is the fIrst universe, may be unfolding as we search for France Donner Professor of Science. Massachusetts Institute mission in an ambitious Soviet program to signs of other civilizations. RAY BRADBURY of Technology poet and author explore the Red Planet. Mission planners Page IS-World Watch-Should human­ PHILIP MORRISON ARTHUR C. CLARKE Institute Professor, Massachusetts are hard at work on a Mars '94 mission that ity set its sights on Mars? For the past few author Institute of Technology may carry balloon probes partly designed years The Planetary Society has worked CORNELIS DE JAGER PAUL NEWMAN Professor of Space Research, actor by The Planetary Society (see the Septem­ hard to convince sometimes skeptical gov­ The Astronomical Institute at Utrecht, The Netherlands BERNARD M. OLIVER ber/October 1988 Planetary Report). A ernment agencies that setting the goal of Chief. SETI Program. FRANK DRAKE NASA/Ames Research Center rover/sample return mission may follow lat­ a human landing on the Red Planet could Professor of Astronomy and Astrophysics, UniverSIty of SALLY RIDE er in the decade. Soviet space leaders make lend direction and purpose to our endeav­ California al Santa Cruz former astronaut no secret of their desire to send humans to ors in space. The effort is beginning to LEE A. DUBRIDGE ROALD Z. SAGOEEV former presidential Institute for Space Research. Mars, preferably in a joint mission, early in payoff. science advisor Academy of Sciences of the USSR the next century. This has been the goal of Page 20-Lunar Polar Explorers-If JOHN GARDNER founder, Common Cause HARRISON H. SCHMITI Soviet dreamers since the early decades of there is water ice hidden among the nooks former US Senator. NM THEODORE M. HESBURGH and former astronaut this century, when rocket pioneer Kon­ and crannies of craters near the Moon's President Emeritus, University of Notre Dame LEWIS THOMAS stantin Tsiolkovsky fIrst visualized travel poles, then lunar settlement may be easier Chancellor. Memorial Sloan SHIRLEY M. HUFSTEDLER Kettering Cancer Center between our planet and Mars. and more profItable that we now think it educator and jurist JAMES VAN ALLEN The Phobos mission is bringing Tsiol­ could be. The Planetary Society has studied GARRY E. HUNT Professor of Physics, space scientist, . United Kingdom University of lowa kovsky's dream one step closer to reality. the possibilities of "cheap, quick" missions We will keep you up-to-date as the mission to search for that water. progresses, and when the science results Page 22-Society Notes-We bring you have been analyzed, you can look forward more news of Planetary Society activities. t~~~~:6ffi~~ ~~~:ftr~~if.~I~ ~1~~:X::~~e~1 Pasadena. CA 91106, (818) 793-5100. II is available 10 members of The to a special issue of The Planetary Report Page 23 -Help Design a Mars Rover­ Planetary Society. Annual dues are $20 in the US, $25 in Canada, and $30 outside the US Of Canada. with all the discoveries. The Soviet Union and its spacefaring part­

Editor. CHARLENE M. ANDERSON; In this issue you'll read about: ners are planning a Mars mission with a Technical Editor. JAMES D. BURKE; Assistant Editor. DONNA STEVENS; Page 3 -Members' Dialogue-The surface-roving lander. You may be able to Copy Editor. SUSAN JUNDANIAN; Moon, the space station, Mars, the Search help design it. Art Director. BARBARA SMITH for Extraterrestrial Intelligence (SETI)­ Page 24-News & Reviews-In this era of Viewpoints expressed in columns or editorials are those of the authors and ~ ~~i~~S~S:~~8~b~e~~I~i~~~ ~::'Ianetary Society, its officers where should we be directing our advanced tight budgets an easy place to cut spending In Canada. Second Class Mail Registration Number 9567 technologies? And what should be the moti­ is scientifIc research and analysis. The plan­ vation behind our exploration-profIt, sci­ etary science community has been particu­ ence, adventure, safeguarding earth? larly hard hit. C;OVER: Comets are frequent visitors to the Page 4-Comets: Mementos of Crea­ Page 26 -Funding Planetary Science: skies of Earth. Since we reside in the Inner tion-These small, frozen bodies may be A National Perspective-Planetary explo­ solar system, as these small bodies of ice remnants of the birth of our solar system. ration is a national program, just one of a and dust pass us by they are heated by the Sun and pummeled by the solar wind, By studying comets we seek a window into kaleidoscope of endeavors supported by sometimes forming spectacular tails that our own past and a greater understanding of the United States government. can stretch out millions of miles behind the universe around us. Page 28-Q & A-Life and lunar tides, them. Comets may be clumps of maner left Page IO-Changing Views of Mars­ planetesimals and protoplanets, atmospheric over from the creation of the solar system, Telescopic observers have been watching pressure and winds are dealt with in this so by studying them we learn about our own origins. Seen here Is Comet Ikeya-Seki, the variable face of Mars for the last few edition of "Q & A." which graced our skies in 1965. centuries. The planet's recent close ap- -Charlene M. Anderson Photograph: Science Graphics ------

NEWS BRIEFS

NASA and the National As leaders of a membership organization, The Planetary Society's Directors and staff care Oceanic and Atmospheric about and are influenced by our members' opinions, suggestions and ideas about the future Administration launched an of the space program and of The Planetary Society. We encourage members to write us and airborne expedition to study create a dialogue with us on topics relating to the planetary program, such as the space sta­ ozone loss in the Arctic. Last tion, the lunar base and the exploration ofMars. Send your letters to: Members' Dialogue, The Planetary Society, 65 N. Catalina Avenue, year scientists were disturbed Pasadena, CA 91106. to fmd that the Arctic also has elevated levels of the same chlorine compounds that are responsible for the ozone hole In spite of all the stirring words and fervent appeals to our sense of adventure, I'm not very over Antarctica. inspired by the prospect of further exploration of the Moon or Mars. It seems irresponsible The project sent aircraft to even think of extending our attitudes and actions to other worlds when we are so thought­ into the stratosphere over the lessly in the process of destroying our own, not to mention the enormous expense and un­ Arctic polar vortex, a region certain return. around the North pole that On the other hand, a greatly increased commitment to SET! would be inspiring. If suc­ becomes isolated from the rest cessful, it would be far more than a giant leap for mankind; it would be a new existence of Earth's atmosphere during with our horizons instantly extended to the limits of the galaxy. We need to analyze and a two-month period each win­ overcome our doubts, even fears, of success and failure and understand that contact and ter. Ozone depletion is not communication is the very essence of development for all forms of life. How much expected to be as bad in the progress could there have been in the history oflife on Earth, particularly intelligent life, Arctic, partially because without it? The stakes are high and the results could be traumatic, but now that we have Antarctica's vortex lasts for the technical capability, SET! is the only reasonable way forward for the human race. five months instead of two. SUSAN SALAMAN, Cambridge, England -from Breck W. Henderson in Aviation Week & Space May I express my thanks, and, I am sure, that of millions of others in the United Kingdom Technology and throughout the world for the way the American people have not only paid for the ex­ ploration of space but have also shared with the rest of us so much of the excitement and Dr. John V. Atanasoff, father the breathtaking pictures of the planets and their satellites. of the modem electronic Those of us in nations who cannot contribute to this enterprise really do appreciate the computer, has been honored way the American people have shared with us the results of this endeavor whilst taking by Bulgarian astronomers the cost entirely to themselves. Membership in The Planetary Society is but a small way (Bulgaria is the country of his of expressing that appreciation. "roots") with the narning of PETER H. LLOYD, Dunstable, England an asteroid for him. Asteroid 3546, now "Atanasoff," was In your "World Watch" column from NovemberlDecember 1988, an error appears regard­ discovered by Vladimir ing the orbital locations of the Tracking and Data Relay Satellites (TDRS). It states that Shkodrov and Violetta Ivano­ "the US will have three TDRS equally spaced in geosyncronous orbit, enabling continuous va with Eleanor Helin of the contact between orbiting satellites ;:;.od Earth stations." In fact, only two of these satellites Jet Propulsion Laboratory. will be used at any given time, and they will be placed at geosynchronous altitude at east Dr. Atanasoff, who is better and west longitudes in direct view of the associated ground station at White Sands, New known for his achievement in Mexico. The third TDRS in orbit will be a spare, midway between TDRS East and West, Bulgaria than in the US, put so that it can be moved to replace either in case of failure. The position of the two opera­ the "ABC" computer together tional satellites will be such that low orbiting spacecraft will be in view of one or the other in the late 1930s. This com­ except while they're in a small region over the Indian Ocean called the "Zone of Exclusion." puter established all the prin­ The TDRS Space Network is, therefore, not directly related to NASA's Deep Space Net­ ciples used in the develop­ work, which maintains continuous contact with distant spacecraft through the use of three ment of modem electronic ground communications complexes that are almost equally spaced apart in longitude. computers. LARRY N. DUMAS, Pasadena, CA - from Ron Helin

I have no quarrel with the Society's stated policy of trying to stimulate a Mars mission. On NASA has a new policy re­ the other hand, it seems apparent that until someone fmds a way to make money in space, garding space shuttle "passen­ the space program is not going to go anywhere. Without getting into value judgments as gers." Shuttle crews will to whether this is a good or a bad thing, I believe the Society should focus an effort on range in number from five to convincing people that there are profits to be made in space. I do not see the United States seven members and will be government in the near future acknowledging the intrinsic value of a space program. limited to professional NASA LAWRENCE L. LANGLEY, Wagoner, Oklahoma astronauts and payload spe­ cialists. The agency will re­ As any research scientist knows, the easy (fun) part of any project is doing the research. view shuttle operations annu­ The hard (ugly) part is talking the boss into paying for it. Unfortunately, research scientists ally to decide when the first (continued on page 27) (continued on page 27) 3 of Creation

squeezes itself into progressively small­ er volumes. As it contracts, the cloud spins faster, for the same reason that a pirouetting ice skater does as she brings her arms in. (The experiment can also be done with a small person, seated on a rotating piano stool, holding a brick in each outstretched hand, and then some sense known. These distant rapidly drawing them in. This demon­ cousins of Earth are the cometary stration must be performed with cau­ nuclei --cold, silent, inactive, slowly tion.) The principle of physics involved is called the conservation of angular tumbling in the interstellar black­ momentum and can be derived from ness. But when they are induced to Newton's laws of motion. fall into our part of the solar system, But as the gas and dust and occasion­ they creak and rumble, begin to al condensations that make up the cloud evaporate and jet, and eventually spin faster around their common axis of produce the tails so admired by the rotation, they experience an increasing inhabitants of Earth. reluctance to continue falling inward, sometimes called centrifugal force (centrifugal means "fleeing the cen­ ter"). A pail of water on a rope whirled sufficiently fast around your head does system, from which the planets some­ not spill-at least not until you stop how condensed? whirling. The centrifugal force bal­ ..... '.' '.' '. ':: ...... :' :.: .. ..:.. '.: ...... ~:~' .,.' .':' '~"" . ,:' .. ,:" ... : ... ~ The Kant-Laplace hypothesis for the ances gravity. origin of the solar system involves the The contracting cloud also will expe­ interplay of rotation and gravitation. rience centrifugal force, which will Imagine some irregular cloud of inter­ slow it down and eventually stop the In the eighteenth century, observational stellar matter made of gas and dust and contraction-but only in the plane of astronomy was making remarkable destined to form the solar system. All rotation. If you are standing on a small progress. Immanuel Kant and Pierre Si­ such clouds known today exhibit slow lump of matter falling toward the center mon, Marquis de Laplace, were in­ rotation. If the cloud is sufficiently of the cloud but along the axis of rota­ trigued by the structure of the rings of massive, the random molecular motions tion, rather than in the equatorial plane, Saturn as had been revealed through the are overwhelmed by self-gravity-the you do not feel any centrifugal force. discoveries of Galileo, Christiaan Huy­ mutual attraction of the atoms and The result is that matter in the equatori­ gens and their successors. Here was a grains in the cloud. The cloud then be­ al plane stops collapsing, while matter planet with a flat disk of particles sur­ gins to contract, the distant provinces along the axis continues to fall in. As a rounding it in its equatorial plane. Did falling inward; the density of the cloud result, an initially irregular cloud in 4 the Sun once have a much larger ring increases as a fixed amount of matter time becomes a flattened disk. The fur------_.-

Nearly five billion years ago the solar nebula condensed from a conglom­ eration of gases, Ices and dust to form our solar system. The planets and their moons have evolved over many millennia, erasing evidence of their primordial selves. But the much smaller comets have spent most of their time drifting at the edge of the solar system, where they have remained relatively unchanged since their births. Thus by studying comets, we study mementos from our solar system's creation. Palntln, by Jon Lomber, from Comet by Carl SaIlan and Ann Oruyan (Random House, NY, 1985).

ther the disk collapses, the more rapidly it rotates and the denser it becomes at the very center. The collapse stops, or at least slows, when the disk starts spin­ ning so fast that matter spews off at the periphery. The Kant-Laplace hypothesis pro­ poses that an irregular, rotating inter­ stellar cloud collapsed in this manner long ago, with the central condensation forming the Sun. There is no doubt to­ day that interstellar matter compressed to the density and temperature of the Sun will initiate thermonuclear reac­ tions and begin to shine like a star. But it was a daring hypothesis for the eigh­ teenth century. Other, smaller nearby condensations, Kant and Laplace pro­ posed, formed the planets, each sweep­ ing out a wide swath of adjacent debris as it grew in size. The result would be a regular spacing of the newly formed planets, something like the layout of the solar system today. Still smaller condensations near the planets would form their moons. The general idea be­ hind the Kant-Laplace hypothesis is more important than the precise details: The solar system, they proposed, clouds around the nearer stars. They are ner solar system, altered their orbits evolved from a very different primor­ called accretion disks. and induced them to impact the Sun. dial state and with no outside interven­ Laplace suggested that during the The drag of the solar nebula cleaned tion, natural or supernatural. formation of the solar system, the Sun's the inner solar system of comets with Because the word nebula means atmosphere once extended far out into nearly circular orbits but left the comets "cloud," and out of analogy with the space, perhaps in consequence of an at much greater distances unaffected. spiral nebulae (which are, of course, of enormous explosion in the Sun. Or per­ Through gravitational perturbations by much larger, galactic dimensions), the haps it was the residuum of the original the jovian planets, an occasional comet contracting cloud that formed the Sun solar nebula. Laplace's interstellar can be induced to visit the inner solar and the planets is traditionally called comets were, he imagined, falling in to­ system. the solar nebula. Today we know a ward the Sun. The material in the solar The idea is remarkable in several re­ much larger variety of flat rotating nebula slowed comets down' in the in- spects. It indicates a kind of natural se- 5 Once lords of Earth, these l Tyranosaurus Rex cower before a force of spectacularly Immense power-an asteroid striking the planet. The Impact of an asteroid or one of Its couslns-a comet­ may have caused the extinction of the dinosaurs and so made possible the rise of the mammals. From the mammals evolved the human species.

1II.ltratlon by Don D•• II

c1uding or excluding the comets) had condensed out of the same rotating and collapsing cloud.

In the last few years, groundbased and space borne observations have con­ firmed that many nearby stars are sur­ rounded by accretion disks. The initial discovery was made by a space obser­ vatory called IRAS, the Infrared As­ tronomy Satellite, a joint Anglo-Dutch­ US endeavor. Vega is one of the bright­ est stars in the night sky, only twenty­ six light years distant, and it was a real surprise to discover that this well-stud­ ied star is surrounded by a previously unsuspected disk of debris. It showed up as an extended source of infrared ra­ diation centered on Vega, a star consid­ erably younger than the Sun. To find an accretion disk around Vega strongly suggests that most, perhaps even all, orC lection in the physical world well be­ pense of adjacent material, swept its dinary stars are surrounded by such a fore Darwin, it proposes that there were surroundings clean of nebular debris. disk during and immediately after their once many more objects in the solar Perhaps he toyed with the idea that time of formation. Something eventual­ system than there are now, and it hy­ many dark breaks should exist in the ly tidies up the disk-perhaps a combi­ pothesizes a large repository of comets rings of Saturn if there are moons nation of radiation pressure, the stellar beyond the most distant planet known. among the rings. However, he urged wind and planetary formation. But it caution in accepting his hypothesis. takes time. And in that time, additional Probably because of his flirtation with a bodies may be condensing out of the possible interstellar origin of comets, it nebula . . ..:~:: .. :.. '::.:::' ':.,...... ':.. ... '. ,,:.::":::.:::. seems not to have occurred to him that IRAS also provided infrared evidence comets as well as planets might con­ of an accretion disk around a star called dense out of the solar nebula. Beta Pictoris, among many others. Soon Why, then, were the planets not similar­ That the rotation and revolution of after, Bradford Smith of the University ly disturbed and induced to collide with the satellites are in the same direction of Arizona and Richard Terrile of the the Sun? Laplace proposed that the as the rotation of their planets; that the Jet Propulsion Laboratory attached a planets had formed by successive con­ planets rotate in the same sense that special highly sensitive camera, devel­ densations in the early solar nebula. A they revolve; and that the orbits of the oped for a forthcoming space observato­ tube of empty space, centered around planets are close to circular, while the ry, to a groundbased telescope and were the orbit of each new planet, was comets have highly eccentric orbits, all able to photograph the Beta Pictoris ac­ 6 formed as the planet, growing at the ex- followed naturally if everything (in- cretion disk in ordinary visible light. ------

The disk extends at least 400 Astro­ Comets are best known nomical Units (l A.U. is the mean dis­ in their dramatic and tance of Earth from the Sun, about 150 ethereal forms with million kilometers) from the central star. spectacular tails If this were a picture of the Sun in its st reaming out behind early history, the accretion disk would them, as Comet West extend much farther from the Sun than appeared as it passed does the orbit of the farthest known by Earth In 1976. The small icy and dusty nu­ planet (some 30 to 40 A.U. out). cleus of a comet spends Smith and Terrile deduce a relative most .of its time in the absence of debris in the interior of the deep freeze of the outer disk and suggest that this region has al­ solar system where the ready been swept up by the condensa­ Sun's heat and the solar tion of planets that are much too small to wind alter it little over be seen directly. Astronomers have re­ the millennia.

cently sighted many other accretion Photograph by Dennis dl Cicco disks around adolescent stars. They have also found accretion disks around infant stars formed only a million years ago. Thus, it now seems that the Kant­ Laplace hypothesis is in its fundamen­ tals verified, and by a technology that would have delighted both of its authors. The Sun, the planets and their moons all condensed out of the same rotating and collapsing disk of gas and dust. This is why all the planets revolve in the same plane in which the Sun rotates. As the nebula contracts and its densi­ Both dust and gas gravitationally ty increases, grains collide more fre­ collapsed to form the disk. But it takes quently. In part because of the organic a great deal of gravity to hold on to so and icy content of these grains, when lightweight and thus fast-moving a .~.. ::::: ...... :.~::: ...... :.:::. "':':::'" ....: ... :::: .•.:.::::.:::::: '::::::.:::::::.:',.:::::::"::::' they collide they tend to stick. Big molecule as hydrogen. In the middle grains annex smaller ones. But all this part of the nebula, the kilometer-sized does not go on in the dark. The primi­ lumps collided and grew into still larger Let us now follow a modem rendition tive Sun has begun brightly shining. In objects until a few aggregations of mat­ of the Kant-Laplace hypothesis, in the outer parts of the disk, it is still suf­ ter were able to retain the cold gas which we pay special attention to the ficiently cold that exotic ices such as around them. This was the evolutionary origin and evolution of the comets. methane or carbon monoxide are per­ line to the jovian planets. The original From direct spectroscopic evidence, we fectly stable in the growing condensa­ accretion core was smothered in a vast know the interstellar gas to be com­ tions of matter. But in the very inner sphere of gas. In the warmer inner solar posed mainly of hydrogen and helium, solar system, it is too hot even for wa­ system the grains, divested of their ice, although it is rich in many other materi­ ter ice. There the ices on the grains grew more slowly, and the temperatures als, including complex organic mole­ evaporate and dissipate, and what sur­ were higher-both effects making it cules. Besides the gas, the other chief vives is made mainly of silicates. You more difficult for the gas to be captured constituent of interstellar space is an have to carry a rock very close to the by the growing rocky spheres. This was enormous number of dust motes. One Sun, only a few million kilometers the evolutionary line to the terrestrial of them, placed on a table before you, away, for it to boil. As a result of all planets. would be entirely invisible. They are, this, the chemistry in the inner solar Big objects would sweep up smaller typically, a tenth of a micron across. system must have been very different ones on adjacent orbits. Because the But concentrate enormous numbers of from the chemistry in the outer solar relative velocities were low, the two them over hundreds or thousands of system-silicates predominating inside bodies would tend to collide softly and light years, and you can have enough and ices with organics outside. merge. Eventually, a few large objects dust to blot out the stars behind them. According to several calculations, a were produced in orbits that never in­ We can also infer the chemistry of the vast number of kilometer-sized objects tersect. These became the planets. A grains. Most seem to be made of ices, should have accumulated throughout kind of collisional natural selection was silicates and organics-very roughly in the nebula-silicate-rich ones on the at work here. Starting out with a large equal proportions. Since this mix of gas inside, ice-rich ones on the outside. number of growing objects in chaotic and grains makes up the interstellar These objects should have been gener­ orbits, through a process of collision clouds everywhere in the Milky Way, it ated, not primarily through grain-by­ and growth and only occasionally the must also have constituted the early grain collisions, but instead by a funda­ shattering of worlds, the solar system collapsing solar nebula. Since interstel­ mental gravitational instability in the became regularized, simplified. The lar space ordinarily holds much more solar nebula, in which objects a few number of worlds steadily declined, gas than grains, this should have been kilometers in size formed quickly and from trillions to thousands to dozens. true for the solar nebula as well. preferentiall y. If you look at the planets today, you 7 A spherical shell of cometary nuclei surrounds our Sun, as calculated to exist by astronomer Jan Oort, for whom the Oort Cloud Is named. Planetary scientists believe that these bodies are remnants from the solar system's formation and that when one of these Ice balls falls Into the planetary part of our solar sys­ tem It becomes a long-period comet.

Pllntln, by Jon Lomberc from Com.t by c.~ &acen and Ann OnIyan (Random Hou .., NY, 1985).

that no vaporization, no collisions, noth­ ing at all could transform them. They are the stuff from which the solar sys­ tem was formed, and they are waiting for us in the Oort Cloud. Even a single comet newly arrived from the solar sys­ tem frontiers is the answer to an as­ tronomer's dream. In the 1960s, V.S. Safronov, a Soviet specialist in the early history of the so­ lar system, and in 1981, J.A. Fernandez, a young Uruguayan astronomer, and W.H. Ip, in Germany, showed that if primitive cometary bodies (those kilo­ meter-sized objects) were formed in the vicinity of Jupiter and Saturn, gravita­ tional perturbations by these massive planets would eject them out of the so­ lar system altogether. But if these proto­ comets were born in the vicinity of the less massive planets, Uranus and Nep­ tune, their gravitational influence would tend to eject the cometary bodies into find them decorously spaced, their or­ ences between the terrestrial and the jo­ the Oort Cloud, but not out of the solar bits by and large almost perfectly circu­ vian planets that we observe today. system. So if these primitive icy and lar; except for the case of Pluto, planets rocky worlds had condensed throughout give each other wide berth. Those early the solar system, most would have been

bodies on highly eccentric orbits were "~: . ': ... :.:. .:.: ': ," ..... :.:.." . :..... : ::'" .. used up in making planets and in being . in danger; very soon they would collide ejected into interstellar space. But tril­ with a world or be ejected from the so­ lions at least would have been relocated lar system. Eventually, the only planets to the Oort Cloud. left were those that had by chance de­ When we calculate the fate of that origi­ If the protocomets had been formed veloped on orbits that quarantined them nal population of small worlds, we dis­ in the vicinity of Jupiter, exotic ices from their neighbors. It is just as well cover that gravitational interactions would not have survived; and, if formed for us that they did; frequent world­ with the newly finished jovian planets still closer to the Sun, even ordinary shattering collisions are probably not would have ejected multitudes of kilo­ water ice would not be retained. Thus, good for the development of life. meter-sized worlds into the outermost two independent considerations-mak­ The planets so formed would be or­ gravitational frontier of the solar sys­ ing the primitive comets out of the right biting the Sun in the sorts of orbits we tem, like an automatic pitching machine stuff, and ejecting them into the right recognize for the planets today. While throwing baseballs into the bleachers orbits-point to an origin in the rough no one has been able to prove that ex­ once a minute for a hundred million vicinity of Uranus and Neptune. actly nine planets should form-and years. This is how the Oort Cloud Comets, it seems, were formed ulti­ not, say, six or forty-three (the entire (named for the Dutch astronomer Jan mately out of interstellar grains within question of the ultimate number of Oort, who first postulated its existence) the solar nebula, just a little before the planets being a matter of collision is thought to have been generated. moons and planets formed, some 4.6 statistics)-the general picture is very There is a population of primitive bod­ billion years ago. Many comets collided successful and explains not only the or­ ies that four and a half billion years ago with each other, forming larger bodies 8 bits but also the overall chemical differ- were sequestered so far from the Sun and sacrificing themselves so the plan- Comets usually grow two types of tails: one a long, straight, faint tall, and the other a short, curved, broad tall. The first type Is the Ion tall, formed when gases released as sunlight vaporizes the surface are Ionized and carried off by the solar wind. The second type Is the dust tall, created as tiny solid particles blow off the nucleus and enter orbits of their own about the Sun. This illustration of Donati's Comet over Paris on October 5, 1858 clearly shows both types of tails. illustration from Am_ Gulllemin'. Lu Comet•• .

ets would be made. Our planet also seems to have been formed from such objects, poor in ice, rich in rock. Many other comets were gravitation­ ally ejected from the solar system alto­ gether as, sooner or later, they made close passes by the jovian planets, es­ pecially Jupiter. But the calculations show very clearly that a substantial population of the original comets must have been ejected to the far reaches of the solar system, where the random gravitational shuffling of passing stars would have forced them into more cir­ cular, randomly inclined orbits. Not all would have been ejected out to the very periphery of the solar system, and the calculations predict a substantial popu­ lation of comets on near-circular orbits from hundreds to tens of thousands of Astronomical Units out-a population of comets fairly impervious to gravita­ tional disturbances by passing stars. Comets may also have formed at these distances in the accretion disk of the solar nebula. It is therefore possible that astronomers on Earth have never seen a typical denizen of the inner Oort the comet back into the planetary part motivation for the dawning age of Cloud. It is entirely plausible that much of the solar system, where close plane­ spacecraft exploration of comets. When bigger comets than those several kilo­ tary encounters-this time especially we study the comets, we study our own meters across were ejected into the with Jupiter-reduce the large elliptical beginnings. Oort Cloud. But there are far fewer of orbit into the more modest dimensions these, and much more rarely will we of a short-period comet. The homecom­ Carl Sagan, President of The Plane­ see one redirected into our small but ing has been long delayed, and the so­ tary Society, is the David Duncan Pro - well-lit volume of space. lar system has changed considerably in fessor of Astronomy and Space Sci­ If this currently popular picture is the interim. ences and directs the Laboratory for correct, a typical short-period comet The comets are way stations in the Planetary Studies at Cornell Universi­ (one that circuits the Sun every few evolution of planets. They have seen ty. Ann Druyan was recently elected years) is an aggregate of interstellar much. As remnants of the forming solar Secretary of the Washington-based matter condensed during the origin of system they can tell us much. Both the Federation of American Scientists. She the solar system almost five billion comets and the planets are formed of was Creative Director of NASA's Voy­ years ago and ejected by the newly interstellar materials. The difference is ager Interstellar Record project and, formed planets to the solar system fron­ that the planets have been enormously together with Sagan and Steven Soter, tiers, its orbit there circularized by reworked, physically and chemically, wrote the Cosmos television series. gravitational encounters with passing since the beginning of the solar system, This article was adapted from Comet, stars. A few billion years later, the cu­ while the comets of the Oort Cloud re­ Copyright 1985 by Carl Sagan and mulative gravitational influence of fur­ main comparatively unscathed by the Ann Druyan and published by Random ther stars and interstellar clouds drives ravages of time. This is the principal House, Inc., New York. 9 ------_ .. _------CHANGING VIE

efore the Mariner, Mars and Viking spacecraft visited Mars, astronomers L-B__-----' engaged in a continuing quest to observe and record the finest martian detail possible. In those pre-spacecraft days, their observations provided the only clues about the nature of Mars' surface and the seasonal changes that affect it. To anyone who has looked through the eyepiece of a moderately large telescope in good seeing (when Earth's atmosphere is clear and still) and when Mars is favorably placed in the sky, the sub­ tle changes and myriad splotches hint of a fascinating world of sandstorms and spec­ tacular landforms. It's not surprising that since the 1960s and 1970s, when the Mariner and Viking spacecraft provided closeup views from orbit, scientific emphasis on groundbased observations has diminished significantly. Yet we still have much to learn from such observations about atmospheric circulation, dust storm propagation, and both long-term and seasonal changes in Mars' bright and dark surface markings. Recently, because of the superior sensi­ tivity of solid-state charge-coupled device (CCD) detectors compared to traditional photographic emulsions, astronomers have been able to obtain higher resolution images of Mars from the ground. The images here, obtained with the 1.54-meter reflector at the Catalina Station of the University of Arizona Observatories;were taken during the recent favorable opposition. One important advantage of CCD imaging is the ability to enhance the small features digitally. We can reduce the contrast be­ tween light and dark regions while increas­ ing the contrast (and hence the visibility) of small features. Carried too far, this process­ ing can produce misleading artifacts, but with the exception of the exaggerated bright limb (the planet's edge), we were able to see all of the small detail in contrast-stretched but unprocessed versions. It is interesting to compare these images with drawings made by talented visual observers using large telescopes around the beginning of this century. Good examples are drawings by E.M. Antoniadi with the 0.8-meter refractor at Meudon Observatory in 1909 when the observing circumstances were very similar to those in 1988. Antoniadi to (continued on page 12) BY STEPHEN LARSON

TRIVIUM CHAAONTIS\

11 (continued/rom page 10) was a very careful and perceptive observer who pointed out that many of the canal-like features reported by Percival Lowell and others resolved into small spots when the see­ ing was very good. In resolving features only 100 to 150 kilometers across, we are still seeing albedo markings (light and dark features) but not topographic structure. Only one feature hints of topography, and that is Valles Marineris. (Early telescopic astronomers saw this 4,OOO-kilometer-long canyon as a surface feature, but it was not understood to be a canyon until imaged by Mariner 9 in 1972.) In the August 18 image, with the Sun overhead, we can see it as a connected series of dark spots north of Solis Lacus, while on the September 10 image it ap­ pears much more rectilinear and canyon­ like. Since the Sun was only a few degrees above the horizon on the later image, some of the canyon slopes were in shadow and may have provided higher contrast to the surrounding area. It is tempting to equate the dark circu­ lar spots with craters, but the fact is that albedo features do not usually correspond to topographic structures. A good example is the crater Huygens located near the cen­ ter of the October 3 image. According to United States Geological Survey maps, us­ ing spacecraft data, the dark circular spot is located on the eastern half of the crater. The small dark streak protruding north from Sinus Sabaeus and due west from Huygens covers only half of the crater Dawes. On the other hand, the dark spot near Mare Sirenum on September 10 seems to correspond to the crater Newton. The dramatic evaporation of the south polar cap is obvious between August 18 and September 9. On August 18, there is a rift bisecting it across the center to the bay nearest Solis Lacus. On September 10, that bay appears much larger at the edge of the smaller cap. Comparing the south polar cap Anto­ niadi drew on September 20, 1909 with our CCD images of October 3, 1988 shows the same detailed outline. Although the characteristic sizes of the smallest details are comparable, there are some differ­ ences attributable to long-term changes in the boundaries of some albedo features. For example, the usually dark Thoth­ Nepenthes and Moeris Lacus were nearly absent in 1988. Trivium Charontis and Cerberus were also less prominent than usual last year. Of course, future spacecraft, such as Mars Observer, will provide much more de­ tail about long-term changes that have oc­ curred since the Mariner and Viking mis­ sions, but groundbased images such as these may help show something of their evolution.

Stephen Larson is an astronomer in the University ofArizona's Lunar and Planetary Laboratory and carries out imaging and 12 spectroscopic studies ofplanets and comets. ------

AN EMERGING COSMOLOGY?

hat place does the idea of ex­ as a cosmological world view, with the Middle Ages. The heliocentric traterrestrial life hold in the characteristics like those in other cos­ Copernican cosmology began a new era W history of science? Evolutionist mologies; and the current search for ex­ in the debate, for by positing an Earth in George Gaylord Simpson once called it traterrestrial intelligence (SETI) may motion Copernicus implied that the a science without a subject, a phrase of­ serve as a test for this new "biophysical planets were worlds like Earth. ten repeated. Physicist Frank Tipler be­ cosmology. " Descartes' vortex cosmology in the sev­ lieves that religion and philosophy have enteenth century first gave a physical dO.minated its history and regards it The "Cosmological Connection" basis to the idea of other solar systems. even today as a pseudoscience. Others We see the universe through the lens of And the Newtonians, pushed along by have seen its history as a fragmented our cosmology. This all-encompassing considerations of natural theology (the­ and umelated series of ideas with little world view determines how we concep­ ology deriving its knowledge of God relation to the mainstream of intellectu­ tualize our planet, our solar system and from the study of nature rather than rev­ al history. Even proponents would ad­ the entire universe around us. Cosmolo­ elation), made a universe full of plane­ mit to its checkered career, with the ex­ gies change with time, fashions and sci­ tary systems an integral part of their hausting furor over martian canals, the entific developments, and what was cosmology. association of the idea with Unidenti­ once accepted as the true nature of the Twentieth-century changes in cosmo­ fied Flying Objects, and a public all too universe may gradually become a mea­ logical world views have also affected willing to believe in little green men de­ sure of our ignorance. belief in life beyond Earth. At the be­ spite the evidence (or lack of it). The idea of other worlds and extrater­ ginning of the century most astronomers But the broad tapestry of the history restrial life is indisputably associated believed that our Sun was located near of science offers another view of the de­ with the great cosmologies of the past. the center of the galactic system, and bate, one that takes into account the The idea of an infinite number of some argued that this was a unique, idea's extraordinarily long history and worlds was a central tenet of the Greek privileged place that allowed life to ex­ the changing nature of science itself. atomist system, generally regarded as ist. Three tumultuous decades later, the From this vantage point three conclu­ the first scientific cosmology. Aristo­ universe, seen through the eyes of the sions seem clear: cosmological world tle's highly ordered geocentric cosmolo­ local intelligent species, had changed: views inspired and have sustained the gy opposed this view. Aristotle argued Our galaxy had greatly enlarged, innu­ extraterrestrial life debate; the concept for a single world, an idea widely debat­ merable galaxies existed outside our of life beyond Earth may itself be seen ed but generally accepted throughout own, the universe was expanding and 13 ------

much older than previously thought, our expressed in his well-known volume physical cosmology. First, this belief solar system was located on the Of Stars and Men, significantly subti­ makes a claim, testable in principle, galaxy's periphery, and Einstein had de­ tled Human Response to an Expanding about the large-scale nature of the uni­ molished Newtonian ideas of space and Universe (1958). In short, opinions on verse-namely, that life is a basic prop­ time. extraterrestrial life have not been mono­ erty of the universe rather than a local We should therefore not be surprised lithic but have changed with our views aberration. As Newton proved the uni­ that the British astronomer Sir James of the universe--our cosmologies. versality of Nature's laws, and nine­ Jeans, who had once championed the teenth-century spectroscopy, by reveal­ rarity of life in the universe (due largely The Biophysical Cosmology ing the same signatures of atoms every­ to his belief in the rarity of planetary It is not enough to say that extraterres­ where, showed the universality of the systems), asserted in 1942 that life trial life is an offshoot or implication of chemical elements on Earth, so the bio­ might not be so rare in the new universe these cosmologies, any more than it suf­ physical cosmology claims universal after all. Nor should we wonder that fices to say that Newtonian physics aris­ uniformity for Nature's biological prin­ Henry Norris Russell, the dean of US es from the Copernican theory. Is this ciples. At what level a principle of bio­ astronomers and a skeptic in the early offshoot or implication a pseudosci­ logical uniformity might apply through­ 1920s about life beyond Earth, by the ence? A science looking for a subject? out the universe, whether to produce in­ early 1940s described "a radical A subdiscipline of astronomy-or of bi­ telligence similar to us or very different, change-indeed practically a reversal" ology? Another run-of-the-mill theory? is a major question. of his earlier view. And Harvard Obser­ Or should we perhaps see it as just an­ Secondly, this large-scale testable vatory Director Harlow Shapley, who other piece tacked onto our current claim is distinct from physical cosmolo­ had so ingeniously demonstrated our ec­ physical cosmology? gy. If the endpoint of evolution in the centric position on the outskirts of the We can make a good case that belief universe is life and intelligence, rather galaxy, went from ridicule of the subject in extraterrestrial life constitutes a cos­ than stars and galaxies, we live in a uni­ in the 1920s to the complete turnabout mology of its own that incorporates the verse very different from the one physi- cal cosmology prescribes. We instead Surely this explains why the subject inhabit a universe where planetary sys­ generates such passionate debate; it is The Atomists' Cosmology tems are common, where life develops not just another theory, but a world Everything in the universe was made of when conditions are right, and where view that dramatically affects each of us tiny, discrete but imperceptible particles the evolution of life may lead to techni­ and our beliefs. -atoms-according to this early and cal civilizations. These are the compo­ Why can't we just regard life in the prescient cosmology taught by the Greek nents of the biophysical cosmology-as universe as an extension of our current natural philosophers Leucippus, Democri­ yet still not proven but given plausibili­ physical cosmology? Because histori­ tus and Epicurus. Atoms floated through ty by the assumption that physical and cally, new cosmologies have gone be­ space, came together in whirls of undiffer­ biological principles are everywhere the yond mere extension. We would not say entiated matter, collided and separated same. that Newtonian physics was a piece out according to type, thus prOViding Finally, like other cosmologies, the added onto the Copernican cosmology, water, mountains, and living matter and biophysical cosmology redefines our or that Einstein's world view was other things that make up the world place in the universe. In Of Stars and tacked onto Newton's. These new world around us. The infinite universe was filled Men Shapley saw the extraterrestrial life views added a new dimension to our with innumerable worlds that might have concept as a "Fourth Adjustment" to knowledge of the universe, and the dis­ planets like Earth, some without Suns, humanity'S place in the universe, fol­ covery of extraterrestrial life may do the some with no moons, some being born, lowing the geocentric, Copernican and same. The biophysical cosmology may some thriving and some dying. No grand what he termed "galactocentric" world well encompass parts of our present design or higher purpose ruled the atom­ views (the last of which he had himself physical cosmology, but it may also al­ ists' universe, but in a universe governed proven). In The Universe (1962) the US ter our perception of the nature of the by random chance, there was always the 'astronomer Otto Struve also compared universe in some unsuspected way, just possibility that lifeforms, perhaps even the extraterrestrial world view with the as Einstein's cosmology transformed humans, existed on other worlds. Copernican and Shapley revolutions. Newton's. (continued on next page) Aristotle's Cosmology There was only one world, and Earth was its center in this cosmology that dominated the Western world for over 1,800 years. This universe was composed ofa series of solid spheres concentric around Earth and carrying the Moon, the Sun and the five known planets, The stars rotated on the outermost sphere, and beyond them, there was nothin~no other worlds, no stars, no empty space, just nothing. To the casu­ alobseroer, Aristotle's cosmology seems to correspond to common sense: Heavenly objects do appear to circle round Earth. But astute astronomers soon noticed that the motions of the wandering planets were not easily explained by Aristotle's cosmolo­ gy, and so amended versions appeared, created by Eudoxus, Callipus, Ptolemy and others. The Ptolemaic system was particu­ larly successful at predicting planetary motion, and it held sway until the appear- , ance of the Copernican system.

Copernicus' Cosmology As in Aristotle's universe, this was a cos­ mology of solid spheres moving with uni­ form circular motion. But there was one distinct difference. The Sun sat at the center of this world, and Earth was but one planet among many orbiting about it. When Copernicus displaced Earth from the center of the universe, he engendered one of the greatest revolutions in the history of science. It was not a bloodless coup. The Inquisition imprisoned Galileo Galilei for holding that the Earth moved about the Sun. The revolution reached its climax when Johannes Kepler, workingfrom Copernicus' ordering of the planets and Tycho Brahe's obseroations, discovered the laws ofplanetary motion, 15 , Descartes' Cosmology SET] as a Cosmological Test Whether we should look, how long we Rene Descartes followed in the traditions We may suspect that the biophysical should look, and how much money we of both Copernicus and the Greek atom­ cosmology will follow a line of devel­ should spend are valid questions of sci­ ists. His corpuscular universe was made opment similar to that of other cos­ ence policy and interesting expressions up of tiny particles that moved, collided mologies. Foremost among these stages of public preference in a democratic so­ and grew into planets and people, all of development are observational tests, ciety with many competing programs. while whirling in a series of vortices that so important in modem science. Just as We should not expect fmal confmna­ gave shape to the world. A subtle matter physical cosmologists search for obser­ tion of extraterrestrial life to come filled space, and the planets were simply vational evidence for the origin and age soon. Centuries elapsed between claims dense spots carried round by the vortices' of the universe, expansion rates, and made for the Copernican theory based motion. The Sun sat at the center of our missing mass, so biophysical cosmolo­ on observation and the actual proof of local vortex, and the stars marked the gists search for life on Mars, planetary Earth's motion by James Bradley's ob­ centers ofother vortices. In Descartes' uni­ systems, intelligent radio signals, or servation of the aberration of starlight verse planetary systems formed of Freeman Dyson's proposed infrared (the tiny but apparent displacement of a necessity from the laws of motion and spheres (shells built around stars by star due to Earth's speed through the there was nothing to prevent life and technologically advanced civilizations galaxy) in 1729 and Friedrich Bessel's possibly civilizations from arising on to harness stellar energy), not merely as measurement of stellar parallax (the ap­ planets whirling about other stars. ends in themselves but as tests of thejr parent shift in a star's position due to cosmological world view. One local Earth's motion) in 1838. The biophysi­ Newton's Cosmology test, Viking's search for life on Mars, cal cosmology has had several disputed As in Descartes' cosmology, this is a me­ failed. For the first time, SETI holds claims but at present has no undisputed chanical universe ofempty space and the promise of testing the biophysical evidence. In proposing extraterrestrial matter, derived from Kepler's discoveries cosmology over large distances, be­ intelligence we are still at the stage of so that planets travel elliptical paths yond the confmes of our solar system. Aristarchus, wondering if the Earth around their parent stars. Sir Isaac New­ ton postulated a universe where law-abid­ ing objects behave according to rationally discovered precepts that could be ex­ pressed in mathematical terms. During his lifetime, Newton's universe was cir­ cumscribed only by the limits of telescopes and astronomers' understanding of bright objects in the sky. Nothing within his cal­ culations limited the world to one solar system, and the theology of the time urged the belief in many solar systems. As tele­ scopes became more powerful and as­ tronomers realized that some fuzzy bright patches were other "island universes" or galaxies, Newton's universe expanded to encompass them as well. This universe is filled with galaxies, perhaps punctuated with innumerable solar systems and whatever might arise on their planets.

The Bioastronomers' Cosmology Since Newton's time we've probed the uni­ i verse with telescopes, spectroscopes and other instruments for discerning Nature's secrets. We've discovered that, as Newton I· claimed, the physical laws ofNature apply i equally and everywhere. We've found the chemical building blocks oflife scattered throughout the universe, even drifting in dark clouds among the stars. This uni­ verse could well be teeming with other so­ lar systems, nurturing planets and amaz­ ing lifeforms. Some of those lifeforms might have followed paths similar to hu­ ! l Ii manity'S and developed radio as an effi­ , I cient means ofcommunication. Ifso, then DESCARTES ~ COS¥OLOGY 1 listeningfor those radio waves is the easi­ est way to discover other technical civi­ lizations. The Search for Extraterrestrial Intelligence (SE71) prOVides for the first t 16 time a test for this cosmology. ------

might move. the history of science, we see its close astronomy and cosmology, or do justice Yet it is interesting that despite the association with major cosmologies. to the complexity of frontier science lack of physical evidence, and excep­ We recognize it as an emerging, embry­ and its practitioners. In short, such a tions such as the 1920s notwithstand­ onic cosmology of its own. And SETI claim does not withstand historical ing, the biophysical cosmology has assumes its importance as a far-reach­ scrutiny. Without cosmology there been widely accepted since about 1750. ing test for this biophysical cosmology. would be no belief in extraterrestrial There is perhaps no greater demonstra­ Frivolous dismissals of bioastronomy life, and without the concept of ex­ tion of the change in human attitude as a science in search of a subject sure­ traterrestrial life, the history of science from the Renaissance to the Enlighten­ ly mistake the nature of science. Any would surely lack one of its most inter­ ment than this: While the Copernican would-be science is by defmition look­ esting, if controversial, cosmologies. cosmology was resisted for centuries, ing for a subject. Like proto stars form­ the biophysical cosmology triumphed ing out of the nebular mass, the age-old Steven 1. Dick, an historian of science in the eighteenth century on far less ev­ concept of extraterrestrial life may to­ at the US Naval Observatory in Wash­ idence-indeed, some might say, on no day best be termed a protoscience, one ington, DC, is the author of Plurality of evidence at all. But we should not con­ that will either coalesce or dissipate in­ Worlds: The Origins of the Extraterres­ fuse acceptance with proof. Although to thin air. trial Life Debate from Democritus to some have accorded the idea the status To attribute belief in extraterrestrial Kant (1982) and The Twentieth Centu­ of accepted myth, we should still re­ life primarily to metaphysics is a gross ry Extraterrestrial Life Debate: A Study gard it as a scientific hypothesis (as a oversimplification that ignores the sub­ of Science at Its Limits (forthcoming). scientific cosmology, I have argued ject's origins in cosmology, and, in­ He presented a longer version of this here), realizing that proof is yet to deed, the existence of philosophy in all article, which will appear in the Con­ come. our cosmologies and all our science. ference Proceedings, in October 1988 When we view the extraterrestrial Nor does it explain the way that indi­ at The Planetary Society's Internation­ life debate within the broad context of viduals' views change with changes in al SET! Conference in Toronto. ------

"LET'S GO TO MARS-TOGETHER." Since President Bush's National Security States' equivocal position, President our President, Carl Sagan, first issued Advisor, and John McElroy, Dean of Gorbachev has on several occasions this call in 1984, The Planetary Society Engineering at the University of Texas publicly called for American-Soviet has enthusiastically embraced the goal at Arlington. They determined that US exploration of Mars. of Mars exploration led by the United space policy coordination is a broken States and the Soviet Union. We have system that needs fixing by White Success? played a key role in focusing the House leadership. They were Admittedly, we don't all agree on how attention of the public and policy­ influenced by the internal NASA to reach the goal of landing humans on makers alike on the need for a well­ "Leadership Report" (Ride study), Mars. But our differences are sec­ planned space program leading to which offers alternative goals for the ' ondary; if we can agree to an inter- human exploration of Mars early in the US civil space program. The CSIS national expedition, scientists and next century. study concluded that human exploration engineers can and will get us there. Some have misunderstood our of Mars should be the United States' Have we won? Some say the Society advocacy, thinking it too narrow or too long-term goal; that it should be a should declare victory and assume that single-minded. (Dr. Sagan dealt with prime purpose of the space station the Mars goal is in place. Others point these and other criticisms in the (along with US technological out that the hard steps have not yet been NovemberlDecember 1988 Planetary competitiveness); and that it should be taken-the space station has not been Report.) That the Mars goal is indeed in international, following a carefully redirected, the US has no launch vehi­ the mainstream of space policy has planned and negotiated series of steps cle policy suitable for human missions recently become evident by wide­ involving both US allies and the USSR. to Mars, the US-USSR Space Cooper­ ranging and varied support. The CSIS also stated that the civil space ation Agreement (see the January/Feb­ program must be structured to serve mary and May/June 1987 Planetary Rethinking Space Policy major US national objectives: edu­ Reports) is still too little and too slow, The US presidential campaign provided cation, environment, competitiveness and many robotic precursor steps to many opportunities to consider space and exploration. Mars are unapproved and unfunded. policies. Several candidates-including The other study, conducted by the But the widespread recognition of our the new chairman of the NASA National Academies of Science and of position gives us reason to believe that authorizing subcommittee in the Senate, Engineering, was chaired by Dr. H. we are making considerable progress. Albert Gore-supported our Mars goal Guyford Stever, the former head of the (see the September/October 1988 National Science Foundation. It too Looking Backward: How We Planetary Report). Although President called for presidential leadership in Put Mars Back on the Agenda Bush has yet to declare himself, a little setting space goals and recognized that In June 1984, when US-Soviet coop­ noted but apparently carefully any major space initiative must be eration in space was moribund and rela­ considered statement in the Republican political in origin. It concluded that tions between the two countries nearly Party platform asserted: "a resurgent human exploration of the solar system non-existent, The Planetary Society America, renewed economically and in should be the guiding principle behind organized a meeting in Graz, Austria, of spirit, must get on with its business of any such initiative and that it was the leading Soviet and US planetary scien­ greatness. We must commit to a right goal for the space station. tists to discuss bilateral cooperation in manned flight to Mars around the year In December 1988, NASA's new planetary missions. This meeting led to 2000 (italics ours) and to continue Office of Exploration issued its first new steps in data exchange among exploration of the moon." We have no report to the Administrator. It studied Viking and Venera scientists as well as way of knowing if this declaration several human exploration scenarios: informal contacts in the Vega and resulted either directly or indirectly establishing a lunar base, landing on Phobos missions and, most important, from The Planetary Society's testimony Mars' moon Phobos, a Mars mission, paved the way for official government to the Party's platform committee, but it and the settlement of Mars. All have as action, especially the renewal of the certainly did follow our Mars advocacy. the major goal human exploration of 1972 intergovernmental agreement on The similar endorsements by both the Mars. And just recently that office US/USSR cooperation in space. Republican Party and the Reverend noted that US-Soviet cooperation is the In September 1984, Dr. Sagan's Jesse Jackson were particularly telling. best and most likely way to carry out article "The Case for Mars" appeared in As each new administration prepares the program. This year the office will Discover magazine, outlining both the to take office, many groups submit begin studying international partnership scientific reasons to return to the planet studies to the transition team in hopes in mission design. and the envisioned goal of international of influencing the President's policies. Notably the House of Repre­ cooperation in peaceful ventures: The Center for Strategic and Inter­ sentatives included the initiation of an "Suppose the people of Earth are one national Studies (CSIS), a Washington American-Soviet Mars mission in its day fortunate enough to discover new "think tank," submitted the first of two 1989 NASA authorization bill. Unfortu­ leaders in Washington and Moscow major space policy studies. The chair­ nately, the Senate's bill did not include dedicated to a new beginning and to 18 men were Brent Scowcroft, now that provision. Despite the United seal that new beginning they embark on l a dramatic joint enterprise-something asteroid, and Mars. It provided the first ing twelve cogent reasons for visiting like the Apollo program but with post-Apollo cost estimate of a piloted our neighboring world. The Mars goal cooperation, not competition, the goal." Mars mission. The Society also co­ captured the imagination of a strikingly That same month Carl Sagan and sponsored "Case for Mars" conferences diverse group of US leaders. Initial sig­ Louis Friedman testified to the Senate in Boulder, Colorado, that brought natories included leaders of peace Committee on Foreign Relations about together professionals and enthusiasts groups and retired Army, Navy, Air international cooperation in space. Dr. developing ideas for Mars exploration. Force and Marine general and flag offi­ Friedman stated, "A cooperative US/ Louis Friedman presented a tech­ cers; astronauts and religious leaders; USSR program in planetary exploration nical description of a program built labor and industry executives; politi­ that might lead to human flight to Mars around a Mars goal, "Towards Becom­ cians and poets; Nobel laureates and would be of enormous significance to ing a Multi-Planet Species," to the sports figures; ambassadors, university the cause of global security and inter­ 1985 International Astronautical Feder­ professors and former presidential advi­ national stability." ation Congress. Bruce Murray touched sors; former cabinet and sub-cabinet By October 1984, through the initia­ upon the political need for human members; and every former NASA Ad­ tive of Senator Spark Matsunaga (D-HI), flights to Mars in his article "Civilian ministrator since the agency's founding the US Congress had passed-and the Space: In Search of Presidential Goals" except the then incumbent. Subse­ President signed-a Joint Resolution for Issues in Science and Technology in quently, tens of thousands have signed urging renewal of the space cooperation 1986. Dr. Sagan described the potential the Mars Declaration, with hundreds of agreement. By then The Planetary impact on society of such flights in new signatures arriving daily. Society was advocating international "USA and USSR: Let's Go to Mars­ US scientists are now working on the cooperation in space as a goal for NASA. Together," read by the 65 million Soviet Phobos mission, and Soviet readers of Parade magazine. The arti­ scientists will work on the US Mars Building Mars Momentum cle appeared in the Congressional Re­ Observer mission; three bills were put The Planetary Society's program cord, was excerpted in Pravda and was before Congress in 1988 setting the gained momentum with a series of reprinted worldwide. goal of human exploration of Mars and symposia, some directly addressing Additionally, The Planetary Report encouraging US/USSR cooperation Mars exploration, others, like the covered Mars exploration with issues toward that goal; and more than 30 symposium "The Potential Effects of such as "Humans on Other Worlds," editorials urging these objectives have Space Weapons on the Civilian Uses of March/April 1985; "Viking: the Tenth appeared in such publications as The Space" (cosponsored by the American Anniversary," July/August 1986; and New York Times, The Los Angeles Academy of Arts and Sciences) in "Exploring Mars," May/June 1987. Times, the Atlanta Constitution, US January 1985, discussing the future use In the summer of 1987, US and So­ News and World Report and the of space. There Academician Roald viet space scientists and policy-makers Christian Science Monitor. Sagdeev, then Director of the Institute met via satellite link-up in the Society­ In 1988 The Planetary Society pre­ for Space Research of the Soviet Acad­ sponsored Spacebridge "Together to sented testimony supporting the US emy of Sciences, suggested a joint Mars?" For four hours experts from the planetary exploration program, in par­ Mars Sample Return-Rover project. two countries discussed Mars explora­ ticular the proposed Comet Rendezvous Panel Chairman Dr. Bruce Murray, tion. Although they reached no con­ Asteroid Flyby, to the Senate Com­ Society Vice President and former sensus as to whether life exists on Mars mittee on Commerce, Science and Director of the Jet Propulsion Labora­ or where the best landing sites are Transportation; urged members to tory, summed up the discussion with an located, everyone agreed that pooling support NASA's Project Pathfinder, a alternative to space weaponry: "We resources and efforts would enhance not technology development program for should be looking toward a future in only future missions but also global future space missions, including a which humans will go to Mars." cooperation. The panelists also defmed piloted Mars mission; and supported To mark the 10th anniversary of the the value of joint robotic missions to development of Mars ballooning for Apollo-Soyuz linkup, The Planetary characterize the martian environment. implementation on the Soviet Mars 94 Society cosponsored the conference That fall PBS televised nationally a mission. This year Dr. Sagan testified "Steps to Mars" with the American one-hour special entitled "Together to for two hours to the House Space Institute of Aeronautics and Astro­ Mars?" based on the Spacebridge; Science and Applications subcommittee nautics in July 1985. Participants similar programs were shown on Soviet about planetary exploration and the included the Apollo-Soyuz astronauts and Japanese television. long-range goal of Mars. and cosmonauts; Roger Bonnet, The Planetary Society continues to . Senator Matsunaga, Astronaut Sally Triumphs Despite Trials advocate cooperation in space, long­ Ride, Thomas Paine (now a Director of In April 1987, when NASA delayed the term mission goals, and a peaceful the Society), and James Beggs, then Mars Observer two years from a focus for the combined energies of the Administrator of NASA. planned 1990 launch, Planetary Society world's superpowers. The time may be The Planetary Society addressed members wrote over 10,000 letters of right to commit to the future, to commit Mars exploration from every angle. protest to Congress and NASA. to the human exploration of Mars. Technical considerations were analyzed Although the 1990 launch date was not in a 1985 Society-commissioned report reinstated, NASA delayed the mission Louis Friedman is The Planetary by the Science Applications Interna­ over strong congressional objections. Society's Executive Director. Susan tional Corporation that studied human The Society broadened its campaign Lendroth is the Society's Manager of missions to the Moon, a near-Earth by circulating a Mars Declaration list- Events and Communications. 19 both poles, but of long-dreamt-of argosies of rocket ships course they could that will someday make the solar sys­ not see into the tem our home. (If the hydrogen is suc­ shadows. In later cessfully mined, an important byproduct years various peo­ will be helium-3, a fusion power fuel.) ple have attempted Engineers are barely beginning to ex­ to improve on the amine these unearthly kinds of mining theoretical argu­ and processing. Assessing their compar­ ments, but highly ative costs is a task that will be made capable scientists feasible by work now in progress at the still reach opposite University of Arizona's Center for the conclusions as to Utilization of Local Planetary Resources the presence or ab­ and at the Space Studies Institute in sence of the ice. Princeton. The only way to settle the question 'DIe Little Spacecraft 1bat Could: is to send a space­ WiD It Ever Fly? craft to look for it. "I think I can" detect the ices-so says Dr. James R. Arnold of the University Importance of of San Diego. Arnold's remote sensing the Poles instruments mapped the parts of the The lunar polar re­ Moon visited by Apollo but have never gions are important flown to the poles. For more than twen­ because only there ty years he and his US, Soviet, and can one enjoy re­ Japanese colleagues have been urging lief from the rest ef their governments to launch a lunar po­ the Moon's succes­ lar orbiter. The tattered history of this­ sion of scorching mission concept is almost as dreary as two-week days and the long, sad story of Galileo, the frigid two-week decade-old, yet-to-be-launched mission nights. [Midday to Jupiter. equatorial tempera­ In December 1972, Harrison Schmitt n 1692 Giovanni Domenico Cassini, tures reach about l30°C (about 260°F). and Eugene Cernan stepped off the lu­ the fIrst Director of the Paris Observ­ At midnight the temperature plunges to nar surface and rejoined Ronald Evans I atory, set forth in detail the Moon's about -lSO°C (about -240° F). At the in orbit. As they left, Schmitt spoke observed laws of motion. Due to causes poles, we fmd temperatures permanently these hopeful words: "As I take man's still unknown, the Moon spins about a below about -230 to -19SoC (about -390 last steps from the surface back home polar axis almost perpendicular to the to -3lYF).] The dark craters are thus for some time to come but we believe plane of the ecliptic (the plane cut by ideal sites for those kinds of astrophysi­ not too long into the future.... As we Earth's orbit about the Sun). Therefore cal telescopes that require cryogenic leave the Moon at Taurus-Littrow, we it has no seasons. At the lunar poles, the (very low) temperatures to reduce back­ leave as we came and, God willing, as Sun is always near the horizon. In ground noise. we shall return, with peace and hope for craters there, some regions must always With or without ice, international all mankind. Godspeed the crew of be in shadow; there may also be moun­ protection of these special, small re­ Apollo 17." But any followup to that tains of perpetual light. gions will be essential for a coming age magnificent beginning was already These facts have led scientists to of lunar settlement. But water ice and doomed. The US, mired in Vietnam and speculate about what may lie in those other frozen volatiles, if present in us­ having achieved its primary political unknown polar regions. In 1961 Bruce able amounts at or near the surface, objective with Apollo, quit the Moon, Murray (now Vice President of The could transform the whole course of lu­ and the Soviets cut their losses when Planetary Society) and his colleagues nar settlement and development. If we their Apollo competitor failed. NASA published a paper suggesting that it cannot fmd hydrogen in ices, we might funded some small studies of an auto­ must be so cold in the perennially dark be forced (with much greater difficulty) mated polar-orbiting mission that would polar craters that ice could accumulate to mine it: a small amount is implanted carry Arnold's gamma-ray spectrometer over geologic time. In the mid-1960s, in lunar soil by the solar wind. Hydro­ and other instruments and might find Lunar Orbiters 4 and 5 photographed gen from water, combined with the the ices, but nothing came of that work. 20 most of the lunar surface, including Moon's abundant oxygen, could fuel the In subsequent years Soviet, Japanese • by James D. Burke

and US groups proffered other fruitless sions and provided a library of space­ Where To, Now? proposals. craft and launch-vehicle data useful in In the present NASA plan, a lunar polar In 1987, The Planetary Society got later work, it did not point toward an in­ orbiter may fly in the mid-1990s. involved. Murray and California Insti­ expensive mission that could defmitely Named Lunar Observer, it will proba­ tute of Technology graduate student confirm or negate the presence of lunar bly be built out of spare parts obtained Tom Svitek revisited the theories, con­ polar ices. An extensive scientific sur­ from the approved Mars Observer pro­ cluding that the anti-ice arguments had vey found that to do remote sensing of ject. Because Mars Observer must re­ great merit but were inconclusive: Per­ the quality required, the mission's cost, tain those parts until its 1992 launch in haps the elusive bonanza could still ex­ though small in NASA terms, would be case of need, the Lunar Observer has no ist. The Society, led by Svitek and an­ too great for a project funded entirely realistic prospect of flight before about other Caltech student, Eric Gaidos, as­ by the Society. But as Friedman rea­ 1996. And of course the parts may be sembled a small team to study propos­ soned: "Sometimes the Society must used for some other mission or for their als for a series of "cheap, quick" mis­ start a research effort and fail--other­ original purpose as spares. sions, one of which was a lunar gamma­ wise we are not trying hard enough." Very recently some Soviet scientists ray probe. This same demand for unambiguous have again been promoting a lunar polar Others shared their interest, including measurements is partly responsible for orbiter for 1992 or 1994. Whether this the Space Studies Institute (SSI) in the lack of a Soviet mission. Up to now, possibility is real or merely promotional Princeton, the (then) L5 Society, and a Soviet proposals have been based on is not clear at this time. Jet Propulsion Laboratory (JPL) team gamma-ray detection in sodium iodide, With such dreary possibilities facing studying low-cost missions. Dr. Lew which is less sensitive than the germani­ governmental lunar programs, it is no Allen, JPL Director, was supporting in­ um now used in US spectrometers. surprise that groups of lunar enthusiasts house funding for small, low-cost mis­ (This situation may change if the Sovi­ have been seeking other avenues. If lu­ sions, one of which was a lunar ice-fmd­ ets start making germanium-based spec­ nar polar ices are present and interna­ er based on NASA's "Getaway Special" trometers or decide to use foreign ones.) tional agreements for their controlled program. That program encourages stu­ Although innovative and well con­ exploitation can be reached, the whole dents to fly small, self-contained experi­ ceived, so far Japanese proposals have course of lunar inhabitation could ments on the shuttle. The JPL design not competed successfully with other change. But even if the ices are absent, used solar-electric propulsion with argon scientific missions in their program. we will still need international agree­ propellant to avoid the hazards of carry­ Thus we are left with the choice of wait­ ments simply because of the other ing chemical propellants in a Getaway­ ing until some government launches the unique environments mysteriously pro­ Special container. Despite analyses and project or of returning to some private or vided by Nature in the polar regions of cooperative meetings of the interested partly private approach. The Space Stud­ the Moon. groups, in the end The Planetary Soci­ ies Institute continues to explore this ety's studies were reluctantly aban­ possibility with collaborating individu­ James D. Burke is a member of the doned. (SSI's effort continues.) als and groups, and in 1989 the Interna­ Technical Staff at the Jet Propulsion While The Planetary Society'S study tional Space University will make it the Laboratory and serves as Technical showed the possibility of low-cost mis- subject of a student design project. Editor of The Planetary Report.

Renaote Sensing 01 Planetary Ices t may seem incredible that a spacecraft a hundred kilometers up can detect frozen volatiles beneath a planet's surface. This remarkable possibility has been demonstrated in laboratories but not yet in flight. It depends on the physics of nu­ I clear particles' interaction with matter. When a cosmic ray particle strikes the nucleus of a deuterium (heavy hydrogen) atom, the nucleus emits a barst of light, a gamma ray with an energy of 2.2 million electron volts, which can be registered in a detector using sodium iodide or germanium as the sensor. With complications caused by the need to cool the detectors and to shield against spurious radiations and particles, this is the principle of gamma-ray spectrometers to be used on both the Mars Observer and the Lunar Observer. Besides detecting deuterium, these spectrometers are also very precise and sensitive detectors of gamma rays at other energies emitted by radioactive elements in a planet's crust. Another way to look for ices is to examine the spectrum of neutrons coming up from the planet. An excess of slow-mov­ ing neutrons may mean that they have been "moderated" (slowed) by light elements, including hydrogen, in the surface materials. finally, a radar altimeter might possibly show surface shapes or patterns caused by subsurface ices. Patterns of this kind are well known on Earth, and some similar ones have been seen in Viking imagery of Mars. However, if the lunar ices have never warmed up toward their melting or sublimation temperatures, no patterns may be evident.-JDB 21 nized one science and one global warming caused by fied opinion finding the Soci­ mathematics teacher from the greenhouse effect and ety's 1988 financial state­ The Planetary Society is every state, the District of what can be done about it, ments in conformity with helping to sponsor Astrono­ Columbia and Puerto Rico. the reliability of climatic pre­ generally accepted account­ my Day, which will be ob­ The Planetary Society gave a dictions, and the relation be­ ing principles. Copies of the served on May 13, 1989 with year's membership to each of tween Earth and the other financial statement, which events throughout the United those exceptional educators. pl anets. To initiate a new includes a report on restricted States. For more informa­ -Charlene M. Anderson, program supporting a "mis­ funds resulting from mem­ tion , send a self-addressed, Director of Publications sion to planet Earth," The bers' donations, are available stamped envelope to Gary E. Planetary Society helped or­ upon request.-Lu Coffing , Tomlinson, Astronomy Day ganize a public meeting of Financial Manager Coordinator, Astronomical interest groups in conjunc­ League, c/o Chaffee Plane­ tion with the conference. tarium, 54 Jefferson Avenue Planetary Society President --Louis D. Friedman, Exec­ SE, Grand Rapids, MI 49503 Carl Sagan highlighted the utive Director or call (616) 456-3985. Con­ Society'S concern for our Paul Vanden Bout, Director tact me c/o The Planetary home planet in his keynote of the National Radio As­ Society if you can help staff address on February 28, tronomy Observatory, has a Society exhibit table at an 1989 at the Global Climate urged Planetary Society event in your area. Change Conference in New Our annual Price Waterhouse members to encourage the - Marshalle Wells. Volun­ York . Dr. Sagan discussed audit resulted in an unquali- US Postal Service to issue a teer Network Coordinator stamp honoring the Very

~ - - - Large Array (VLA) radio . ~. ;

- Ji4- ~ • -'. . ~1_~:ef~/l~:!iJ ~\~-;~C~I~:;: "... ~' .J ••• • ,,;; telescope. The most used and . '1/2!= 0 ;I(F;-:,~ (if:l-~­ most productive telescope on t J.1... . _)~3 ]-1: _ ; /_ (jl,l CELEBRATE MAGELLAN Earth, the VLA has operated The Society'S Mars Declara­ On Friday, April 28, 1989, The Planetary Society and in New Mexico since the tion videotape, which ex­ NASA Kennedy Space Center's Spaceport USA, operat­ 1980s and can be used for plains the Mars goal and in­ ed by TW Recreational Services, Inc., will sponsor a planetary observations. Let­ cludes dramatic footage of public event at the Kennedy Space Center in Florida to ters of support may be sent Mars and other space pro­ celebrate the launching of the Magellan mission to to: Citizens Stamp Advisory jects, is available for loan or Venus. Speakers will discuss not only the Magellan mis­ Committee, Stamp Informa­ purchase ($35, 24 minutes sion itself but also how a serious return to planetary ex­ tion Branch, 475 L' Enfant long). Contact me for more ploration could shape the future of the US space pro­ Plaza, Washington, DC information.-Tim Lynch , gram. Admission is free; the Society must receive writ­ 20260.-CMA Director of Programs and ten requests for tickets (two per request) by April 18th. Development - Susan Lendroth, Manager of Events and Communi­ cations Our mailing address: INTERNATIONAL VOYAGER WATCH The Planetary Society The Planetary Society will celebrate Voyager 2's en­ 65 N. Catalina Avenue The Planetary Society has counter with Neptune in August 1989 by sponsoring Pasadena, CA 91106 been honored with a certifi­ Voyager Watch, a program funded by the Norris Founda­ Callforan updated events cate of thanks from the Na­ tion and designed to educate and excite the general pub­ calendar: tional Science Foundation lic about space exploration. The major activity will be (818) 793-4328 east of the and the National Science Planetfest '89, a five-day, multi-media event in Pasade­ Mississippi Teachers Association ac­ na, California. The Society will also create a master tape (818) 793-4294 west of the knowledging our contribu­ program of Jet Propulsion Laboratory Voyager videos Mississippi tion to the 1988 Presidential and a slide program with 40 slides and an audiocassette General calls: Awards for Excellence in featuring Voyager's Grand Tour. Both will be duplicated (818) 793-5100 Science and Mathematics and loaned out free of charge to educators and members Sales calls ONLY: 22 Teaching. The awards recog- wishing to sponsor regional events. Contact me for your (818) 793-1675 free Voyager Watch information packets, special educa­ tors' packets or more information.- Susan Lendroth -- ~~-" ------.. , ..- .... -_ -~...... -- ..... ---.....,...,.,...,-:::c------_ -_-----_-----_------

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arely do we have a chance to enable solar system, even when we looked back at Planetary Society members to help plan Earth from near space, we have been surprised. ii: and design an actual spacecraft mission. We want any Mars rover to be able to seek out We have held contests to name both a spacecraft unusual things, to recognize them and investi­ (Magellan, which will orbit Venus and image it gate them, just as you or I would do if we were with radar) and an asteroid (named for space lucky enough to be the first humans to explore artist Chesley Bonestell), but we have never had Mars. The martian terrain will not·be easy to traverse, even with the an opportunity for members to contribute to Dr. Szego's questions to Planetary Society best deSigned rover, and the mission design. members are these: How do we teach a Mars most scientifically interesting This possibility has been suggested to us by rover to recognize the curious, strange or unex­ regions may be the most Karoly Szego of the Central Research Institute pected? What should it look for- size, color, treacherous. Valles Marineris (above), the rift stretching in Budapest, Hungary. Dr. Szego has been a brightness, flavor, smell, sound, motion? How one-fifth of the way around principal experimenter on several Soviet space do we use the rover to gather information and Mars, could reveal much of missions, including Vega to Halley's Comet, and satisfy our curiosity? the planet's geologic history, just as the Grand Canyon has has also spoken at several Planetary Society Planetary Society members are invited to taught us much about Earth. .. events in the United States. write us with ideas for teaching the Mars rover But its kilometers-cieep At the recent meetings in the Soviet Union to explore. We will review your ideas and pass canyons are probably too . about future Mars missions, Dr. Szego noted that the most promising ones along to our colleagues dangerous for an early rover mission. But even relatively there are many requirements for a Mars rover­ in the Soviet, US and European space programs. safe regions, such as the a robotic vehicle that will travel across the planet The first-prize winner will receive a library of Viking Lander 1 site seen here to explore different terrains. The first rover may books about Mars. Other entries that pique the (top left), can be rocky and fly on the Soviets' Mars '94 mission; it would judges' interest will be recognized as well. difficult to move across. land in 1995 to begin its experiments to analyze All entries must be received by June 30, 1989. Images from JPUNASA the martian environment and surface. Send your ideas to Mars Rover Contest, The However, Dr. Szego noted, perhaps its most Planetary Society, 65 N. Catalina Ave., Pasade­ important job is to be prepared for the unexpect­ na, CA 91106. ed. Every time we have gone anywhere in the We look forward to seeing your suggestions! 23 ------_..------_.. _------

er year and ·the fIrst lunar landing imminent. Despite the elegant venue for the 1988 meeting, the gloomy re­ ality of NASA's planetary research program belied the meeting's superfIcial success. Research Funding Cuts I spoke with a scientist who is the only remaining ex­ pert using a crucial technique. Her research group's funding had been slashed, so she was put in charge of trying to recoup. Her efforts had been partly successful, by Clark R Chapman but at a cost: The funds she won back would have to come from a colleague's hide, and the 20 percent effort she now spends managing is that much less time on her research. A few weeks earlier, another scientist-the alloween is that peculiarly American holiday world's expert in an important specialty-had all of his that celebrates the contrast of appearance and funding terminated by NASA. He came to Austin in a H reality. The 20th annual meeting of the Divi­ desperate, last-ditch attempt to save his failing career. sion for Planetary Sciences of the American Astronom­ One ex-officer of the DPS, whose group's funding ical Society was held Halloween week in Austin, had shrunk so much that he is pursuing a more lucrative Texas, where the "DPS" began. It is the chief society of career part-time, was absent. I didn't see another regu­ planetary scientists, especially those with an astronomi­ lar DPS-er, from whom I had just gotten a bitter letter. cal bent. Although the DPS is an American society, NASA has stopped supporting his project, a lifelong Catherine de Bergh of France was elected this year to dream. Instead of venting his anger at NASA officials the DPS Committee. Most things ran smoothly, on the who had always underfunded his project, robbing it of surface, as researchers reported their latest discoveries, its potential, he railed against his colleagues. I learned interpretations and calculations. There were talks about in Austin that others had also received his retort to the sodium emissions from the thin lunar atmosphere, the anonymous referees. In fact, I had not advised NASA curious brightening of distant Chiron, hints of planets on this one. But his letter reminded me how NASA around other stars, a new phenomenon ("solid-state wastes scientists' precious time in mutual criticism, de­ greenhouse") that revises our notions about icy satel­ flecting blame for cuts from NASA's mismanagement lites, and pictures of heat leaking through Venusian onto other scientists. The shrinking research communi­ clouds. The research advances were real, but major dis­ ty should be doing science, but NASA frustrates that by coveries seemed to be missing. Was this appearance or fostering a flood of proposals that have to be written reality? (and evaluated) to chase ever-dwindling funds. Thanks to the depressed Texas economy, the DPS Just a month before Austin, NASA Administrator could celebrate its 20th anniversary at bargain-base­ James Fletcher sliced another $10 million from plane­ ment prices in Hyatt Regency opulence, a far cry from tary research and analysis (R&A) for 1989, despite the shabby Austin motel where the fIrst one-day DPS Congress' clear intent and despite last spring's promis­ meeting was held in 1968. Planetary science was then es by other NASA officials that priority would go to on its way up, with Mariners being launched every oth- augmenting planetary R&A because it was in the worst

n Austin Bruce Hapke of the University of Pittsburgh became THE C.HAlVGING FACES the Chairman of the Division for Planetary Sciences. In 1981, I Hapke organized the Pittsburgh DPS meeting. That was an exciting time, just two months after Voyager 2 encountered Sat­ urn. It was also depressing, as Office of Management and Budget an HST Science Institute contractor-as he says, "earning a living Director David Stockman advocated ending the US Planetary Pro­ doing industrial astronomy." By company policy, he has no money gram and tried to "zero out" Calileo's budget. or time for the DPS. He hopes to return to science when HST is up. I checked registrants at both the Pittsburgh and Austin meetings Iohn Dickel of the University of Illinois never was a full-time and asked why some came to one and not the other. There were planetary radio astronomer, but a student, Imke de Pater, got him mundane reasons like illness, but others reflect the evolution of involved with planets. In the early 1980s, NASA cut out nearly planetary science. all planetary radio funding, so Pittsburgh was Dickel's last DPS meeting. A new student "might well have kept me interested in Where Are They Now? planetary research," but he had no funds for a student. He remains Ionathan Cradie works at the University of Hawaii studying as­ a DPS member but has "gotten out of the planets game." His heart teroids, but also half time at a Honolulu company. In 1981, he was is in supernova remnants. at the Pittsburgh DPS meeting. Last year he had traveled so much Dave Pieri, who fIrst studied martian geology with Carl Sagan, (partly for his non-planetary work) that he passed up Austin and talked about sulfur volcanism on 10 at Pittsburgh. Then he moved "got some work done when everybody else was away." Because of into terrestrial research and now leads a volcanology group at JPL. "very, very tight" NASA funding, Gradie must gather funds from He is fmding many opportunities to advance his career in NASA's different sources to "put together a salary." He is not demoralized Earth Science and Applications programs. "It was like a steeple­ because there are "lots of other interesting things to do out there." chase," Pieri says of hurdles facing planetary researchers, while 24 Ben Zellner works on Hubble Space Telescope operations for Earth Applications is "like a paved freeway." Due to cutbacks, shape of all of NASA's generally hurting science pro­ say that the emperor wore no clothes. A tenure-track grams. Following the usual approach in Washing­ professor at a major university told me later that he was ton-mortgage the future to battle current crises­ l itching to speak but couldn't risk his vulnerable career. NASA is using smoke and mirrors to put off some of The NASA official returned to Washington, probably the problem until next year: Most NASA-funded plane­ oblivious to the frantic despair of "his" scientific com­ tologists are being given just two-thirds of their ap­ munity, which must be made healthy if it is to provide proved funds this year; they must write renewal propos­ intellectual and instrumental substance to the spacecraft als just eight months after their last ones in the imprac­ missions NASA hopes to fly. tical hope that NASA can pay from new funds just as The European Space Agency had just OK'd the joint the next fiscal year begins. This ploy requires the new Cassini mission to Saturn, it was reported at Austin, Bush administration to undo the willful cutback, impelling the US to commit to its half of the mission. Congress to pass the budget in time, and NASA's con­ Indeed, a combined comet/Saturn project is now going tracts and grants office to process paperwork with un­ through the federal approval process. But NASA plans precedented efficiency. Even if successful, the trick will to use fewer scientists on missions; it is even throwing stave off only some of the damage. Research on data instruments off Mars Observer. With NASA's planetary about Comet Halley and Uranus will be stopped regard­ office absorbed with big, not-yet-flying missions and less, not to mention the career-ending and project-end­ ignoring human infrastructure, the quality of the Amer­ ing decisions already implemented. ican planetary science community will be badly weak­ ened before Cassini flies in the late 1990s. It may be Halloween Horror Show unable to perform its wider mandate of researching the On Halloween evening, many DPS-ers joined throngs solar system, which is a vital facet of NASA's charter... of Austin citizens parading as ghosts and goblins on unless, of course, there is a change of vision within Sixth Street. But the real horror show was witnessed by NASA and a resolve never again to strangle research scientists who attended the traditional "NASA night programs in our universities and national laboratories to session," where officials come from Washington and solve short-term cost-overruns on big projects. habitually promise how much better things will be next To try to explore the solar system without a robust year (always next year). There was a ghoulish feeling community of the brightest, most talented scientists and of deja vu as one official explained, for the fourth year, engineers on board is like trying to fly blind. Unfortu­ that next year was the year for a Comet Rendezvous nately, NASA's recent history has been to build fancy mission new start. Worse, he exceeded his pollyannaish vehicles, a space station and costly spacecraft--ostensi­ optimism of previous years by claiming that NASA's bly for scientific purposes-and then to fail to foster planetary program was already in good shape! the creative human intelligence needed to use the hard­ The scientists sat in stunned silence. Many left in dis­ ware productively. If talk I heard in the hallways in gust; some later reported feeling sick. The tension was Austin was typical, it is late in the day for NASA to as palpable as if Halloween skeletons had invaded the save planetary science. That is the reality behind the hotel. The gulf separating perceptions of the NASA of­ mask of continued planetary research productivity. It is ficial from those of the scientists had opened so wide tragic that NASA officials don't seem to know it. that, during the question-and-answer period, hot a word was spoken about what was on everyone's mind. I Clark R. Chapman served on various NASA Advisory knew of a dozen planned retorts, but nobody dared to Committees from 1975 until last October. ------

AT DPS .MEETINGS wasn't at Pittsburgh since she was just back in school after work­ ing on Voyager. She went to Austin to give her results on spectra of glasses, to talk with colleagues and to look for a job. "A lot of us who have been graduate students in the last five years are not just 20 percent of his funds are now for planetary work. "In a going to get jobs," Nelson feels. But after seven years studying way it's a shame," he says, "but I enjoy the terrestrial research planets, "I'm not going to throw in the towel without a fight," she immensely." says, despite rumors of better prospects in Earth science. She ex­ lim Cutts' last DPS meeting was Pittsburgh; then his group pects to get a post-doctoral job but worries about the long term. lost its planetary funding. He is now Deputy Director of a center Alan Hildebrand hardly knew about planetary science in 1981, for space microelectronics technology. It gets only a quarter of when he worked in Canada as a minerals exploration geologist. its $20 million per year budget from NASA. "I'm very excited Now a planetary student at Arizona, Hildebrand went to Austin about what I'm doing," he says. "Microelectronics is very much because he hadn't been to a DPS meeting before. Also, Austin is a growth area." near an exposure of the Cretaceous-Tertiary boundary where he Tom Gehrels, whose Spacewatch Camera suffered NASA wanted to do fieldwork for his thesis on the impact hypothesis for budget cuts, stayed in Tucson to work while everyone was away. mass extinctions. He is often at the telescope because he can't hire an observer. Jacklyn Green would have gone to the 1988 meeting even if it Gehrels' autobiography, "On the Glassy Sea: An Astronomer's hadn't been in Austin, where she was completing her PhD. In Journey," will be published soon by the American Institute of 1981 she was studying cataclysmic variable stars before she real­ Physics. He wishes he could have met his old friends in Austin. ized she really wanted to study planetary science. Green feels it's premature to think beyond her new post-doctoral job in Hawaii. "I And Some New Faces want to make the most of this job so that I'll be ready for the next Marcia Nelson hopes to finish her PhD in Hawaii by May. She one. I'm an optimist," Green admits. -CRC 25 Congress will vote this spring on the President's budget request for both the Comet Rendezvous Asteroid Flyby (CRAF) mission and the Cassini mission to study Sat­ urn and its satellite Titan. What is the national context of planetary exploration and the role of the planetary scientists it supports? Plan­ etary exploration is a unique consequence of NASA's formation and of President Kennedy's declaration that Americans would travel to the Moon in the decade of the 1960s. Scientists contributed to the success of the Moon landing, and they assured the ensuing bonanza of new knowledge about the space environment of Earth ANational Perspective and about the nature and history of the Moon itself. A community of researchers was formed, and it laid far­ reaching plans for science in, from and about space. A multiplicity of national needs gave birth to the by Robert A. Brown Apollo program. It and the subsequent exploration pro­ grams into the solar system beyond the Moon­ Mariner, Pioneer, Viking and Voyager-delivered a snowstorm of benefits both scientific and otherw Ise. Beyond science, these benefits have fallen across a In his "News & Reviews" column, Clark Chapman expresses the broad spectrum of national aspirations, including inter­ feelings of some planetary scientists about their primary funding national cooperation, national security, competitiveness agency, NASA. Such feelings are not exclusive to the planetary field, in high technology, scientific and technical education, but are part of a larger turmoil over the evolving relationship of sci­ culture, and the pride and prestige of the United States. ence and government. Similar debates are now roiling between the Planetary exploration has expanded and enriched our biomedical community and the National Institutes of Health, and cosmic map--our understanding of humanity's place between physicists and the Department of Energy. The future of plan­ and scope of action, which is the quintessential effect of etary exploration rests on the outcome, and so this debate is vital to exploration. From society'S standpoint, the primary re­ the interests of The Planetary Society. To continue the discussion, we turn on investment in planetary exploration consists of print here another view of the current situation in planetary science. the rich cluster of non-scientific benefits it delivers. The future direction of the planetary program is now the subject of lively debate, as the readers of The Plan­ etary Report know well. This is another sign of health. lark Chapman's "News & Reviews" column gives Planetary exploration is not an entitlement program, one scientist's snapshot of an astonishingly pro­ and its value and potential contributions must be con­ Cductive national program. He captures the frustra­ tinually reassessed. The program's content must tion of adjusting to evolving circumstances, but he respond to the thoughtfully defmed needs of the United identifies neither the nature nor the source of funda­ States. Among these needs, of course, are advances in mental change. His perspective invites a broader view pure knowledge: Progress in planetary science im­ of the space program and offederally funded science in proves our understanding of the atmospheres, oceans order to see where the planetary program is grounded in and interiors of planets, including Earth. the national interest and to understand how the program To illustrate that the proper plarming process is open attempts to serve it. Viewed broadly, our space explo­ and broad and not restricted to scientific interests, con­ ration program is a brilliant servant of national policy, sider three themes that are discussed in the context of and it holds out ever-fresh opportunities to those who the future planetary program: continued scientific ex­ join it with realistic expectations. ploration, a big Mars initiative and a search for extra­ The United States' planetary program has offered solar planets. Of course, these options are not mutually three generations of scientists-as well as engineers exclusive, but they are different. Associated with each and managers-exciting challenges, new skills and is a particular mix of programmatic elements and a va­ knowledge, and the chance to contribute conspicuously riety of benefits that could accrue to society in return. to the nation's life, but it has not offered them tenure. This breadth demonstrates what it means for planetary Universities do. Nevertheless, like universities and un­ exploration to be a national program. It teaches why like nature, program evolution and the selection of indi­ planetary scientists guide and serve the program, not as viduals for term support by NASA are based on peer a priesthood, but joined with other voices in the public review. It is healthy to examine one's activities and to arena so as to assure that a wide national interest is met. have them assessed by others. The current approach In this view, the unique contributions of scientists-to tries to be fair and at the same time assure the planetary introduce the constraints of science, to draw distinc­ program a workable balance of competence, continuity tions of scientific merit and to extract scientific re­ and responsiveness to changing needs. sults-will be more effective because they are not mis­ Planetary exploration, with the rest of the space pro­ taken for the whole. gram, has had to absorb the unexpected costs and de­ lays from the Challenger accident. Nevertheless, two Robert A. Brown served as Chairman of the Division planetary missions-Magellan to Venus and Galileo to for Planetary Sciences of the American Astronomical 26 Jupiter-are scheduled to be launched in 1989, and Society from 1987 to 1988. NEWS BRIEFS ~ ''t)~ /continuedfrompage3 (continued from page 3)

"non-essential" passengers tend to see only the research side of any endeavor. Well, it's about time the Society quit may fly. First priority will be dreaming about the fun part of this program. Anybody can do that, and they are. That's the given to the "teacher in space." problem. The Society, with all its genius and clout, ought to tackle the ugly part of this pro­ -from the Langley Research gram-building a plan that will convince the boss to pay for a trip to Mars and beyond, and Center's Researcher News then convincing the boss. I urge the Society to propose a fundamental, far-reaching and cooperative world plan for Valentin P. Glushko, a promi­ the exploration of our solar system (including Mars) by a consortium of governments and nent but secretive figure in the companies with a view toward commercial exploitation of space-not just a sightseeing trip. Soviet space program ,died in I could support a plan like that. I cannot support the one currently proposed by the Society. January at the age of 80. DANIEL J. POTIER, Shorewood, Illinois In the 1930s Glushko and his colleague Sergei P. Korolyov Does a mountain climber scale a mountain because it's the prudent thing to do? No. Does (who was later credited with that person climb a mountain "because it's there"? Maybe, but I doubt it. What motivates a founding the Soviet space pro­ mountain climber or any other person attempting something equally challenging? Pure gram) pioneered the develop­ emotion. Adventure, romance, fame, excitment, risk, triumph! And that's exactly what is ment of the liquid-fueled en­ needed in our space program today--emotion. gines now used in all Soviet Will a child choose a scientific profession just to orbit Earth in a space station? Not all rockets. The key roles that that exciting, I think. It's lamentable that our educational system doesn't encourage scien­ Glushko and Korolyov played tific study. Wouldn't dreaming of going to Mars be a more compelling reason for children in the Soviet space effort were to go into a scientific profession than a few days in orbit onboard the shuttle? kept secret until 1963. [Mr The Mars Declaration has in it the stuff of dreams to fire the imagination of even our Glushko co-authored "The youngest. Who cares if we don't have the technology yet? The most awesome trait of the Way to Mars" in the Novem­ American people is their ability to devise a way to make their dreams come true. Let's cast berlDecember Planetary Re­ prudence to the winds and put some emotion into walking on Mars! port.] DONNA MOORE, Gardena, California -from The New York Times

Your articles on whether or not Venus had oceans in the past are very interesting. (See the Researchers at the Jet Propul­ NovemberlDecember 1988 Planetary Report.) However, does it really matter? Can we sion Laboratory are studying change the situation? Can we ever go and live on Venus after we have destroyed the face of the possibility of putting a Earth as a place to live? Yes, keep probing the questions about Venus, Mars and other parts robotic spacecraft into orbit of the universe as exercises to keep the mind alert, sharp and useful, but what about Earth? around Mercury. Chen-Wan Look at what humans have done to the surface of our planet in just the past 200 years. At Yen of JPL notes that while the present speed of destruction how long do we have before Earth looks like Mars or Mariner 10 (the only other Venus? mission to Mercury) merely Is it possible for great minds like James F. Kasting, David Grinspoon and others to tum flew past the planet in 1974, an their attention to what is happening to our Earth? Can they come up with a plan to save orbiter could study it for many what we have-a paradise that is being destroyed right before our eyes? months, photographing the I am all for going to the Moon and then on to Mars, but I would like to see planet Earth whole planet (unlike Mariner included in the plans and thinking of The Planetary Society. 10) and studying its surface SAMUEL J. McELREA, Eugene, Oregon compostion. -from Final Frontier Planetary scientists have been at the forefront of those calling for the spacefaring nations to use the knowledge and technology gained from planetary exploration to better under­ Phobos 2, one of the Soviet stand Earth. Infact, researchers studying the greenhouse effect on Earth use Venus as an space probes launched last July example of a greenhouse gone wild. Scientists who had studied martian dust storms used to study Phobos, has begun that experience to develop the Nuclear Winter hypothesis. Recognizing that the planets sending back its first pictures have much to teach us about our own world, The Planetary Society is actively developing of the quirky martian moolliet. a new intiative to encourage the study of Earth as a planet. Look for a special issue of Western scientists were The Planetary Report on this topic later this year.--Editor somewhat concerned about the condition of several instruments As a new member and first-time reader of The Planetary Report, I see that the members as aboard the small spacecraft, and .. well as world scientific communities are taking sides on whether or not to go to Mars, it was not known until the last launch the space station or fix world hunger. Dear members, let's not get upset and ques- minute whether the television . tion our membership if others express interest in one project over another. NASA needs, camera would work. But "a and has, a budget. They will not be able to fund every worthy mission. high-quality image of Phobos I think we should support missions with the maximum learning potential for humankind. from various angles was Once missions are chosen, we should all support them and see that they are doing all they recorded on nine television se­ can with their technology. quences," the Soviet news I believe the space station is a worthy mission. I like the idea of research from outside agency Tass announced from the atmosphere-to better see the wonders of the universe and to look back at our Earth to Moscow. better see what might work to fix all that humankind has broken. -from Lee Dye in the Los NICK EDGE, Sussex County, Delaware Angeles Times 27 It seems to me that the rate and na­ Scientists have wondered what would around on the beach by tides; this would ture of evolution might be profoundly have happened if Earth hadn't had a reduce pressures on lifeforms in this affected by tidal action. Has this as­ moon. Without the Moon, you'd think, "intertidal zone" to learn to adapt to life pect been given due consideration by there wouldn't be any sloshing of the in the air as well as in the water. Land­ those who search for intelligent life oceans from the pull of lunar gravity based, tool-using life might not arise at elsewhere? that we call tides. Then, if life arose iIi all. -William V. Medlin, Houston, Texas the ocean, critters wouldn't be sloshed In our own solar system, most planets have only feeble, distant moons, not powerful enough to raise respectable tides. Does that mean that life capable of transmitting radio signals is rare? Not to worry. Few people realize it, but the The pull of the Sun also generates tides. They're about Moon on EBrth's oceans regularly half the height of lunar tides. exposes and then The presence of the Moon has proba­ covers intertidal bly affected the evolution of life here, regions along the sea's edge. Many especially since it's now slowly moving plants and animals away from us, so it must once have have adapted to life been closer and raised much bigger alternately In the air and the water, and - tides. Indeed, some of The tidal drag has also slowed down these regions are our spin, so Earth may once have had a the most biologi­ day closer to the lO-hour period of plan­ cally productive on EBrth. It's possible ets like Jupiter and Saturn. This too that from these could have affected evolution. special ecological In niches lifeforms any event, we are just barely able eventually moved at present to detect planets around near­ permanently to land, by stars. It will be some time before and their descen­ we'll be able to see how common moons dants became the technology-uslng are around other planets. The bottom organisms that are line is that without the Moon, the series now scanning the of evolutionary accidents that led to us skies In search of other technological would probably have been different. beings. Life would still have arisen here, and probably land life too, perhaps even in­ telligent life-but we might not have. -TOM McDONOUGH, Planetary So­ ciety SET! Coordinator

What is the difference between a plan­ etesimal, a planetoid and a proto­ planet? -Barney M. Colver, Hell, Michigan This is a good question because these terms have been used widely but with­ out any precise definitions. They are in­ formal terms used mostly by scientists who discuss the ~rigins of planets. Planetesimals refers to any small bodies that are aggregating to make planets. They can be any size from dust grains to the size of the Moon. Mostly the term refers to bodies ranging from mil­ than those on Earth. limeter scale to the size of small as­ Several major features produce Recent infrared observations of asteroids and teroids a few kilometers across orbit­ large pressure differences on Mars: laboratory analyses of meteorites suggest that ing around the early Sun or around Its topography is extreme, with outer belt asteroids are made of some of the newly forming stars. mountains that would dwarf Everest most primitive material in the solar system­ Protoplanet generally refers to a and chasms that could swallow the only comets deeper in space are more pris­ much larger mass, the size of a plan­ Grand Canyon. Great, dense dust tine. They also suggest that asteroids, as well et or even larger. Protoplanet is a storms absorb sunlight, creating tem­ as comets, could have added water to plane­ word that originated in earlier theo­ perature differences among different tary atmospheres during the early bombard­ ries of planet formation. These early parts of the atmosphere. The bound­ ment of the solar system. theories assumed that planets formed aries between the reflective ices of Larry A. Lebofsky and Thomas D. Jones when large regions of the early solar the polar caps and the darker sur­ of the University of Arizona's Lunar and nebula became gravitationally unsta­ rounding soil generate surface tem­ Planetary Laboratory have searched almost ble and contracted under their own perature contrasts. Global and Earth­ 40 of the largest carbonaceous asteroids for gravity to form planets. Such large like frontal circulations also con­ water. In their sample from the main asteroid portions of the nebula were called tribute to the winds that may gener­ belt, two out of three were rich in mineral­ protoplanets. Many modem theorists ate dust storms. In places like Olym­ ogical water. But contrary to popular belief think the giant planets formed this pus Mons or Valles Marineris, the that the outer asteroids should contain more way. So "protoplanet" is used to re­ nighttime buildup of a cold layer water and carbon than those in the main belt fer to an extended region of the neb­ near the surface causes strong (because colder temperatures would cause ula that is contracting to make a "mountain" or "valley" winds as the less evaporation), the researchers find the Jupiter or a Saturn, for example. It cold and denser atmosphere in the outer bodies' surfaces to be water-free. might include a nearly Jupiter-sized surface inversion drains down the "That we're seeing no spectral evidence central core with a massive, extend­ slope at night and early evening. At for water is a surprise," Jones said, "because ed atmosphere around it, still con­ the Viking I Lander site, a slope of these objects should look much like an in­ tracting to make the finished planet. only one percent causes winds of active comet." Planetoid is now a nearly obsolete five to ten miles per hour, and on -from Lori Stiles in the University of word for asteroid, but "asteroid" or larger slopes the winds could be far Arizona "A" News "minor planet" has taken its place. stronger. Occasionally it is still used to refer to At the edge of the south polar cap, o any small, present-day interplanetary shortly after winter, the Sun shines According to David G. Jankowski and body, such as a comet nucleus, aster­ on the contrasting red soil and white Steven W. Squyres of Cornell University, oid or meteoritic body, without im­ polar cap, producing large tempera­ Uranus' moons Ariel and Miranda once had plying a distinction about what kind ture differences. This generates volcanoes that spewed frozen ice rather than of body it is. strong winds and large local dust molten lava. This is the frrst example of sol­ -WILLIAM K. HARTMANN, Plan­ storms every year. This effect is id-state volcanism in the solar system. etary Science Institute stronger in the south because Mars' Careful study of Voyager 2 's 1986 photos highly elliptical orbit brings it signif­ shows that some of the icy moons' mysteri­ icantly closer to the Sun during late How can Mars' extremely thin at­ ous surface features are best explained by southern spring. resurfacing due to solid, icy materials. But mosphere stir up such ferocious, Although the Viking Landers pro­ planet-wide dust storms with winds because water ice at such a great distance vided us with years of data, we still from the Sun would be frozen so hard it that sometimes reach hurricane have major questions about the great force? couldn't possibly flow, the scientists con­ martian dust storms. What combina­ clude that other elements like ammonia and -Charley Levinson, Smyrna, tions of meteorological conditions Georgia methane were probably mixed in to increase are responsible for the large local the water ice's mobility. High winds in the martian atmo­ dust storms, and are they the same in -from D. Jankowski and S. Squyres in sphere are mainly caused by its very the northern and southern hemi­ Science low density (only one percent that of spheres? How do they differ with the o Earth) and the sunlight warming the season, and, especially, why are planet (only 44 percent of that reach­ there intense global storms some The devastating Northern California forest ing Earth). These combine to pro­ years and not others? Also, are there fires in 1987 caused a self-perpetuating duce the pressure differences that any unusual triggering mechanisms? inversion layer to trap a pall of smoke over drive the winds. Their speeds are di­ Some answers may be forthcoming the Klamath River canyon. As a result, daily rectly proportional to pressure differ­ from model studies, some might be high temperatures for one week in Septem­ ences between adjacent points and discovered if it were possible to ber averaged 27 degrees less than normal. inversely proportional to Mars' total compute winds measured by Viking University of Maryland meteorologist Alan atmospheric pressure. Although the I's lander during the last three years Robock says this lends credence to but absolute pressure of Mars limits the of operation, and the final answers doesn't prove the Nuclear Winter theory, winds' driving force, the lOO-times­ may have to come from the Mars which holds that there would be catastrophic less density means that moderate Observer and other future missions. global cooling in the aftermath of a nuclear pressure differences on Mars will -JAMES E. TILLMAN, University war. [The concept of Nuclear Wmter grew produce velocities 100 times greater of Washington out of studies of martian dust storms.] -from Larry B. Statnmer in the Los Angeles Times 29 ----~------.------

WE"HAVE ASPACE - PROBLEMf- · Not outer space, but shelf space. The merchandise listed on this page will no longer be sold through The Planetary Report. A limited number of items are still available and must be sold to make room for new inventory. So we are having a sale! Prices are good through 4/30/89 (subject to availability).

#156 Saturn by Seymour Simon Simple, effective text and beautiful glossy photographs make this the perfect book to capture your child's imagination. Age 8-11. 28 pages. $5.00

#154 Rings - Discoveries from Galileo to Voyager by James Elliot and Richard Kerr Share the excitement of scientific exploration as uranian and jovian rings are discovered and Saturn unveils a complex, multi-ring system. 209 pages. $5.00

#124 Entering Space by Joseph P. Allen Astronaut Joe Allen writes of his journeys beyond this planet, allowing us an intimate sharing of day-by-day life in space. 239 pages . $7.00

REMINISCE ABOUT HALLEY REMEMBER MARS WATCH #110 Comet #015 The Return of the Comet by Carl Sagan and Ann Druyan by Dennis Schatz This lavishly illustrated New York Times This well-designed book contains an exciting bestseller is an enthralling encounter in words variety of information and activities, both and pictures with the myth and science of entertaining and scientific. Adult guide included. comets, with special emphasis on Comet Halley. Age 9-14. 42 pages. $4.00 398 pages. $12.00 #004 The Comet and You by E.C. Krupp, illustrated by Robin Rector Krupp This humorous and informative book deals with all aspects of Halley's Comet in a format designed to capture the imaginations of your children. Age 5-9. 48 pages . $5.00 #572 Mars Watch BuHons $.25 each #571 Mars Watch Decal $.25 each #003 Comet! The Story Behind Halley's Comet #175 The Mars Project by Greg Walz-Chojnacki by Senator Spark M. Matsunaga An exciting, fast-paced book written for older This timely and important book for future children, Comet supplies information and space exploration includes Senator Matsunaga's activities with a refreshing enthusiasm. Age proposals to Congress and the President. 12 + . 64 pages. $5.00 215 pages . $5.00

#002 Comet Halley - Once in a Lifetime #530 I Love Mars. That's Why I Joined the by Donald K. Yeomans Planetary Society T-Shirt Historical anecdotes highlight this fact-filled This attractive, burnt-orange shirt is knit from book about comets. A very enjoyable reading 50/50 polyester/cotton yarn . Medium and Small experience. 175 pages. $5.00 sizes only. $5.00 #320 Halley Encounter 2 pictures from the Vega and Giotto missions. To verify availability of merchandise, call 818-793-1675 and use your credit card to order. $1.00 PRICE (IN PRICE (IN PRICE (IN N~R~::R • Color Reproductions US DOLLARS) N~R~::R • Sale Items us DOLLARS) N~~::R • Books US DOLLARS) 002 Comet Halley - Once in a Lifetime 158 Space-The Next 25 Years 335 Voyager 1 at Saturn by Donald K. Yeomans. $ 5.00 by Thomas R. McDonough. (set of five posters) $16.00 003 Comet! The Story Behind 237 pages. $16.00 336 Solar System in Pictures - $10.00 Halley's Comet 165 The Grand Tour: A Traveler'S Guide 9 pictures by Greg Walz-Chojnacki. $ 5.00 to the Solar System 337 Uranus - sunlit crescent 004 The Comet and You by Ron Miller and (16"x20" laser print) $ 8.00 by E.C. Krupp, illustrated by William K. Hartmann. 192 pages. $10.00 340 "You Are Here" (23"x29" poster) $ 5.00 Robin Rector Krupp. $ 5.00 170 The Home Planet PRICE (IN 110 Comet edited by Kevin W. Kelley. 256 pages. $36.00 N~~::R • 35mm Slide Sets US DOLLARS) by Carl Sagan and Ann Druyan. $12.00 183 The Search for Extraterrestrial 205 Chesley Bonestell's Vision 015 The Return of the Comet Intelligence: Listening for Life in 01 Space by Dennis Schatz. $ 5.00 the Cosmos (40 slides with sound cassette) $15.00 by Thomas R. McDonough. 124 Entering Space 256 pages. Soft Cover $13.50 210 Remember Halley's Comet by Joseph P. Allen. $ 7.00 (20 slides with description) $10.00 185 The Surface of Mars 154 Rings - Discoveries from Galileo by Michael Carr. 232 pages. $16.00 213 Mars (20 slides with description) $10.00 to Voyager 220 Viking 1 & Z at Mars by James Elliot and Richard Kerr. $ 5.00 PR ICE (IN (40 slides with sound cassette) $15.00 N~~::R • Videotapes US DOLLARS) 156 Saturn 225 Voyager 1 & 2 at Jupiter by Seymour Simon. $ 5.00 415 VHS Jupiter, Saturn & Uranus: (40 slides with sound cassette) $15.00 175 The Mars Project 416 BETA The Voyager Missions 417 PAL (60 min. videotape) $30.00 230 Voyager 1 Saturn Encounter by Spark M. Matsunaga. $ 5.00 (40 slides with sound cassette) $15.00 320 Halley Encounter (pictures) $ 1.00 425 VHS Mars and Mercury $30.00 426 BETA (60 min. videotape) 231 Voyager 2 Saturn Encounter 530 I love Mars T-Shirts S M only $ 5.00 427 PAL (40 slides with sound cassette) $15.00 $ .25 571 Mars Watch Decal 440 VHS Universe $30.00 235 Voyager Mission to Uranus 572 Mars Watch Bullon $ .25 441 BETA (30 min. videotape) (20 slides with description) $ 7.00 442 PAL PRICE (I N PRICE (IN N~~::R • Other Items US DOLLARS) Ng~~~ • Books US DOLLARS) 460 VHS Together to Mars? $15.00 461 BETA (60 min. videotape) 505 An Explorer's Guide to Mars 108 Beyond Spaceship Earth: 462 PAL (color map of Mars) $ 5.00 Environmental Ethics and the Back Issues of The Planetary Solar System PRICE (IN 510 edited by Eugene C. Hargrove. N~~::R • Color Reproductions US DOLLARS) Report - each volume contains six 336 pages. $20.00 issues (Vol. 1-5,6; Vol. 11-1,6; Vol. 305 Apollo - photograph of Earth, full 111-2,6; Vol. IV-2; Voi. VI-l,4; Vol. 126 First Light: The Search for the disk (16"x20" laser print) $ 8.00 VII-4,5 have been sold out.) Specify Edge of the Universe 308 Earth at Night (23"x35" poster) $ 6.00 the issues you are ordering by by Richard Preston. 263 pages. $17.00 310 Earthprint- photograph of North volume and number. Each $ 2.00 129 Living in Space-A Manual for America (8"x10" laser print) $ 4.00 515 The Planetary Society logo - Space Travellers bookmark (6"x2") (2 for $1.50) $ 1.00 by Peter Smolders. 160 pages. $13.50 315 Earthrise - photograph of Earth from the Moon (16"x20" laser print) $ 8.00 516 We're Saving Space lor You - 133 Mirror Maller: Pioneering bookmark (6"x2") (2 for $1.50) $ 1.00 Antimaller Physics 321 Uranus Encounter - 4 pictures from by Robert L. Forward and Joel Davis. Uranus and its moons $ 4.50 520 Exploring the Universe - 262 pages. $17.00 322 Jupiter - photograph of southern 1989 calendar $ 4.50 135 Nemesis: The Death-Star and hemisphere (16"x20" laser print) $ 8.00 526 Hugg-A-Planet Earth - Other Theories of Mass Extinction 323 Mars - landscape from Viking Orbiter 14" -diameter pillow $14.00 by Donald Goldsmith. 166 pages. $14.00 (16"x20" laser print) $ 8.00 540 Men's T-Shirt- white with blue 140 Out of the Cradle: Exploring the 324 The New Explorers (22"x34" logo. S M L XL $ 9.00 Frontiers Beyond Earth poster) $ 7.00 543 Mission Stamps -10 sets by William K. Hartmann, Ron Miller (4 stamps per set) $ 1.00 and Pamela Lee. 190 pages. $11.00 325 Other Worlds (23"x35" poster) $ 7.00 330 Planelfest '81 - Saturn and the 545 Planetary Report Binder - blue with 152 The Quickening Universe: Cosmic gold lettering (2 for $16.00) $ 9.00 Evolution and Human Destiny F-ring (two 22"x35" posters) $ 5.00 by Eugene T. 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MAIL ORDER AND PAYMENT TO: THE PLANETARY SOCIETY, 65 N. CATALINA AVE., PASADENA, CA 91106 In this painting by Michael Carroll, Galileo is quickly gathering data as it flies past Jupiter's turbulently volcanic moon, 10. The Galileo spacecraft is sched­ uled to be launched in October of this year to investigate the jovian moons and drop a probe into Jupiter!s mas­ sive and stormy atmosphere.

Michael Carroll is a freelance artist who works as an astro­ nomical illustrator and lecturer at San Diego's Rueben H. Fleet Space Theater. Mr. Carroll is also helping to organize a series of art shows by The Soviet Union of Artists and the International Asso­ ciation for the Astro­ nomical Arts and made possible by The Planetary Society.

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