MARSBUGS: The Electronic Astrobiology Newsletter Volume 6, Number 3, 10 February 1999. Editors: Dr. David Thomas, Department of Biological Sciences, University of Idaho, Moscow, ID, 83844-3051, USA. Marsbugs@aol.com or davidt@uidaho.edu. Dr. Julian Hiscox, Division of Molecular Biology, IAH Compton Laboratory, Berkshire, RG20 7NN, UK. Julian.Hiscox@bbsrc.ac.uk Marsbugs is published on a weekly to quarterly basis as warranted by the number of articles and announcements. Copyright of this compilation exists with the editors, except for specific articles, in which instance copyright exists with the author/authors. While we cannot copyright our mailing list, our readers would appreciate it if others would not send unsolicited e-mail using the Marsbugs mailing list. The editors do not condone "spamming" of our subscribers. Persons who have information that may be of interest to subscribers of Marsbugs should send that information to the editors. E-mail subscriptions are free, and may be obtained by contacting either of the editors. Article contributions are welcome, and should be submitted to either of the two editors. Contributions should include a short biographical statement about the author(s) along with the author(s)' correspondence address. Subscribers are advised to make appropriate inquiries before joining societies, ordering goods etc. Back issues and Adobe Acrobat PDF files suitable for printing may be obtained via anonymous FTP at ftp.uidaho.edu/pub/mmbb/marsbugs or at the official Marsbugs web page at http://members.aol.com/marsbugs/marsbugs.html. The purpose of this newsletter is to provide a channel of information for scientists, educators and other persons interested in exobiology and related fields. This newsletter is not intended to replace peer-reviewed journals, but to supplement them. We, the editors, envision Marsbugs as a medium in which people can informally present ideas for investigation, questions about exobiology, and announcements of upcoming events. Astrobiology is still a relatively young field, and new ideas may come out of the most unexpected places. Subjects may include, but are not limited to: exobiology and astrobiology (life on other planets), the search for extraterrestrial intelligence (SETI), ecopoeisis and terraformation, Earth from space, planetary biology, primordial evolution, space physiology, biological life support systems, and human habitation of space and other planets. ------------------------------------------------------------------ CONTENTS 1) GOING COMET WILD By Tony Phillips 2) AEROGEL RIDES AGAIN: LAUNCH OF STARDUST IS LATEST ADVENTURE FOR "FROZEN SMOKE" By Leslie Mullen 3) STARDUST MISSION STATUS JPL release 4) "A UNIVERSE OF LIFE?" ASTROBIOLOGY ART By David A. Hardy 5) SPACELAB ACCOMPLISHMENTS FORUM National Academy of Sciences (USA) release ------------------------------------------------------------------ GOING COMET WILD By Tony Phillips From NASA Space Science News 5 February 1999 This weekend a NASA spacecraft will blast off from the Kennedy Space Center for an historic rendezvous with periodic comet Wild- 2. Its ambitious goal is to intercept Wild-2 in 2004, to capture tiny bits of comet dust and debris, and then return them to Earth for analysis in 2006. Stardust is the first comet rendezvous mission since the European Giotto spacecraft's fly-by of Comet Halley (1986) and Comet 26P/Grigg-Skjellerup (1992), and the first ever to attempt to return a comet sample to Earth. It's a long, 7-year mission, but one most scientists feel is worth the wait. Scientists are curious about comets because they are thought to be the oldest, most primitive bodies in the solar system. Comets are made up of the same stuff as the early Solar Nebula that collapsed to form the sun and planets. It is now known that comets contain significant amounts of water ice, dust, and carbon based compounds. They may have been an important source of water and organic molecules for Earth when many comets collided with our planet during a period of heavy bombardment over 4 billion years ago. Modern-day comets are like a time machine. They offer a window into the past when the Solar System was young and life on Earth was just beginning. Why comet Wild-2? History is filled with famous comets. Halley's comet, Hale-Bopp, Hyakutake and others have dazzled observers with their brilliant nuclei and dramatic tails. Recent comets like Hale-Bopp have been viewed by hundreds of millions of people, and Halley's comet has had a real impact on history, as in 1066 when it was so bright that it terrified millions of Europeans and was widely credited with the Norman victory at the Battle of Hastings. Unlike its famous cousins, comet Wild-2 is a relatively dim, new arrival to the inner solar system. Until recently it circled the sun in an orbit between Jupiter and Uranus, but everything changed in September 1974 when Wild-2 passed within 0.006 AU of Jupiter. That encounter with the giant planet, at only 10 times the distance which fragmented P/Shoemaker-Levy 9 in 1994, altered Wild-2's orbit so that its closest approach to the sun now lies just inside the orbit of Mars. During its first passage relatively near to Earth (1.21 AU) on January 6, 1978, the comet was discovered by Paul Wild. Since then, the best apparition of Wild-2 was in March 1997 when it passed within 0.85 AU of our planet, brightening to an unimpressive 10th magnitude. That's too faint to be seen with the naked eye, but bright enough for modest amateur telescopes. So, why visit an obscure, hard-to-see object like Wild-2, when there are so many more notorious comets to choose from? There are two important reasons. #1 It's fresh. Before its near miss with Jupiter in 1974 comet Wild-2 was well-preserved in the frigid outer solar system. With its new orbit, Wild-2 now comes much closer to the sun. When a comet passes close enough to the sun, some of its material is boiled off into interplanetary space. After about a thousand trips past the sun, it loses most of its volatile materials and no longer generates a coma or tail. Since Wild-2 has passed the sun only a few times, it still has most of its dust and gases--it is "pristine." By the time Stardust encounters the comet, Wild-2 will have made only five trips around the sun. By contrast, Comet Halley has passed the sun more than 100 times. #2 It's in the right place at the right time. Wild-2 presents a unique opportunity--it is in the right place at the right time. Scientists have found a flight path that allows the spacecraft to fly by the comet at a relatively low speed, only 13,600 mph. Because of this "low velocity" flyby, comet dust can be captured by collectors on the spacecraft, rather than blowing right through the collectors and out the back side! This comet dust can then be brought back to the Earth to be analyzed. Catching comet fluff When Stardust catches up with comet Wild-2 in January 2004, both the comet and the spacecraft will be beyond the orbit of Mars. Although they will be far from the sun, solar heating will still be sufficient to cause particles to bubble off the surface of the comet's nucleus. The spacecraft will pass within 100 km of Wild- 2. Cometary debris will hit the dust catcher at up to six times the speed of a bullet fired from a high-powered rifle. A unique substance called aerogel is the medium that will be used to catch and preserve the high-speed dust samples. Aerogel is the lightest known solid, and is considered the best substance available for capturing fragile particles from a comet without damaging them. When a high-velocity dust particle hits the aerogel, it buries itself in the material, creating a carrot- shaped track up to 200 times its own length. Since aerogel is translucent scientists can use these tracks to find the tiny particles. The track is largest at the point of entry, and the particle can be collected intact at the point of the cone. After the flyby is done, Stardust will return to Earth. In 2006 the craft's aerogel sample collectors will descend by parachute toward the U.S. Air Force Test and Training range in Utah, about 100 miles southwest of Salt Lake City in the desert. By the time the Stardust mission is over, comet Wild-2--dim, obscure, and little- known--will take its rightful place in the pantheon of historic comets. [More information on this topic can be obtained at http://science.nasa.gov/newhome/headlines/ast04feb99_1.htm] ------------------------------------------------------------------ AEROGEL RIDES AGAIN: LAUNCH OF STARDUST IS LATEST ADVENTURE FOR "FROZEN SMOKE" By Leslie Mullen From NASA Space Science News 5 February 1999 Everything in the universe, from planets to the particles of your skin, is composed of stardust. But even though stardust is the clay from which all things are formed, actually going into space to capture a pure sample is not an easy task. Yet NASA plans to do just that, using a lightweight insulating material called aerogel. Composed of over 95 percent air, aerogel is the lightest man-made material on earth. And although aerogel will be used in the depths of space to conduct research in astrophysics, it has hundreds of down-to-earth applications, as well. To catch a falling star This Saturday, NASA will launch StarDust, a spacecraft designed to sample and return material from the comet Wild-2. The comet travels a path from just outside Jupiter's orbit to just inside the orbit of Mars. StarDust will sweep through the comet's coma, the ball of gas surrounding the nucleus of the comet, at 136,000 miles per hour. NASA will use an aerogel "catcher's mitt" designed by Dr. Peter Tsou and his colleagues at the Jet Propulsion Laboratory in Pasadena, CA. Rather than catch fly balls, this "mitt" will catch particles coming off the comet. After a 7-year journey, StarDust will return to Earth, dropping its newly obtained cargo onto the Utah desert. Because the comet originally came from the Oort cloud, which extends beyond the orbit of Pluto, the StarDust mission will bring back matter from the deepest recesses of our solar system. Passing through cometary debris, however, can be more dangerous than standing in front of a machine-gun. The particles coming off the comet will probably be smaller than grains of sand, but they will be hitting the aerogel at an extremely high velocity. This impact is so powerful that, with any substance other than aerogel, the particles would either vaporize upon impact or become so distorted that scientists couldn't study them. "I like to call this NASA's version of collecting bugs on the windshield," says Dr. David Noever, an aerogel researcher at NASA's Marshall Space Flight Center. "In actuality, aerogel is low enough density to collect the "bugs" without destroying them, even though the satellite will be traveling through the comet debris at 20 times the speed of a bullet. That's a soft touch." When the particles hit the aerogel, they will drill through the material, gradually slowing down, creating furrows that scientists will use to track the paths of the particles. Orange jello, lemon jello, and aero jello? Aerogel is the result of a friendly wager between Dr. Steven Kistler and Dr. Charles Learned, two Stanford University scientists. They competed to see if one of them could replace the liquid inside a jelly jar with gas without causing any shrinkage. Kistler won the bet, and published his findings in a 1931 edition of the journal Nature. But the potential of aerogel didn't come to light until the 1960s and 70s, when many in the aerospace industry were trying to develop an extremely lightweight, heat-resistant material to put on airplanes and spacecraft. To illustrate the impossibility of ever developing such a material, some in the aerospace industry dubbed it "unobtainium." Modern silica aerogel starts as a liquid (mainly water, alcohol and silica), and then gels into something that looks like Jello. Just as Kistler replaced the liquid in jelly with gas without causing the jelly to shrink, the trick to making areogel is to dry the "aero-Jello" without collapsing it into a dense slab. Exchanging the alcohol with liquid carbon dioxide, and then by removing the carbon dioxide at high pressure can accomplish this. "The whole process is not that different from how coffee is decaffeinated," comments Noever. The end result is "frozen smoke," one of the lightest solid materials known. Researchers are currently developing techniques to dry aerogel under normal atmospheric pressure. Although aerogel looks like it could float away, it has very high compression strength for its mass. "But aerogel is not really so much of interest as a structural material," says Noever. "The real clincher is its incredible insulating effects on any kind of energy transfer: thermal, electrical or acoustic. Aerogel can damp out almost any kind of energy." That's the primary reason aerogel was used as insulation on the Sojourner Mars rover in 1997. As night fell on Mars, the temperature dropped down to -67°C (-88°F). Although the temperature outside was colder than Antarctica in winter, it remained a balmy 21°C (70°F) inside the Rover, where sensitive electronics were protected from the hard freeze. The Rover performed spectacularly, gathering information on the surface of Mars for almost three months following the Pathfinder's landing on July 4. A toast to jelly Aerogel's superior insulation can be used down here on Earth, as well. Currently, a large portion of a home's heating bill literally goes out the window. A single one-inch thick windowpane of silica aerogel is equivalent to the insulation provided by 20 windowpanes of glass (R-20 insulation factor). Aerogel is such a good insulator that a house with aerogel windows could be kept warm and toasty by using only a fraction of the energy currently needed. Aerogel windows would help people save on their home heating bills, and subsequently would reduce the worldwide production of carbon dioxide and other greenhouse gases. So why aren't we currently using aerogel windows? First, because it is expensive to produce. Also, aerogel is not perfectly transparent. Aerogel's slightly bluish cast presently makes it only practical for use in skylights or bathroom windows. According to Noever, "The Holy Grail of aerogel applications is transparent, superinsulating household windows." The problem lies in the size of the material's pores. Most of the pores in aerogel are too small to scatter visible light, but once in a while a few of the pores are larger. The larger pores scatter light as it passes through aerogel, and this creates the hazy appearance. It is thought that the elimination of these larger pores would result in an aerogel of better optical quality. NASA is developing techniques to produce a clearer aerogel. There is evidence that the pore irregularities are diminished when the substance is manufactured in the microgravity environment of space. Experiments on suborbital rockets have shown that producing aerogel in space can reduce the number of large pores that form. "But the rocket only offered seven minutes of reduced gravity and results are not yet conclusive," says Dr. Laurent Sibille of the Universities Space Research Association, working at NASA/Marshall. "That is why we are repeating these experiments on the Space Shuttle." Aerogel experiments were conducted on the recent STS-95 mission with Senator John Glenn, and are planned for the upcoming STS-93 mission, which will also launch the Chandra X-Ray Observatory. "The goal of our research is to establish the role of gravity in the manufacturing of materials and suggest Earth-based techniques to modulate or counter these effects," states Sibille. By finding out how gravity affects the production of aerogel, researchers can develop better ways to produce it down here on Earth. As progress continues, we can look forward to a future where the use of clear aerogel insulation will better our chances that neither hazy windows nor atmospheric pollution will cloud our view of the stars. [More information on this subject can be obtained at http://science.nasa.gov/newhome/headlines/msad05feb99_1.htm] ------------------------------------------------------------------ STARDUST MISSION STATUS JPL release 7 February 1999 NASA's Stardust spacecraft successfully shot into a clear blue sky atop a Delta II rocket from Florida's Cape Canaveral Air Station at 4:04:15 PM EST (1:04:15 PM PST) today to become the first U.S. mission destined for a comet, and the first-ever spacecraft sent to bring a sample of a comet sample back to Earth. The Stardust team reported that the spacecraft was in excellent health and that its power and temperature levels are normal. The spacecraft is in communication with NASA's Deep Space Network, and is controlled through the mission operations area at Lockheed Martin Astronautics, Denver, Colo., and monitored at NASA's Jet Propulsion Laboratory, Pasadena, Calif., where the mission is managed. Sixty-six seconds after liftoff, the four solid rocket motors on the Delta were discarded and the first stage continued to burn until it shut down and fell away about 4 minutes, 30 seconds into the mission. A few seconds later, the Delta's second stage ignited and burned for about 5 minutes, cutting off at 9 minutes, 55 seconds into the mission. Almost immediately after the second- stage ignition, the fairing or nose cone enclosure around the Stardust spacecraft was jettisoned. After coasting for about 11 minutes, the second-stage engine restarted and burned for about 2 minutes. The third stage separated from the second stage 24 minutes, 27 seconds into the mission; the Star 37 third stage ignited 25 minutes, 4 seconds into the mission, burning for about 2 minutes. At 27 minutes, 19 seconds into the mission--or 4:31:34 PM EST--the Stardust spacecraft separated from the Delta's third stage, stopping its spinning by firing onboard thrusters. About 4 minutes after separation, Stardust's solar arrays began to unfold and pointed toward the Sun. The NASA Deep Space Network complex in Canberra, Australia, successfully acquired the spacecraft's signal 51 minutes after launch at 4:55 PM EST. Stardust is on a flight path that will deliver it to Comet Wild-2 (pronounced "Vilt-2" on January 2, 2004. The spacecraft will gather particles flying off the nucleus of the comet. In addition, Stardust will attempt to gather samples from a stream of interstellar dust that flows through the solar system. Captured in a glass foam called aerogel, the comet and interstellar dust samples will be enclosed in a clamshell-like capsule that will be dropped off for reentry into Earth's atmosphere in January 2006. Equipped with parachutes, the capsule will float to a pre-selected spot in the Utah desert, where it will be retrieved and its contents delivered to scientists for detailed analysis. ------------------------------------------------------------------ "A UNIVERSE OF LIFE?" ASTROBIOLOGY ART By David A. Hardy The UK magazine, Astronomy Now, is producing an astrobiology issue currently planned for June 1998. This cover art (a PhotoShop montage) [shown in the PDF version] includes: our planet Earth-- the only world known to possess life (though whether intelligent is sometimes debatable); a nebula, of the type known as a "stellar nursery"; the planet Mars; asteroids; comets; and an amino acid molecule. David A. Hardy illustrated his first book, for Patrick Moore, in 1954 at the age of 18. He is the first non-American President of the International Association of Astronomical Artists (IAAA), which has a web site at http://www.iaaa.org. David's own site (which, apart from many varied examples of his work, contains links to other artists and astronomical/space sites) is at http://www.hardyart.demon.co.uk ------------------------------------------------------------------ SPACELAB ACCOMPLISHMENTS FORUM National Academy of Sciences (USA) release 4 February 1999 NASA's Office of Life and Microgravity Sciences and Applications (OLMSA) announces a Spacelab Accomplishments Forum to be held at the National Academy of Sciences, 2100 C Street NW (off Constitution Avenue), Washington, DC on March 10 and 11, 1999. This forum will recognize the history and achievements of the Spacelab series of Shuttle missions from 1981 to 1998 and their role in advancing a broad range of space-based research objectives. In addition to substantial space science and earth science research efforts, Spacelab-based life and microgravity research resulted in over 1,000 refereed articles and over 750 investigations. The Spacelab forum will also celebrate Spacelab's role in the evolution of space-based research towards a permanent presence in space. The forum will begin March 10 with registration from 7:30 am. The opening address will take place at 9:00 am. The forum will conclude ~ 4:00 PM March 11. There will be a reception at the National Academy of Sciences the evening of March 10. Forum topics will include: * Building and Operating Spacelab * Earth Observations * Space Science * Life Science * Microgravity Science * International Research * Commercial Research Hotels in close proximity to the forum are as follows--attendees to make own arrangements: * Holiday Inn Capitol, 550 C Street SW, refer to Spacelab forum, phone: 202-479-4000 * State Plaza Hotel, 2117 E Street NW, refer to group # 4609, phone: 800-424-2859 Reservations must be made by February 27 to confirm group rate. The registration fee for the forum is $25, which includes a reception the evening of March 10 in the Great Hall of the National Academy of Sciences. Please register by close of business Friday, February 26, 1999. Registrations will be accepted after that date, but you are highly encouraged to register in advance. Registration information is provided below. For more information regarding the forum, please refer to the Spacelab web site at http://www.hq.nasa.gov/office/olmsa. You can also contact Mr. John Emond at 202-358-1686 or e-mail at john.emond@hq.nasa.gov. Registration can be done by mail or phone. To register by mail, please include the following information. NAME: ADDRESS: ORGANIZATION: Phone/e-mail: If paying by check, registration fee of $25 should be made payable to WESTOVER CONSULTANTS, INC. Payment can also be made by credit card. Include name as it appears on the card, card number and expiration date. Send information to Antoine Holley, Westover Consultants, Inc., 7833 Walker Drive, Greenbelt, MD 20770. If registering by phone, please contact Mr. Holley at 301-345- 3211. Mr. Holley can also be contacted through email at aholley@westover-gb.com ------------------------------------------------------------------ End Marsbugs Vol. 6, No. 3