MARSBUGS: The Electronic Astrobiology Newsletter Volume 6, Number 42, 20 December 1999. Editors: Dr. David J. Thomas, Biology and Chemistry Division, Lyon College, Batesville, AR 72503-2317, USA. Dthomas@lyon.edu Dr. Julian A. Hiscox, School of Animal and Microbial Sciences, University of Reading, Reading, RG6 6AJ, United Kingdom. J.A.Hiscox@reading.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 from the official Marsbugs web page at http://www.lyon.edu/webdata/users/dthomas/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 from 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) ASTROBIOLOGY--A NEW SCIENCE FOR THE NEW MILLENNIUM British National Space Centre release 2) SCIENCE MINISTER ANNOUNCES FUNDING FOR SMALL SATELLITES, MICROGRAVITY, ASTROBIOLOGY AND LAUNCHERS British National Space Centre release 3) MEET CONAN THE BACTERIUM-- HUMBLE MICROBE COULD BECOME "THE ACCIDENTAL (SPACE) TOURIST" By Dave Dooling 4) BALLOON FLIGHT WILL HELP SCIENTISTS UNDERSTAND HOW TO SHIELD MARS CREWS By Dave Dooling ---------------------------------------------------------------- ASTROBIOLOGY--A NEW SCIENCE FOR THE NEW MILLENNIUM British National Space Centre release 13 December 1999 The search in the UK for life in the Universe is on. Astrobiology--a new science to search for life across the universe--is launched in Britain today and the excellence of UK scientists puts us in a strong world position. A panel of experts in the field has spent the last year investigating work currently underway in the UK. Today it has presented its findings to the British National Space Centre, saying Astrobiology is poised to take the step from a number of separate disciplines to being an integrated science. Key findings include: * Astrobiology is a science in which the UK already has significant expertise across the board. * There is great potential for the UK to develop its expertise further * Collaboration between the different strands will improve the science * Disciplines and organizations need to join up to meet the potential of astrobiology * A UK Astrobiology Panel should be set up to focus scientific endeavors. Panel chair Dr. Don Cowan said, "This is a really exciting time in astrobiology. In our investigations we found many British scientists who were astrobiologists without knowing it; biologists were studying how life survives in the harsh environment of Antarctica, astronomers were developing new missions to find new planets, chemists were developing new techniques to identify biochemical markers, geologists were studying the way life transforms the properties of our planet. Brought together they make a powerful force in astrobiology which will enable us to find out still more about where we come from and what other life might exist or have existed in the universe. I firmly believe we have the potential to find another evolutionary experiment like the one on earth." ---------------------------------------------------------------- SCIENCE MINISTER ANNOUNCES FUNDING FOR SMALL SATELLITES, MICROGRAVITY, ASTROBIOLOGY AND LAUNCHERS British National Space Centre release 13 December 1999 A £15M investment in the UK small satellite sector was announced today by Science Minister Lord Sainsbury. The funding is intended to help transfer the UK's world-leading capability in small satellites from the academic into the scientific and commercial markets. Lord Sainsbury said, "I hope this initiative will stimulate industry to invest in small satellite missions, particularly for satellite communications, the largest and most rapidly expanding market for space products. He also announced that research into microgravity and astrobiology is to get a £1.4M boost from UK Government. Welcoming a report from a panel of experts, seeking to establish astrobiology as a new science for the millennium, Lord Sainsbury announced that the UK is to invest in the research opportunities offered by the European Space Agency's EMIR-2 program. He said, "EMIR-2 will offer our scientists experimental and research opportunities in astrobiology and microgravity. UK teams will be able to lead challenging research designed to improve our development and preparation of important new drugs, smart fluids and high performance sensors. Their initial results will allow us to evaluate the relevance of the International Space Station to achieving UK priorities. We will accelerate our involvement in a new science that will exploit our lead role in the Mars lander, Beagle 2." Lord Sainsbury went on to say that the UK would not enter ESA's Future Launch Technology Programme (FLTP), preferring instead to press ahead with more immediate national measures in partnership with UK firms that are already having success exporting to European and International builders of launch vehicles. He confirmed that the National Space Technology program would be extended to provide specific opportunities to support innovative ideas at the equipment and component level, rather than at the vehicle level. "My decision supports the priorities set out in the UK Space Strategy published in August", the Minister said. "The Strategy confirmed major investments in space science, remote sensing, satellite communications, technology and navigation. We gave relatively low priority to launch vehicles. After careful consideration, I have decided that the high costs of FLTP in the longer term would have an unacceptable effect on other, higher priorities. To enter Phase 1 and then to withdraw later on would have confused our partners in ESA and those firms seeking a consistent approach from Government in the high priority sectors." ---------------------------------------------------------------- MEET CONAN THE BACTERIUM-- HUMBLE MICROBE COULD BECOME "THE ACCIDENTAL (SPACE) TOURIST" By Dave Dooling From NASA Space Science News 14 December 1999 Like a muscle-bound movie hero, it withstands attacks from acid baths, high and low temperatures, and even radiation doses. Then, in a science fiction sequel, it dispenses lifesaving medications and reshapes a planet for new settlers. And in true Hollywood fashion, the star of this epic had humble beginnings, living in cow patties and elephant dung, and coming to the attention of scientists when it refused to die in food sterilization tests. You need a microscope to see this miniature future hero listed as Deinococcus radiodurans and known to its fans as Conan the Bacterium. "Deinococcus radiodurans beats most of the constraints for survival of life on Mars--radiation, cold, vacuum, dormancy, oxidative damage, and other factors," said Dr. Robert Richmond, a research biologist at NASA's Marshall Space Flight Center. With other scientists, he is investigating the possible utility of extremophiles to serve human exploration to inhospitable locations. Humble origins Richmond and his colleagues see D. radiodurans as playing the part of possible martian microbes in simulations to help direct the search for life on Mars. Next, it could be genetically altered to produce medicines for astronauts in the short-term, rather than hauling an entire pharmacy along on the trip, and restructuring Mars for human habitation in the long-term. With R. Sridhar of Howard University Medical Center in Washington, DC and Dr. Michael J. Daly of the Uniformed Services University of the Health Services in Bethesda, MD, Richmond presented a paper at the 1999 SPIE Conference in Denver on the "Physico-Chemical Survival Pattern for the Radiophile D. radiodurans: A Polyextremophile Model for Life on Mars." Daly and his co- workers, in a recent article in Science magazine, announced that they had completed sequencing the genome of D. radiodurans. This opens the way for exploitation of its ability to integrate external genes selected to express products useful to explorers on Mars or other such places. "Radiodurans' beginnings are thought to be from early Earth," Richmond said, and paralleled a time when the environment may have also approximated that existing on Mars for a few hundred million years. Given the presumed sharing of debris generated from meteorite impacts amongst the early planets, origins of D. radiodurans might even be accidentally common between Mars and Earth. "By nature, it is selected to survive radiation damage very well," D. radiodurans can withstand without loss of viability a dosage that is 3,000 times greater than what would kill a human. "The fact that you can genetically engineer these things is the key to the utility of this bug." It's heady stuff for a primitive organism, but D. radiodurans has a feature that is considered all-important in aerospace-- redundancy. Its genetic code repeats itself many times so that damage in one area can be recognized and quickly repaired. Coupled with its range of other survival characteristics, D. radiodurans has been dubbed a polyextremophile by Richmond, Sridhar, and Daly. Extremophiles have been known to scientists for decades but often were regarded a laboratory oddity. The discovery of what appears to be nanobacteria (or nanobes, smaller than microbes) in a meteorite from Mars (Alan Hills 84001, or ALH84001) catapulted extremophiles into the spotlight as a model for possible lifeforms on Mars. The debate over whether the ALH84001 forms ever were nanobes (or just non-living imitations) led to recent discoveries of probable nanobes living in such odd places as human kidney stones and in limestone 4 kilometers under the surface of the Earth. "We have a new door opening on the possibilities of lifeforms," Richmond said, "not just new species but whole new life forms that could connect to the origins of life on Earth and could be a common link to the possible beginnings of life on Mars." Most extremophiles have optimized themselves for one or two extreme conditions and settled into wonderful ecological niches like the hot springs of Yosemite [Yellowstone?]. Radiodurans has been dubbed a polyextremophile because it can endure many extremes, including the most dangerous space hazard, radiation. "Radiation-induced DNA damage is an oxidizing type of damage," Richmond said. It happens when radiation energizes an atom enough to break a chemical bond and then act like an atom of oxygen and bind with another atom. Such free radicals have been implicated in a range of cancers and genetic mutations. D. radiodurans, though, is hypothesized by Daly to resist such damage by virtue of repair specialized to utilize its redundant strands of DNA. This also means that it should resist damage from the chemistry of Mars, which chemical experiments done by the labs aboard the two Viking landers indicate may be highly oxidative. D. radiodurans was discovered in the 1950s. Scientists experimenting with radiation to kill bacteria and preserve food for long periods found that something kept growing back after treatment. It remained a laboratory oddity for several years until the arrival of genetic engineering, the science of altering an organism's basic biological code, sometimes by splicing into it portions of another organism's code. Daly's group is inserting specialized genes to help in eliminating dangerous chemicals from waste sites. An established example of the value of such genetic engineering is found with E. coli, the bacteria found in the human gut, that has been engineered to produce large quantities of human insulin, which once had to be refined from human cadavers. "Daly has been active in developing D. radiodurans as a special model for bioremediation to clean radioactive supersites left over from the Cold War," Richmond explained. Some of those sites contain radioactive materials that are not easily removed by other microbes. While some other bacteria are being genetically engineered to thrive in toxic conditions while converting hazardous waste into reusable effluent, none can resist radiation the way D. radiodurans can. Already, Daly and his colleagues have devised D. radiodurans variants that can clean up mercury, a deadly heavy metal, and toluene, a dangerous solvent. The U.S. Department of Energy sponsored this work. The capability to insert genes also makes D. radiodurans a candidate for Mars pharmacists and to become "the plow that broke the plains" on Mars. But first, it may help search for life on Mars as a stand-in for Martian microbes in simulated Mars environments. The changing face of Mars Mars has gone through radical changes in our perception as a haven for life. After Sir Percival Lowell and a number of science fiction stories popularized Mars as a dying planet, U.S. space probes in the 1960s and 1970s rewrote the book to show Mars as long dead, perhaps never alive. Then came the discoveries hidden inside ALH84001. Soon thereafter, images and data from the Mars Global Surveyor, Mars Pathfinder, and Sojourner Rover spacecraft showed Mars indeed has significant quantities of water, and once had running water. While Mars has become more tantalizing, it is far from Eden. So the question is, if life was there, or is there, what are the best places to find it? Spacecraft surveying the planet to determine where water might survive beneath the surface, or where it once may have existed, are addressing this. Even within those regions, you have to figure out which spots are best since a lander will have limited time and resources compared to the open wilds of Mars. One approach is to culture D. radiodurans in Mars simulations on Earth. "We are restricted in the search for life right now to Earth- based microbes," Richmond explained. "We have to ask, What are the restraints on life that those microbes will have to surmount in order to plausibly exist on other planets?" Extremophile habitats on Earth cover a range of conditions: temperatures near boiling or below freezing; a nearly total lack of water, or water that ranges from alkaline to acidic or salty; non-carbon foods; and a lack of oxygen. One of the tricks that less durable life forms use to survive such tough times is to hibernate as spores. Such was the case with Streptococcus mitus discovered inside a TV camera recovered by the Apollo 12 crew from the Surveyor 3 spacecraft on the Moon. To everyone's amazement, the bacteria were viable and quickly revived in a culture on Earth. But that was after just a three-year stay. "The restraints become temporal, too," Richmond explained. "Dormancy has to carry on for thousands or millions of years" if a life form is to last until conditions on Mars become hospitable for growth, somewhat like the floral seeds waiting in the desert for the rare fall of rain. And that's where radiation resistance comes in handy. While radiation issues are usually associated with nuclear power or exposure to the space environment, it is not commonly recognized as being inescapable. We are exposed through our entire lives to potassium-40, radon, carbon-14 and other radioactive sources. Living in the mountains or flying also increases exposure slightly. Surviving a long winter's nap But the total dosage from these is small during our life spans, so the impact normally is insignificant. However, for an organism in hibernation for a million years or so, the cumulative exposure can be like sitting inside a reactor for several minutes. That's why crawling under a rock to escape solar ultraviolet light on Mars is not a perfect strategy. The rock itself emits trace quantities of radiation over time. "Within responsible imagination, no long-dormant life form can be expected on the surface of Mars due to combined build up of damage over time caused by both incoming space radiation plus the background radiation," Richmond said. The best hope is that life got started some billions of years ago when conditions were more hospitable, and that a few microbes adapted to extreme conditions or learned how to hibernate below the surface. "But if they wake up too late, they run into the ultimate restriction, too much radiation damage that has accumulated if it's not repaired," Richmond said. "At that point, the population is dead." So even if something like D. radiodurans evolved on early Mars, it's possible that winter has lasted too long for any survivors to reawaken in the artificial spring of a Petri dish. Even so, D. radiodurans may yet travel to Mars as a Pharmacist's Mate First Class. "Because of genetic engineering, you might do a lot with this bug to enhance the survivability of man in extraterrestrial environments," Richmond said. Altering the human genome to take on survival characteristics like D. radiodurans is far too complex a task (the human genome hasn't been completely sequenced, nor all of its 100,000+ genes decoded). But D. radiodurans could be altered to serve man. "The interesting things about drugs we use is that about two- thirds are natural products or derived from natural products," Richmond said. "Anything that is a natural product ultimately comes down to a gene and can be genetically managed, in theory." Living off the land--after you reshape it Richmond, Sridhar, and Daly suggest that D. radiodurans can be genetically manipulated to produce various drugs that humans might need while exploring Mars, then put on ice during the mission. If someone became ill, treatment would start with drugs in from a small supply kept on hand, while the appropriate bugs were awakened to produce a regular supply. (This need was presaged this summer by the need to airdrop tamoxifen, a breast cancer chemotherapy agent, at the South Pole for a medical doctor who had diagnosed herself with breast cancer.) With such an approach, the issues of shelf life for drugs could also be circumvented. This would also reduce the weight that a spaceship would have to haul to Mars and back. Radiodurans next might be drafted as a Seabee (Navy Construction Battalion, or C.B.) as humans set up camps and even homesteads on Mars. Other engineered versions of D. radiodurans could recycle wastes--producing clean water and oxygen--and perhaps even food supplements. "Its own food stock might even be Mars," Richmond suggested, giving new meaning to "living off the land." Again, the bug's genetic design might help ensure a renewable grocery store for explorers. The ultimate step would be the popular notion of terraforming, reshaping the environment of Mars to make it more hospitable to humans. Terraforming was first performed by ancient life forms that converted Earth's environment from a carbon dioxide atmosphere and calcium-rich seas to the more hospitable world we have today. Because these early life forms spoiled their home, they now survive in what we consider to be extreme environments. Mars, too, is considered to be an extreme environment. But with a little help from D. radiodurans, it may be made more accessible and, eventually, attractive. After all, a Seabee's motto is, "The difficult we do now. The impossible takes a little longer." [For more information on this story see http://science.nasa.gov/newhome/headlines/ast14dec99_1.htm] ---------------------------------------------------------------- BALLOON FLIGHT WILL HELP SCIENTISTS UNDERSTAND HOW TO SHIELD MARS CREWS By Dave Dooling From NASA Space Science News 17 December 1999 If it rains, you put up an umbrella. If you expect a meteor shower, you build the spacecraft with shielding that blunts the blow when particles arrive. But what do you do for radiation? After almost four decades of human space flight, we still are grappling with the challenge of protecting space crews from cosmic rays and other radiation hazards. Part of the problem is in understanding fully the composition and energies of cosmic rays. In the next week or two, two small instruments will piggyback on a ride around the South Pole so they can help scientists develop a better understanding of cosmic radiation that might endanger astronauts on deep space missions. "They're going to record the dose from different cosmic ray energies and particles," said Dr. Leonard Howell, a member of the cosmic ray group at NASA's Marshall Space Flight Center. "The dosimeters will be mounted on a balloon gondola for a 10- day exposure to cosmic rays." NASA has recently developed the capability to fly high-altitude research balloons on paths that circle either the North or South Pole for about 10 days exposure. These balloon-borne platforms provide frequent and relatively low-cost opportunities to perform experiments utilizing the full cosmic ray spectrum. The balloon, carrying several radiation-related experiments, will be launched from the U.S. research station at McMurdo, Antarctica, because the polar regions are where the Earth's atmosphere is directly exposed to the space environment, and thus to cosmic rays. At 125,000 feet altitude (38 km), the balloon will continues to be above most of the Earth's atmosphere. Despite a similar name, cosmic rays are not electromagnetic radiation like X-rays and gamma rays. Cosmic rays are actually atoms stripped of their electrons and accelerated by supernova explosions and other violent events in the universe. By far the most dangerous components of cosmic rays are called HZE, meaning high mass (HZ) and high energy (HE). These are fast atomic nuclei zipping along close to the speed of light. If they run into denser matter--like the wall of a spaceship or the flesh of a human body--the particle will shatter itself and its target, and create a cascade of secondary particles. It's like a musket ball plowing into a wall, shattering, and leaving a trail of debris. Secondary particles also present a hazard. Because the particles are electrically charged, all but the most energetic are deflected by the Earth's magnetic field, and what does get through is absorbed by the upper atmosphere. But around the magnetic poles, the magnetic field lines are vertical, and the full spectrum of particles can barrel straight in from space. Howell explained that the experiments being launched this month are a modest start for a larger effort to acquire the knowledge that will let scientists devise better shielding and strategies to protect Mars crews. The experiment comprises two packages, each housing three identical sets of dosimeters--film emulsions, plastic sheets, and thermoluminescent detectors--each covering about 2 square inches. The film emulsions, made at NASA/Marshall, will be developed after the flight to reveal cosmic ray tracks. The plastic sheets are CR-39 Plexiglas which will be chemically etched to reveal tiny holes bored by cosmic rays. The thermoluminescent detectors (TLDs) will record the total doses. When heated, TLDs radiate visible light that is proportional to the absorbed dose of ionizing radiation. Thermistors in the packages will keep a record of the temperature ranges during the flight. (A fourth set will stay on the ground as a control unit.) "The three dosimeters in each tube are positioned behind different amounts of shielding in order to understand more fully the effects of the shielding," Christl said. "Two different materials were chosen as shielding at this stage of the investigation, aluminum and polyethylene." The housings for the dosimeters is decidedly low-tech, as balloon experiments often are: a 4-inch-diameter length of PVC tubing from a hardware store, with end caps screwed in place and made air tight by Teflon tape. One end of each tube has a bicycle-like valve sticking out so the tube can be pressurized to 1 atmosphere just before flight. Then the tubes are placed inside shielding sleeves--one made ofaluminum, to stand in for the spacecraft wall, and the other made of polyethylene, a type of plastic--and mounted on the sides of the balloon gondola. "These are two shielding material types that might be used in a space mission," said Dr. Mark Christl, a cosmic-ray scientist at NASA/Marshall. "The main purpose of this experiment is to characterize the environment and get some data for comparison with computer simulations." Aluminum was selected because its properties are well known, "but we don't want to give the impression that we have chosen it over anything else" as a spacecraft structure. The aluminum shielding on this experiment is 7.6 cm (3 inches) thick. "A major constraint in the design of space transit vehicles and surface habitats for a manned Mars mission," said Dr. Tom Parnell, the former director of high-energy astrophysics at NASA/Marshall, "is the thickness of material required to protect flight crews from the hazards of radiation resulting from the galactic cosmic rays (GCR) and solar flare particles." Parnell explained that studies are underway to define the best shielding approaches and the accuracy with which the hazards can be predicted. The fastest approach to test the calculations and the effectiveness of shielding is to use the cosmic ray flux itself. "Some experiments have already been carried out on spacecraft," Parnell continued. "However, the full cosmic ray spectrum is only available near the Earth's magnetic poles or in deep space because of the shielding effects of the Earth's magnetic field." The launch date for the experiment will depend on weather conditions in the Antarctic. The dosimeter packages should be returned to NASA/Marshall sometime in January 2000 for analysis. NASA's Human Exploration and Development of Space (HEDS) enterprise supports the project. Balloon launches are managed by the Wallops Flight Facility of NASA's Goddard Space Flight Center. [For more information on this story see http://science.nasa.gov/newhome/headlines/ast17dec99_1.htm] ---------------------------------------------------------------- End Marsbugs Vol. 6, No. 42