MARSBUGS: The Electronic Astrobiology Newsletter Volume 6, Number 11, 4 May 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 ------------------------------------------------------------------ MAGNETIC STRIPES PRESERVE RECORD OF ANCIENT MARS JPL release NASA's Mars Global Surveyor has discovered surprising evidence of past movement of the Martian crust, further evidence that ancient Mars was a more dynamic, Earth-like planet than it is today. Scientists using the spacecraft's magnetometer have discovered banded patterns of magnetic fields on the Martian surface. The adjacent magnetic bands point in opposite directions, giving these invisible stripes a striking similarity to patterns seen in the crust of Earth's sea floors. On the Earth, the sea floor spreads apart slowly at mid-oceanic ridges as new crust flows up from Earth's hot interior. Meanwhile, the direction of Earth's magnetic field reverses occasionally, resulting in alternating stripes in the new crust that carry a fossil record of the past hundreds of million years of Earth's magnetic history, a finding that validated the once-controversial theory of plate tectonics. "The discovery of this pattern on Mars could revolutionize current thinking of the red planet's evolution," said Dr. Jack Connerney of NASA's Goddard Space Flight Center, Greenbelt, MD, an investigator on the Global Surveyor's magnetometer team. "If the bands on Mars are an imprint of crustal spreading, they are a relic of an early era of plate tectonics on Mars. However, unlike on Earth, the implied plate tectonic activity on Mars is most likely extinct." Alternate explanations for the banded structure may involve the fracturing and breakup of an ancient, uniformly magnetized crust due to volcanic activity or tectonic stresses from the rise and fall of neighboring terrain. "Imagine a thin coat of dried paint on a balloon, where the paint is the crust of Mars," explained Dr. Mario Acuņa of Goddard, principal investigator on the Global Surveyor magnetometer. "If we inflate the balloon further, cracks can develop in the paint, and the edges of the cracks will automatically have opposite polarities, because nature does not allow there to be a positive pole without a negative counterpart." Peer-reviewed research based on the observations will be published in the April 30 issue of the journal Science. The observations of the so-called magnetic stripes were made possible because of Mars Global Surveyor's special aerobraking orbit. This process of dipping into the upper atmosphere of Mars to gradually shape the probe's orbit into a circle was extended due to a problem with a solar panel on the spacecraft. The lowest point of each elliptically shaped orbit curved below the planet's ionosphere, allowing the magnetometer to obtain better-than- planned regional measurements of Mars. "At its nominal orbit more than 320 kilometers (200 miles) high, the instruments face too much magnetic interference, and they do not have the resolution to detect these features," Acuņa noted. "We began with misfortune, and ended up winning the lottery." The bands of magnetized crust apparently formed in the distant past when Mars had an active dynamo, or hot core of molten metal, which generated a global magnetic field. Mars was geologically active, with molten rock rising from below cooling at the surface and forming new crust. As the new crust solidified, the magnetic field that permeated the rock was "frozen" in the crust. Periodically, conditions in the dynamo changed and the global magnetic field reversed direction. The oppositely directed magnetic field was then frozen into newer crust. "Like a Martian tape recorder, the crust has preserved a fossil record of the magnetic field directions that prevailed at different times in the ancient past," Connerney said. When the planet's hot core cooled, the dynamo ceased and the global magnetic field of Mars vanished. However, a record of the magnetic field was preserved in the crust and detected by the Global Surveyor instrument. The mission's map of Martian magnetic regions may help solve another mystery--the origin of a striking difference in appearance between the smooth, sparsely cratered northern lowlands of Mars and the heavily cratered southern highlands. The map reveals that the northern regions are largely free of magnetism, indicating the northern crust formed after the dynamo died. "The dynamo likely died a few hundred million years after Mars' formation. One possibility is that later asteroid impacts followed by volcanic activity heated and shocked large areas of the northern crust, obliterating any local magnetic fields and smoothing the terrain," Acuņa said. "When the crust cooled, there was no longer a global magnetic field to become frozen in again." The map also identifies an area in the southern highlands as the oldest surviving unmodified crust on Mars. This area on Mars is where the magnetic stripes are most prominent. The bands are oriented approximately east-to-west and are about 160 kilometers (100 miles) wide and 965 kilometers (600 miles) long, although the longest band stretches more than 1,930 kilometers (1,200 miles). "The bands are wider than those on Earth, perhaps for a couple of reasons," Connerney said. "The Martian crust could have been generated at a greater rate, causing a given magnetic field to be imprinted over a wider area before it reversed direction. Second, the Martian magnetic field may have reversed direction less frequently, which would have given more time for any one field direction to imprint itself in the steadily moving crust, resulting in wider bands. "In order to call this pattern a crustal spreading center like that observed in the mid-oceanic ridges on Earth, we need to find a point of symmetry, where the pattern on one side matches the pattern on the other. We have not yet found evidence of this type of symmetry," Connerney added. Graphics of the magnetometer data, other supporting material and general information on the Global Surveyor mission may be found on the Internet at ftp://pao.gsfc.nasas.gov/newsmedia/MARS/MAGNETIC/ http://mpfwww.jpl.nasa.gov/mgs/index.html The Jet Propulsion Laboratory manages the Mars Global Surveyor mission for NASA's Office of Space Science, Washington, D.C. JPL's industrial partner is Lockheed Martin Astronautics, Denver, CO, which developed and operates the spacecraft. JPL is a division of the California Institute of Technology, Pasadena, CA. ------------------------------------------------------------------ MARS DATA HINT AT OLD HOT SPRINGS--POOLS MAY HAVE CRADLED MICROBES By John Fleck, Albuquerque Journal 2 May 1999 Mars may once have bubbled with hot springs, warm cozy pools where Martian microbes could have evolved, according to a team of New Mexico researchers. Using data from NASA's Mars Pathfinder spacecraft, the scientists found chemicals in the Martian soil similar to what's found around hot springs on Earth. Scientific backing has dwindled for a 1997 NASA claim that a meteorite from Mars contained evidence that microbes once lived on the planet. But the search for other possible evidence of life continues. The full story is at http://www.abqjournal.com/scitech/1sci05- 02.htm ------------------------------------------------------------------ NASA'S MARS ROVER TEST DRIVE RACKS UP MILES AND SMILES JPL release 29 April 1999 It is the ultimate test drive for the newest otherworldly vehicle. A few practice spins around an ancient lake bed in the Mojave desert this week with the next-generation Mars rover are helping NASA scientists and engineers learn more about driving the real thing on Mars. "It's pretty exciting out here. We want to rack up a lot of miles and see how far this rover can go," said Dr. Raymond Arvidson, a geologist from Washington University in St. Louis, MO, and mission director for the field tests. "We are doing an 'end-to-end' test, using systems similar to what we will use on Mars. These test drives will help ensure that we will have a successful Mars rover mission." Future robotic rovers on Mars will need to find the best rocks to bring back to Earth, samples that are likely to contain the evidence scientists need to prove that life once existed on the red planet. The rovers are being built and tested by NASA's Jet Propulsion Laboratory, Pasadena, CA. To find the best sample, scientists need a good retriever. This week they're testing the work horse, er dog, named FIDO--Field Integrated Design and Operations--that is helping them figure out how to use the kinds of instruments the next Mars rovers will need to fetch the most scientifically interesting rocks. FIDO is designed to test the advanced technology of the Athena flight rover and science payload that will be launched as part of NASA's Mars Sample Return missions in 2003 and 2005. "No place on Earth is like Mars, but our field site on an ancient lake bed in the Mojave Desert comes close. So far we've been able to use the rover's mini-corer to drill a rock sample and we've used the microscopic camera to look inside the hole," Arvidson said. "We're practicing looking for rocks that contain carbonate minerals. If we find those kinds of rocks on Mars it may tell us if the early planet had a carbon dioxide atmosphere." "We've had a fantastic week. In just a few days, we've shown that we can find good rocks, drill samples out of them, and take the samples back to a lander. That's a huge step forward in preparing to bring the first samples back from Mars," said Dr. Steven Squyres, principal investigator for the Athena rover payload from Cornell University, Ithaca, NY. "FIDO's advanced technology includes the ability to navigate over distances on its own and avoid natural obstacles without receiving directions from a controller," said Dr. Eric Baumgartner, a robotics engineer at JPL and mission engineer for the desert field tests. "The rover also uses a robot arm to manipulate science instruments and it has a new mini-corer or drill to extract and cache rock samples. There are also several camera systems onboard that allow the rover to collect science and navigation images by remote-control." FIDO is about the size of a coffee table and weighs as much as a St. Bernard, about 70 kilograms (150 pounds). It is approximately 85 centimeters (about 33 inches) wide, 105 centimeters (41 inches) long, and 55 centimeters (22 inches) high. The rover moves up to 300 meters an hour (less than a mile per hour) over smooth terrain, using its onboard stereo vision systems to detect and avoid obstacles as it travels "on-the-fly." During these tests, FIDO is powered by both solar panels that cover the top of the rover and by replaceable, rechargeable batteries. "FIDO is about six times the size of Mars Pathfinder's Sojourner and is far more capable of performing its job without frequent human help," Dr. Paul S. Schenker, who directs FIDO rover development at JPL as part of the NASA Exploration Technology Program. "FIDO navigates continuously using on-board computer vision and autonomous controls, and has similar capabilities for eye-to-hand coordination of its robotic science arm and mast. The rover has six wheels that are all independently steered and can drive forward or backward allowing FIDO to turn or back up with the use of its rear-mounted cameras." In addition to testing FIDO, the scientists and engineers are supporting students from four schools around the country in designing and carrying out their own mission with the rover. This is the first time students have been able to remotely operate a NASA/JPL rover. The students, from Los Angeles, Phoenix, Ithaca, NY, and St, Louis, (LAPIS), form an integrated mission team and are responsible for planning, conducting and archiving a two-day mission using FIDO. "It is important to excite young people about space exploration and discovery and these tests provide an excellent educational opportunity," Arvidson said. "We're including high school students in the FIDO tests as a pilot experiment in which the students gain a sense of participation in the field trials by planning their own mission segments and working with us to implement the rover's assignments." The FIDO rover development and the Mars Sample Return 2003/2005 missions are managed by NASA's Jet Propulsion Laboratory for NASA's Office of Space Science Washington, DC. JPL is a division of the California Institute of Technology, Pasadena, CA. More information about FIDO is available at http://wundow.wustl.edu/rover. ------------------------------------------------------------------ MARS GLOBAL SURVEYOR MISSION STATUS JPL release 30 April 1999 NASA's Mars Global Surveyor spacecraft returned to mapping operations Thursday with its high-gain telecommunications antenna in a fixed position. On May 6, when Mars and the Earth are at favorable angles from each other, the spacecraft will return to a normal mapping mission that will use the antenna in its steerable mode to return continuous data to Earth. The spacecraft is in good health and all the science instruments are turned on. The flight team has conducted all planned troubleshooting tests to analyze the antenna hinge that stopped moving. These tests have shown that there appears to be an obstruction that prevents the hinge from operating through its complete range of motion. Flight controllers say they can conduct normal mapping operations through February 2000 when the Mars-to-Earth geometry will again prevent the antenna, with its limited range of motion, from pointing continuously at Earth. The flight team is still performing additional reviews of the flight data to develop a plan of action if the obstruction has not been resolved and the spacecraft needs to use its antenna in a fixed position to complete the mapping mission. Mars Global Surveyor is managed by JPL for NASA's Office of Space Science, Washington, DC. JPL's industrial partner is Lockheed Martin Astronautics, Denver, CO, which developed and operates the spacecraft. JPL is a division of the California Institute of Technology. Further information about the mission is on the Internet at http://mars.jpl.nasa.gov/mgs/ ------------------------------------------------------------------ MARS SURVEYOR 98 MISSION STATUS JPL release 29 April 1999 Mars Climate Orbiter (MCO)/Mars Polar Lander (MPL) Both the MCO and MPL spacecraft continue to perform well in cruise. The flight team is gradually turning its focus from ongoing cruise operations to preparations for the arrival of the two spacecraft at Mars this fall. The attitude determination and control group is nearing completion of an extensive series of tests in the MCO ground-based simulator, in preparation for an in- flight test of the "all-stellar" mode. The in-flight checkout is being delayed by one week (from May 3-7 to May 10-14) for some additional testing to first be completed, in order to ensure a smooth flight test and transition into this new mode. Another significant test activity nearing completion is stress-testing of the Mars Orbit Insertion (MOI) software and command sequence. The test team reports that, thus far, all of the MOI stress tests run in the MCO simulator have been successful in dealing with a variety of simulated sensor failures and off-nominal conditions. For more information on the Mars Surveyor 98 missions, please visit our web site at http://mars.jpl.nasa.gov/msp98. ------------------------------------------------------------------ MARS SURVEYOR 2001 SEEKS EYE-CATCHING LOGO DESIGN JPL release 26 April 1999 Two years from now NASA's newest spacecraft will be launched to Mars, but right now it is still missing one crucial detail: a mission logo. That's where you come in. The Mars Surveyor 2001 mission is sponsoring a contest to pick its new logo to illustrate the orbiter, lander and rover that will be the next visitors to Mars. "The logos can be done individually for the orbiter, lander and rover or incorporate all three aspects into one design. They can be any shape and color, and may include the spacecraft, the planet Mars, and/or the surface of Mars," said Cathy Davis, Mars Exploration Program outreach coordinator at NASA's Jet Propulsion Laboratory, Pasadena, CA. "Anyone can enter. The designs must be eye- catching and should avoid small details that would be missed in a large format. Be creative!" The 2001 orbiter will be launched from California's Vandenberg Air Force Base--the first launch of a planetary spacecraft from the west coast of the United States. A few weeks later the lander and rover will launch together from Cape Canaveral, FL. The lander will touch down near the Martian equator, carrying a spare Mars Pathfinder rover, a robotic arm and several other science instruments, including three that will return data in support of eventual human exploration. Entries for the logo contest are due June 30, 1999. Winners will be announced August 2. Mail entries to: Mars Outreach, Mail Stop 264-380, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109. Entries may be emailed to catherine.l.davis@jpl.nasa.gov. Questions about the contest can be directed to Davis at (818) 354-6111. The winner(s) will be acknowledged with a picture and biographical information posted by JPL on the Mars Surveyor 2001's web site, and "will receive the prestige of seeing their creations on the spacecraft, products and documents," Davis said. JPL reserves the right to modify the winning designs to correct errors and/or to guarantee conformance with JPL graphics standards. Designs will be judged on style and content. Decisions of the judges are final. Designs become the property of JPL, and will not be returned. More information on the Mars Surveyor 2001 mission is available at JPL's Mars missions web site at http://mars.jpl.nasa.gov/. JPL manages the Mars Surveyor 2001 mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology. ------------------------------------------------------------------ GALILEO EUROPA MISSION STATUS REPORTS JPL releases 28 April 1999 NASA's Galileo spacecraft is once again beaming back to Earth pictures and other scientific information collected during its January 31 flyby of Jupiter's icy moon Europa. Data transmission from the spacecraft was on hold for three weeks while the Sun was positioned between Earth and Jupiter. During that time, the Sun interfered with Galileo's radio signal and made communications difficult. There was a bright side to this situation, however, because it enabled scientists to study the way the solar wind distorted Galileo's radio signal. This helped them learn more about that powerful wind, which consists of electrified particles emitted by the Sun. The solar wind has a very strong effect on Earth and all other objects in our solar system. Galileo will finish transmitting its latest batch of Europa data, which had been stored on the spacecraft's tape recorder, on April 30. This information includes observations that tell scientists more about the surface composition and texture of Jupiter's largest moon, Ganymede. Other observations help differentiate between possible crystalline forms of water ice on Europa. The shape of the crystals relates to the temperature at which they formed, and a certain form of ice would indicate that it solidified when liquid water spewed from a geyser and froze. This might be yet another hint of an ocean beneath Europa's icy crust. Galileo's flight team is preparing for a May 5 flyby of Jupiter's moon Callisto by updating software for the spacecraft's computer. The idea is to prepare the spacecraft for any false power reset signals, like those that occurred twice last year. The software would allow the spacecraft to recover by itself and continue with its pre-programmed schedule of activities. Engineers believe false reset signals are triggered when debris accumulates in the electrical connections between the spacecraft's spinning and non- spinning sides and causes an electrical short. The debris may come from wear and tear on the slip rings that connect the two sides. 2 May 1999 Galileo starts the ninth encounter of the Galileo Europa Mission today, and with it, also starts a series of four close flybys of Callisto. These Callisto flybys are also called the Perijove Reduction Campaign, and are designed to incrementally change the spacecraft's orbit to allow for a close flyby of the innermost Galilean satellite, Io. In addition to the trajectory-altering objective, these four orbits also present extensive science opportunities. These opportunities include monitoring volcanic activity on Io, exploration of the Io plasma torus, observations of Callisto, and observations of Jupiter's atmosphere and magnetosphere. During the Perijove Reduction Campaign, the spacecraft's Perijove distance, or closest distance to Jupiter for a given orbit, will be changed from its current distance at about the orbit of Europa (9 Jupiter radii, 643,000 kilometers, or 400,000 miles) to a distance that allows Galileo to fly within the orbit of Io (5.5 Jupiter radii, 393,000 kilometers, or 244,000 miles). With this reduction in the distance from Jupiter also comes an increase in the amount of radiation to which the spacecraft will be exposed. Flight team members will be closely monitoring spacecraft performance during the upcoming months to diagnose and mitigate any radiation effects the spacecraft might exhibit. This week's encounter spans the next six days, ending on Friday, May 7. During this time, the spacecraft will be approximately 880 million kilometers (548 million miles) from Earth, and it will take Galileo's radio signals 49 minutes to travel between the spacecraft and Earth. This orbit's close flyby of Callisto occurs on Wednesday, May 5, just prior to 7 am PDT [see note 1], at a distance of 1315 kilometers (817 miles). Today's flyby schedule calls for a distant flyby of Io, at 12:52 PDT and a distance of 780,000 kilometers (485,000 miles). With the start of the encounter comes the resumption of the magnetospheric survey performed every orbit by the Fields and Particles instruments. During this survey, the instruments sample the inner portions of Jupiter's magnetosphere, allowing scientists to study the long-term variations in the plasma, dust, and electric and magnetic fields that comprise it. The survey is scheduled to continue through Wednesday. The remote sensing observation schedule starts with an observation of Io performed by the Near-Infrared Mapping Spectrometer. The observation is designed to provide information on the surface composition of the Prometheus volcano region. Later in the day, the spacecraft camera, or Solid-State Imaging subsystem, the Near- Infrared Mapping Spectrometer, and Ultraviolet spectrometer take a look at Europa while it is in Jupiter's shadow. The observations are designed to detect atmospheric emissions, best seen in the dark, that could be an indication of geologic surface activity. The observations then focus on Jupiter. In two observations, the Photopolarimeter Radiometer makes observations of Jupiter's clouds, looking for small temperature variations within cloud bands. Finally, the Near-Infrared Mapping Spectrometer performs a series of observations that have been repeated every orbit and are designed to detect long term, global variations in the composition and temperature of Jupiter's clouds. 3 May 1999 Today, Galileo continues with day two of the ninth encounter of the Galileo Europa Mission. On today's observation schedule the Near-Infrared Mapping Spectrometer, Photopolarimeter Radiometer, and Fields and Particles Instruments focus their attention completely on Jupiter. The spacecraft flies past Europa today at about 5:37 am PDT [see note 1] at a distance of 908,000 kilometers (564,000 miles). Closest approach to Jupiter also occurs today at about 10:00 am PDT at a distance of 9.4 Jupiter radii (672,000 kilometers or 418,000 miles) from Jupiter's center. The Near-Infrared Mapping Spectrometer takes the first observations of the day. In a series of three observations, the spectrometer takes a look at a turbulent region in the wake of the Great Red Spot. One of the observations is made while the Great Red Spot is in darkness, the other two while it's in daylight. The Near-Infrared Mapping Spectrometer observes a hotspot region. Hot spots are particularly interesting because they are known to be nearly cloud-free regions, and are believed to be associated with violent downdrafts in Jupiter's atmosphere. Again, one of these observations is taken at night, and another during daylight. These observations will allow an increased understanding of local meteorology, regional dynamics, and cloud particle size, distribution and composition. As it did yesterday, the Photopolarimeter Radiometer takes another look Jupiter's clouds, searching for small variations in temperature within a given cloud band. The Near-Infrared Mapping Spectrometer will also observe Jupiter's clouds, hoping to detect long-term global variations in the composition and temperature. During the Perijove Reduction Campaign (the next four encounters), the Fields and Particles instruments will perform a series of recordings to measure plasma and magnetic and electric fields as Galileo passes through the Io torus. The torus is a region of intense plasma and radiation activity, in which there are strong magnetic and electric fields. Constantly replenished by the volcanic activity on Io, it is a vital part of the Jovian magnetosphere. Recordings in this region provide important information on the dynamics of Jupiter's magnetosphere. This orbit's recording is centered at closest approach to Jupiter and is performed for two hours. For more information on the Galileo spacecraft and its mission to Jupiter, please visit the Galileo home page http://www.jpl.nasa.gov/galileo Galileo has been orbiting Jupiter and its moons for nearly 3-1/2 years, gathering pictures and other information. The spacecraft is currently more than halfway through a two-year extended Galileo Europa Mission, a follow-on to the primary mission that ended in December 1997. The mission is managed by JPL for NASA's Office of Space Science, Washington, DC. Note 1. All times listed correspond to the Pacific Time zone (currently daylight time) and spacecraft event time. Radio signals indicating that an event has occurred on the spacecraft reach the Earth 33 to 50 minutes later, depending on the time of year. Currently, Pacific Daylight Time (PDT) is 7 hours behind Greenwich Meridian Time (GMT), and it takes radio signals 49 minutes to travel between the spacecraft and Earth. ------------------------------------------------------------------ GALILEO--COUNTDOWN TO CALLISTO By Ron Baalke, Galileo webmaster 3 May 1999 It is now 1 day, 23 hours to the Galileo spacecraft's closest approach to Callisto. A special Countdown to Callisto home page is now available on the Galileo Home Page at http://www.jpl.nasa.gov/galileo/countdown/ Launched in October 1989, Galileo entered orbit around Jupiter in December 1995, and completed its primary 2-year orbital tour around the solar system's largest planet. Galileo has since embarked on a two-year extended mission, called Galileo Europa Mission (GEM). During GEM, Galileo had made 8 close flybys of Europa, and will encounter Callisto four more times, followed by two close encounters with Io provided the spacecraft is still alive. The main purpose of the four Callisto flybys during GEM is to reduce the Galileo's perijove, or the closest distance to Jupiter, in order to encounter Io. The ninth encounter for GEM is scheduled for Callisto on May 5, 1999 at 13:56 UT. Referred to as Callisto 20, since this will occur on the 20th orbit since Galileo entered orbit around Jupiter, this encounter will be Galileo's first close flyby of Callisto during GEM. With a diameter of 4,800 km, Callisto is the third largest satellite in the solar system, and has the most cratered surface ever observed. Previous encounters by the Galileo spacecraft has found surprising evidence that Callisto may have a liquid ocean underneath its icy crust. On the upcoming encounter, the spacecraft will pass by Callisto at a distance of about 1,315 km, which is over 94 times closer than Voyager's closest approach. During this encounter, observations of Io and Jupiter will also be taken. Highlights of the Countdown to Callisto home page: * A virtual flyby of Callisto with computer-generated approach images of Jupiter and Callisto displayed at the top of the home page. These images are all updated every 5 minutes in sync with the actual flyby by the spacecraft. * Simulated animation of the Callisto 20 flyby. * Daily Galileo status reports reporting on the Callisto 20 encounter. * Fact sheets and Europa, Callisto and Io. * A detailed timeline of events and sequences that the spacecraft will perform for the Callisto 20 encounter. * Voyager 1 & 2 images of Callisto, Ganymede, Europa and Io. * Hubble Space Telescope images of the Galilean satellites. * Pioneer 10 & 11 images of Callisto, Ganymede, Europa and Io. ------------------------------------------------------------------ CALTECH STUDENTS DEVELOP A NEW PLAN TO SEND HUMANS TO MARS Mars Society of Caltech/JPL release 26 April 1999 Forget the new Star Wars--an ambitious project by students at the California Institute of Technology could be bringing an epic space saga to a solar system near you. "This could be the plan to send the first humans to Mars," beams Chris Hirata, 16, a sophomore at Caltech, who, along with three other Caltech undergrads and the support of Caltech's 80 member chapter of the Mars Society, has developed a new plan that would land the first humans on Mars on May 25, 2014. "On May 25th? Don't you mean by May 25th?" asks Kara Swedlow, a Caltech senior who was treated to an early version of the plan. But Hirata makes it clear: "On May 25th. We calculated the trajectory exactly." The Caltech team calculated a lot of things exactly-from parachutes and retro-rockets for landing on Mars to the chances-good, it turns out-of returning the crew safely. The team of undergrads, which also includes Jane Greenham and Derek Shannon, 19, and Nathan Brown, 18, all Caltech freshmen, will present their plan, the Mars Society Mission, to NASA's top thinkers on human Mars exploration at the Mars Exploration Forum May 7th at the Lunar and Planetary Institute in Houston. The Mars Society Mission is part of the Mars Society's political and technical efforts to make a human Mars mission a reality, "And having the safest, most reasonable plan possible is a big part of that," explains chapter president Derek Shannon. In 1989, when then President George Bush announced a new initiative to send humans to Mars and back to the Moon, the effort fell apart when extravagant designs caused the price tag to skyrocket. A reasonable plan using conventional technology, says Shannon, could mean success for a new Mars initiative in the next year or two. Continues Shannon, "Based on cost estimates for earlier plans that the Mars Society Mission improves upon, we could send humans to Mars using just a fraction of NASA's budget over the next ten years," for a total cost between 30 to 50 billion dollars, less than the current cost of the International Space Station and less than the inflation-adjusted cost of the Apollo missions to the Moon. Team member Nathan Brown, who designed the Mars Ascent Vehicle that will bring the five-person Mars Society Mission crew back from the Martian surface, explains the need for a new plan. According to Brown, two leading plans have previously been the focus of debate: lightweight, four-person Mars Direct, created by aerospace engineer and national Mars Society leader Dr. Robert Zubrin, and the bulkier, six-person NASA Reference Mission, developed by NASA's Mars Study Team. Says Brown, "The Mars Society Mission fixes the problems with these plans by avoiding over-optimistic assumptions and politically sensitive technologies, such as nuclear thermal rocketry." The Mars Society Mission instead shows how all conventional launch vehicles, similar to those used to launch today's robotic missions, can send the tomorrow's crew of Mars explorers to the Red Planet. So how does the Mars Society Mission work? The Caltech team tells an intriguing story, with the figures-and even illustrative computer generated movies-to back it up. It all begins on July 1, 2011, when the first payload, the uncrewed Earth Return Vehicle that will wait in orbit around Mars to return the crew to Earth, is sent toward the Red Planet by the Qahira (from the Arabic word for "Mars") Launch Vehicle, which the team also designed. The Earth Return Vehicle is followed by a Mars Ascent Vehicle and a cargo payload, which reach Mars and begin making methane and oxygen propellant out of the Martian atmosphere for the return home. In January 2014, the five-person crew departs Earth in a Crew Return Vehicle that is almost identical to the Earth Return and Mars Ascent Vehicles. This craft meets with a habitat module ("hab") launched separately to Low Earth Orbit, and together the Crew Return Vehicle and hab take the crew on a 134 day transit to Mars, landing on the potentially famous date of May 25, 2014. After 612 days exploring, learning, and living on the Martian surface, where the crew will try to answer fundamental questions about life and whether humans will be able to live permanently on Mars, the crew boards their Mars Ascent Vehicle, which blasts off to meet the Earth Return Vehicle in Mars orbit. Both vehicles take the crew on a 129-day trip back to Earth, where they finally arrive on June 4, 2016, after two and a half years away. Safety was a primary consideration in designing the Mars Society Mission, says team member Jane Greenham. According to Greenham, a native of South Africa who lived in Jordan before coming to Caltech, but whose favorite exotic locale is Mars, the team performed a risk analysis of their plan compared to Mars Direct and the NASA Reference Mission, and the Mars Society Mission came out safer every time. Greenham, who performed much of the safety study, says, "Because the Mars Society Mission uses more complete back-up systems on the way there and back, we can make the crew's safety much more of a sure thing." Derek Shannon clarifies, saying, "The Mars Society Mission doesn't add more components, it simply finds ways of extending the uses and reuses of the vehicles that will already be necessary to put people on Mars. And because we don't use new technologies like nuclear thermal rocketry, starting a humans-to-Mars program will be less of a problem politically." The Caltech team has high hopes that the Mars Society Mission will influence NASA's Mars plans for the better, and increase the possibility for a new initiative to send humans to Mars. Jim Burke, a veteran of several robotic interplanetary missions and the team's faculty advisor, says, "NASA is doing a terrific job of encouraging the new ideas that will make the mission happen." In addition to their May 7th talk in Houston, the team will be presenting the Mars Society Mission to the general public, at a level accessible to all, on the Caltech campus in Room 119 of the Kerckhoff Laboratory on Sunday, May 2nd, at 3:00 PM, and again in Kerckhoff 119 on Tuesday, May 4th, at 7:30 PM. Admission is free. Both talks will last approximately forty minutes, and be followed by Q&A and a press session. The team created extensive graphics to illustrate the Mars Society Mission and "bring it alive for everyone, by using computer generated movies of key points," according to Shannon. Frequently updated draft versions of the Mars Society Mission are available at the Caltech/JPL chapter's web site, http://www.cco.caltech.edu/~mars, along with additional info on Mars exploration and maps of the Caltech campus. The national Mars Society page can be found at http://www.marssociety.org. Questions can be sent to mars@caltech.edu. The Mars Society of Caltech/JPL is a chapter of the international Mars Society, founded in August 1998. The purpose of the Mars Society is to further the goal of the exploration and settlement of the Red Planet. This will be done by (1) Broad public outreach to instill the vision of pioneering Mars; (2) Support of ever more aggressive government funded Mars exploration programs around the world; and (3) Conducting Mars exploration on a private basis. Starting small, with hitchhiker payloads on government funded missions, the Mars Society intends to use the credibility that such activity will engender to mobilize larger resources that will enable stand-alone private missions and ultimately human exploration. ------------------------------------------------------------------ INTERPLANETARY POLITICS: THE POLITICS OF EXPLORING MARS AND THE OTHER PLANETS Lecture announcement Lecture by W. D. Kay, Ph.D. Thursday, May 6, 1999 at 7:30 PM At the MIT Lab for Computer Science 8th floor, room NE43-800, 545 Tech Square Cambridge, MA Dr. Kay will discuss how political processes (budgetary, bureaucratic, electoral, legislative, international, etc.) affect the planning and execution of major space projects, including the exploration of Mars and other planets. Dr. Kay is an associate professor at Indiana University in the areas of public policy and administration, organizational theory, and science and technology. ------------------------------------------------------------------ THE IMPACT OF COMETS AND ASTEROIDS UPON THE EARTH Lecture announcement 3 May 1999 Lecture by Donald K. Yeomans Supervisor, Solar System Dynamics Group Jet Propulsion Laboratory Monday, May 17, 1999 7:30 p.m. at Griffith Observatory Comets and asteroids have been receiving bad press of late. In two recent movies, they have been portrayed as Earth threatening villains. While comets and asteroids do smack into the Earth from time to time, it is also likely that they helped deliver the water and carbon-based molecules to the early Earth, thus providing the building blocks for the formation of life. Subsequent collisions may have punctuated life's evolutionary cycles allowing only the most adaptable species to evolve further. We mammals may owe our preeminent position atop the Earth's food chain to a collision some 65 million years ago that wiped out most of our competition-- including the dinosaurs. Ironically, the same comets and asteroids that can most closely approach the Earth are also the most accessible in terms of exploiting their vast supplies of water and metals. Comets and asteroids could easily supply the raw materials necessary for colonizing the inner solar system in the next century. In addition to the utility of assessing their potential as future threats and resources, there are compelling scientific reasons for studying these primitive leftovers from the solar system formation process. Knowledge of their compositions and structures will provide important clues to the conditions and chemical mix from which the planets formed some 4.6 billion years ago. The nature and chemical composition of these enigmatic objects should soon become clear as spacecraft missions closely study a dozen comets and asteroids in the next 13 years. At the Jet Propulsion Laboratory, Don Yeomans is a Senior Research Scientist and Supervisor for the Solar System Dynamics Group. Dr. Yeomans is the Project Scientist for the MUSES-CN mission to explore the surface of a near-Earth asteroid and Radio Science Team Chief for the Near-Earth Asteroid Rendezvous (NEAR) mission. He is the current Chairman for the Division of Planetary Sciences and has recently been appointed manager of NASA's Near-Earth Object Program Office. His research work is focused upon the physical and dynamical modeling of comets and asteroids. He has been active in providing the observing community and flight projects with position predictions for hundreds of comets and asteroids including those that have been, or will be, mission targets. In refining the motions of comets and asteroids, he has used data types as diverse as recent radar measurements, Hipparcos-based astrometry, and ancient Chinese observations. Don has received 10 NASA Achievement awards including an Exceptional Service Medal in 1986. He has published three books and over 100 technical papers. Asteroid 2956 was renamed 2956 YEOMANS to honor his professional achievements. Friends Of The Observatory (FOTO) is the non-profit support group for Griffith Observatory. Currently, one of FOTO's primary goals is to support the renovation and expansion of the Observatory, so that it continues to provide the nearly 2 million visitors and 50,000 school children annually with accurate astronomical and scientific information and programs and remains the internationally recognizable icon of Los Angeles. Admission: $2 for FOTO members, $5 for non-members; tickets are available at the door. (Children under 5 are not admitted.) Griffith Observatory Griffith phone: (323) 664-1181 2800 East Observatory Road Griffith fax: (323) 663-4323 Los Angeles, California 90027 USA http://www.GriffithObs.org e-mail: list@GriffithObs.org ------------------------------------------------------------------ End Marsbugs Vol. 6, No. 11