MARSBUGS: The Electronic Astrobiology Newsletter Volume 6, Number 8, 23 March 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) NEW IMAGES SHOW ADDITIONAL EVIDENCE OF POSSIBLE ANCIENT LIFE ON MARS From the JPL web site 2) LUNAR DATA SUPPORT IDEA THAT COLLISION SPLIT EARTH, MOON NASA release 99-43 3) MAKING OXYGEN ON MARS University of Arizona release 4) STAR TRAILS SOCIETY UPDATE By Tony Philips 5) PLANETS IN A BOTTLE: "LIFE ON THE EDGE" ENTERS THE CLASSROOM By Tony Phillips 6) MARS POLAR LANDER MISSION STATUS REPORT JPL release 7) NEW MARS GLOBAL SURVEYOR IMAGES By Ron Baalke 8) STARDUST MISSION STATUS JPL release ------------------------------------------------------------------ NEW IMAGES SHOW ADDITIONAL EVIDENCE OF POSSIBLE ANCIENT LIFE ON MARS From the JPL web site (http://www.jsc.nasa.gov/pao/flash/marslife/photos.htm) 19 March 1999 A NASA research team of scientists at the Johnson Space Center and at Stanford University has found evidence that strongly suggests primitive life may have existed on Mars more than 3.6 billion years ago. The NASA-funded team found the first organic molecules thought to be of Martian origin; several mineral features characteristic of biological activity; and possible microscopic fossils of primitive, bacteria-like organisms inside of an ancient Martian rock that fell to Earth as a meteorite. [Stories related to the original meteorite findings appeared in several issues of Marsbugs during and after August 1996.] New images show additional evidence of possible ancient life on Mars from another, younger meteorite. [The images described here appear in the PDF version of Marsbugs.] [Image] 1075. These are possible Martian fossilized microbial cells attached to a mineral in the Egyptian meteorite Nakhla. They range from about 1 to 2 micrometers in size and each one is firmly attached to the crystal by clay minerals which are known to commonly form on cells as part of the mineralization or fossilization process. The scale bar is 5 micrometers or about 1/10 the thickness of a human hair. [Image] 2058. This shows two possible fossilized Martian cells and the fragments of others. The cell in the center has the remains of a fossilized biofilm partly covering its surface. The cell to the right is partly embedded in the clay mineral that fills veins or cracks in the meteorite (Nakhla). This clay mineral is now known to have formed on Mars about 700 million years ago. If these bumps are truly fossilized Martian microbes, they are then about 700 million years old. [Image] 2060. This shows a possible elongated fossilized Martian cell on the surface of a clay mineral that fills veins or cracks in the meteorite (Nakhla). Other possible fossilized microbes are partly embedded in the clay mineral. This clay mineral is now known to have formed on Mars about 700 million years ago. If these embedded bumps are truly fossilized Martian microbes, they are then about 700 million years old. The elongated bump on the surface may have formed later or it may be the same age as the embedded bumps. [Image] 2154e. This image shows a series of partly embedded bumps in clay minerals in the Nakhla meteorite. Our interpretation is that these bumps are individual fossilized Martian microbes. That interpretation must be checked by further data on chemistry and structure of the bumps. Note the three bumps lined up near the center. These bumps bear a striking resemblance to earth microbes that are in the process of reproduction. If the bumps are truly Martian microbes, they are about 700 million years old, the age of the surrounding clay minerals as dated by radioactive isotope techniques. [Image] 2165e. This image shows a series of bumps partly embedded in a tiny slab of Martian clay (Nakhla). The slab is wrapped and partially covered by another layer of Martian clay free of bumps. We interpret that the bumps are fossilized Martian microbes trapped the clay layers about 700 million years ago on Mars. Our interpretation must be checked by further detailed data to determine if they are really fossilized microbes and to confirm that the clay mineral formed on Mars, but the existing data supports both of those theories. [Image] 4181e. This image shows a fossilized elongated microbe resting in a hollow in clay minerals from the meteorite Nakhla. The microbe appears to be somewhat corroded and partly covered with the remains of biofilm (slime generated by living cells). It closely resembles many kinds of earth bacteria. [Images of the original suspected microfossils in the ALH84001 meteorite are also shown on the web page cited in the title.] ------------------------------------------------------------------ LUNAR DATA SUPPORT IDEA THAT COLLISION SPLIT EARTH, MOON NASA release 99-43 16 March 1999 Analysis of data from NASA's Lunar Prospector spacecraft has confirmed that the Moon has a small core, supporting the theory that the bulk of the Moon was ripped away from the early Earth when an object the size of Mars collided with the Earth. Scientists presented this result and other findings today in a series of papers at the 30th Lunar and Planetary Science Conference in Houston, TX. Their data show that the lunar core contains less than four percent of the Moon's total mass, with the probable value being two percent or slightly less. This is very small when compared with the Earth, whose iron core contains approximately 30 percent of the planet's mass. "This is a critical finding in helping scientists determine how the Earth and Moon formed," said Dr. Alan Binder of the Lunar Research Institute, Tucson, AZ, principal investigator for Lunar Prospector. Similarities in the mineral composition of the Earth and the Moon indicate that they share a common origin. However, if they had simply formed form the same cloud of rocks and dust, the Moon would have a core similar in proportion to the Earth's. A third theory suggests that the moon was captured fully intact by the Earth's gravity. Based on information first gathered during the Apollo era, scientists suggested that the Moon was formed when a Mars-sized body hit the Earth during its earliest history. "This impact occurred after the Earth's iron core had formed, ejecting rocky, iron-poor material from the outer shell into orbit," Binder explained. "It was this material that collected to form the Moon. "Further analysis of Lunar Prospector data to refine the exact size of the lunar core and the amounts of elements like gold, platinum and iridium in lunar rocks--all of which are concentrated with metallic iron--is required," Binder added. "This will do much to pin down for good if the 'giant impact' model of the formation of the Moon is correct, or if the Moon formed in a different manner." The current data come from gravity measurements conducted by Dr. Alex Konopliv of NASA's Jet Propulsion Laboratory, Pasadena, CA. His results indicate that the Moon's core radius is between 140 and 280 miles (220 and 450 kilometers). This result is consistent with independent magnetic data, evaluated by Dr. Lon Hood of the University of Arizona, Tucson, which suggest that the core radius is between 180 and 260 miles (300 and 425 km). In other results from Lunar Prospector, Dr. Robert Lin of the University of California at Berkeley, Dr. Mario Acuna of NASA's Goddard Space Flight Center, Greenbelt, MD, and Hood also found that a broad section of the southern far-side of the Moon has large localized magnetic fields in its crust. These fields occur opposite the large Crisium, Serenitatis and Imbrium basins--three of the "seas" that cover much of the Moon's near side. This result supports earlier evidence linking strong magnetized concentrations on one side of the Moon with young, large impact basins on the other side. Results of efforts to map the composition of the lunar crust have surpassed the expectations of the spectrometer team, led by Dr. William Feldman of the Department of Energy's Los Alamos National Laboratory in New Mexico. Data obtained are so good that the distribution of thorium has been mapped with a resolution of 36 miles (60 kilometers). At this amount of detail, scientists can detect individual deposits rich in thorium and related elements. Their current observations suggest that thorium was excavated by impacts of asteroids and comets, and then distributed around craters, rather than being deposited by volcanic activity. Lunar Prospector conducted its primary mapping mission at an altitude of 63 miles (100 kilometers) for almost one year after its arrival in lunar orbit on January 11, 1998. In December and January, the spacecraft's altitude was lowered to approximately 15 miles by 23 miles (24 kilometers by 37 kilometers). Analyses of data from the lower-altitude observations are expected to further improve scientific understanding of the origin, evolution and physical resources of the Moon. The $63 million mission is managed by NASA's Ames Research Center, Moffett Field, CA, and was developed under NASA's Discovery Program of lower-cost, highly focused small scientific spacecraft. Further information about Lunar Prospector, its science data return, and relevant charts and graphics can be found on the project web site at http://lunar.arc.nasa.gov ------------------------------------------------------------------ MAKING OXYGEN ON MARS University of Arizona release 23 February 1999 Professor K. R. Sridhar and his 20-member team at The University of Arizona Aerospace and Mechanical Engineering (AME) Department are building an Oxygen Generating Subsystem (OGS). In January 2002, it will suck in Martian atmospheric gases--predominately carbon dioxide--and process them to produce pure oxygen. "This is a landmark experiment," Sridhar says. "It is the first time in human history that we will produce a consumable of use to humans from extraterrestrial resources." It will be the space exploration equivalent of standing on the brink of the Industrial Revolution, but with a gigantic resource base--all the materials found on planets, their satellites, and asteroids in the solar system. The oxygen could be used as propellant in rocket motors or for life support for humans on Mars. Since this is a demonstration experiment, the oxygen will not be put to immediate use on the Mars Surveyor 2001 lander. But Sridhar hopes to have an experiment aboard the Mars Surveyor 2003 mission that will produce both fuel and oxygen from Martian resources. In that case, the oxygen and fuel would be used to launch a small rocket from the surface of Mars or to power a drill that would take core samples of the Martian surface. "In the larger scheme of things, in 2007 we hope to perform a sample return mission that will rely on the propellant production technology we are developing to produce both the fuel and oxygen for a rocket to bring the sample back to earth," Sridhar says. "We are working very vigorously on this." The OGS will fly to Mars aboard Mars Surveyor 2001, which is scheduled to land on the Red Planet on January 22, 2002. Once on Mars, it will use solid oxide electrolysis to produce oxygen. The technology is based on an electrochemical cell that works as a solid state filter for oxygen. The electrolyte used in the OGS will transfer only oxygen ions across its crystal structure. The unit weighs about two pounds and will consume less than 15 watts of electrical power to produce more than one cubic centimeter of oxygen per minute. This is twice the amount NASA specified in its contractual requirements for the oxygen generator. "The challenges were to miniaturize the technology and to make the process very energy efficient, while producing a device that is rugged enough to withstand launch loads up to 35 Gs (35 times the force of gravity at sea level)," Sridhar says. The space-qualified OGS is being built entirely in the UA AME Space Technologies Laboratory, where Program Manager Matthias Gottmann is supervising a team made up of staff engineers, graduate students, undergraduates, post docs, and exchange students. OGS construction includes producing ceramic heating elements from scratch that heat up faster and go to higher temperatures than commercially available ones. Producing resources in situ has many advantages, Sridhar explains. "By using extraterrestrial resources, you lower the launch mass from Earth and thereby reduce the cost. You also reduce the overall risk of a mission because you can produce safety caches of valuable consumables that will be available to humans at the destination." But, he adds, perhaps the most significant aspect of in situ resource utilization is that it is the enabling technology that will make possible permanent settlements on other planets and their satellites. ------------------------------------------------------------------ STAR TRAILS SOCIETY UPDATE By Tony Philips 16 March 1999 The Life on the Edge project is well underway. Microbes have been delivered to a summit in California for exposure to extreme conditions, and testing of microbiology protocols are ongoing in elementary classrooms. To find out more please see the following URLs. Planets in a bottle [featured in this issue of Marsbugs] http://science.nasa.gov/newhome/headlines/msad16mar99_1.htm (this story includes a sample lesson plan for educators at http://science.nasa.gov/newhome/headlines/msad16mar99_1a.htm) Sled dogs carry astrobiology to dizzying heights [featured in a previous issue of Marsbugs] http://science.nasa.gov/newhome/headlines/msad11mar99_1.htm We invite you to participate in Life on the Edge now by trying some of the protocols discussed in "Planets in a Bottle" and, of course, when the yeast packets are returned from the White Mountains they will be made available to members of the Star Trails Society for experimentation. Dr. Tony Phillips (phillips@spacesciences.com) http://www.SpaceWeather.com http://www.StarTrails.com http://www.SouthPole.com ------------------------------------------------------------------ PLANETS IN A BOTTLE: "LIFE ON THE EDGE" ENTERS THE CLASSROOM By Tony Phillips From NASA Space Science News 16 March 1999 NASA/Marshall's "Life on the Edge" program is barely a month old but it's already producing results in some grade school classrooms. "It was wonderful," says Mrs. Nancy Walters, whose 3rd grade class recently tried some simple microbiology experiments with yeast. "The kids felt like they were doing real science, and they couldn't stop talking about it for days." Life on the Edge is an educational program that aims to expose grade school students to some of the basic principles of astrobiology and to explore the possibilities for life elsewhere in the Solar System. The program began just over a month ago when 50 lb. of yeast and other microbes were delivered to a summit in California's White Mountains. Conditions there present severe challenges for most forms of life, so it is a good place to test the response of microbes to extreme environments. Some of the microorganisms will remain there for months, and some for longer than a year, before they are retrieved and distributed to classrooms for experimentation. "Eventually we'll be sending thousands of yeast packets to schools around the country," says Dr. John Horack, director of science communications at the NASA/Marshall Space Sciences Lab. "But even before the microbes are in a Bottle ready to go we have to develop some simple lab protocols that kids can use to measure how their samples were affected by exposure. That's why we're going into classrooms now to test some of our ideas." One of these ideas, called "Planets in a Bottle," was field-tested in a 2nd/3rd grade class room in February. "'Planets in a Bottle' is a simple way to test the viability of yeast samples, and a great way to teach young students about conditions on other planets," explained Dr. Tony Phillips, who is evaluating the concept in classrooms. "The basic ingredients for a planet in a bottle are 1 cup of warm water, 3 sugar cubes, a 1/4 oz. packet of yeast, a half liter plastic water bottle, and a nine inch party balloon. Simply mix the sugar, water, yeast in the bottle, and cap the bottle with the balloon. A healthy sample of yeast will inflate the balloon to 12 inch circumference in less than an hour." What happens is this: In the nutrient broth--warm water containing both dissolved oxygen and sugar--yeast metabolizes the sugar and produces carbon dioxide. The rate of carbon dioxide production at any given instant is proportional to the number of healthy microbes in the bottle. Because the yeast are constantly reproducing through cell division the number of microbes increases exponentially. Likewise, carbon dioxide production increases. The balloon inflates slowly at first, then rapidly accelerates. In practice the balloon inflates to maximum volume in about 45 minutes. That's when the yeast have consumed the entire available nutrient. At room temperature the cells remain viable for several hours afterward and then begin to die. The maximum volume of CO2 and the time required to produce the gas can be used to estimate the number of healthy microbes in the original sample. [A sample lesson plan for this experiment is available at http://science.nasa.gov/newhome/headlines/msad16mar99_1a.htm. Please send comments and suggestions to phillips@spacesciences.com.] "Two weeks ago we visited Mrs. Walter's 3rd grade classroom in Bishop, CA" continued Dr. Phillips. "The class was divided into seven groups, each with the basic ingredients for a Planet in a Bottle. Rather than have every group do the same experiment, we added variations so that each bottle would represent a different planet. For example, the Moon has no atmosphere to protect its surface from solar UV radiation. So one group exposed their yeast to an ultraviolet lamp before adding the microbes to the nutrient mix, creating a "Moon in a Bottle." Another group used scalding hot orange juice as a nutrient mix for 'Venus in a Bottle.' Citric acid in the orange juice served as a substitute for sulfuric acid in Venus's hot atmosphere." "Clearly we can't reproduce true planetary conditions in a simple water bottle, nor did we pretend to, but these exercises have powerful teaching value. Every kid in Mrs. Walter's class now knows that Venus has acid in its atmosphere thanks to the orange juice experiment, and they also learned that weak acids are not deadly to yeast," Phillips said. "My students were really excited when their balloons began to inflate," recalled Mrs. Walters, "but the best part came at the end when we measured the sizes of the balloons and held a classroom debate about the results. We argued about which planet was most congenial to yeast and what the limitations of our results were. It felt like real science." NASA scientists have a crowded schedule of classroom visits planned in the months to come, even though the Life on the Edge yeast container won't be retrieved for some time. The goal is to develop safe and effective classroom protocols before the yeast packets are distributed nationally. "We don't want to spoon feed students with overly-detailed protocols," says John Horack," That's not science. But, we do want to give them a good starting point for their own creative experiments with extremophiles. The only way to do that is by spending lots of time in the classroom now, while the microbes are still in the White Mountains." [For more information on this and other topics see http://science.nasa.gov/newhome/headlines/msad16mar99_1.htm] ------------------------------------------------------------------ MARS POLAR LANDER MISSION STATUS REPORT JPL release 15 March 1999 The Mars Polar Lander has successfully completed its second course correction to refine its flight path to the red planet. At 5:05 AM Pacific time today, the spacecraft fired its four maneuvering jets for just under 10 seconds changing its speed by a mere 0.89 meter per second (2.0 miles per hour). The spacecraft's next maneuver is scheduled for September 1, when its flight path will be targeted for a specific landing zone near the planet's south pole. Observations of the south polar region by instruments onboard the currently orbiting Mars Global Surveyor will be used to pick a safe landing spot. Mars Polar Lander is now 16,510,000 kilometers (10,070,000 miles) from Earth, traveling at a speed of 1,680 meters per second (3,700 miles per hour). The spacecraft will land on Mars on December 3, 1999. ------------------------------------------------------------------ NEW MARS GLOBAL SURVEYOR IMAGES By Ron Baalke 16 & 18 March 1999 The following new images from the Mars Global Surveyor spacecraft have been added to the MGS web site at http://mars.jpl.nasa.gov/mgs/msss/camera/images/index.html Valleys on Northwest Flank of Alba Patera Volcano Boulder Tracks on Schiaparelli Basin South Wall Eroded Layered Material in Southwest Utopia Planitia Layers in Cratered Highland Crust Exposed by Tagus Vallis Small Impact Craters with Dark Ejecta Deposits Hot Dog and Butterfly, Nereidum Montes Mariner 4 Meets Mars Global Surveyor--Mariner Crater 1965 and 1999 Mars Global Surveyor Mars Orbiter Camera Valleys on Northwest Flank of Alba Patera Volcano MGS MOC release number MOC2-92, 16 March 1999 In 1972, Mariner 9 images revealed a variety of branched and networked valleys on Alba Patera, a volcano in northern Tharsis. Since then, the question has always been, "what made these valleys, water or lava?" Because the Alba Patera volcano was considered to be a relatively young feature on Mars, it seemed that if water was involved in the formation of the valleys, then it would imply that liquid water flowed on this part of Mars at a relatively recent time in the planet's history. Thus, it was hoped that Mars Global Surveyor (MGS), with its super-high resolution Mars Orbiter Camera (MOC), would help answer this key question about evidence for past water on the red planet. However, when MOC peered down upon these valleys it became clear that the camera might not help answer the question of their origin. As the picture above shows, these valleys--which trend from lower right to upper left in the picture--are old and have been cut by younger faults that created graben--e.g., the wide, straight valley running diagonally from upper right to lower left. Worse, the close-up views revealed that the valleys are covered up by a lumpy-textured material that also partly fills nearby impact craters. The origin of the textured material is unknown but might result from years and years of wind erosion of surface 'soil' or volcanic ash. However it formed, this covering obscures so much of the details of the valleys that high-resolution pictures are unlikely to solve this mystery. The picture above covers an area approximately 8 kilometers (5 miles) wide by 15 kilometers (9 miles) high. Illumination is from the right. The picture was acquired in August 1998 during the MGS Science Phasing Orbits imaging campaign, and was presented at the 30th Lunar and Planetary Science Conference in Houston, Texas, March 1999. Boulder Tracks on Schiaparelli Basin South Wall MGS MOC release number MOC2-93, 16 March 1999 The above Mars Orbiter Camera (MOC) image shows a portion of the slope just inside the south rim of the approximately 400 kilometer (250 mile)-wide Schiaparelli Basin near the martian equator. The large white arrow points to a steep cliff exposure of dark-toned rock. The small white arrow points to one of several ~18 meter (59 feet) diameter boulders that apparently broke off the steep, dark cliff and rolled down the slope to the basin floor. Each boulder left behind a trail on the relatively soft, dusty slope. In addition, some of the boulders exhibit a bright wind streak pointing toward the lower left/center, indicating that these boulders have been sitting there long enough to influence local wind distribution of sediment. Before the Mars Global Surveyor (MGS) mission, boulder tracks such as these had never been seen on Mars before, but in the 1960s and 1970s several examples on the Moon and Earth were documented. The picture shown here covers an area approximately 2.8 kilometers (1.7 miles) by 4.4 kilometers (2.7 miles). Illumination is from the lower left. The picture was acquired in January 1998 during the MGS Aerobrake-1 Orbits imaging campaign, and was presented at the 30th Lunar and Planetary Science Conference in Houston, Texas, March 1999. Eroded Layered Material in Southwest Utopia Planitia MGS MOC release number MOC2-94, 16 March 1999 Images from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) dramatically illustrate that many places on the red planet have outcrops of layered geologic materials. The two pictures above show the remains of layered material inside craters in southwestern Utopia Planitia (see inset for detailed view). These remnant layers indicate that the craters--and perhaps the plains that surround them--were once buried beneath a deposit that has since been eroded away. This theme of layered outcrops and exhumed craters appears to be one of the dominant observations that MGS MOC has made--to date--about Mars. The origin and composition of the layered material--and its ultimate fate once it was largely eroded away--are unknown. Each of the two pictures shown here covers an area about 4 kilometers (2.5 miles) by 6.3 kilometers (3.9 miles). Illumination is from the lower right. These are subframes of a single MOC image acquired in July 1998 during the MGS Science Phasing Orbits imaging campaign. This figure was presented at the 30th Lunar and Planetary Science Conference in Houston, Texas, March 1999. Layers in Cratered Highland Crust Exposed by Tagus Vallis MGS MOC release number MOC2-95, 16 March 1999 Mars Orbiter Camera (MOC) images of the Valles Marineris chasm walls obtained early in the Mars Global Surveyor (MGS) mission demonstrated that the upper martian crust--at least in the location of the Valles Marineris--is layered down to depths of several kilometers/miles. Over the past year, examination of additional MGS MOC images of other parts of Mars--including the vast, heavily cratered terrains of the red planet--also exhibit a layered crust. On Earth, geologists use the composition, texture, and sequence of layered rocks to decipher clues about the planet's history. Mars might offer a similar opportunity. Shown here is a picture of Tagus Vallis in the martian southern hemisphere. The picture on the left shows this valley in a view that is about 7 kilometers (4.4 miles) wide by 11 kilometers (6.8 miles) high. Tagus Vallis is the deep, steep-walled valley that runs almost diagonally from upper left to lower right. The white box shows the location of the magnified view of the valley walls on the right. Layered rock can be seen, exposed in the upper slopes of the valley. Bright sand dunes are visible on the valley floor (lower left) and on the upland plain (upper right). In this picture, the illumination is from the upper right. This image was obtained in April 1998 during the MGS Science Phasing Orbits imaging campaign. This result was presented at the 30th Lunar and Planetary Science Conference in Houston, Texas, March 1999. Small Impact Craters with Dark Ejecta Deposits MGS MOC release No. MOC2-96, 18 March 1999 When a meteor impacts a planetary surface, it creates a blast very much like a bomb explosion. Shown here are two excellent examples of small impact craters on the martian surface. Each has a dark- toned deposit of material that was blown out of the crater (that is, ejected) during the impact. Materials comprising these deposits are called ejecta. The ejecta here is darker than the surrounding substrate because each crater-forming blast broke through the upper, brighter surface material and penetrated to a layer of darker material beneath. This darker material was then blown out onto the surface in the radial pattern seen here. The fact that impact craters can penetrate and expose material from beneath the upper surface of a planet is very useful for geologists trying to determine the nature and composition of the martian subsurface. The scene shown here is illuminated from the upper left and covers an area 1.1 km (0.7 mile) wide by 1.4 km (0.9 mile). The larger crater has a diameter of about 89 meters (97 yards), the smaller crater is about 36 meters (39 yards) across. The picture is located in Terra Meridiani and was taken by the Mars Global Surveyor Mars Orbiter Camera. Hot Dog and Butterfly, Nereidum Montes MGS MOC release No. MOC2-97, 18 March 1999 Some of the pictures returned from Mars by the Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor (MGS) spacecraft show features that--at a glance--resemble familiar, non-geological objects on Earth. For example, the picture above at the left shows several low, relatively flat-topped hills (mesas) on the floor of a broad valley among the mountains of the Nereidum Montes region, northeast of Argyre Planitia. One of the mesas seen here looks like half of a butterfly (upper subframe on right). Another hill looks something like a snail or a hot dog wrapped and baked in a croissant roll (lower subframe on right). These mesas were formed by natural processes and are most likely the eroded remnants of a formerly more extensive layer of bedrock. In the frame on the left, illumination is from the upper left and the scene covers an area 2.7 km (1.7 miles) wide by 6.8 km (4.2 miles) high. The "butterfly" is about 800 meters (875 yards) in length and the "hot dog" is about 1 km (0.62 miles) long. Mariner 4 Meets Mars Global Surveyor--Mariner Crater 1965 and 1999 MGS MOC release No. MOC2-98, 18 March 1999 Mars exploration in the last half of the 20th Century comes full circle with a modern view of Mariner Crater obtained by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) in early March 1999. Mariner 4 was the first spacecraft to reach the red planet and take close-up pictures that revealed its ancient, cratered surface. The picture on the left, above, is the 11th image taken by Mariner 4 during its July 1965 flyby. The center of the Mariner 4 image is dominated by a crater that is about 155 kilometers (96 miles) in diameter and located at 32°S latitude and 164°W longitude. The crater was named "Mariner" in 1967 by the International Astronomical Union in honor of its discovery by Mariner 4. The white arrow indicates the location of the new MGS MOC image. The picture on the right represents an improvement in resolution of almost a factor of 400. It shows a view of a tiny portion of the southeastern floor of Mariner Crater, as it appeared to the MGS MOC in 1999. In 1965, it was a surprise to find that the martian surface is pocked with craters. In 1999, using the MGS MOC, we now have the ability to see objects the size of automobiles on the martian surface. This view of the Mariner Crater floor has a spatial resolution of 1.5 meters (5 feet) per pixel and covers an area only 1.5 km (0.9 mi) wide by 2.2 km (1.4 mi) long. Illumination is from the upper left in both the Mariner and MGS images. A mercator-projected Viking 1 Orbiter view of this crater (obtained in 1978) also is available. Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. ------------------------------------------------------------------ STARDUST MISSION STATUS JPL release March 15, 1999 NASA's Stardust spacecraft is in excellent heath as it ventures away from Earth. Last week, the spacecraft switched over to its medium gain antenna and a higher data rate than is possible with the low-gain antenna used in previous weeks when Stardust was much closer to Earth. Stardust sent back new data from two instruments--one that measures "hits" by dust particles and another that will analyze comet and interstellar dust samples. With the higher data rate, the spacecraft also successfully sent back an engineering test image--Stardust's first--taken by the star camera navigation aid. The instrument data and star camera image had been "backlogged" on board while the low-gain antenna and its lower data rate was in use. The star camera's first image shows Mars shining brightly against the star background as seen from the Stardust's view. The image will be posted on the Stardust web site at http://stardust.jpl.nasa.gov this week. The dust particle counter, called the dust flux monitor, continues to operate normally, and high voltage was switched on for the comet and interstellar dust analyzer for the first time last week. Testing of the star camera was started late Monday, March 8, to prepare for its use in tracking so that the spacecraft will not have to rely on its gyro system, called an inertial measurement unit, to control its orientation in space. Moving to "all stellar" control will preserve operating life on the inertial measurement unit for Stardust's encounter with Comet Wild-2, in addition to other operations where the gyro will be needed. After an hour of successful testing, an error occurred in the star camera's data readout, causing the spacecraft to automatically move to its "safe" mode, switching back to the low- gain antenna and minimizing operations until it received new commands from controllers on Earth. Such fault-protection software is used on all of NASA's robotic spacecraft to ensure a controlled response to unplanned events or anomalies. This protects the spacecraft and allows engineers to find any problems, develop solutions and resume routine operations. The flight operations team moved back to communications with the spacecraft over the low-gain antenna and verified that the spacecraft was in its expected state and in excellent health. Late Tuesday, March 8, the spacecraft's data history on the testing was radioed to mission controllers so that a detailed tracing could be performed to identify the cause of the data error and subsequent triggering of the spacecraft's fault protection system. Detailed analysis is underway to understand the suspect operation and correct it. Stardust's objectives are to gather particles flying off the nucleus of Comet Wild-2 and return them to Earth for scientific analysis, and to collect and return samples of interstellar dust flowing through our solar system. Stardust is the first spacecraft ever launched on a mission to bring back material from beyond the Moon. It is also the first U.S. mission to a comet. Stardust's sample return capsule is due to parachute into Earth's atmosphere and land on the U.S. military's Utah Test and Training Range near Salt Lake City on January 15, 2006. Stardust, launched February 7, 1999, is now 15 million kilometers (9.3 million miles) from Earth. The spacecraft was built and is operated by Lockheed Martin Astronautics, Denver, and is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California. JPL is a division of the California Institute of Technology, Pasadena, California. ------------------------------------------------------------------ End Marsbugs Vol. 6, No. 8