MARSBUGS: The Electronic Astrobiology Newsletter Volume 9, Number 18, 6 May 2002. Editors: Dr. David J. Thomas, Science 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 monthly 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. Information concerning the scope of this newsletter, subscription formats and availability of back-issues is available from the Marsbugs web page at http://welcome.to/marsbugs or http://www.lyon.edu/webdata/users/dthomas/marsbugs/marsbugs.html. _____________________________________________________________________ CONTENTS 1) SENDING RATS TO MARS NASA/JPL release 2) LOSS IN SPACE By Harvey Black 3) SPACE TRAVELERS SHOULD TAKE CARE TO AVOID GETTING RADIATED From SpaceDaily 4) DANGERS ON MARS REQUIRE EXTENSIVE EVALUATION BEFORE HUMAN EXPLORATION COULD PROCEED National Academy of Sciences publication announcement 5) DETECTING OTHER WORLDS VIII: RADIO DETECTION By Laurance Doyle 6) REVEALING THE RED PLANET: FREE LECTURES ON AN ODYSSEY TO MARS NASA/JPL release 7) NASA TO TEST MICROWAVE EFFECTS ON PLANT GROWTH By John Bluck 8) THE CHANCE OF FINDING ALIENS By Alan M. MacRobert and Govert Schilling 9) NASA JPL SOLAR SYSTEM TALK SERIES JPL release 10) NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas 11) CASSINI SIGNIFICANT EVENTS NASA/JPL release 12) GLOBAL SURVEYOR CONTINUES ITS WATCH ON THE RED PLANET NASA/JPL release 13) MARS GLOBAL SURVEYOR AGING GRACEFULLY NASA/JPL release 14) MARS ODYSSEY THEMIS IMAGES NASA/JPL/ASU release 15) STARDUST STATUS REPORT NASA/JPL release _____________________________________________________________________ SENDING RATS TO MARS NASA/JPL release http://mars.jpl.nasa.gov/spotlight/rat01.html 29 April 2002 NASA and JPL are sending RATS to Mars to work as field geologists. A RAT is not quite a furry little friend, but rather a high-tech robot with diamond teeth, called a Rock Abrasion Tool (RAT). One RAT will ride on each of the twin Mars Exploration Rovers, launching to Mars in the summer of 2003. These RATS will allow humans to remotely "crack open" rocks on Mars for the first time in the history of Mars exploration. "This is terribly exciting, but it's a little intimidating because no one has ever tried to get into a rock on Mars before," says Stephen Gorevan. Gorevan is the chairman of Honeybee, the small robotics contractor for the Rock Abrasion Tool that sits half a mile away from ground zero in New York City. Gorevan explains that past Mars missions to the surface had different science and technology objectives. " The Viking landers in the 1970's scooped up dirt on Mars and the Sojourner rover proved we could move around on Mars in 1997." Digging into a rock is the next step for the maturing Mars program. Bringing a rock back from Mars or sending a human geologist comes with prohibitive costs, so sending the RAT is the next best thing. The tool will enable scientists to peer inside a rock, where they can analyze unweathered minerals and learn about the origins of rocks. Rick Paynter, deputy lead for Quality Assurance on the Mars Exploration Rover project at NASA's Jet Propulsion Laboratory, explains that the RAT will help "peel off the orange rind" and reveal new information about the evolution of Mars. It will also help with comparing rocks on Mars to rocks on Earth. The Mars Exploration Rover will traverse Mars, find a rock that's interesting, nuzzle up to it, and maneuver its robotic arm to press the RAT up against the chosen rock. The RAT, which is the size of a soda can, will shave away the top layers of the rock. That process may take anywhere from 30 minutes to three hours to remove a round hole about 45 millimeters (1.5 inches) in diameter and 5 millimeters (1/8th inch) deep, depending on the texture of the rock. It's more like an electric shaver than a drill, says Steve Kondos, contract technical manager at JPL. "The difference is, the shaver heads move in and out rather than being stationary--this takes less power. Power, energy, and mass are precious on the rover, so in order to be efficient, we shave the rock rather than drill it, which is power intensive." The RAT brushes its teeth After the RAT shaves off part of a rock, it scurries aside via a Dr. Seuss-like arm device, which also holds a camera and chemical analysis tools to explore the newly exposed rock layers. Before it goes to grind another rock, it turns around and brushes its "teeth" against a RAT brush that acts like a shoe polisher as the RAT "teeth" spin against it to clear out leftover rock. The RAT is designed to grind away one rock, but could shave up to as many as 10 rocks. The RAT with the right stuff Like any aspiring astronaut, the RAT must prove it has the right stuff before it can launch. The Rock Abrasion Tool is the brainchild of Mars Exploration Rover Principal Investigator , Steve Squyres of Cornell University, Ithaca, NY. Gorevan of Honeybee says, "Squyres thought of the need to expose a rock on Mars, and got us from point A to point B. Our job has been to get from point B to point Z." After winning the competitive instrument contract, the Honeybee team has had to follow strict size, mass, and pressure requirements generally dictated by the strength limitations set by the robotic arm. The Honeybee team had to use its ingenuity to come up with the optimum way to provide a mini crater in a Martian rock. Gorevan says, "We cobbled and cogitated together to test ideas, and we're at about point W on the way to Z." Last week, Steve Kondos and Rick Paynter from JPL hand-delivered to Honeybee the motors that run the RATS. "We're really conservative at JPL. The value of the instrument far exceeds the cost," says Paynter. "We split the motors and carried them in different pieces of luggage and took separate planes to New York City." Now that JPL delivered the motors, "we have a clear path to finish our environmental tests and 'shake and bake' the RAT." "Shake and bake" is a process used by engineers to ensure that instruments can withstand the intense vibrations and heat of launch, the extraordinary impact of landing on Mars, and the strong radiation exposure during interplanetary cruise. As time races toward launch, other challenges still remain. "One surprise has been to find how much dust is created by the RAT," explains Gorevan at Honeybee. As the robot grinds away at a rock, it generates dust plumes and leaves RAT "droppings" that can blow onto the solar arrays of the rovers or the cameras. "Honeybee's claim to fame in NYC is a long way from its new role with Mars--they created the giant moving parts on the Coca-Cola sign in Time Square," says Rick Paynter from JPL. Steve Kondos from JPL calls the RAT people at Honeybee ingenious. "They are concerned with cost and schedule milestones, and best of all, they are fun to be with. Since we come from LA, the Honeybee team introduces us to little known spots, like a deli where the bread is so good that Frank Sinatra used to have loaves shipped from Manhattan to Hollywood every week." New York, 9/11, and Mars "After September 11 happened, the first thought was how the team at Honeybee was affected", explains Kondos. "We called immediately, but of course couldn't get in contact with them." Luckily, no one on the team was hurt. NASA Headquarters just approved putting an American flag on the rock shield of the Rock Abrasion Tool. "It's not the equivalent of placing the American flag in the rubble pile, but it's something like that." Kondos is quiet for a moment, then adds, "We're not stopping our progress and hiding, we're rising to the stars." An additional article on this subject is available at http://www.spacedaily.com/news/mars-robot-02e.html. _____________________________________________________________________ LOSS IN SPACE By Harvey Black From The Scientist 29 April 2002 When transatlantic steamers traversed the oceans, one line touted itself with ads saying: "Getting there is half the fun." Not so with space travel. Here, an unhealthy situation exists because the travelers' bones lose mass and weaken. Severe bone loss leads to fractures. A recent Institute of Medicine (IOM) report labeled bone loss as one of the most serious problems facing those who would make long-duration space voyages, such as traveling to Mars. Until now, space scientists had information only about short-term missions. But NASA was anxious about the astronauts' overall health during long- term space travel and asked the IOM for its input. The IOM's overall conclusion: NASA needs more data. So, researchers at NASA and various universities are exploring countermeasures, including exercise and medication, to determine what would mitigate space travel's effects. It is possible that a multi-year trip to Mars may never occur. "If no method is found to mitigate loss of bone density, which could be as great as 50% or more, if left untreated over a three-year period, long-duration, interplanetary missions may be impossible," plainly states the IOM summary. Get the full story at http://www.the- scientist.com/yr2002/apr/research_020429.html. _____________________________________________________________________ SPACE TRAVELERS SHOULD TAKE CARE TO AVOID GETTING RADIATED From SpaceDaily 30 April 2002 Space expeditions will fly to the Mars in fifteen years if all prerequisites are successfully met. For the future interplanetary expedition Moscow scientists have developed an efficient system to protect the crew from space radiation during the long-term travel to the Mars and back. Russian scientists have designed automated systems of radiation control and safety for the Martian expedition. During this expedition a lot of things will be executed for the first time, e.g. a complicated sensor system, controlled by the on board computer, will protect the cosmonauts from the destructive space radiation. Get the full story at http://www.spacedaily.com/news/mars-base- 02i.html. _____________________________________________________________________ DANGERS ON MARS REQUIRE EXTENSIVE EVALUATION BEFORE HUMAN EXPLORATION COULD PROCEED National Academy of Sciences publication announcement 1 May 2002 When NASA's Mars Pathfinder landed on the Red Planet in 1997, it released a rover that monitored the landscape, recorded weather conditions, and broadcast pictures of the surface to Earth. Presently, there is no official date or funding for a human mission to Mars, but the knowledge gained from the Pathfinder and other missions would contribute to plans for eventual human exploration of the planet. Before astronauts can take the first steps on Mars, however, much research needs to be done to guide mission planners and hardware designers. A new report from the National Academies' National Research Council outlines the environmental, chemical, and biological hazards that NASA needs to assess before sending a human mission to Mars. The agency's robotic engineering and design program should be expanded to develop larger rovers specifically for human use in exploration and surface transport, the report says. To ensure a safe landing and to aid rover and human movement on the planet, NASA should develop an accurate high-resolution, three-dimensional map of the terrain that would be explored, and assess the land's makeup to determine its strength and stability. In addition, when a spacecraft lands on Mars, soil and dust might be brought in through the air lock, which occurred during the Apollo missions to the moon. Potential contamination of the astronaut habitat while on the Martian surface could pose a health hazard to the crew. For example, dust could contain high concentrations of sulfur and chlorine, compounds that could degrade human lung tissue if inhaled and corrode equipment. There is also uncertainty as to the quantity of toxic metals, such as hexavalent chromium, in the soil. While small amounts of these metals may not affect the astronauts immediately, they could have long-term effects, such as cancer. Robotic sampling of soil and airborne dust could determine the presence and extent of any harmful organisms or compounds. If certain experiments, such as testing for chromium, cannot be conducted on the Mars surface, a sample must be returned to the Earth for evaluation. Although chances are slim that life exists on the planet, NASA must identify zones of minimal biologic risk to humans through unmanned missions, using organic carbon detection techniques or by analyzing a sample returned to Earth. At the same time, NASA needs to implement a series of safeguards to protect the Earth from potential contamination when the missions return from space. NASA and its international partners plan to send data-gathering robotic missions to Mars every two years until 2011 to study the environment, climate, and geology, and to determine if life ever arose on the planet. This study was requested and funded by NASA. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit institution that provides science and technology advice under a congressional charter. The report, Safe on Mars: Precursor Measurements Necessary to Support Human Operations on the Martian Surface, is available on the Internet at http://www.nap.edu. Copies will be available for purchase later this summer from the National Academy Press: phone 202-334-3313 or 1- 800-624-6242. Reporters may obtain a pre-publication copy from the Office of News and Public Information (contacts listed below). The full report is available for online viewing at http://www.nap.edu/books/0309084261/html/. Contacts: Nicole Ruediger, Media Relations Officer Andrea Durham, Media Relations Assistant Phone: 202-334-2138 E-mail: news@nas.edu An additional article on this subject is available at http://www.cnn.com/2002/TECH/space/05/01/mars.visitors.ap/index.html. _____________________________________________________________________ DETECTING OTHER WORLDS VIII: RADIO DETECTION By Laurance Doyle From Space.com 2 May 2002 We have discussed to date seven methods for detecting extrasolar planets in this series. During that time another two dozen extrasolar giant planets have been discovered, and the Kepler Mission, which will detect Earth-like planets around Sun-like stars, has been accepted by NASA as a Discovery Program. Within the next decade, therefore, we should have an idea if other "Earths" exist. Could there be a more exciting time than the beginning of such a Renaissance in our perspective of our place in the universe? ...Today we will discuss the detection of extrasolar planets using radio telescopes. Jupiter, for example, puts out radio signals due to its huge magnetic field. An extremely simplified model of magnetic fields requires two components: a metallic core and movement. Jupiter's hydrogen core is metal-like and the planet itself rotates about twice as fast as the Earth, giving it a magnetic field that can, for example, deliver 5 million amps of electric current to its nearest large moon, Io... ...As far as detecting evidence of exobiology, radio is a very good candidate... The main endeavor, of course, is to detect narrow-band radio signals from another civilization. Get the full story at http://www.space.com/searchforlife/seti_doyle_020502.html. _____________________________________________________________________ REVEALING THE RED PLANET: FREE LECTURES ON AN ODYSSEY TO MARS NASA/JPL release 2 May 2002 There is good reason Mars is named after the Roman god of war. It has been a battle getting to and researching the elusive red planet. The Jet Propulsion Laboratory, Pasadena, CA, continues to lead NASA's exploration of Mars. In a pair of free lectures titled "The Odyssey to Mars," JPL's newly appointed Mars Odyssey project manager, Roger Gibbs, will discuss the challenges of Mars exploration. The first lecture will be held May 9 at JPL, and the second on May 10 at Pasadena City College. The presentation will focus on the success of Mars Odyssey, and how learning from past mistakes assured the Odyssey spacecraft arrived on time and on target into orbit around Mars last October. Gibbs will also describe how Odyssey is unveiling the mysteries of the red planet's mineral and chemical composition and how the mission fits into NASA's broader Mars Exploration Program. A webcast of the lecture will be available at 7:00 PM Thursday, May 9, at http://www.jpl.nasa.gov/events/lectures/may02.html. Both lectures are open to the public and will start at 7:00 PM. Seating is on a first-come, first-served basis. Thursday's lecture will be in JPL's von Karman Auditorium, located at 4800 Oak Grove Drive in Pasadena, off the Oak Grove Drive exit of the 210 (Foothill) Freeway. Friday's lecture will be at the Pasadena City College Forum, located at 1570 East Colorado Blvd. For more information, call 818-354-0112 or go to http://www.jpl.nasa.gov/events/lectures.html. JPL is a division of the California Institute of Technology in Pasadena. Contact: Colleen Sharkey Phone: 818-354-0372 _____________________________________________________________________ NASA TO TEST MICROWAVE EFFECTS ON PLANT GROWTH By John Bluck NASA/ARC release 02-055AR 2 May 2002 Microwaves derived from solar power and transmitted by orbiting satellites to electric power stations on Earth may someday enable U.S. energy self-sufficiency, but is this method safe for local plant life? NASA scientists are about to test that hypothesis by evaluating the effects of continuously beaming weak microwaves on alfalfa plants during laboratory tests. "One of our main questions is how organisms will respond to sustained microwave exposure because the beam from space will be on all the time," said scientist Jay Skiles of NASA Ames Research Center in California's Silicon Valley. Skiles has designed a series of experiments to test the effects of weak microwave illumination on plants at 2.45 GHz frequency. "We expect that the microwave intensity at ground level will be about a million times less than that in a typical microwave oven." "Our hypothesis is that plants exposed to microwaves will be no different from those plants that are not exposed to microwaves," Skiles said. He now is conducting a prototype experiment in which he illuminates alfalfa plants with low-power microwaves. "The experiment is designed so that the only variable to which the plants are subjected is microwave exposure," he explained. The space solar power concept envisioned by some engineers requires putting satellites into a geosynchronous orbit at an altitude of 22,300 miles (40,140 kilometers) over the equator. In such an orbit, satellites revolve around the Earth at the same speed as the planet rotates, causing the satellites to appear to 'hover' over the same point on the ground below. And at that altitude, they are continuously in sunlight. Solar cells on the satellites would change energy from sunshine into electricity. A satellite system would convert the electricity into microwaves and beam them to receiving antennae on the Earth's surface. There, systems would convert the microwave energy back into electricity and feed it into the nation's power grid. Microwaves are a small part of the electromagnetic spectrum that includes energy frequencies from x-rays to visible light and radio waves. "These microwaves are in the radio frequency range, at the same frequencies at which many cell phone services operate," according to Skiles. During his current prototype experiment, Skiles broadcasts microwaves over a tray of alfalfa plants in a laboratory. The microwaves reflect onto the test plants. At the same time, nearby 'control plants' are not subjected to microwaves. A 'control' in a scientific experiment is something used as a standard for comparison. Both the test plants and the control plants are subjected to the same temperature and lighting regime, and they are grown in the same size pots in the same kind of potting mix. Skiles is measuring plant gas exchange and leaf chlorophyll concentration. "Also measured are gross plant variables, such as stem length and overall vigor," he said. "This prototype experiment will provide preliminary results based on a 14-hour artificial day and constant temperature." Skiles also is preparing to conduct a longer, 6-month experiment in a rooftop greenhouse at NASA Ames starting in late spring. "We are going to duplicate the prototype experiment in natural sunlight, and we will have night and day temperature changes that will give us more realistic environmental values," he said. "Alfalfa begins to flower in late September, when we begin to get shorter days in the Northern Hemisphere, and we will end the experiment then when the plants are getting ready to winter." "Nobody has accomplished 2.4 GHz sustained microwave plant- illumination experiments before, to the best of our knowledge," he said. Skiles chose to test alfalfa because it is an important crop that animals and people eat. Alfalfa also is representative of a broad class of economically important plants, he added. Skiles said he is planning additional, longer experiments to test a variety of plants under various conditions. "Long-duration mixes of plant species experiments as well as testing single plant species for response to microwaves under stressful conditions, including plants from a desert ecosystem, will be future tests," he said. In 1968, Peter Glaser first described the concept of space solar power in an article, "Power from the Sun: Its Future," which appeared in the journal Science. "In the late 60's, the science, engineering and technology available made the implementation of space solar power infeasible," Skiles said. "Recently, the National Research Council, an arm of the National Academy of Sciences, in a publication called, 'Laying the Foundation for Space Solar Power: an Assessment of NASA's Space Solar Power Investment Strategy,' gave a qualified go-ahead for initial space solar power technology research and development. In prior assessments, the NRC had indicated that it was premature to pursue this field of R&D," Skiles said. The National Academy of Sciences qualified its recommendation that a space solar power project is feasible by stating that NASA should partner with other government agencies such as the Department of Energy, Skiles said. "This effort could be important for national security because space solar power provides one more option that might enable energy independence in the future," he said. The NASA Glenn Research Center, Cleveland, Ohio, manages the space power project. NASA's Human Exploration and Development of Space strategic enterprise, Washington, DC, directs the space solar power investigations for the agency. High-resolution images in publication format are available on the World Wide Web at http://amesnews.arc.nasa.gov/releases/2002/02images/microwaveplants/m icrowaveplants.html. Contact: John Bluck NASA Ames Research Center, Moffett Field, CA Phone: 650-604-5026 or 604-9000 E-mail: jbluck@mail.arc.nasa.gov An additional article on this subject is available at http://www.spacedaily.com/news/ssp-02b.html. _____________________________________________________________________ THE CHANCE OF FINDING ALIENS By Alan M. MacRobert and Govert Schilling From Sky and Telescope 3 May 2002 In 1961 astronomer Frank Drake wrote the equation that put the search for alien civilizations on a scientific footing and launched the modern SETI movement. How do the numbers look today? Searching for extraterrestrial life has become a hot topic among astronomers, biologists, and the general public. But not many remember how the subject was jump-started more than 40 years ago. Get the full story at http://skyandtelescope.com/resources/seti/article_244_1.asp. _____________________________________________________________________ NASA JPL SOLAR SYSTEM TALK SERIES JPL release http://www.rhfleet.org/site/education/eduprograms/jpltalk.html 5 May 2002 NASA Jet Propulsion Laboratory Ambassadors: Captain Dorice Odell, James Butts and Grace Chen. Sponsored by the Jet Propulsion Laboratory in Pasadena, a lead research and development center for the National Aeronautics and Space Administration (NASA), this exciting program brings the wonder of the latest solar system exploration to you. This new, ongoing talk series will keep you updated with the very latest information from NASA's space probes, as they explore Mars, Jupiter, Saturn and beyond. A limited number of free NASA posters, photos, stickers and other items will also be available at these events. Saturday, May 4th, 2002 On the nearest weekend to SPACE DAY 2002, find out more about our nearest star, that makes life on Earth possible--our sun. SOHO, the Solar and Heliospheric Observatory is a joint mission between NASA and the European Space Agency, studying the sun 24 hours a day, 365 days a year, probing the intriguing mysteries of "space weather". 1:00 - 2:00 PM Saturday, May 18th In collaboration with our latest IMAX movie, SPACE STATION, NASA's Ambassadors will share with you the latest information on what's happening on this International effort to live and work in space permanently. 2:00 - 3:00 PM Saturday, July 20th To celebrate the anniversary of the day the Apollo 11 mission landed on the Moon, we will take a look back at this historic event where humankind left footprints in the lunar dust. 1:00 - 2:00 PM Saturday, August 17th Learn the latest from the Galileo and Cassini space probes--the most ambitious planetary space exploration missions ever! See the remarkable accomplishments of these two successful probes exploring the Saturn and Jupiter systems, including visiting many of their mysterious moons, and parachuting a probe onto Titan's surface. 1:00 - 2:00 PM Saturday, September 21st JASON 1--San Diego residents know what an important effect the oceans have on our weather, our livelihoods and our economy. Jason 1, a joint mission of the United States and France, provides a unique global view of the oceans that is impossible to acquire except from space. Jason 1 is able to measure the large and small hills and valleys of the ocean's surface, allowing scientists to calculate the speed and direction of ocean currents and monitor global ocean circulation. 1:00 - 2:00 PM These talks take place in the Lecture Hall, and are free with science center admission. For more information, please call the Education Department at 619-238-1233 x808. _____________________________________________________________________ NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/webdata/users/dthomas/astrobiology/astrobiology.h tml 6 May 2002 Astrobiology, exobiology and terraformation articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s1.html L. Doyle, 2001. Changing phases: detecting other worlds with the fade-in/fade-out method. Space.com. L. Doyle, 2001. Detecting other worlds: the 'flash' (gravitational lens) method. Space.com. L. Doyle, 2001. Detecting other worlds: the photometric transit or 'wink' method. Space.com. L. Doyle, 2001. Detecting other worlds: the 'pulse' method. Space.com. L. Doyle, 2001. Detecting other worlds: the wobble method. Space.com. L. Doyle, 2001. Timing eclipsing binary stars or the 'do-si-do' method. Space.com. L. Doyle, 2002. Detecting other worlds VIII: radio detection. Space.com. Human space exploration and microgravity effects articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s3.html Associated Press, 2002. Report: Mars explorers must weigh contamination risks. CNN. H. Black, 2002. [Bone] Loss in space. The Scientist, 16(9):21. SpaceDaily, 2002. Space travelers should take care to avoid getting radiated. SpaceDaily. Search for extraterrestrial intelligence (SETI) articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s4.html A. M. MacRobert and G. Schilling, 2002. The chance of finding aliens. Sky and Telescope. Astrobiology and extreme environments book list http://www.lyon.edu/webdata/users/dthomas/astrobiology/astrobiology_b ooks.html D. J. Darling, 2002. Life Everywhere: The Maverick Science of Astrobiology. Basic Books, New York. D. Goldsmith and T. Owen, 2001. The Search for Life in the Universe, 3rd Edition. University Science Books, Sausalito. M. J. Rees, 2001. Our Cosmic Habitat. Princeton University Press, Princeton. _____________________________________________________________________ CASSINI SIGNIFICANT EVENTS NASA/JPL release 25 April - 1 May 2002 The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, May 1. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" web page located at http://saturn.jpl.nasa.gov/cassini/english/where/. This week marks the four-year anniversary of the Cassini Venus 1 flyby. Onboard activities this week included Periodic Instrument Maintenance for the Ultraviolet Imaging Spectrograph, Imaging Science Subsystem decontamination activity #1, clearing of the ACS high water marks, and an autonomous CDS Solid State Recorder memory load partition repair. The C32 sequence was approved at the Preliminary Sequence Integration and Validation meeting. The sequence will be uplinked and begin execution next week. As part of validation for the new command system, C32 will be radiated using the new Spacecraft Message File format rather than the old Command Packet File. C32 will be the largest file sent so far using the new command system. Cassini participated in a DSN array test at the DSS complex in Goldstone, California. Cassini results indicated the test was a success with a 1 dB gain in signal level and 3 dB gain in telemetry signal to noise ratio. DSN personnel are still analyzing test data. Science Planning is preparing for the kickoff of the first tour Science Operations Plan (SOP) implementation activity. This process will implement sequences 9 and 10 of the tour. An SOP implementation schedule has been developed using two concurrent processes and two sequences per process approach, and a kickoff package is being generated. The Huygens Implementation team held its second quarterly progress meeting at Alcatel in Cannes. The team has agreed upon a set of flyby conditions that are independent of the decision to pre-heat the probe prior to entry into Titan's atmosphere. The decision on whether to pre-heat the probe will be made later after the probe instruments can make a complete assessment of the impact. Other topics discussed were link budget updates, mission analysis and robustness studies, and entry sensitivity studies. The Navigation team has released a new reference trajectory for the orbital tour and the remainder of interplanetary cruise. This new trajectory includes the latest flyby geometry for the revised Huygens mission and the final icy satellite adjustments and changes made for G-ring crossings. This trajectory will serve as the reference for the Science Operations Plan that will begin development in May. An updated strawman presentation of DSN coverage to be requested for [revisions] 20 through end of tour was presented at this week's Mission Planning Forum. Discussion included the plan's consistency with overall data volume requirements, navigation tracking requirements, orbital trim maneuver placement, sequence boundaries, Target Working Team boundaries, and engineering events. A meeting was held to finalize Uplink Operations development of the Automated Sequence Processor. A preliminary version will be available in the fall of 2002, with a final version being delivered in fall of 2003. This software subsystem will be a Cassini adaptation of what is already in use within the Mars Program. It will allow for a more automated way to process real-time command requests from remote users. Mission Assurance coordinated the first Quarterly Risk Team Meeting to assess and re-assess risks in the Cassini Significant Risk List. This meeting produced some valuable discussion on risk issues and focused on addressing Cruise Risks. Four new consumables risks were identified, for addition to the Significant Risk List (SRL). Future Risk Team Meetings will be scheduled to address SOI, tour, and Probe mission risks. Mission Assurance completed a trend analysis of sequence and command errors experienced since launch. Error rates were trended with the rate of uplink activity to the spacecraft. Trend analysis indicates that the error rate has decreased since launch, and despite periodic fluctuations, has remained relatively stable. An RFP was released this week for a Saturn/Cassini-Huygens updateable planetarium show. Total show length will be approximately 20-30 minutes. The Cassini/Huygens mission seeks proposals for shows serving both the small and rural planetaria community through the mid and upper range community. The initial version of the show is to be ready for release in 2003 and will highlight the launch, cruise flight, flyby of Jupiter, approach to Saturn, and the events that will occur upon arrival at Saturn. A second version is planned to be released in mid-2005. Outreach staff traveled to Berkeley, California to meet with individuals from the Bay Area Writing Program (BAWP) and project FIRST. This meeting was the first organizational step toward implementation of Cassini's K-4 language and reading program. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, CA, manages the Cassini mission for NASA's Office of Space Science, Washington, DC. _____________________________________________________________________ GLOBAL SURVEYOR CONTINUES ITS WATCH ON THE RED PLANET NASA/JPL release http://mars.jpl.nasa.gov/spotlight/mgscontinuesAll.html 26 April 2002 Weather reports from Mars, global mapping, inspection of potential landing sites, more data about the red planet than from all previous missions--no problem for the hardworking Mars Global Surveyor spacecraft. In fact, the Global Surveyor has been so successful that it earned an extension following conclusion of its prime mapping mission early in 2001. The second extension began in April 2002 and will continue the mission into late 2004. "Things are going well," said Tom Thorpe, Mars Global Surveyor project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We've accomplished all of our primary mission objectives to date and the science instruments have returned a tremendous amount of data. Now we're looking forward to all the science to come in the second extension." In addition to mapping operations, the spacecraft is targeting images of potential landing sites for the 2003 Mars Exploration Rovers. In its extended mission, the Surveyor has been given latitude to take pictures at different angles and target areas missed in the prime mission. One of the tasks that scientists want to do is obtain stereo (three-dimensional) images of some areas already covered. To do this, the spacecraft has to be pointed off-nadir. Nadir is the point directly below the observer; hence if the spacecraft is "tipped," the target can be imaged up to 30 degrees away from the original ground track. When a place imaged from one angle is pictured again from another angle, the images can be overlaid to create a stereo picture. This technique is useful for providing dramatic views of the planet's surface and to study the vertical profile of its atmosphere. For example, scientists want as complete a picture as possible of potential landing sites for the 2003 Mars Exploration Rovers. The stereo images taken by Global Surveyor will help substantially in the final site selection. "There is still so much to learn about Mars," said Mars scientist Dr. Ken Edgett, Malin Space Science Systems, San Diego, Calif. "Our high-resolution camera is testing hypotheses formulated over the past two decades using Mariner 9 and Viking data and even new theories from Surveyor and Mars Odyssey images. We're seeking to understand previous observations, and to monitor changes that are taking place due to weather and changes in polar frost." So how's the weather on Mars? Mars has seasons, just as Earth does. Using the Mars orbiter camera on Surveyor, scientists are now able to monitor the red planet's weather changes from one Martian year (about twice as long as an Earth year) to the next. One of their discoveries has been that the southern polar ice cap, long thought to be permanent, isn't so permanent. "What we're finding is just short of incredible," said Edgett. "For most of the Mars year, the weather patterns are very predictable. Last year, in late June, we had global dust storms that obscured the planet for three months--an event that did not fit the patterns we'd otherwise seen. We found that there were lots of storms going on at once, not that there was one gigantic global dust storm, as was thought during previous events." Thorpe said, "The weather reports are very important, since weather will affect future spacecraft landings and operations on the surface of Mars, including the 2003 Mars Exploration Rovers." Weekly Mars weather reports are available by going to the Mars Exploration page at http://mars.jpl.nasa.gov and clicking on the "How's the Weather on Mars" box. Students interested in exploring Mars further can go to http://mars.jpl.nasa.gov/classroom/students.html for more information on the red planet. Extensions lead to discoveries "One of the reasons I'm so very excited about the second extension is because every week there is something new and surprising in our data," said Mars scientist Ken Edgett. "And what's really cool is that every four to six months we discover something totally amazing. Last year, we were flabbergasted to find that the southern polar "permanent" ice cap isn't so permanent. We're now tracking changes to the cap on shorter time scales." Each winter, frost forms a seasonal polar cap covering everything from 60 degrees latitude to 90 degrees latitude; it retreats in spring. The permanent ice cap, which is mostly carbon dioxide, remains through the entire summer and was previously thought to be permanent. "We now know that even in summer the ice is subliming (converting directly from solid to vapor) at a rate that suggests the entire cap could disappear in a few thousand to tens of thousands of years," said Edgett. "There's a lot of carbon dioxide in the permanent cap, but we're finding that it is going away on a larger time scale [than the seasonal frost], independent of season." For more information and images, please see http://www.msss.com/mars_images/moc/CO2_Science_rel/. _____________________________________________________________________ MARS GLOBAL SURVEYOR AGING GRACEFULLY NASA/JPL release http://mars.jpl.nasa.gov/spotlight/mgsage01.html 3 May 2002 As an automobile ages, it usually requires more trips to a mechanic. Spacecraft are designed for a primary mission; when all is going well, the mission is often extended to obtain more data for other research objectives. But spacecraft are also subject to the ravages of time and wear. The Mars Global Surveyor is now in its second extension following a very successful primary mission and is providing scientists with valuable information about how the red planet changes over time. Since there are no service garages in space, mission planners have to perform any needed repairs from the ground, including finding ways to save fuel. Fuel savings important To make mission extensions possible, it is important to economize on the fuel that keeps the spacecraft in its proper alignment in space. The spacecraft's power comes from its solar panels, but it needs fuel to continually adjust its position in space so it can keep itself steady to make observations and turn to communicate with Earth. The spacecraft is currently in a position 16 degrees off-nadir, looking slightly backwards. (Nadir is the point directly below the spacecraft.) Scientists call this position Relay 16. This saves fuel because in this orientation the spacecraft is more aerodynamic, thus reducing drag that occurs when any vehicle travels through air or space. The more fuel Surveyor saves, the longer the mission can be extended to continue science activities. The off-nadir position also aids scientists in their studies, since it enables them to obtain three-dimensional images of some areas already imaged. Problem-solvers "R" us "We've been so successful because the operations team has always found a way to overcome any problem the mission has had over all the years it's been in operation," said Mars Global Surveyor Mission Manager Gene Brower. "The high-gain antenna fix is a prime example." Shortly after mapping began in March 1999, the high-gain antenna experienced an obstruction when commanded to point at directions less than 41.5 degrees azimuth. (Altitude and azimuth form an astronomical coordinate system for defining position.) In consequence, during times of the year when the Earth reaches this location as seen from Mars, a special operation known as a "beta supplement" is required. Between March 2002 and September 2003, the high-gain antenna must be flipped over against its boom to drive it in the opposite direction. The antenna must then flip back as it crosses the equator of Mars each orbit in this configuration. All of this movement combines to "disturb" the motion of the spacecraft slightly, increasing momentum buildup in the reaction wheels that control attitude. Excess momentum is removed by using the thrusters to apply torque. This technique consumes fuel too, but that use is partially offset by the off-nadir configuration of the spacecraft. "That ingenious fix solved the problem," Brower said. Do spacecraft age? "I do get concerned as Surveyor ages," said Mars Global Surveyor Project Manager Tom Thorpe. "The spacecraft has gone into contingency mode four times during the past six months, but each time we were able to restore communications." The contingency mode situation is the result of confusion with the spacecraft's star tracker. The star tracker fixes on a star pattern to help the spacecraft orient itself in space. Several times, the tracker fixed on a wrong star field after the spacecraft turned back from off-nadir targeting. The onboard software wasn't originally programmed to account for the Relay 16 attitude and the star tracker became confused. This caused the spacecraft to turn the high-gain antenna away from Earth. A built-in script placed Surveyor in contingency mode, as it was programmed to do. Ground controllers restored communications with the spacecraft and are now updating the software code. "This fix should keep us out of star sensor-induced contingency mode," said Thorpe. "We're confident in the Surveyor's abilities and, all in all, we have a healthy spacecraft," he added. Science: A+ The Global Surveyor has studied the entire Martian surface, atmosphere, and interior, and has returned more data about the red planet than all other Mars missions combined. Observations by the spacecraft are expanding our understanding of the Martian climate and may indicate the climate is changing significantly even today. Among key science findings, Surveyor has taken pictures of gullies and debris flow features that suggest there may be current sources of liquid water, similar to an aquifer, at or near the surface of the planet. _____________________________________________________________________ MARS ODYSSEY THEMIS IMAGES NASA/JPL/ASU release 29 April - 3 May 2002 * Crustal Fractures of Ophir Planum (Released 29 April 2002) http://themis.la.asu.edu/zoom-20020429a.html * Cratered terrain in Terra Meridiani (Released 30 April 2002) http://themis.la.asu.edu/zoom-20020430a.html * Syrtis Major (Released 1 May 2002) http://themis.la.asu.edu/zoom-20020501a.html * Clouds in the Northern Tempe Terra (Released 2 May 2002) http://themis.la.asu.edu/zoom-20020502a.html * Degraded Crater Rim (Released 3 May 2002) http://themis.la.asu.edu/zoom-20020503a.html All of the THEMIS images are archived at http://themis.la.asu.edu/latest.html. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, DC. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. Dr. Philip Christensen leads the THEMIS investigation at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena. _____________________________________________________________________ STARDUST STATUS REPORT NASA/JPL release 3 May 2002 There were two Deep Space Network (DSN) tracking passes this past week. The spacecraft health was excellent with no ill effects due to the passage through aphelion--its furthest distance from the Sun. Analysis of the recorded engineering data indicates there was sufficient power margin at aphelion. The average solar array usage was 84 percent or 5.8 amps. The Battery State of Charge (SOC) was 90.5 percent at the end of the last DSN pass. Although Stardust has passed aphelion, the Battery SOC is expected to continue to decrease because the Sun-Probe-Earth (SPE) angle is increasing. The SPE angle will reach its maximum of 21.8 degrees later this month. For more information on the Stardust mission--the first ever comet sample return mission--please visit the Stardust home page at http://stardust.jpl.nasa.gov. _____________________________________________________________________ End Marsbugs, Volume 9, Number 18.