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Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: Lunar Prospector Update - March 18, 1998 Привет всем! Вот, свалилось из Internet... Lunar Prospector Status Report #25 March 18, 1998 - 7:00 p.m. EST (4:00 p.m. PST) The Lunar Prospector spacecraft continues to perform nearly flawlessly, and all instruments are collecting good data, according to Mission Control at NASA's Ames Research Center. On the evening of Thurs., March 12 (PST), the Moon (and the spacecraft circling it) were participant to a penumbral lunar eclipse, in which sunlight (shining on the Moon) was partially blocked by the positioning of the Earth relative to the Sun. In general, a lunar eclipse takes place when the Moon falls -- either partially or entirely -- into the Earth's shadow. However, during what's called a "penumbral" lunar eclipse, in which the Moon enters an only partially darkened region of the Earth's shadow (called the penumbra), the entire Moon is thus only partially shadowed, dimming the lunar surface, and consequently, diminishing solar array current on an orbiting spacecraft. This is in contrast to a "partial total" lunar eclipse, when only a section of the Moon falls into the Earth's completely shadowed region (called the umbra), causing that wedge of the Moon to be completely blocked from sunlight. (See Lunar Prospector Status Report #21 for a diagram depicting penumbral lunar eclipses). During the March 12 penumbral eclipse, mission controllers noted a predictable decrease in solar array current. In addition, Prospector's battery showed a slight discharge before the spacecraft entered its usual 46-minute eclipse while traversing the night side of the Moon. Recharge following the eclipse was nominal. ---------------------------------------------------- The current state of the vehicle (as of 4:00 p.m. (PST) on Wed., March 18, 1998), according to Mission Operations Manager Marcie Smith, is as follows: General Spacecraft Orbit Number: 797 Data Downlink Rate: 3600 bps Spin Rate: 11.95 rpm Spin Axis Altitude: (see below) Trajectory Periselene: 84 km Aposelene: 115 km Period: 118 minutes Inclination: 90.4 degrees Occultations: 40 minutes in duration Eclipses: 46 minutes in duration ---------------------------------------------------- On Fri., March 13 (PST), mission controllers reset the spacecraft's spin axis approximately 2 degrees, to position the Sun just above the top part of the spacecraft, for reasons of thermal control (since the booms are located on the bottom part of the spacecraft, they could potentially shadow some of the solar panels if the Sun were shining on the bottom of the spacecraft).. Also on that day, controllers trimmed the spin rate, in order to correct for small changes which had perturbed it during the orbit trim maneuver performed a week earlier. The precise command timeline was as follows: Fri., March 13, 12:00 p.m. (PST) Thruster heaters on Fri., March 13, 12:04 p.m. (PST) Maneuver parameters loaded Fri., March 13, 12:26 p.m. (PST) Thruster A1 and A4 fired (13 pulses) to adjust spin axis 1.7 degrees Fri., March 13, 12:31 p.m. (PST) Thruster heaters on Fri., March 13, 12:40 p.m. (PST) Maneuver parameters loaded Fri., March 13, 12:50 p.m. (PST) Thruster T1 fired for 0.81 seconds Fri., March 13, 12:51 p.m. (PST) Thruster parameters resest Mission controllers are still investigating the results of the spin axis re-orientation by reviewing spacecraft attitude (positioning) data both before and after the maneuver. The spin trim was exactly on target, adjusting the spin rate from 12.17 rpm to 11.95 rpm. Alison Davis Lunar Prospector Mission Office NASA Ames Research Center Moffett Field, Calif. 94035 Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: Cassini Update - March 20, 1998 Привет всем! Вот, свалилось из Internet... Cassini Significant Event Report For Week Ending 03/20/98 Spacecraft Status: The Cassini spacecraft is presently traveling at a speed of approximately 142,000 kilometers/hour (~88,000 mph) relative to the sun and has traveled approximately 413 million kilometers (~257 million miles) since launch on October 15, 1997. The most recent Spacecraft status is from the DSN tracking pass on Thursday, 03/19, over Madrid. The Cassini spacecraft is in an excellent state of health and is operating nominally. The C6 sequence activities concluded Sunday, 03/15. The C7 sequence activities began on Sunday, as planned. The C7 sequence will run through Sunday, May 10. Inertial attitude control is being maintained using the spacecraft's hydrazine thrusters (RCS system). The spacecraft continues to fly in a High Gain Antenna-to-Sun attitude. It will maintain the HGA-to-Sun attitude, except for planned trajectory correction maneuvers, for the first 14 months of flight. Communication with Earth during early cruise is via one of the spacecraft's two low-gain antennas; the antenna selected depends on the relative geometry of the Sun, Earth and the spacecraft. The downlink telemetry rate is presently 40 bps. Spacecraft Activity Summary: On Friday, 03/13, and Saturday, 03/14, there were no changes in spacecraft configuration. On Sunday, 03/15, the two 44 Watt Infrared Optics decontamination heaters of the Visual and Infrared Mapping Spectrometer (VIMS) instrument were turned off, the requirement having been met to operate these heaters for the first 150 days of flight. These heaters have served to keep spacecraft outgassing products, which decrease during the first few months of flight, from accumulating on otherwise cold optical and radiative surfaces of the VIMS instrument. Two lower power VIMS heaters were left on, continuing the decontamination for the instrument at a lesser level. On Monday, 03/16, there were no changes in spacecraft configuration. On Tuesday, 03/17, the Solid State Recorder (SSR) record and playback pointers were reset, according to plan. This housekeeping activity, done approximately weekly, maximizes the amount of time that recorded engineering data is available for playback to the ground should an anomaly occur on the spacecraft. Also on Tuesday, and extending into Wednesday, 3/18, the SRU-B Decontamination mini-sequence was uplinked and executed. This activity heats the stellar reference unit (SRU) radiator to eliminate any contamination that may have accumulated early in flight. Following the heating period, the radiator is allowed to cool; star data is then collected using the SRU to verify proper functionality. Although both activities executed as planned, the radiator heating on Tuesday fell short of the expected temperature; this result is being analyzed by the thermal engineers. Star data was successfully collected on Wednesday and is presently being analyzed. No changes are needed to the upcoming SRU decontamination activity for SRU-A (scheduled for 3/24 and 3/25). Also on Wednesday, the now standard SSR Flight Software Partition maintenance activity was performed. This activity repairs any SSR double bit errors (DBEs) which have occurred in the code-containing portions of the Flight Software partitions during the preceding period. On Thursday, 03/19, there were no changes in spacecraft configuration. Upcoming events: Events for the week of 03/20 through 03/26 include: SSR Pointer reset (03/20), AACS Mass Properties MRO prior to TCM #3 (03/24), uplink and execution of SRU-A Decontamination (03/24 - 03/25), SSR Pointer reset (03/26), and Huygens Probe Check-out #2 (03/26). DSN Coverage: Over the past week Cassini had 10 DSN tracks occurring daily from Friday (03/13)through Thursday (03/19). In the coming week there will be 8 DSN passes. Science Office Activity Summary: The last Cassini Facility Instrument Letter of Agreement has now been signed by the Cassini Radio Science Team Leader and the Cassini Program Manager. United States Geological Survey work orders are now in place for the services of two more Cassini Science Team members, bringing the total to 35 of 37 science contracts or work orders now in effect. The remaining two, also with USGS, are expected to be completed soon. Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: Galileo - Countdown To Europa Привет всем! Вот, свалилось из Internet... GALILEO - COUNTDOWN TO EUROPA March 25, 1998 It is now 3 days and 19 hours to the Galileo spacecraft's next encounter with Europa. A special Countdown to Europa home page is now available on the Galileo Home Page: 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 embarked on a two-year extended mission, called Galileo Europa Mission (GEM). During GEM, Galileo will make 8 close flybys of Europa, four flybys of Callisto, and two close encounters with Io provided the spacecraft is still alive. The third encounter for GEM is scheduled for Europa on March 29, 1998 at 13:23 UT. With a diameter of 3,138 km, Europa is slighty smaller than our own Moon and is the smoothest object in the solar system. On Galileo's previous encounters with Europa, evidence of a possible ocean were found, including the discovery of ice vocalnoes (non active), probable icebergs, and salt deposits on the surface. Galileo will continue its attempt to find additional evidence of a liquid ocean underneath Europa's icy crust and look for signs of active volcanism on the moon's young surface. On the upcoming encounter, the spacecraft will pass by Europa at a distance of 1,649 km, which is 124 times closer than Voyager's closest approach. Galileo will focus on Mannann'an crater and Tyre macula. Observations of Io, Ganymede and Callisto will also be taken. Highlights of the Countdown to Europa home page: o A virtual flyby of Europa with computer-generated approach images of Jupiter and Europa displayed at the top of the home page. These images are all updated every 5 minutes. o Live Doppler plots of Galileo spacecraft radio signal as it received on Earth. Watch the gravity of Europa change the frequency of the radio signal in real-time. The Doppler plots will be updated every minute on encounter day (March 29). o Flyby animation of the Europa 14 flyby. o The latest Galileo status reports reporting on the Europa 14 encounter. o Fact sheets and Europa, Callisto and Io. o A detailed timeline of events and sequences that the spacecraft will perform for the Europa 14 encounter. o Voyager 1 & 2 images of Callisto, Ganymede, Europa and Io. o Hubble Space Telescope images of the Galilean satellites. o Pioneer 10 & 11 images of Callisto, Ganymede, Europa and Io. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ Pasadena, CA | The truth always turns out /___| | | | ___/ | |/__ /| | to be simpler than you |_____|/ |_|/ |_____|/ | thought. Richard Feynman Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: WDC-A R&S Launch Announcement 12926: Iridium 51 Привет всем! Вот, свалилось из Internet... COSPAR/ISES WORLD WARNING AGENCY FOR SATELLITES WORLD DATA CENTER-A FOR R & S, NASA/GSFC CODE 633, GREENBELT, MARYLAND, 20771. USA SPACEWARN 12926 COSPAR/WWAS USSPACECOM NUMBER SPACECRAFT INTERNATIONAL ID (CATALOG NUMBER) LAUNCH DATE,UT IRIDIUM 51 1998-018A 25262 25 MARCH 1998 ..JOSEPH H. KING, DIRECTOR, WDC-A-R&S. [PH: (301) 286 7355. E-MAIL: KING@NSSDCA.GSFC.NASA.GOV 25 MARCH 1998, 22:40 UT] Dr. Edwin V. Bell, II _/ _/ _/_/_/ _/_/_/ _/_/_/ _/_/ Mail Code 633 _/_/ _/ _/ _/ _/ _/ _/ _/ NASA Goddard Space _/ _/ _/ _/_/ _/_/ _/ _/ _/ Flight Center _/ _/_/ _/ _/ _/ _/ _/ _/ Greenbelt, MD 20771 _/ _/ _/_/_/ _/_/_/ _/_/_/ _/_/ +1-301-286-1187 ed.bell@gsfc.nasa.gov NSSDC home page: http://nssdc.gsfc.nasa.gov/ Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: WDC-A R&S Launch Announcement 12927: Iridium 61 Привет всем! Вот, свалилось из Internet... COSPAR/ISES WORLD WARNING AGENCY FOR SATELLITES WORLD DATA CENTER-A FOR R & S, NASA/GSFC CODE 633, GREENBELT, MARYLAND, 20771. USA SPACEWARN 12927 COSPAR/WWAS USSPACECOM NUMBER SPACECRAFT INTERNATIONAL ID (CATALOG NUMBER) LAUNCH DATE,UT IRIDIUM 61 1998-018B 25263 25 MARCH 1998 ..JOSEPH H. KING, DIRECTOR, WDC-A-R&S. [PH: (301) 286 7355. E-MAIL: KING@NSSDCA.GSFC.NASA.GOV 26 MARCH 1998, 13:50 UT] Dr. Edwin V. Bell, II _/ _/ _/_/_/ _/_/_/ _/_/_/ _/_/ Mail Code 633 _/_/ _/ _/ _/ _/ _/ _/ _/ NASA Goddard Space _/ _/ _/ _/_/ _/_/ _/ _/ _/ Flight Center _/ _/_/ _/ _/ _/ _/ _/ _/ Greenbelt, MD 20771 _/ _/ _/_/_/ _/_/_/ _/_/_/ _/_/ +1-301-286-1187 ed.bell@gsfc.nasa.gov NSSDC home page: http://nssdc.gsfc.nasa.gov/ Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: JPL Recruits Two Experts To Help Hunt For New Planets and Life Привет всем! Вот, свалилось из Internet... MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov Contact: Jane Platt FOR IMMEDIATE RELEASE March 5, 1998 JPL RECRUITS TWO EXPERTS TO HELP HUNT FOR NEW PLANETS AND LIFE Two newly-arrived scientists at NASA's Jet Propulsion Laboratory will play a key role in the search for planets around other stars and the hunt for life beyond Earth. The appointments highlight a new JPL initiative to unite scientists from various disciplines, such as biology and astronomy, to study the evolution of planets and life in the universe. Dr. Didier Queloz, a Swiss astronomer who co-discovered the first known planet around a star similar to our Sun, is a distinguished visiting scientist at JPL for the next year and a half. Dr. Kenneth Nealson has joined JPL as a senior researcher in astrobiology, a new field whose goal is to understand how planets and life co-evolve. While at JPL, Queloz will continue his search for planets and help the Lab develop sophisticated search technologies. His work will benefit NASA's Origins Program, a series of planned missions to study the formation of galaxies, stars, planets and life. The program has gained momentum from discoveries by Queloz and, subsequently, other astronomers, of several planets orbiting stars beyond our Sun. Many scientists believe this raises the odds that an Earth-like planet exists with suitable conditions for life. Queloz, a Swiss citizen, received his degree in physics in 1990 from the University of Geneva and worked on his doctoral thesis at Geneva Observatory with Professor Michel Mayor from 1991 to 1995. Using the French Elodie telescope in Haute Provence, France, they looked for signs of a Doppler shift in nearby stars. As a star moves closer and then farther away from Earth, the star's color shifts from red to blue. By detecting this motion, astronomers can infer that the star is being tugged by gravity from an orbiting planet. "Back then, these experiments were considered a bit nutty," recalled Queloz. When Queloz and Mayor first detected a Doppler shift from the star 51 Pegasus, Queloz said their first reaction was, "We'd better check our instruments." Even after they verified the instruments' accuracy, Queloz and Mayor spent several weeks monitoring 51 Pegasus to confirm the discovery. In July of 1995, they were confident enough to buy a large cake and hold a celebration party in the south of France for family and friends. Queloz and Mayor formally announced their discovery, a Jupiter-sized planet orbiting 51 Pegasus, at an October 1995 scientific meeting in Florence, Italy. Queloz has received several honors, including the Swiss Society for Physics' Balzers Award, the Bioastronomy Medal from the International Astronomical Union, Commission 51, and a Best Thesis in Science honor from a Swiss corporation, Vacheron Constantin. Queloz is continuing his hunt for new planets with the Elodie telescope and its twin, Coralie, a Swiss telescope in La Silla, Chile. But he and other astronomers face great challenges in finding new and better ways to detect planets more like Earth. Current techniques allow only for the detection of giant, Jupiter-sized planets, which are considered unlikely candidates for life. While at JPL, Queloz will share his planet-finding experience with engineers who are designing more advanced technologies. Queloz is using a testbed interferometer at Caltech's Palomar Observatory to run tests on stars and prepare for an observing program. This work will help pave the way for other Origins projects, including the W.M. Keck Observatory interferometer in Hawaii, the Space Interferometry Mission, and the Terrestrial Planet Finder, all being planned by NASA. Interferometry combines and processes light from several telescopes to simulate a much larger telescope, and holds great promise as a tool in the search for Earth-sized planets. "I'd like to play a role in future exploration by helping to define interferometry techniques," Queloz said. During his stay at JPL, Queloz is living in Pasadena with his wife and their two children. Until very recently, an astronomer like Queloz would have had little if any interaction with a biological scientist like Dr. Kenneth Nealson. But various disciplines, such as astronomy, geology, biology and chemistry, are joining forces to study the development of life on Earth and the prospects of life elsewhere. Therefore, the work of scientists like Nealson and Queloz is converging to form a broad, interdisciplinary approach. "After all," said Nealson, "life is not a simple system and no science operates in a vacuum. Younger students are studying several disciplines to gain a more comprehensive view." Nealson is part of this new wave of scientific training, as a geobiology teacher and faculty associate in Caltech's geology and planetary sciences division. At JPL, a division of Caltech, Nealson has been appointed to head a new astrobiology unit. Nealson said over the next few years, his astrobiology group will develop an understanding of the way life and planets have evolved, and will define the signatures of life. "Not many foolhardy souls have ventured into this area," Nealson said. "After all, how can you find life if you don't know what you're looking for? This is a very, very important problem to be solved because right now we're not sure how to distinguish life from non-life. Our goal is to develop tools to make that distinction clearly." In recent years, microbiologists have made startling discoveries about the hardiness of life on Earth, studying living organisms in thermal vents, acid lakes and other unlikely environments. Nealson pointed out, "This has opened the eyes of scientists to the notion that life could exist under seemingly inhospitable conditions on other planets." Astrobiologists will also study changes in Earth's chemical composition over billions of years. They will then apply this knowledge to other planets to look for "chemical signatures" that might indicate that life has existed or could exist there. Nealson said astrobiology will be useful for numerous space missions, including the Mars sample return mission, scheduled to bring back Martian rocks in the middle of the next decade. Astrobiology will also benefit the Origins Program's Terrestrial Planet Finder, which will look for Earth-like planets around other stars and hunt for signs of life-sustaining chemicals. Nealson said astrobiological studies may prove valuable in the study of Jupiter's moon, Europa, which may have liquid oceans under its frozen surface. This icy moon is currently being studied by NASA's Galileo Europa Mission, and a new Europa Orbiter has a planned launch in 2003. Originally from West Liberty, Iowa, Nealson got his bachelor of science degree in biochemistry in 1965 from the University of Chicago. He earned his Ph.D. in microbiology from the University of Chicago and did postdoctoral studies at Harvard University. Nealson taught at Scripps Institution of Oceanography, San Diego, CA, and at the Center for Great Lakes Studies, University of Wisconsin, Milwaukee, WI. His honors include the Guggenheim Fellowship for Sabbatical Leave in 1981, and an appointment as an elected fellow in the American Academy of Microbiology, which he received in November 1993. Nealson and his wife live in South Pasadena, CA. ##### Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: Don Yeomans To Lead US Science Team On Asteroid Lander Mission Привет всем! Вот, свалилось из Internet... MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov Contact: Mary Beth Murrill FOR IMMEDIATE RELEASE March 5, 1998 YEOMANS TO LEAD U.S. SCIENCE TEAM ON ASTEROID LANDER MISSION Astronomer Dr. Donald K. Yeomans has been named project scientist for the NASA portion of a joint U.S.-Japanese mission that will be the first ever to send a lander and robotic rover to an asteroid, and return an asteroid sample back to Earth. Yeomans is a senior research scientist at JPL and supervisor of the Laboratory's Solar System Dynamics Group, which is responsible for tracking all the planets, natural satellites, comets and asteroids in the solar system. He specializes in identifying the orbital paths of comets, asteroids and other bodies. Yeomans will lead the work of the U.S. science team in utilizing the scientific instruments on the tiny book-size rover being built at JPL for the asteroid lander mission, which is called MUSES-C. The U.S. and Japanese science teams will collaborate on the analysis of scientific data returned by the spacecraft, including work on the asteroid sample that will be brought back to Earth. Scheduled for launch from Kagoshima, Japan on a Japanese M5 rocket in January 2002, MUSES-C will be the world's first asteroid sample return mission and will be the first space flight demonstration of several new technologies. "MUSES-C" stands for Mu Space Engineering Spacecraft (the "C" signifies that it is the third in a series). It is part of a series of flight technology and science missions managed by the Institute of Space and Astronautical Science of Japan (ISAS). NASA's Jet Propulsion Laboratory (JPL) in Pasadena, CA, is managing the U.S. portion of the mission. Ross M. Jones is the project manager at JPL. Asteroid 4660 Nereus, a small, near-Earth asteroid nearly one mile in diameter, is the target of the MUSES-C mission that will set a lander down on the asteroid's surface, let loose a miniature rover to gather photos of the terrain, and collect and return to Earth three samples from the asteroid's surface. The lander and sample return vehicles are provided by Japan and the rover is being provided by JPL. All three vehicles will be combined as one package for flight to the asteroid. Asteroids are thought to be remnants of the material from which the inner solar system was formed 4.6 billion years ago. They are representative of the fundamental building blocks that coalesced into the terrestrial planets -- Mercury, Venus, Earth and Mars. Scientists want to study asteroids because of the clues these small bodies may hold to the origin and evolution of the solar system. Eventually, metal-rich asteroids could also serve as resources for space mining and human exploration. Yeomans is well-known for his precise orbit determinations of solar system objects. He provided the accurate position predictions that led to the first telescope sighting of comet Halley on its return visit to the inner solar system in 1982. He provided the predictions that led to the successful flybys of five international spacecraft past comet Halley in March 1986. Yeomans also provided the position predictions for asteroids 951 Gaspra and 243 Ida that helped the Galileo spacecraft to make the first close-up images of an asteroid. More recently, he worked with Dr. Paul Chodas, also of JPL, to provide the accurate predictions for the impacts of comet Shoemaker-Levy 9 with Jupiter in July 1994. Yeomans is currently a science investigator on a NASA mission to fly past three different comets. He is also the radio science team chief for NASA's Near-Earth Asteroid Rendezvous (NEAR) mission, a spacecraft headed for an encounter with the asteroid Eros. Yeomans has been given seven NASA awards including an Exceptional Service Medal in 1986. In addition, he was presented with a Space Achievement Award by the American Institute of Aeronautics and Astronautics, an award of appreciation by the Goddard Space Flight Center, Greenbelt, MD. Asteroid 2956 was re-named 2956 in Yeomans' honor. He has authored four books and more than 80 technical papers on comets and asteroids. A native of Rochester, NY, Yeomans received his bachelor's degree in mathematics in 1964 from Middlebury College in Middlebury, VT, and a master's degree in 1967 and doctorate in astronomy in 1970 from the University of Maryland. Yeomans and his wife, Laurie, have two adult children and reside in La Canada-Flintridge, CA JPL is a division of the California Institute of Technology. ##### Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: This Week on Galileo - March 9-15, 1998 Привет всем! Вот, свалилось из Internet... THIS WEEK ON GALILEO March 9-15, 1998 After ending an uneventful period of limited communications, Galileo resumes the processing and transmission of pictures and science information stored on the spacecraft's onboard tape recorder. The data was acquired and stored on the tape recorder during the spacecraft's close flyby of Jupiter's moon Europa in Dec. 1997. The 2-1/2 week period of limited communications was caused by solar conjunction, a period of time during which the sun passes between the Earth and the spacecraft and solar activity causes radio signals to and from the spacecraft to become noisy or garbled. The data scheduled for processing and transmission to Earth this week includes primarily information from the spacecraft's Near Infrared Mapping Spectrometer's (NIMS) observation of the Pwyll impact crater region on Europa. The NIMS information will allow scientists to learn more about the different types of materials found in this region. To see what this region looks like you can look for images taken by the spacecraft's camera that were recently released on our home page. Other information scheduled for transmission toward the end of this week includes data from the spacecraft's suite of fields and particles instruments that will add to the repository of information characterizing the interaction of Europa with the magnetic and electric fields surrounding Jupiter. Finally, the camera team has scheduled the processing and transmission of a picture of the Conamara Chaos region and another picture of a region of mottled terrain. If some of these information sets sound familiar, it is because they are part of Galileo's normal period of re-processing and re-transmission of observations that have previously been transmitted to Earth. This second "pass" through the recorded data allows the science teams to fill up gaps in information caused by transmission problems the first time around. The second pass also provides the opportunity to replay portions of observations that have been identified as particularly interesting or to simply add additional data from a particular observation. Also scheduled this week is a test of the spacecraft's attitude control system. This test will provide engineers with information to help them determine whether the attitude control system's anomalous behavior has stabilized or is getting worse. Remember that the spacecraft performed a close flyby of Europa just prior to the start of our period of limited communications. During this flyby, the spacecraft was once again exposed to Jupiter's intense radiation environment. Radiation is considered a leading candidate as a cause of the hardware fault in one of the attitude control system's gyroscopes, and which has led to the anomalous behavior. Limited information contained in the spacecraft's normal engineering data set suggests that the anomalous gyroscope behavior has not deteriorated. At the end of this week, the spacecraft is scheduled to perform the next flight path correction. This correction will fine tune the spacecraft's orbit as it heads back toward the Jupiter system and another close encounter with Europa. For more information on the Galileo spacecraft and its mission to Jupiter, please visit the Galileo home page: http://www.jpl.nasa.gov/galileo/ Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: Galileo Update - March 25, 1998 Привет всем! Вот, свалилось из Internet... MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov Galileo Europa Mission Status March 25, 1998 NASA's Galileo spacecraft is sending to Earth the final pictures and science information stored on its onboard tape recorder during the December 1997 flyby of Jupiter's moon Europa. These data include an observation of a region on Europa with wedge-like features, which may indicate that a liquid ocean lies under the surface, and another observation of volcanic activity on Jupiter's moon Io. An observation by the photopolarimeter radiometer is part of a series designed to look for hot spots which might offer evidence that a heat source on Europa led to the creation of a liquid ocean or slush. The flight team is preparing for Galileo's next Europa flyby, scheduled for Sunday, March 29, at an altitude of about 1,645 kilometers (1,022 miles). A flight path correction was performed on Friday, March 13, and an attitude update was performed Thursday, March 19. Both events went well, even though they used the gyroscopes, the known cause of recent anomalous behavior of the attitude control system. Precautions were taken to prevent the gyroscope anomaly from affecting activities. The flight team has decided the upcoming Europa flyby will be performed without the gyros. This means there will be no way to compensate for any wobble that may be present in the spacecraft's spin axis, and instrument pointing and stability are likely to be degraded somewhat. Only very minimal effects on images taken by the spacecraft's camera are expected, with a somewhat greater impact anticipated for another instrument, the near infrared mapping spectrometer. On Thursday, March 26, Galileo will perform its final flight path correction before Sunday's Europa flyby, and the flight team will send computer commands to control all spacecraft activity during the encounter period. Regular maintenance of Galileo's onboard tape recorder will be performed Friday. Galileo's flight team is nearing completion of modifications to the attitude control system flight software that would allow the spacecraft to operate with only one gyro. Although this won't be a complete "fix," it will eliminate the need for workarounds currently being used for maneuvers and attitude updates. The recent anomalies may be caused by Galileo's long-term exposure to Jupiter's intense radiation. The spacecraft successfully completed its primary mission in December 1997 and is now in its two-year extension, the Galileo Europa Mission. The flight team will continue to monitor the radiation's impact, but current plans include five more Europa flybys, four Callisto encounters, and one or two of Io, depending on spacecraft health. ##### Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: Planetary Society Honors Eugene Shoemaker Привет всем! Вот, свалилось из Internet... Planetary Society Honors Eugene Shoemaker with Comet and Asteroid Discovery Grant Program Named for Astronomer Shoemaker Supports Searches for Potentially Dangerous Near-Earth Objects One year ago today, this web site announced that the Planetary Society had launched its Near-Earth Object (NEO) Grant Program to help discover the comets and asteroids known to be in our planet's celestial vicinity. Since then, this ongoing program has been dubbed the Gene Shoemaker Near-Earth Object Grants -- to honor the late comet and asteroid discoverer -- and the program has given $35,000 to researchers from around the world who search for asteroids and comets with orbits close enough to Earth to pose a potential hazard to our planet. The first four recipients of the grants are now putting their grants to work in NEO detection efforts in the United States, Russia, and Australia. In the US, Walter Wild in Chicago, Illinois, and Bill Holiday in Corpus Christi, Texas lead searches that involve amateur astronomers. Wild, an astronomer at the University of Chicago, leads a group of amateur astronomers who are conducting a NEO search from Yerkes Observatory in Wisconsin. Amateur astronomer Holiday is using his grant to upgrade his home-built rotating roof observatory. Kirill Zamarashkin is the project coordinator for a joint Russian-Ukrainian search program at the Crimean Astrophysical Observatory. This research team has used its Gene Shoemaker grant money to help construct the first element of an automatic complex to search for NEOs. Based in Loomberah, New South Wales in Australia, Gordon Garradd is using his Gene Shoemaker NEO Grant to complete a 45-centimeter (18-inch) Newtonian telescope and to acquire a larger, higher-grade imaging sensor (a CCD, or charge coupled device). A recent report of Earth's impending close encounter with an asteroid (featured in an earlier headline article on this web site) emphasized the importance of detecting the comets and asteroids whose orbits might intersect Earth's. Astronomers estimate that there are several thousand NEOs larger than one kilometer and 150,000 to perhaps 100 million larger than 100 meters in size. While various astronomical groups and NASA advisory committees have made strong recommendations to accelerate discovery of these asteroids, government support for NEO search programs remains very modest. Thus, the Planetary Society's Gene Shoemaker Near-Earth Object Grants help fill this funding gap. The Planetary Society launched its Near-Earth Object Grant Program to increase the rate of discovery and to permit wider participation by amateur observers; observers in developing countries; and professional astronomers who, with seed funding, could greatly increase the potential of their programs to contribute significantly to the search. The Society accepts applications for these grants continuously. To apply for a Gene Shoemaker Near-Earth Object Grant, read the guidelines and fill out the application form, which are provided on this web site: http://planetary.org/NEO/neo-guidelines.html Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: Cassini Update - March 26, 1998 Привет всем! Вот, свалилось из Internet... MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109 TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov Cassini Mission Status March 26, 1998 Cassini's fault protection system worked as planned Tuesday after the spacecraft detected a very small orientation difference between its two stellar reference units, according to preliminary data received from the spacecraft yesterday. The event has had no impact on the mission and all planned activity for Cassini's Venus flyby next month remains on schedule. The second stellar reference unit, part of Cassini's attitude and articulation control subsystem, was in the process of taking over while the first stellar reference unit was to undergo a routine maintenance "bake-out" heating to remove normal post-launch contaminants from its aperture. This was the first use of the second stellar reference unit, and as it began operating, Cassini's attitude control software found a very small difference in the orientation of the units. Sensing this difference, the computer that controls the attitude control subsystem executed pre-programmed commands that brought the spacecraft into a low-activity state to await instruction from ground controllers. The spacecraft executed this response exactly as designed and the spacecraft remains healthy, project officials said. Cassini has remained in contact with ground controllers throughout, and engineering data on the event and the spacecraft's overall operations were received yesterday. Preliminary analysis indicates that the discrepancy was within specifications, but that control limits were set too tightly, triggering the preprogrammed commands that set the spacecraft in its low-activity state. This problem is expected to be solved easily with an adaptation made to the spacecraft's attitude and articulation control software. By early this afternoon, ground controllers will have sent commands to return the spacecraft to normal operations. Cassini remains on course for its April 26 flyby of Venus, with the last fine-tuning of the flight path, if it is needed, scheduled for early April. During its Venus flyby, Cassini's radio and plasma wave science instrument will take advantage of the opportunity to search for lightning in Venus's atmosphere. Today, the spacecraft is approximately 17 million kilometers (about 10.5 million miles) from Venus and is traveling at a speed of about 143,000 kilometers (about 88,800 miles per hour). It has traveled about 440 million kilometers (about 273 million miles) on its Saturn-bound trajectory since launch on October 15, 1997. ##### Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: Mars Global Surveyor To Attempt Imaging of 'Face' On Mars, Viking & Pa Subject: Mars Global Surveyor To Attempt Imaging of 'Face' On Mars, Viking & Pa Привет всем! Вот, свалилось из Internet... MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov Contact: Diane Ainsworth FOR IMMEDIATE RELEASE March 26, 1998 MARS GLOBAL SURVEYOR TO ATTEMPT IMAGING OF FEATURES OF PUBLIC INTEREST NASA's Mars Global Surveyor spacecraft is about to begin a summer-long set of scientific observations of the red planet from an interim elliptical orbit, including several attempts to take images of features of public interest ranging from the Mars Pathfinder and Viking mission landing sites to the Cydonia region. The spacecraft will turn on its payload of science instruments on March 27, about 12 hours after it suspends "aerobraking," a technique that lowers the spacecraft's orbit by using atmospheric drag each time it passes close to the planet on each looping orbit. Aerobraking will resume in September and continue until March 1999, when the spacecraft will be in a final, circular orbit for its prime mapping mission. It will not be possible to predict on which orbit the spacecraft will pass closest to specific features on Mars until Global Surveyor has established a stable orbit and flight controllers are able to project its ground track. This process should be completed in the next few days. The exact time of observations and the schedule for the subsequent availability of photographs on the World Wide Web are expected to be announced early next week. "Global Surveyor will have three opportunities in the next month to see each of the sites, including the Cydonia region, location of the so-called 'Face on Mars,' " said Glenn E. Cunningham, Mars Global Surveyor project manager at NASA's Jet Propulsion Laboratory, Pasadena, CA. "The sites will be visible about once every eight days, and we'll have a 30- to- 50-percent chance of capturing images of the sites each time." Several factors limit the chances of obtaining images of specific features with the high-resolution mode of the camera on any one pass. These factors are related primarily to uncertainties both in the spacecraft's pointing and the knowledge of the spacecraft's ground track from its navigation data. In addition, current maps of Mars are derived from Viking data taken more than 20 years ago. Data obtained by Global Surveyor's laser altimeter and camera during the last few months have indicated that our knowledge of specific locations on the surface is uncertain by 1 to 2 kilometers (0.6 to 1.2 miles). As a result, the locations of the landing sites and specific features in the Cydonia region are not precisely known. In addition, the Mars Pathfinder and Viking landers are very small targets to image, even at the closest distance possible, because they are the smallest objects that the camera can see. The Cydonia features, on the other hand, are hundreds to thousands of times larger and the camera should be able to capture some of the features in that area. Global Surveyor's observations of the Viking and Pathfinder landing sites will provide scientists with important information from which to tie together surface observations and orbital measurements of the planet. Data from landing sites provide "ground truth" for observations of the planet made from space. As for the "Face on Mars" feature, "Most scientists believe that everything we've seen on Mars is of natural origin," said Dr. Carl Pilcher, acting science director for solar system exploration in NASA's Office of Space Science, Washington, DC. "However, we also believe it is appropriate to seek to resolve speculation about features in the Cydonia region by obtaining images when it is possible to do so." Information about Viking observations of the Cydonia region and a listing of those images are available on the World Wide Web at http://www.hq.nasa.gov/office/pao/facts/HTML/FS-016-HQ.html . New images of the landing sites and Cydonia region taken by Mars Global Surveyor will be available on JPL's Mars news site at: http://www.jpl.nasa.gov/marsnews and on the Global Surveyor home page at http://mars.jpl.nasa.gov . These sites will also carry detailed schedules of the imaging attempts once they have been determined. Images will also be available on NASA's Planetary Photojournal web site at http://photojournal.jpl.nasa.gov . So far in the aerobraking process, Global Surveyor's orbit has been reduced from an initial 45-hour duration to less than 12 hours. During the aerobraking hiatus, the spacecraft will be orbiting Mars about once every 11.6 hours, passing about 106 miles (170 kilometers) above the surface at closest approach and about 11,100 miles (17,864 kilometers) at its farthest distance from the planet. The pause in aerobraking allows the spacecraft to achieve a final orbit with lighting conditions that are optimal for science observations. Mars Global Surveyor is part of a sustained program of Mars exploration, managed by JPL for NASA's Office of Space Science, Washington, DC. Lockheed Martin Astronautics, Denver, CO, which built and operates the spacecraft, is JPL's industrial partner in the mission. Malin Space Science Systems, Inc., San Diego, CA, built and operates the spacecraft camera. JPL is a division of the California Institute of Technology, Pasadena, CA. ##### Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: MGS Prepares To Photograph Landing Sites, Cydonia Regio [1/3] Привет всем! Вот, свалилось из Internet... http://mars.jpl.nasa.gov/mgs/target/pressrel.html MARS GLOBAL SURVEYOR COMPLETES FIRST AEROBRAKING PERIOD AND PREPARES TO PHOTOGRAPH THE MARS PATHFINDER LANDING SITE AND FEATURES IN THE CYDONIA PLAIN The Mars Global Surveyor spacecraft is about to resume scientific observations of the surface of Mars with its first objective to attempt to photograph the Mars Pathfinder landing site, the features in the Cydonia region, and the Viking lander sites. Surveyor is coming up on a period beginning near the end of March and continuing for about a month in which orbital and lighting conditions will be suitable for these observations. The opportunities to see these targets from the Surveyor spacecraft will occur in three clusters of two and a half days each during the next month. Each target will be visible once in each cluster and the clusters will be separated by eight days. It will not be possible to predict on which orbits, and thus, on which days, the spacecraft will come closest to the targets until after aerobraking has been terminated on Friday, March 27th. Then several orbits of navigation tracking data have been obtained in order to pin point Surveyor's new orbital characteristics. The exact time of the observation opportunities and the schedule and process for the release of the resulting photographs will be announced in a few days. Within a few days before the actual observations, a detailed sequence of the spacecraft's activities will be posted on this webpage, and the project staff will provide a near real time commentary on the events as they occur. Surveyor's science instruments will be turned on again on Friday, March 27th, after having been off since February 20th when the orbital period became too short for both science and aerobraking operations to be conducted simultaneously. Now that aerobraking will be on hold for five months, Surveyor can return to acquiring science data. End of Aerobraking and Science Phasing Orbit Transition Timeline ( Subject to change, depending on level of drag encountered ) Date Time Orbit Event A = apoapsis P = periapsis 3/23/98 A194 UP ABM to 0.1 N/m2 (0.5 m/s) Took orbit up to an 23:10 UTC aerobraking altitude where the dynamic pressure is 0.1 N/m2 so that aerobraking is slowed to more easily manage the arrival at the target period of 11.6 hours. THIS EVENT HAS BEEN COMPLETED IN A SATISFACTORY MANNER! 3/26/98 A201 ABX-1 (Aerobraking Termination Maneuver) (4.43 m/s) A 21:20 UTC bi-propellant main engine burn to terminate aerobraking by raising the altitude of periapsis to 170 km establishing the science phasing orbit 3/27/98 A202 Instrument Turn-On command window opens (shortly after A201 08:57 UTC apoapsis which is at 08:52) 3/28/98 P203 P202 First PERISCAN (Periapsis Science Acquisition) Pass. 02:24 UTC This will be the first time in the science phasing orbit that science data will be acquired, and the start of the six orbit period where the navigation baseline for targeted opportunities will be established. Science acquisition will continue until early September when aerobraking will be resumed. PHOTOGRAPHING THE FEATURES IN THE CYDONIA PLAIN At the launch of the Mars Global Surveyor mission, NASA announced that it would re-photograph the Cydonia region of Mars -- an area that contains a number of features including the famous "Face on Mars" -- when Surveyor was over that region during its mapping mission. In addition, NASA said it would announce to the public when these opportunities would occur and when the resulting pictures would be released. The opportunity to accelerate the schedule of photographing these areas significantly before the mapping period has been afforded by the recent modification of Surveyor's mission. This modification was made to extend aerobraking for a year in order to compensate for a structural weakness discovered in one of Surveyor_s solar panels. TARGETS FOR OBSERVATIONS Mars Pathfinder landed last July 4th, deployed the Sojourner rover and captivated world interest as it explored a small region in Aris Vallis. The two Viking landers that NASA placed on the surface of Mars in 1976 conducted inconclusive experiments to try to discover life in the Martian soil. The Cydonia region has become notable from the discovery of an object that looks much like a human face in several pictures taken by the Viking Orbiter spacecraft over 20 years ago. Some researchers have proposed arguments that the "Face" and other objects in its vicinity are artifacts of an extinct civilization and have pressed NASA for further investigations of the region. Latitude and Longitude of four targets located in East longitude Target Latitude Longitude Cydonia Region 41.0 North 350.5 East Pathfinder 19.01 North 33.52 East Viking 1 Lander 22.27 North 312.03 East Viking 2 Lander 47.67 North 134.48 East Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: MGS Prepares To Photograph Landing Sites, Cydonia Regio [2/3] Привет всем! Вот, свалилось из Internet... HOW THESE OBSERVATIONS WILL BE MADE It is anticipated that Surveyor's ground track will not pass directly over any of the targets so it will be necessary to rotate the spacecraft to sweep the field of view of its cameras across the targets as the spacecraft travels south from over the Martian north pole as the spacecraft gets closer and closer to the surface Photographs will be taken as long, narrow strips as the field of view is sweeping across the targets. The orbital conditions chosen for the next five month period when Surveyor will not be aerobraking offer a particularly advantageous pattern of near overflights of these targets. Because of the position of the targets in longitude around the planet (Viking 2 is 182 degrees to the east of Viking 1, Mars Pathfinder is 14 degrees to the east of Viking 1, and Cydonia is 24 degrees east of Viking 1) the near overflights will occur in clusters of five orbits every 17 orbits. Surveyor's orbital period of 11.6 hours, which is slightly less half a Martian day, causes the spacecraft's ground track to alternate sides of the planet on consecutive revolutions. At every closest approach to the planet or periapsis, the spacecraft is about 190 degrees to the east of where is was one orbit ago and about 20 degrees to the east of where it was two orbits ago. These observations are termed "targeted" because mission controllers will take extraordinary steps to try to assure that the selected targets are within the high resolution camera's field of view. This is a difference process than has been used in the past or will be used in the future to collect images of Mars from Global Surveyor. The normal manner of acquiring images and other science data is to point the instruments straight down at the surface or to take science data as the instrument fields of view sweep across the planet as the spacecraft performs maneuvers to accomplish aerobraking. During the aerobraking hiatus last Fall, the instruments were pointed straight down at the surface during the few minutes that the spacecraft was closest to the planet. During the two years of mapping that will start in March 1999, the instruments will always point straight down at the planet's surface. The photographs that have been acquired during the just concluding aerobraking phase were acquired on each orbit, a few minutes after the closet approach to the planet's surface and after aerobraking had completed, as the spacecraft was being rotated from the aerobraking attitude to the array normal spin attitude used during the rest of each orbit. WHY ARE THESE OBSERVATIONS BEING MADE NOW? Surveyor is just completing its first period of aerobraking -- a portion of the mission in which the spacecraft skims through the top of the Martian atmosphere at each closest approach to the planet in order to circularize its orbit. Currently, Surveyor's orbital period has been reduced from its initial 45 hour duration to under 12 hours. The orbital period will stay at 11.6 hours until early September when aerobraking will resume again for the final five months of aerobraking to reach the exact orbital conditions necessary to begin Surveyor's two year long mapping mission. During the period without aerobraking, Mars will move around the Sun to a position where the lighting of the Martian surface under Surveyor's flight path will be optimum for the mapping observations. The upcoming opportunities appear to be the best of the period because the periapsis location will be migrating to higher latitudes and going over the north pole later in the period, and thus, the distance to the targets will be increasing. In the next few weeks the elevation of the sun will be between 15 and 20 degrees at the high latitude targets (Cydonia and Viking 2) which will make for good imaging. The sun elevation will be between 40 and 45 degrees for the low latitude sites (Viking 1 and Mars Pathfinder) which will make for acceptable imaging. HOW WELL WILL WE BE ABLE TO SEE THE TARGET IN THE IMAGES? For Example, the field of view of high resolution camera covers a width of 3 km (1.9 miles) when the camera is 400 km (249 miles) from its target. The length of the image will be several kilometers (several miles). The resolution, or smallest feature discernible in the image varies with the distance to the target, but at this distance will be approximately 1.4 meters (4.6 feet). The Mars Pathfinder and Viking landers are about 2 meters (6.6 feet) in diameter, or very close to the minimum resolution obtainable. The features in the Cydonia region are on the scale of 1 to 2 km (0.6 to1.2 miles) and should be readily visible and may nearly fill the width of field of view of the images. Until the exact orbit characteristics are known, we will not know the exact distance to the targets. It could be further than the 400 km quoted in the example above and the resolution would be poorer, or it could be closer. The Mars Pathfinder and Viking landers are very small targets, at the limit of resolution of the camera, even at the closest distance. It will be an extraordinary event if they are recognized in the images. Features in the Cydonia region, however, being hundreds to thousands of times larger, will be very easily seen, even at the more distant ranges, and while all features in this area may not be within the field of view due the expected targeting errors, there is a high probability that many will be seen with good resolution. The best known location of the "Face" will be the target point in Cydonia. Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: MGS Prepares To Photograph Landing Sites, Cydonia Regio [3/3] Привет всем! Вот, свалилось из Internet... WHAT IS THE PROBABILITY THAT THIS IMAGING WILL BE SUCCESSFUL? OR ARE WE SURE WE'LL GET THE PICTURES? The probability that the targets of interest will be within the camera's field of view varies between 30 and 50 percent. This is because there are a number of sources of error or uncertainties associated with the targeting process. One such error source relates to how good the current maps of Mars are. As all early explorers on Earth found, early maps contain many inaccuracies. The data obtained by Surveyor's laser altimeter and cameras in the last few months have indicated that locations of observed objects on the surface are displaced 1 to 2 km (0.6 to 1.2 miles) from where the Viking era maps locate them. Another source of error is the accuracy with which the spacecraft's trajectory is predictable. This involves where the ground track of the flight path lies or will lie on the surface, and the time the spacecraft will fly over or near the desired targets. The accurate prediction of the ground track allows the mission controllers to decide how much to rotate the spacecraft to point the camera, and the timing prediction will be used by the camera operators to control when to record the image. In preparing the Surveyor's sequences for these observations, mission controllers will use the results of orbit computations made as near to the planned observation time as possible in order to minimize this uncertainty. In addition, some error is introduced by the planet's rotation translating downtrack error into crosstrack error. The last source of error is how accurately the spacecraft can be rotated and pointed. The design specifications for Global Surveyor call for it to be pointable with an accuracy of 10 milliradians ( 0.057 degrees), that is, mission controllers should be able to point the instruments to within 10 milliradians (0.057 degrees) of a target. Experience with the spacecraft indicates that it actually performs much better, and that a pointing accuracy of 3 milliradians (0.017 degrees) is possible. Combining these error sources together in the proper statistical manner with the distance from the spacecraft to the targets tells us the probability that the targets will be within the camera's field of view. This probability varies from about 70% when the targets are 1000 km (621 miles) from the spacecraft, to about 25% when the targets are 400 km (249 miles) from the spacecraft. WHY ARE THESE IMAGES IMPORTANT? A great deal of scientific controversy rages over the interpretation of the features seen in the Viking images of the Cydonia Plain. Additional photographs with the much better resolution that Surveyor's camera will provide and perhaps different lighting conditions can provide new information to aid in the understanding of what is seen there. In addition, the observations of the previous landing sites provide scientists with important knowledge to tie together the observations made on the surface from the landers with those made from orbit above the planet. The Viking 1 Lander site is the first location on Mars where humans were able to see and touch the Martian surface at a familiar scale. This site, the following higher latitude Viking 2 Lander site and the Pathfinder site play a large role in understanding the processes which have operated on the Martian surface over time and the state of the surface and atmosphere at present. These sites serve as "ground truth" locations where ideas developed from orbital observations can be tested, verified and then extended to other regions of Mars such as those we may wish to visit in the future. Several examples of this use of the sites for ground truth illustrates their significance. One of the results of the Viking Orbiter Infrared Thermal Mapper experiment was a rock abundance map based on the observed change in surface temperature over time (large rocks cool more slowly than sand or dust). The only way to verify the results of this rock abundance map was with the two Viking landing sites where, fortunately, numerous rocks were present. Rock abundance knowledge helps in understanding the depositional history of the surface and large rocks represent a landing hazard. Mars Global Surveyor carries an advanced version of the Viking instrument called the Thermal Emission Spectrometer (TES) which will be able to map rock abundance at more than one hundred times higher spatial resolution than Viking and the TES experimenters will have another site (Pathfinder) to use to verify their deductions. The high resolution mode of the Mars Orbiter Camera (MOC) carried by the Mars Global Surveyor spacecraft is capable of returning images of objects as small as 1.4 meters across. Some of the largest rocks in the area of the landing sites may be visible and such rock or boulder fields have been seen in MOC images at other locations on Mars. The careful surveys which have been done of the distribution of rocks as a functions of rock size can now be used with MOC images to estimate rock populations at other locations on Mars. THE CURRENT STATUS OF MARS GLOBAL SURVEYOR The Global Surveyor spacecraft is in excellent health. For the next five months, Surveyor will be maintained in an 11.6 hour period elliptical orbit around Mars. Its closest point to the planet's surface will be 170 km (106 miles) and its furthest distance will be 17,864 km (11,100 miles). WHAT'S NEXT AFTER THESE SPECIAL OBSERVATONS? The observations described above will occur three times during the month of April. Surveyor will continue to acquire science data from its other instruments during the month. Then, during May, Mars, and hence Global Surveyor will move behind the Sun as seen from Earth. During this period of solar conjunction, communications with Surveyor will be greatly degraded. Surveyor will cease science observations and will be put into a special attitude to assure proper temperatures of the science instruments. For two out of every eight hours it will point its high gain antenna to Earth to conduct radio communications propagation experiments, and, for part of the time, to allow mission controllers to monitor the spacecraft's health. At the end of May, Surveyor will return to acquiring science data from all its instruments. Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: Dust Devils Discovered In Mars Pathfinder Images Привет всем! Вот, свалилось из Internet... Univerity of Nevada, Reno Contact: Greg Bortolin (bortolin@scs.unr.edu) 702-784-6216 March 26, 1998 University of Nevada, Reno researchers make major discovery in Mars images Dust devils on the surface of Mars have been discovered in images being examined by researchers at the University of Nevada, Reno. Mars' famous dust storms - which can be seen from backyard telescopes and sensationally cover the red planet's surface every several years - may be triggered by dust devils. "Mars' atmosphere is extremely thin and very high wind velocities are needed to pick up dust. These dust devils, or mini-twisters, cause these high winds," said professor James R. Carr of the Department of Geological Sciences at the university's Mackay School of Mines. Stephen Metzger, a doctoral student at Nevada, made the discovery from Mars Pathfinder imagery, using methods suggested by Carr. Metzger made the discovery in images downloaded from the NASA Jet Propulsion laboratory in Pasadena, Calif., using color filters. By comparing and contrasting the Mars data with that from arid regions on Earth, such as Nevada, Metzger said much can be learned about local air pollution, acid rain and global climate change. "Dust devils were thought to have been discovered by the Viking orbiter in 1976, but that was difficult to confirm," Carr said. "The significance of this discovery is that it confirms the Viking discovery and shows that dust devils are an important geological process on Mars. In fact, dust devils may be the primary soil erosion process on Mars." Upon making the initial discovery, Metzger contacted Timothy Parker, a NASA scientist in Pasadena, and Jeff Johnson, U.S. Geological Survey scientist, in Flagstaff, Ariz., for verification and further image processing. Results of this image processing were presented Tuesday, March 17, in Houston at the Lunar and Planetary Science Conference. After seeing these results at last week's international gathering of planetary scientists in Houston, several NASA science teams are eager to use the dust devil images in their atmospheric science and geology research, Metzger said. NASA officials have credited Metzger and Carr as the first researchers to discover the dust devils in Pathfinder imagery. Metzger is a NASA Fellow, funded by the University of Nevada System Space Grant Consortium. He also is involved with the Desert Research Institute, a sister institution of the University of Nevada, Reno. An image showing the dust devils is available at this website: http://www.unr.edu/nevadanews/vol2no118.htm Hа сегодня все, пока! =SANA=

Дата: 27 марта 1998 (1998-03-27) От: Alexander Bondugin Тема: The "Face On Mars" Привет всем! Вот, свалилось из Internet... http://www.hq.nasa.gov/office/pao/facts/HTML/FS-016-HQ.html The "Face On Mars" Background: The Viking Images The Viking missions to Mars in the late 1970s produced more information about the Red Planet than had been gathered in all the previous centuries of study by Earth-bound astronomers and observers. The primary mission of the Viking program was to search for signs of life on the surface of Mars. Two landers containing sophisticated biological laboratories studied soil samples in a variety of tests which, it was hoped, would prove or disprove the existence of life. The results of these tests indicated that Mars contained no life, at least at these landing sites. However, Viking gathered volumes of data on the weather, soil chemistry and other surface properties and mapped the surface using low-to-moderate resolution cameras on the two orbiters. Shortly after mapping began in 1976 an interesting image taken by the Viking 1 Orbiter was received at the Jet Propulsion Laboratory, Pasadena, Calif., which contained a surface feature resembling a human or ape-like face. The photo was immediately released to the public as an interesting geological feature and dubbed the "Face on Mars." Shortly afterwards other photos of the same area were taken, and some scientists believed that the formation appeared to be a face due to the lighting angles as seen from the Orbiter. Origin Of Features Examined Over the years, some people began to raise questions about the origins of the features. A few ideas and theories arose speculating that the features may have been built by aliens in the distant past. These theories are based largely on the results of computer photo enhancements and other analytical techniques performed on the Viking images beginning in the early 1980s. Most planetary geologists familiar with the set of photos, however, concluded that the natural processes known to occur on Mars -- such as wind erosion, Mars quakes, and erosion from running water in the distant past -- could account for the formation of the complicated fretted terrain of the Cydonia region, including the face. Because the entire data set includes only nine low-to-moderate resolution photos, scientists say that there just is not enough data available to justify what would be an extraordinary conclusion that the features are not natural in origin (many scientists question whether images alone would be enough to settle the matter). Such a proven discovery of extraterrestrial life or artifacts would be one of the greatest discoveries in human history, and, as such, demand the most rigorous scientific investigation. However, despite the phenomenal nature of such a potential discovery, no one in the scientific community -- either in the U.S. or worldwide -- has ever proposed an investigation for a mission to study these features. Until more data is gathered, many scientists consider the probability that the features are anything other than natural in origin are just too low to justify the major expenditure of public funds which such an investigation would entail (more on this below). What is agreed on is that a greater number of high resolution images of this area should be gathered. Following the failure of the Mars Observer mission in August, 1993, NASA proposed a decade-long program of Mars exploration, including orbiters and landers. The program, called Mars Surveyor, would take advantage of launch opportunities about every 2 years to launch an orbiter and a lander to the Red Planet. The first mission, consisting of an orbiter to be launched in 1996, will map the surface and take high- and medium-resolution images of particular features on the Martian surface that are of high interest. NASA intends to make observations of the Cydonia region making the best effort feasible, either with the first orbiter or on follow-on missions, to obtain images of the "face" and nearby landforms. Quite aside from the interest generated by these curious features, Cydonia has long been regarded as an area of high scientific importance, ever since the first detailed images were returned by NASA's Viking spacecraft in the late 1970s. The Cydonia region of Mars is part of the so-called fretted terrain, a belt of landforms that circles Mars at about 30-40 degrees North Latitude. In this region, the ancient crust of Mars has been intensely eroded by weathering processes, leaving high remnants of older crust surrounded by lower plains of eroded debris. The landforms of Cydonia resemble in some respects those of terrestrial deserts, but they probably have been shaped by a unique range of peculiarly martian agencies: wind, frost and possibly running water in ancient times. Deciphering the geological age and origin of this terrain will yield important insights into the evolution of the martian surface, into the role of ice and water in its development and into the nature of the martian climate in times past. Proposing Investigations The selection of goals and scientific priorities for NASA to undertake on future space science missions starts in the scientific and academic communities, as well as within NASA. Scientific associations, such as the National Academy of Science, determine the research priorities in any given field of science. For instance, the most important questions remaining about Mars include gaining an understanding of the amount of water on the planet; mapping the surface in detail to gain a complete understanding of the geological processes, history and composition; and gaining a global understanding of the atmosphere, including climate and weather. When NASA receives permission to proceed with a science mission, the Agency publishes an Announcement of Opportunity (AO). The AO solicits interest in providing high priority scientific investigations and instruments that will be part of the new mission. The AO receives the widest possible circulation throughout the university and research communities and industry. Proposals are submitted and reviewed through a competitive peer review process. In this process, scientists from various institutions and organizations evaluate each proposal's scientific and technical merit, and then rank the relative merit of each. NASA receives the reports of the review panels and makes a final selection as to which instruments will be built and actually flown. This rational selection process ensures that only the most useful research, with a high probability of returning good science, is done at taxpayer expense. After selection, each Mars Surveyor Principle Investigator (PI) team will develop its instrument, build it, test it and prepare it for launch and the 10-month journey to Mars. They are also charged with developing, testing, and using the software required to properly calibrate their instrument's data. Most of the scientists working on the various Mars Surveyor missions will have several years invested in their instrument before the spacecraft arrives at Mars and they can actually receive the bulk of the data they have been waiting for. Obtaining Images of the "Face" and Other Planetary Data Since the release and subsequent widespread circulation of the 'face' images, scientists and individual members of the public have freely drawn their own conclusions about the nature and origin of this feature. NASA encourages anyone seriously interested in this topic to obtain the photo(s) and decide for themselves, just as every day many hundreds of independent researchers and scientists make use of NASA-provided data on a variety of subjects. The most noteworthy image of the 'face' feature is available to the public, for a nominal fee, through Headquarters and JPL. A photo catalogue can be provided to select images. The phone numbers for ordering photos are: HQ: 202/358-1900 JPL: 818/354-5011 All imaging data obtained by the Mars Surveyor program, as well as other types of data, will be deposited in open data archives. Two such archives widely used are the Planetary Data System (PDS), an open archive accessible to thousands of scientists and other individuals, and the National Space Science Data Center (NSSDC) where images and other data will be readily available to the general public (generally on CD-ROMs or as hard copy, as appropriate), for a nominal charge that covers the materials and time needed to produce the copies. For information about ordering copies of NASA science mission images, including on CD-ROM format, contact the NSSDC at: National Space Science Data Center Request Coordination Center Goddard Space Flight Center Greenbelt, MD 20771 Telephone: 301/286-6695 Listed below are the photo numbers of every image taken by Viking of the 'face' feature and the surrounding Cydonia terrain. When ordering from the data archive centers, refer to the Viking picno (photo number). Sun Picno Scale Emission Incidence Phase Elevation Period of (m/pixel) (deg) (deg) (deg) Day (deg) 035A7247.13 10.53 79.89 86.26 10.11 morning 070A1343.42 12.36 62.61 71.77 27.39 morning 561A25162.7 32.83 76.59 45.63 13.41 morning 753A33232.82 10.25 35.3 25.12 54.7 afternoon 753A34232.51 10.13 35.15 25.14 54.85 afternoon 814A07848.86 38.15 65.93 103.25 24.07 too low 257S69821.24 42.06 43.83 8.66 46.17 cloudy 673B54226.02 23.22 64.94 77.76 25.06 morning 673B56225.7 21.33 67.77 76.7 22.23 morning NASA Headquarters Public Affairs Office Washington DC 20546-001 Email: eweigel@hq.nasa.gov Document: FS-1995-08-016-HQ Modified: August 1995 Hа сегодня все, пока! =SANA=

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