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Дата: 06 марта 1998 (1998-03-06) От: Alexander Bondugin Тема: Mars Pathfinder Manager Brian Muirhead Named Engineer Of The Year 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, JPL Robert Tindol, Caltech, 626-395-3631 David Salyers, 312-346-3131 FOR IMMEDIATE RELEASE March 3, 1998 PATHFINDER MANAGER BRIAN MUIRHEAD NAMED ENGINEER OF YEAR Brian Muirhead, manager of NASA's innovative and highly successful Mars Pathfinder mission, has been named 1998 Engineer of the Year by the readership of Design News, which represents a national audience of engineers and aeronautics specialists. Muirhead was cited by readers of the magazine for his leadership of a high-risk, low-budget mission, developed on a fast track, which demonstrated a novel approach to landing a spacecraft on the surface of Mars. The Pathfinder mission, developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, landed on Mars on July 4, 1997, and returned a phenomenal amount of data and images of the surface, atmosphere and weather on Mars. Muirhead, 46, will receive a $25,000 educational grant, to be designated to his alma mater, the California Institute of Technology, Pasadena, CA, from the magazine's Engineering Education Foundation. He will also share an additional $10,000 educational grant with other winners of the magazine's Special Achievement and Quality awards. Both grants have been earmarked for economically disadvantaged engineering students attending Caltech, where Muirhead earned his master's degree in aeronautical engineering in 1982. He also holds a bachelor's degree in mechanical engineering from the University of New Mexico. In its March 2 issue, Design News reports that the Mars Pathfinder mission was an engineering demonstration and a radical departure from the billion-dollar-class spaceflight projects of the recent past. Operating on a skeleton budget of $170 million - - a small fraction of the cost of the Viking missions of the mid- 1970s -- Pathfinder dove directly into the Martian atmosphere and landed with the aid of a parachute, airbags and retro-rockets. The spacecraft also delivered the first microrover ever to photograph the surface of another planet and the first vehicle to measure the chemical composition of Martian rocks. In addition to its unique entry, descent and landing, the Mars Pathfinder mission introduced more than 25 new technologies and broke new ground in the application of commercially derived hardware that could be used in the extremely harsh environment of space, the magazine says. For example, Pathfinder relied on a single radiation-hardened flight computer derived from an IBM RS6000-series workstation. Pathfinder also became a model of teamwork and an inspiration for future missions by providing proof that NASA's goal of faster, better and cheaper missions was a reality, the magazine reports. New space missions of the 21st century -- destined for Mars, the outer solar system and asteroids and comets -- will build on the legacy of Mars Pathfinder. Muirhead himself will be moving into a managerial role on one of these new missions, the fourth deep space technology validation mission to be flown under NASA's New Millennium program, known as Deep Space 4/Champollion. This mission will attempt the first-ever rendezvous and landing on the surface of a comet. Once on the surface, the 100-kilogram (220-pound) lander will analyze the surface composition and gather a sample for return to Earth. Mars Pathfinder was exemplary as the first of these new- generation, fast-track missions -- able to meet its development schedule and cost constraints through the skill and dedication of a tightly knit team, the magazine notes. Muirhead's leadership as flight system manager was critical to the development of the Pathfinder spacecraft and the spectacular success of this very challenging mission. Muirhead will be honored at an awards ceremony to be held March 17 at the Ritz Carlton Hotel, Chicago. Contact David Salyers of Salyers Carman & Associates, 312-346-3131, for additional information about the banquet. For information about Muirhead's grant to Caltech, contact Robert Tindol at the Caltech Media Relations Office, 626-395-3631, or Diane Ainsworth at the JPL Media Relations Office, 818-354-5011. ##### Hа сегодня все, пока! =SANA=

Дата: 06 марта 1998 (1998-03-06) От: Alexander Bondugin Тема: Nakhla Mars Meteorite Available For Scientific Study Привет всем! Вот, свалилось из Internet... Antarctic Meteorite Newsletter February 1998 Nakhla To Be Distributed By Dr. Monica Grady Natural History Museum, London Nakhla is a 1300 million year old Martian meteorite, the first one in which carbonates were identified. Nakhla fell as a shower of stones in 1911; several of the stones are in the collection of the Natural History Museum in London. One completely fusion-crusted stone has been kept unbroken since its acquisition in 1913. The Natural History Museum is now prepared to offer samples of this stone to scientists for appropriate analyses. The Antarctic Meteorite Processing Group had kindly agreed to allow the stone to be broken and sub-divided at the Curatorial Facility at the Johnson Space Center in Houston, prior to the LPSC in March. There is no formal deadline for sample requests, but the material available is limited. Coordinated approaches from groups of scientists undertaking complementary studies are encouraged. Those requests submitted to the Museum by April 3 will be processed in April. Those arriving later will be delayed for several months. For further details and to submit requests, contact: Dr. Monica M. Grady Dept. of Mineralogy The Natural History Museum Cromwell Road London SW7 5BD E-Mail: mmg@nhm.ac.uk Hа сегодня все, пока! =SANA=

Дата: 06 марта 1998 (1998-03-06) От: Alexander Bondugin Тема: New Lunar Meteorite Discovered (EET96008) Привет всем! Вот, свалилось из Internet... A new lunar meteorite has been discovered in the Antarctic. The meteorite is labeled EET96008. It was discovered in the Elephant Moraine region in the Antarctic, and was the 8th meteorite analyzed from the 1995-96 collecting season. Below is the technical decription of the meteorite from the February 1998 issue of the Antarctic Meteorite Newsletter. Ron Baalke Sample no: EET96008 Location: Elephant Moraine Dimensions (cm): 4.5 x 3.5 x 1.5 Weight (g): 52.97 Meteorite Type: Lunar Basaltic Breccia Macroscopic Description: Kathleen McBride 50% of the meteorite is covered by a black glassy fusion crust. Areas that lack fusion crust appear virtually unweathered. The fusion crust is very thinly distributed over the surface of the rock. The matrix is fine grained, medium gray and tan are are angular and subangular in shape. Metal and rust are not visible. This is a breciated basalt, possibly lunar in origin. Thin section (,4) Description: Brian Mason The section shows a microbreccia of pyroxene and plagioclase clasts, up to 1.2 mm across; traces of nickel-iron and sulfide are present, as small scattered grains. Microprobes analyses show that most of the pyroxene ranges from Wo11Fs31 to Wo40Fs18, with a few more iron-rich grains; plagioclase composition in An93-96. A few olivine grains of variable compositions, Fa41-64, were analyzed. Fe/Mn in pyroxene is about 70. The meteorite is a lunar basaltic breccia. Hа сегодня все, пока! =SANA=

Дата: 06 марта 1998 (1998-03-06) От: Alexander Bondugin Тема: New Satellite Animation Shows El Nino Moisture In Atmosphere 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 Hardin (818) 354-0344 VIDEO & INTERNET ADVISORY March 3, 1998 NEW SATELLITE ANIMATION SHOWS EL NINO MOISTURE IN ATMOSPHERE New satellite animation shows the movement of atmospheric water vapor over the Pacific Ocean during the 1997-98 El Nino condition. Higher than normal ocean water temperatures increase the rate of evaporation, and the resulting warm moist air rises into the atmosphere, altering global weather patterns. The February 1998 segment also shows high levels of atmospheric moisture above Southern California. The animation was created from data obtained by the Microwave Limb Sounder (MLS) instrument onboard NASA's Upper Atmosphere Research Satellite (UARS) from September 1997 to February 1998. A NASA TV video file will feature the new animation at 9 a.m., noon, 3 p.m., 6 p.m. and 9 p.m. Pacific time today. NASA Television is available on GE-2, transponder 9C at 85 degrees west longitude, with vertical polarization. Frequency is on 3880.0 megahertz, with audio on 6.8 megahertz. In addition, the most recent still images of the El Nino water vapor are now available online at: http://www.jpl.nasa.gov/elnino The MLS instrument is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, a division of the California Institute of Technology, also in Pasadena. ##### Hа сегодня все, пока! =SANA=

Дата: 06 марта 1998 (1998-03-06) От: Alexander Bondugin Тема: Galileo Experts Invite Public To Join Internet Chat 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 INTERNET ADVISORY March 4, 1998 GALILEO EXPERTS INVITE PUBLIC TO JOIN INTERNET CHAT Scientists and engineers from NASA's Galileo Europa Mission will share their knowledge and latest findings from the spacecraft with the general public during a live Internet chat this Friday, March 6 from 1 p.m. to 4 p.m. Pacific Standard Time. Cyberspace participants will have the opportunity to ask questions about any aspect of the Galileo mission, which has spent two years orbiting Jupiter and its moons. Web chat organizers anticipate a flurry of questions about the icy moon, Europa, which may have a liquid ocean, and therefore a greater potential for life than many other celestial bodies. Anyone who would like to join in the web chat is invited to go to the following URL: http://www.jpl.nasa.gov/galileo/chat Earlier this week, new Europa pictures were unveiled, showing new evidence of slush on the moon's surface, intriguing views of ice cliffs as high as the face of Mt. Rushmore, and images of icy surface plates which have broken apart and moved around. The pictures were the closest ever taken of Europa, obtained by Galileo during its December 16, 1997 flyby. The Galileo spacecraft has completed its primary mission and is now in a two-year extended journey, called the Galileo Europa Mission. The mission includes seven more Europa flybys, as well as encounters with two of Jupiter's other moons, Callisto and Io. JPL manages the Galileo mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of California Institute of Technology, Pasadena, CA. General information and the latest Europa images can be found at the URL http://www.jpl.nasa.gov/galileo ##### Hа сегодня все, пока! =SANA=

Дата: 06 марта 1998 (1998-03-06) От: Alexander Bondugin Тема: Eileen Collins Named First Female Shuttle Commander Привет всем! Вот, свалилось из Internet... Jennifer McCarter Headquarters, Washington, DC March 5, 1998 (Phone: 202/358-1639) Eileen Hawley/James Hartsfield Johnson Space Center, Houston, TX (Phone: 281/483-5111) RELEASE: 98-37 COLLINS NAMED FIRST FEMALE SHUTTLE COMMANDER Astronaut Eileen Collins (Lt. Col., USAF) will become the first woman to command a Space Shuttle when Columbia launches on the STS-93 mission in December 1998. First Lady Hillary Rodham Clinton made the announcement today in the Roosevelt Room at the White House. Collins will be joined on the flight deck by Pilot Jeffrey S. Ashby (Cmdr., USN) and Mission Specialists Steven A. Hawley, Ph.D., and Catherine G. "Cady" Coleman, Ph.D (Major, USAF). CNES Astronaut Michel Tognini (Col., French Air Force) was named to the crew on November 12. Selected as an astronaut in 1990, Collins has served as a pilot on her two previous space flights. Her first space flight was STS-63 in February 1995 as Discovery approached to within 30 feet of Mir, in a dress rehearsal for the first Shuttle/Mir docking. In May 1997, she visited the Mir space station as pilot on board Atlantis for the sixth Shuttle/Mir docking mission, delivering Astronaut Mike Foale and returning Jerry Linenger to Earth. STS-93 will be the first flight for Ashby. Hawley will be making his fifth space flight during STS-93, having flown previously on STS-41D in 1984, STS-61C in 1986, STS-31 in 1990 and STS-82 in 1997. Coleman has one previous space flight to her credit, having flown on STS-73, the second United States Microgravity Laboratory mission in October/November 1995. Tognini, who spent 14 days on the Mir space station in 1992, will be making his first Shuttle flight on STS-93. During the five-day mission, the crew will deploy the Advanced X-ray Astrophysics Facility Imaging System (AXAF), which will conduct comprehensive studies of the universe. AXAF will be the most advanced X-ray telescope ever flown. When scientists begin using AXAF next year, they will finally be able to unlock the secrets of some of the most distant, powerful and violent objects known to exist in the universe. They will study such exotic phenomena as exploding stars called supernovae, strange powerful objects called quasars, and mysterious black holes which are so massive that everything near them is pulled inside causing an explosion of X-rays that AXAF can study. For additional information on the STS-93 crew, or any astronaut, see the NASA Internet biography home page at URL: http://www.jsc.nasa.gov/Bios/. -end- Hа сегодня все, пока! =SANA=

Дата: 06 марта 1998 (1998-03-06) От: Alexander Bondugin Тема: Lunar Prospector Finds Evidence Of Ice At Moon's Poles Привет всем! Вот, свалилось из Internet... Douglas Isbell Headquarters, Washington, DC March 5, 1998 (Phone: 202/358-1753) David Morse Ames Research Center, Moffett Field, CA (Phone: 650/604-4724) John Gustafson Los Alamos National Laboratory, Los Alamos, NM Department of Energy (Phone: 505/665-9197) John Watson Jet Propulsion Laboratory, Pasadena, CA (Phone: 818/354-6478) RELEASE: 98-38 LUNAR PROSPECTOR FINDS EVIDENCE OF ICE AT MOON'S POLES There is a high probability that water ice exists at both the north and south poles of the Moon, according to initial scientific data returned by NASA's Lunar Prospector. The Discovery Program mission also has produced the first operational gravity map of the entire lunar surface, which should serve as a fundamental reference for all future lunar exploration missions, project scientists announced today at NASA's Ames Research Center, Moffett Field, CA. Just two months after the launch of the cylindrical spacecraft, mission scientists have solid evidence of the existence of lunar water ice, including estimates of its volume, location and distribution. "We are elated at the performance of the spacecraft and its scientific payload, as well as the resulting quality and magnitude of information about the Moon that we already have been able to extract," said Dr. Alan Binder, Lunar Prospector Principal Investigator from the Lunar Research Institute, Gilroy, CA. The presence of water ice at both lunar poles is strongly indicated by data from the spacecraft's neutron spectrometer instrument, according to mission scientists. Graphs of data ratios from the neutron spectrometer "reveal distinctive 3.4 percent and 2.2 percent dips in the relevant curves over the northern and southern polar regions, respectively," Binder said. "This is the kind of data 'signature' one would expect to find if water ice is present." However, the Moon's water ice is not concentrated in polar ice sheets, mission scientists cautioned. "While the evidence of water ice is quite strong, the water 'signal' itself is relatively weak," said Dr. William Feldman, co-investigator and spectrometer specialist at the Department of Energy's Los Alamos National Laboratory, NM. "Our data are consistent with the presence of water ice in very low concentrations across a significant number of craters." Using models based on other Lunar Prospector data, Binder and Feldman predict that water ice is confined to the polar regions and exists at only a 0.3 percent to 1 percent mixing ratio in combination with the Moon's rocky soil, or regolith. How much lunar water ice has been detected? Assuming a water ice depth of about a foot and a half (.5 meters) -- the depth to which the neutron spectrometer's signal can penetrate -- Binder and Feldman estimate that the data are equivalent to an overall range of 11 million to 330 million tons (10-300 million metric tons) of lunar water ice, depending upon the assumptions of the model used. This quantity is dispersed over 3,600 to 18,000 square miles (10,000-50,000 square kilometers) of water ice- bearing deposits across the northern pole, and an additional 1,800 to 7,200 square miles (5,000-20,000 square kilometers) across the southern polar region. Furthermore, twice as much of the water ice mixture was detected by Lunar Prospector at the Moon's north pole as at the south. Dr. Jim Arnold of the University of California at San Diego previously has estimated that the most water ice that could conceivably be present on the Moon as a result of meteoritic and cometary impacts and other processes is 11 billion to 110 billion tons. The amount of lunar regolith that could have been "gardened" by all impacts in the past 2 billion years extends to a depth of about 6.5 feet (2 meters), he found. On that basis, Lunar Prospector's estimate of water ice would have to be increased by a factor of up to four, to the range of 44 million to 1.3 billion tons (40 million to 1.2 billion metric tons). In actuality, Binder and Feldman caution that, due to the inadequacy of existing lunar models, their current estimates "could be off by a factor of ten in either direction." The earlier joint Defense Department-NASA Clementine mission to the Moon used a radar-based technique that detected ice deposits in permanently shadowed regions of the lunar south pole. It is not possible to directly compare the results from Lunar Prospector to Clementine because of their fundamentally different sensors, measurement "footprints," and analysis techniques. However, members of the Clementine science team concluded that its radar signal detected from 110 million to 1.1 billion tons (100 million to 1 billion metric tons) of water ice, over an upper area limit of 5,500 square miles (15,500 square kilometers) of south pole terrain. There are various ways to estimate the economic potential of the detected lunar water ice as a supporting resource for future human exploration of the Moon. One way is to estimate the cost of transporting that same volume of water ice from Earth to orbit. Currently, it costs about $10,000 to put one pound of material into orbit. NASA is conducting technology research with the goal of reducing that figure by a factor of 10, to only $1,000 per pound. Using an estimate of 33 million tons from the lower range detected by Lunar Prospector, it would cost $60 trillion to transport this volume of water to space at that rate, with unknown additional cost of transport to the Moon's surface. From another perspective, a typical person consumes an estimated 100 gallons of water per day for drinking, food preparation, bathing and washing. At that rate, the same estimate of 33 million tons of water (7.2 billion gallons) could support a community of 1,000 two-person households for well over a century on the lunar surface, without recycling. "This finding by Lunar Prospector is primarily of scientific interest at this time, with implications for the rate and importance of cometary impacts in the history and evolution of the Solar System," said Dr. Wesley Huntress, NASA Associate Administrator for Space Science. "A cost-effective method to mine the water crystals from within this large volume of soil would have to be developed if it were to become a real resource for drinking water or as the basic components of rocket fuel to support any future human explorers." Before the Lunar Prospector mission, historical tracking data from various NASA Lunar Orbiter and Apollo missions had provided evidence that the lunar gravity field is not uniform. Mass concentrations caused by lava which filled the Moon's huge craters are known to be the cause of the anomalies. However, precise maps of lunar mass concentrations covering the moon's equatorial nearside region were the only ones available. Lunar Prospector has dramatically improved this situation, according to co-investigator Dr. Alex Konopliv of NASA's Jet Propulsion Laboratory, Pasadena, CA. Telemetry data from Lunar Prospector has been analyzed to produce a full gravity map of both the near and far side of the moon. Konopliv also has identified two new mass concentrations on the Moon's nearside that will be used to enhance geophysical modeling of the lunar interior. This work has produced the first-ever complete engineering-quality gravity map of the moon, a key to the operational safety and fuel-efficiency of future lunar missions. "This spacecraft has performed beyond all reasonable expectations," said NASA's Lunar Prospector mission manager Scott Hubbard of Ames. "The findings announced today are just the tip of the iceberg compared to the wealth of information forthcoming in the months and years ahead." Lunar Prospector is scheduled to continue its current primary data gathering mission at an altitude of 62 miles (100 kilometers) for a period of ten more months. At that time, the spacecraft will be put into an orbit as low as six miles (10 kilometers) so that its suite of science instruments can collect data at much finer resolution in support of more detailed scientific studies. In addition, surface composition and structure information developed from data returned by the spacecraft's Gamma Ray Spectrometer instrument will be a crucial aspect of additional analysis of the polar water ice finding over the coming months. The third launch in NASA's Discovery Program of lower cost, highly focused planetary science missions, Lunar Prospector is being implemented for NASA by Lockheed Martin, Sunnyvale, CA, with mission management by NASA Ames. The total cost to NASA of the mission is $63 million. Additional informaiton about the Lunar Prospector mission can be found on the Internet at URL: http://lunar.arc.nasa.gov -end- Hа сегодня все, пока! =SANA=

Дата: 06 марта 1998 (1998-03-06) 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: 06 марта 1998 (1998-03-06) От: Alexander Bondugin Тема: Pioneer 10 Update - March 2, 1998 Привет всем! Вот, свалилось из Internet... STATUS UPDATED: 2 March 1998 Pioneer 10 (Launched 2 March 1972) * Distance from Sun (2 March 1998): 69.49 AU * Speed relative to the Sun: 12.24 km/sec (27,380 mph) * Distance from Earth: 10.43 billion kilometers (6.479 billion miles) * Round-trip Light Time: 19 hours 19 minutes HAPPY BIRTHDAY, PIONEER 10 (SEE EXPANDED FAQ's BELOW)! The Energizer bunny of NASA spacecraft marches on - 26 years today! At approximately 22:10 GMT on 17 February 1998, Voyager 1 caught up with Pioneer 10 to become the most distant human-created object in space at a heliocentric distance of 6.46 billion miles (10.39 billion kilometers). The two are headed in almost opposite directions away from the Sun. The Pioneer mission formally ended on 31 March 1997 at 19:35 GMT. However, we still contact the Pioneer spacecraft on a non-interference basis to other NASA projects for the purpose of training Lunar Prospector controllers in Deep Space Network coordination of tracking activities. As part of the training program, we have now successfully performed two CONSCAN precession maneuvers - 2 February 1998 and 9 August 1997 - both again in the blind, as was first done on the maneuver of 26 January 1997. The Iowa Geiger Tube telescope instrument is operating nominally. The Chicago charged particle instrument is cycled on for 4 hour periods once every two weeks (when a round-trip light time (RTLT) opportunity is available). Three-way Doppler data for Radio Science are obtained whenever a RTLT is available. Current operation dips into the batteries, sometimes resulting in a low value of 0.94 volts during a track. This indicates further degradation of the RTGs. Nevertheless, we anticipate the transmitter to continue working until sometime in 1998. Limited 70 meter DSN coverage will be available through June of 1998. Pioneer 10 will continue into interstellar space, heading generally for the red star Aldebaran, which forms the eye of Taurus (The Bull). Aldebaran is about 68 light years away and it will take Pioneer over 2 million years to reach it. Pioneer 11 (Launched 5 April 1973) The Mission of Pioneer 11 has ended. Its RTG power source is exhausted. The last communication from Pioneer 11 was received in November 1995, shortly before the Earth's motion carried it out of view of the spacecraft antenna. The spacecraft is headed toward the constellation of Aquila (The Eagle), Northwest of the constellation of Sagittarius. Pioneer 11 may pass near one of the stars in the constellation in about 4 million years. Frequently-asked Questions (FAQ's): Question: How far will Pioneer travel and on what path? Answer: Pioneer 10 will be in galactic orbit for billions of years. It is moving in a straight line away from the Sun at a constant velocity of about 12 km/sec. Until Pioneer 10 reaches a distance of about 1.5 parsec (309,000 AUs) - about 126,000 years from now - it will be dominated by the gravitational field of the Sun. After that Pioneer 10 will be on an orbital path in the Milky Way galaxy influenced by the field of the stars that it passes. Question: Why does the RTG power decrease? Answer: Power for the Pioneer 10 is generated by the Radioisotope Thermoelectric Generators (RTG's). Heat from the decay of the plutonium 238 isotope is converted by thermoelectric couples into electrical current. The electrical output depends on the hot junction temperature, the thermal path to the radiator fins, and the cold junction temperature. It is the degradation of the thermoelectric junction that has the major effect in decreasing the power output of the RTG. In the 26-year time scale operation of Pioneer 10, the 92 year half-life of the isotope does not appreciably affect the RTG operation. The nuclear decay heat will keep the hot junction temperature hot for many years but unfortunately will not be able to be converted into enough electricity to power the transmitter for much longer. Question: How much has Pioneer been eroded? Answer: All the wear, pitting, and erosion that Pioneer 10 has sustained are probably over now. The asteroid belt and the severe conditions of Jupiter have already been experienced. Now, Pioneer is in the vacuum of space where the average spatial density of molecules is one trillionth the density of the best vacuum we can draw on Earth. We expect Pioneer to last an indeterminate period of time, probably outlasting its home planet, the Earth. In 5 billion years, the Sun will become a red giant, expand, envelop the orbit of the Earth, and consume it. Pioneer will still be out there in interstellar space. Erosional processes in the interstellar environment are largely unknown, but are very likely less efficient than erosion within the solar system, where a characteristic erosion rate, due largely to micrometeoritic pitting, is of the order of 1 Angstrom/yr. Thus a plate etched to a depth ~ 0.01 cm should survive recognizable at least to as distance ~ 10 parsecs, and most probably to >> 100 parsecs. Accordingly, Pioneer 10 and any etched metal message aboard it are likely to survive for much longer periods than any of the works of Man on Earth. Question: What about Pioneer 1 to 5? Answer: Pioneers 1 through 5 were launched from 1958 through 1960 and made the first thrusts into space toward the Moon and into interplanetary orbit. Pioneer 1 was the first spacecraft launched by NASA and provided data on the extent of the Earth's radiation belts. Pioneer 2 suffered a launch vehicle failure. Pioneer 3 discovered a second radiation belt around Earth. Pioneer 4 was the first American spacecraft to escape Earth's gravitational pull as it passed within 58,983 km (36,650 miles) of the moon. The spacecraft did return data on the Moon radiation environment, although the desire to be the first man-made vehicle to fly past the moon was lost when the Soviet Union's Luna 1 passed by the Moon several weeks before Pioneer 4. Pioneer 5 was designed to provide the first map of the interplanetary magnetic field. The vehicle functioned for a record 106 days and communicated with Earth from a record distance of 36.2 million km (22.5 million miles). The early Pioneers were exploratory missions that led to intriguing new questions that required more advanced types of spacecraft capable of exploring space to considerable distances within and beyond Earth's orbit. This led to the Pioneer 6 through 9 series that made the first detailed comprehensive measurements of the solar wind, solar magnetic field, and cosmic rays. Question: Why and how is Pioneer 10 being maneuvered? Answer: The Pioneer spacecraft is spin-stabilized, spinning at approximately 4.28 rpm (Revolutions Per Minute), with the spin axis running through the center of the dish antenna. If a person were to sit in the spacecraft, looking through a hole in center of the dish antenna with a telescope, he would see the Sun traveling very slowly to the left. The Earth's path would describe a very narrow ellipse (the orbit is seen nearly edge-on) around the Sun. In July the Earth is near the right hand edge of the ellipse, and 6 months later will be near the left hand edge of the ellipse. The angle to the spacecraft between the left edge of the ellipse and the right edge is less than 2 degrees. In order to communicate with the spacecraft, the Earth has to be within 0.8 degrees of the boresight of the spacecraft antenna. Since the Earth moves by almost 2 degrees, the spacecraft has to be re-aimed at the Earth about twice a year. This is done by a "CONSCAN (conical scan) precession maneuver" executed by the spacecraft. The radio signal transmitted from an antenna on Earth is focused and reflected by the spacecraft dish antenna toward a small feed horn located on a tripod which is centered in front of the spacecraft dish antenna, and then conducted to a receiver in the spacecraft. During a CONSCAN maneuver, the feed horn is physically moved by 8 inches to one side. A ground command turns on a heater in a bellows filled with liquid Freon. The Freon boils, the bellows expands, and moves a mechanical piston and cam attached to the feed horn mounting plate against a mechanical stop. A micro switch cycles the heater power on and off to keep the feed in the offset position. With the feed in the offset position, the radio signal from the tracking station is seen by the spacecraft receiver as varying sinusoidally in amplitude (amplitude modulated). This error signal contains amplitude and phase information on the pointing angle between the spacecraft spin axis and the Earth and the direction to the Earth during the spin cycle. The minimum amplitude occurs during the spin cycle when the antenna points to the Earth, whereas the maximum occurs when the antenna dish points away from the Earth. The frequency of the modulation is equal to the spacecraft spin rate (4.28 rpm). The error signal is processed on board the spacecraft to calculate the timing requirements for firing the jets at the appropriate instant in the spin cycle to precess the spin axis towards the Earth. The CONSCAN processor averages the modulation over two revolutions of the spacecraft. On the third revolution, it orders two hydrazine thrusters (mounted 180 degrees apart on the rim of the dish antenna) to fire a short pulse of 0.0312 seconds duration. This moves the spacecraft spin axis a tiny amount toward the minimum amplitude value, i.e., the Earth, reducing the amplitude of the modulation by a small amount. This process is repeated each three revolutions, each time reducing the pointing angle error and the modulation amplitude. When the pointing angle is within 0.3 degrees of boresight, the processor terminates the maneuver automatically. Typically, about 20 to 28 pulses are fired. A ground command then executes to turn off the power to the feed offset heater, the liquid Freon condenses to pull the mechanism back to the normal centered position, and the maneuver is completed. Question: If the spacecraft are leaving the Solar System, why does the distance from Earth sometimes get shorter? Answer: It is a matter of a hyperbolic escape trajectory, geometry, and relative velocity vectors. The distance from the Sun is always increasing. However, since the Earth travels around the Sun faster than the spacecraft moves away from the Sun, the spacecraft-earth distance decreases for a few months, and then rapidly increases again. Project Manager: Dr. Lawrence Lasher (e-mail:llasher@mail.arc.nasa.gov) Hа сегодня все, пока! =SANA=

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