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Дата: 23 апреля 1998 (1998-04-23) От: Alexander Bondugin Тема: Mission Prepares To Collect Pieces of Stardust Привет всем! Вот, свалилось из Internet... From The Planetary Society Home Page: http://planetary.org/articlearchive/headlines/1998/headln-041698.html Mission Prepares To Collect Pieces of Stardust April 16, 1998 Earth's First Cometary Dust Sample Return Mission Will Fly Planetary Society Member Names to a Comet and Back Scientists and engineers continue to prepare the Stardust spacecraft for its February 1999 launch. Earlier this month, Stardust Project Manager Ken Atkins reported that mission planners continue to make impressive progress in piecing together the spacecraft's flight system. Set for launch in February 1999, Stardust will be the first US mission dedicated solely to a comet and the first robotic return of extraterrestrial material from outside the orbit of the Moon. Its primary goal is to collect comet dust and volatile samples during a planned close encounter with comet Wild-2 in January of 2004. Aboard the spacecraft will be a microchip that carries the name of thousands of planetary exploration supporters -- including all Planetary Society members as of November 1997. These names are now posted on line on the Stardust web site (http://stardust.jpl.nasa.gov/microchip/names.html). The Stardust spacecraft will also bring back samples of interstellar dust, including the recently discovered dust streaming into the solar system from the direction of Sagittarius. These materials consist of ancient pre-solar interstellar grains and nebular condensates including remnants left over from the formation of the solar system. Their analysis is expected to yield important insights into the evolution of the Sun and planets and possibly into the origin of life itself. Preparing Stardust for Flight Earlier this month, the team from Germany's Max Planck Institute delivered the flight cometary and interstellar dust analyzer (CIDA). Mission engineers completed setting up the analyzer and checking it out, testing the instrument's ability to transmit examples of the kind of data it will collect in flight. The navigation camera team also made some important progress as they completed testing and calibrating the camera at the Jet Propulsion Laboratory in preparation for delivery to Lockheed Martin Astronautics in Denver, Colorado. This camera will be used to provide pictures to the navigators as they make the final course corrections for the cometary flythrough. It will also be the instrument for taking the "up-close-and-personal" images of Comet Wild 2 as the spacecraft cruises some 150 miles (about 240 kilometers) above the now-unknown surface of the comet's nucleus. The team at Lockheed Martin Astronautics also completed some deployment testing on the spacecraft's solar array. These tests demonstrated how Stardust will "spread its wings" following launch and separation from the launch rocket. Finally, engineers reviewed a test unit of the aerogel collector in preparation for using it to test how we will keep it extremely clean during its installation and launch. It is partially loaded with examples of flight-quality aerogel. Hа сегодня все, пока! =SANA=

Дата: 23 апреля 1998 (1998-04-23) От: Alexander Bondugin Тема: Mission to Asteroid, Mars, and Comet Delayed Привет всем! Вот, свалилось из Internet... From The Planetary Society Home Page: http://planetary.org/articlearchive/headlines/1998/headln-042098.html Mission to Asteroid, Mars, and Comet Delayed April 20, 1998 Software Troubles and Late Electronics System Force NASA To Postpone Deep Space 1 The planned July 1998 launch of NASA's Deep Space 1 technology validation mission from Cape Canaveral, Florida, has been rescheduled for October. The delay is due to a combination of late delivery of the spacecraft's power electronics system and an ambitious flight software development schedule, which together leave insufficient time to test the spacecraft thoroughly for a July launch. The power electronics system regulates and distributes power produced by not only the solar concentrator array, a pair of experimental solar panels composed of 720 cylindrical Fresnel lenses, but also by an on-board battery. Among many other functions, it helps the solar array to operate at peak efficiency, and ensures that the battery is able to cover temporary surges in power needed so that the ion propulsion system (which needs electricity for its basic operations) receives a steady power supply. "With a new launch date for this bold mission, we can be more confident that we will be ready to fully exercise our payload of important technologies," explained Chief Mission Engineer Marc Rayman of NASA's Jet Propulsion Laboratory in Pasadena, California. "The entire DS1 team looks forward to this opportunity to make a significant contribution to science missions of the future through the capabilities we are testing on DS1." Deep Space 1 is the first launch in NASA's New Millennium program, a series of missions designed to test new technologies so that they can be confidently used on science missions of the 21st century. Among the 12 technologies the mission is designed to validate are ion propulsion, autonomous optical navigation, a solar power concentrator array and an integrated camera and imaging spectrometer. The earlier July launch period for DS1 allowed it to fly a trajectory encompassing flybys of an asteroid, Mars, and a comet. By the end of May, the mission design team is scheduled to finalize new target bodies in the solar system for DS1 to encounter based on an October launch date. Editor's note: Deep Space 1 will no longer visit asteroid 3352 McAuliffe, Mars, and comet West-Kohoutek-lkemura. The launch delay was announced after this article went to press. Mission planners will announce the new targets for this mission by the end of May. The full text and graphics for this article will appear in the May/June 1998 issue of The Planetary Report. This publication goes out to all members of the Planetary Society. If you're not already a member, we encourage you to join. Deep Space 1: Exploration Technology for the 21st Century by Robert M. Nelson and Marc D. Rayman This summer NASA takes a revolutionary step when it launches Deep Space 1 (DS1). During its flight, the spacecraft will visit asteroid 3352 McAuliffe, the planet Mars, and comet West-Kohoutek-lkemura. But its primary goal is not to study these fascinating bodies; rather, as a member of the New Millennium program, its job is to pave the way for future, even more exciting, space science missions. NASA has already flown missions to asteroids, comets, and Mars, so what makes DS1 unusual? It will demonstrate a dozen technical innovations that will serve as foundation technologies for the next generation of deep-space missions. Foremost among these new technologies will be solar electric propulsion (SEP), which will enable a whole class of ambitious missions that are simply impractical or unaffordable, with the standard chemical propulsion available today. A Test Drive DS1 will be launched from Cape Canaveral on the first Delta 7326 rocket, a low-cost member of the Delta 11 family. DS1 is so small that even this economy-class launch vehicle will be able to carry a second spacecraft -- SEDSAT-1, an Earth orbiter built at the same time by students at the University of Alabama in Huntsville. Once in space, DS1 will be checked out and certified by the mission operations team, and then the SEP system will begin thrusting. Instead of burning a strong, short pulse of chemical propellant, followed by a long interplanetary cruise, the SEP system will sustain a tenuous but very high-velocity stream of ionized xenon. This stream will create a gentle, steady thrust that will propel the spacecraft almost continuously during interplanetary cruise. Although the thrust of SEP is small, its advantage accrues because the exhaust velocity of the ion rocket is many times greater than the exhaust velocity of a conventional chemical system. The bottom line is that SEP requires far less propellant than a chemical rocket to deliver the same payload mass to a target, It takes time for the gentle thrust to build up high spacecraft velocity, so SEP is appropriate only for missions requiring high energy or long trips. Within a month of launch, DS1 will have accomplished most of its major objectives, and we will have assessed its payload of advanced technologies. If a technology fails during the flight, even if it causes the loss of the spacecraft, we may still regard the mission as a success if it achieves the program goal of reducing the risk for future science missions. It is in these future missions that the real science return of DS1 will be found. But this high-risk project will attempt to return science during its test flight.... The flight of DS1 will test new autonomy technologies, solar concentrator arrays, and a variety of telecommunications and microelectronics devices. Autonomy, which in this case means the ability of the spacecraft to make its own decisions, can help reduce the heavy burden on NASA's Deep Space Network (DSN). As more and more probes are sent into space in the coming years, it will be harder for the DSN to communicate with all of them as frequently as it has done in the past. With autonomy technologies allowing spacecraft to operate for longer times without detailed instructions from Earth, the precious resources of the DSN can go further. In addition, by placing more responsibility on the spacecraft, we reduce delays caused by signal travel times and limited communications rates. Despite the potential advantages, it is easy to see that onboard decision-making systems entail risk for the first user. If the autonomy systems on DS1 perform as planned, future mission teams can be more confident about leaving important decisions to the spacecraft. One of the powerful autonomy technologies on DS1 is the navigation system. It uses images of main-belt asteroids viewed against the background stars to compute the spacecraft's position. As the spacecraft travels, foreground objects (the asteroids) will appear to move relative to the background stars. The apparent shift, or parallax, gives the navigation system information from which to triangulate the spacecraft position. The navigation system then uses positions calculated at earlier times to determine trajectory, making allowances for SEP thrusting, gravitational pulls of the Sun and planets, and other forces. If the navigation system finds that it is off course, it can make a course correction by adjusting the direction or duration of SEP thrusting.... Hа сегодня все, пока! =SANA=

Дата: 23 апреля 1998 (1998-04-23) От: Alexander Bondugin Тема: Washington Reins in NASA's Budget Привет всем! Вот, свалилось из Internet... From the Planetary Society home page: http://planetary.org/articlearchive/headlines/1998/headln-042198.html Washington Reins in NASA's Budget April 21, 1998 Search for Extraterrestrial Life and Human Exploration of Mars May Be in Jeopardy While the Clinton administration's overall budget for NASA in fiscal year 1999 once again declines, it does contain a modest increase in funding for space science -- from $1.983 billion in fiscal year 1998 to $2.058 in fiscal year 1999 -- that must be safeguarded, according to Louis Friedman, Executive Director of The Planetary Society. "The budget allows NASA to meet its obligations and fund a new mission start to explore Europa, the moon of Jupiter that may have an ocean capable of supporting life," Friedman said in testimony to a house appropriations subcommittee. "The slight increase is minimal considering the extraordinary results and opportunities in space science." The orbiter to Europa is scheduled for launch in 2003. It will measure the thickness of the moon's surface ice and seek to determine whether a liquid ocean exists below. Other instruments will examine the interior processes. In our solar system, Europa and Mars are the best candidates for having conditions that might be conducive to life. As a consequence, they are a priority in the search for evidence of extraterrestrial life. Robotic and Human Exploration The Planetary Society also urges members of Congress to appropriate an additional $42 million in new funding so NASA's Office of Space Flight can participate in the Mars 2001 lander mission as originally planned. Budget pressures within NASA recently forced the office of space flight to withdraw its participation in the mission. It earlier had agreed to provide $57 million for several experiments. But because of a shortfall in available funding, the office cannot now afford the financial contribution. The office of space science is now managing the experiments, although its budget was augmented by only $15 million, introducing severe technical constraints in the mission. Having the office of space flight participate in robotic missions is important for many reasons, Friedman said. Working together cross-fertilizes engineering and operations to promote innovative designs. The advanced technologies for robotic spacecraft have applications for human exploration missions and vice versa. The integration also will enhance scientific objectives. "It is critical for engineers to better understand the separate capabilities of humans and robotic technology," Friedman said. "As now envisioned, a future crew on Mars will rely heavily on robotic tools to explore the planet and collect scientific data. Building bridges between the two offices will ensure future success." Public Supports Exploration Sixty-eight percent of the public believe it was "worth it" to send humans to explore the Moon in the Apollo Program, according to a July 1997 poll by CBS News. Fifty-four percent favor "sending astronauts to explore Mars." In a Roper poll (7/11/97), 62 percent of the public said they would support "the United States sending astronauts to explore Mars." "Clearly, a human Mars mission on some time scale is a goal backed by a large majority of Americans," Friedman said. The Clinton Administration recently attempted to restrict investments in research for human exploration beyond low Earth orbit. Members of Congress and space organizations, including The Planetary Society, voiced opposition to the new directive and it was rescinded. Until 1996, the National Space Policy contained language establishing as a goal of America the human exploration of the Moon, then Mars. But this provision was removed by the Clinton Administration. As a consequence, activities at NASA in support of eventual human exploration beyond low Earth orbit are being challenged. "If the United States is not preparing to explore the Moon and Mars," Friedman said, "why then are we building the space station in the first place? When the space station is completed early in the next century, astronauts will be all dressed up with no place to go." Friedman said our nation cannot afford to sit on its hands until the station's assembly is completed before determining our next step in space. "We must not build fences at low Earth orbit, fearing to venture beyond," Friedman said. "Americans rise to great challenges. They want to be emboldened to have their spirit enlivened. By stabilizing NASA's budget, the agency can focus all its attention on managing programs, not budget cuts. NASA must have the wherewithal to make investments in future technology. We must begin now to establish a coherent vision for our nation following the completion of the space station." Overall Budget Every year since 1992, NASA's budget has been cut. The Clinton Administration is seeking to reduce spending in fiscal year 1999 by another $173 million. The rollback, when accounting for inflation, totals $445 million. Friedman said NASA deserves better. The space agency has enacted far-reaching reforms. It is innovating advanced technologies in aeronautics, space transportation, human exploration, and space science, which are being transferred to the marketplace to maintain America's economic health. "There is a limit to what NASA can withstand and still remain successful," Friedman said in Congressional testimony. "Budgets are now being squeezed to a breaking point, sapping vitality. The time is long past to stabilize NASA's funding. Our nation's space program merits no less." Hа сегодня все, пока! =SANA=

Дата: 23 апреля 1998 (1998-04-23) От: Alexander Bondugin Тема: Irakli Simonia, Tsitsino Simonia, Abastumani Astrophysical Observatory Subject: Irakli Simonia, Tsitsino Simonia, Abastumani Astrophysical Observatory Привет всем! Вот, свалилось из Internet... IRAKLI SIMONIA, TSITSINO SIMONIA ABASTUMANI ASTROPHYSICAL OBSERVATORY REPUBLIC OF GEORGIA E-mail: irsim@nilc.org.ge The Dust Around Cool Stars The cosmic dust, as a form of the matter, a carrier of relic information, and information on the cosmic environment, keeps causing growing interest among specialists working in different areas of research. The dust in the solar system, the interstellar medium surrounding stars of different types, has become an object of regular and, frequently, coordinated research. Theoretical and practical studies have provided us with fundamental knowledge of the cosmic dust. Meanwhile, the recent research results, including those obtained from cosmic missions to Halley=92s comet, have demonstrated that the dust observed in various shapes, forms and types in the <b style="color:black;background-color:#ffff66">universe</b> possesses common, universal features. Better and deeper understanding of those properties of the dust will require more intensive comparative studies, with the results of terrestrial laboratory experiments, cosmic sounding of the solar system bodies and astronomical observations of distant stars and nebulas being compared and summed up. Considering the physical, chemical and biological aspects of the problem, the pride of place is to be given to more intensive comparative studies of the dust that contains organic components, in particular, C2, CH, CN. In this work we made an attempt to define some properties of cool crystalline hydrocarbons from the dust shell around stars of the late types, on the basis of laboratory investigations of terrestrial crystalline hydrocarbons. It is common knowledge that both carbon stars and M-type stars are rich in hydrocarbon and other carbon-containing substances including CH. According to S.Pickelner (1959), S.Kaplan, S.Pickelner (1959) and M.Grinberg (1970) and some other authors, the stellar wind molecules, carried to a certain distance away from the carbon stars, turn into a material providing solid particles, is grains of dust. In this way, solid particles of silicon =96 carbide, graphite, etc., can= form in the vicinity of the carbon stars. Taking into consideration the chemical composition of carbon stars, on the one hand, and the complex structure of the "star"-dust shell" system on the other one can suggest that the dust around stars of the mentioned types may contain solid carbon particles formed as separate, equally dispersed crystals, as well as complex unequally dispersed polycreistals. Investigation of the dust around cool stars, using radio and IR methods, will certainly give some information on its character, but the results thus obtained ought to be compared with those of the terrestrial laboratory experiments. One of the most interesting properties of solid crystalline hydrocarbons is their ability to luminance when being exited by UV radiation. Solid crystalline hydrocarbons become luminescent under the action of UV radiation in the visible spectrum. The phenomenon of luminescence of hydrocarbon has been sufficiently well studied by specialists of photochemistry. As far as the luminescence of crystalline hydrocarbons in the cosmic medium is concerned, it has hardly been studied, so far. We find it possible to identify some luminescence properties of crystalline hydrocarbons contained in the dust around cool stars, using laboratory investigation results of luminescence properties revealed in terrestrial hydrocarbons. It is common knowledge that luminescence of organic substances can be categorized as metastable or induced luminescence. The hydrocarbons discussed in this paper produced metastable luminescence. Cold crystalline hydrocarbons produce two basic luminescence spectra at negative temperatures: I.A striped spectrum of wide bands in the visible area. II. A striped spectrum of very narrow bands in the visible area. This type of spectrum is also called quasilinear. The luminescence spectra of such hydrocarbons as C23.3 H19.3, C24 H18.4, C36 H27.8 are sets of wide bands (see the Table for maximum wavelengths) at negative temperatures. Hydrocarbon of the C14H10 type at negative temperature produces a quasilinear luminescence spectrum of very narrow bands in a 4000-5000 Ao range. Speaking of specific features of the cold crystalline hydrocarbon luminescence spectra, the following should be pointed out. a) as the hydrocarbon molecules become more complex, their luminescence spectra shift towards longer waves; b) as the temperature of cold crystalline hydrocarbon decreases, the wide bands in the luminescence spectra grow narrower. At 20oK the spectra appear as quasilinear ones. In our view, the feature described in (B) should, in principle enable evaluation of the proper temperature of cold crystalline hydrocarbons by their luminescence spectra. This can be performed, for instance, by comparing the observed band widths with standard bands. An important characteristic of luminescence is its energy output: ? =3D h c/? where h is the Planck's constant and ? is the wavelength of the exciting radiation. Assuming that cold crystalline hydrocarbon luminescence is induced by UV radiation of ?=3D3600 Ao wavelength, the energy output of the luminescence is ? =3D 5,6 x 10-19J It actually means that every quantum of UV radiation induces luminescence of hydrocarbon with the energy output of 5,6 x 10-19J. This fact provides corresponding information on the energetics of the phenomenon in question. Solid crystalline hydrocarbons obtained from various grades of petroleum were studied by L.Melikadze, T.Eliava (1958) and L.Melikadze, D.Varfolomeev (1980), who demonstrated that luminescence of hydrocarbons of the aromatic series occured only under UV radiation of 3600-3800 Ao, with Stokes' Law ?lum>?absorb being permanently in effect. No anti-Stokes lines were observed. The crystalline hydrocarbons under study luminesced under UV radiation in the yellow-green visible spectrum, with the maximum wavelength of 5500 Ao. It was experimentally proved that at the intrinsic temperature of the studied hydrocarbons of 270oK and more, the UV radiation excited luminescence of those hydrocarbons was of the fluorescence type. The after-glow period was equal to zero. When, however, the intrinsic temperature was below 270oK the UV-excited luminescence was of the phosphorescence type. The after-glow time at 230oK was as a rule, equal to several seconds. The table