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    Архив RU.SPACE.NEWS за 13 марта 1998

    Дата: 13 марта 1998 (1998-03-13) От: Alexander Bondugin Тема: More Evidence Points To Impact As Dinosaur Killer Привет всем! Вот, свалилось из Internet... Douglas Isbell Headquarters, Washington, DC March 12, 1998 (Phone: 202/358-1547) Diane Ainsworth Jet Propulsion Laboratory, Pasadena, CA (Phone: 818/354-5011) RELEASE: 98-42 MORE EVIDENCE POINTS TO IMPACT AS DINOSAUR KILLER Two new impact crater sites in Belize and Mexico add further evidence to the hypothesis that an asteroid or comet collided with Earth about 65 million years ago, subsequently killing off the dinosaurs and many other species on the planet. Researchers Adriana Ocampo of NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA, and Kevin Pope of Geo Eco Arc Research, La Canada-Flintridge, CA, led an international team that discovered the two new sites during a recent expedition sponsored by NASA's Exobiology Program and The Planetary Society, Pasadena, CA. "We discovered an important new site in Alvaro Obregon, Mexico, about 140 miles (230 kilometers) from the rim of the Chicxulub crater. This crater was formed when a 6-to-8-mile diameter (10-to-14-kilometer diameter) asteroid or comet collided with Earth," Ocampo said. "The site contains two layers of material, or ejecta, thrown out by the impact that flowed across the surface like a thick fluid, known as fluidized ejecta lobes," added Pope. "This is the closest surface exposure of ejecta to the Chicxulub crater that has yet been found and the best example known on Earth from a really big impact crater." Centered on the coast of Yucatan, Mexico, the Chicxulub crater is estimated to be about 120 miles (200 kilometers) in diameter. The impact 65 million years ago kicked up a global cloud of dust and sulfur gases that blocked sunlight from penetrating through the atmosphere and sent Earth into a decade of near-freezing temperatures. The drop in temperature and related environmental effects are thought to have brought about the demise of the dinosaurs and about 75 percent of the other species on Earth. The Earth orbits the Sun in a swarm of so-called near-Earth objects, whether they are comets or asteroids, yet the science of detecting and tracking them is still relatively young. Only a handful of astronomers around the world search for these objects, and they estimate that currently only about one-tenth of the population of near-Earth objects has been detected. Chicxulub is the only impact event that has been correlated with mass extinctions to date. The site has been dated geologically to the boundary between the Cretaceous and Tertiary periods, also known as the K/T boundary. Local geologist Brian Holland of Punta Gorda, Belize, guided the expedition to another new ejecta site about 290 miles (480 kilometers) from the crater rim. This Belize site contains tiny spheres of altered green glass, called tektites. Tektites are rocks that have been melted to glass by the severe heat of an impact. Expedition member Jan Smit of Free University, Amsterdam, noted that the Belize tektites were similar to those found in Haiti and northern Mexico. This finding links the stratigraphy of the Belize sites to the more distant Caribbean and Mexican ejecta sites. Alfred Fischer of the University of Southern California, Michael Gibson of the University of Tennessee at Martin, and Jaime Urrutia and Francisco Vega of the National Autonomous University of Mexico helped the team collect 900 pounds (400 kilograms) of samples, including drill cores, for paleomagnetic studies. They also collected fossils from the site to help date the deposits and add new pieces to the puzzle of what happened at Chicxulub 65 million years ago. Impact ejecta is very rare on Earth, but covers much of the surface of Mars because Mars' surface has remained stable and unchanged for billions of years, thus preserving debris from these rare impact events. Also, such fluidized ejecta lobes have never been observed directly on Earth before and can serve as an excellent laboratory for studying the ejecta lobes surrounding many Martian craters. "The discovery of these new ejecta sites is very exciting," said team co-leader Ocampo. "It is like seeing a bit of Mars on Earth." The exact nature of these ejecta lobes on Mars remains a mystery, Ocampo noted. Some scientists think they were created by an abundance of water in the Martian crust, which turned the ejecta into a muddy, molasses-like material. Others suggest the fluidized ejecta lobes were enabled by a much thicker atmosphere in Mars' early history. As flying ejecta from an impact event flew through the Martian atmosphere, it was reduced by friction to a very dense, turbulent cloud of debris, which also flowed like water. Study of the Chicxulub fluidized ejecta may help settle this debate and shed new light on theories that the Martian surface may once have been more hospitable for life. Volunteers who assisted The Planetary Society and the scientists in the field have posted their photographs of the expedition on The Planetary Society web site at the following URL: http://planetary.org Information about and images of newly discovered near-Earth objects found by JPL's ongoing Near-Earth Asteroid Tracking (NEAT) program are available at: http://huey.jpl.nasa.gov/~spravdo/neat.html Ocampo and Pope's research was funded in part by the Exobiology Program of NASA's Office of Space Science, Washington, DC. NASA's Jet Propulsion Laboratory is a division of the California Institute of Technology, Pasadena, CA. -end- Hа сегодня все, пока! =SANA=
    Дата: 13 марта 1998 (1998-03-13) От: Alexander Bondugin Тема: Assembly Of NASA's X-Ray Telescope Completed Привет всем! Вот, свалилось из Internet... Donald Savage Headquarters, Washington, DC March 12, 1998 (Phone: 202/358-1547) Dave Drachlis Marshall Space Flight Center, Huntsville, AL (Phone: 205/544-0034) A. Brooks McKinney TRW Space and Electronics Group, Redondo Beach, CA (Phone: 310/814-8177) RELEASE: 98-43 ASSEMBLY OF NASA'S X-RAY TELESCOPE COMPLETED Assembly of the world's most powerful X-ray telescope, NASA's Advanced X-ray Astrophysics Facility, was completed last week with the installation of its power-generating twin solar panels. AXAF is scheduled for launch aboard Space Shuttle mission STS-93, in December 1998. The last major components of the observatory were bolted and pinned into place March 4 at TRW Space & Electronics Group in Redondo Beach, CA, and pre-launch testing of the fully assembled observatory began March 7. "Completion of the observatory's assembly process is a big step forward toward launch scheduled for the end of this year," said Fred Wojtalik, manager of the Observatory Projects Office at NASA's Marshall Space Flight Center, Huntsville, AL. "With all the major components in place, we are now concentrating on a thorough pre-launch checkout of the observatory." "We're delighted to reach this major milestone for the program," said Craig Staresinich, TRW's Advanced X-ray Astrophysics Facility program manager. "The entire observatory team has worked hard to get to this point and will continue an exhaustive test program to ensure mission success. We're looking forward to delivering a truly magnificent new space capability to NASA later this summer." The first pre-launch test of the Advanced X-ray Astrophysics Facility was an acoustic test, which simulated the sound pressure environment inside the Space Shuttle cargo bay during launch. A thorough electrical checkout before and after the acoustic test verifies that the observatory and its science instruments can withstand the extreme sound levels and vibrations that accompany launch. "With 10 times the resolution and 50-100 times the sensitivity of any previous X-ray telescope, this observatory will provide us with a new perspective of our universe," said the project's chief scientist, Dr. Martin Weisskopf, of Marshall. "We'll be able to study sources of X-rays throughout the universe, like colliding galaxies and black holes, many of which are invisible to us now. We may even see the processes that create the elements found here on Earth." Assembly of the observatory began in 1997 with the arrival of the high resolution mirror assembly at TRW Space and Electronics Group. In August 1997, the telescope's optical bench was mated with the mirrors, followed by integration of the telescope with the spacecraft in October. In February 1998, the observatory's science instrument module was mated to the top of the telescope. The complete observatory is 45 feet long, has a solar array wing span 64 feet wide, and weighs more than 5 tons. Using glass purchased from Schott Glaswerke, Mainz, Germany, the telescope's mirrors were built by Raytheon Optical Systems Inc., Danbury, CT. The mirrors were coated by Optical Coating Laboratory Inc., Santa Rosa, CA, and assembled by Eastman-Kodak Co., Rochester, NY. The observatory's charged coupled device imaging spectrometer was developed by the Pennsylvania State University at University Park, and the Massachusetts Institute of Technology (MIT), at Cambridge. One diffraction grating was developed by MIT, the other by the Space Research Organization Netherlands, Utrecht, in collaboration with the Max Planck Institute, Garching, Germany. The high resolution camera instrument was built by the Smithsonian Astrophysical Observatory. Ball Aerospace & Technologies Corporation of Boulder, CO, developed the science instrument module. The Advanced X-ray Astrophysics Facility program is managed by Marshall for the Office of Space Science, NASA Headquarters, Washington, DC. The Smithsonian Astrophysical Observatory, Cambridge, MA, will operate the observatory for NASA. - end - Hа сегодня все, пока! =SANA=
    Дата: 13 марта 1998 (1998-03-13) От: Alexander Bondugin Тема: X-38 Atmospheric Vehicle Completes First Unpiloted Flight Test Привет всем! Вот, свалилось из Internet... Michael Braukus Headquarters, Washington, DC March 12, 1998 (Phone: 202/358-1979) James Hartsfield Johnson Space Center, Houston, TX (Phone: 281/483-5111) Fred Brown Dryden Flight Research Center, Edwards, CA (Phone: 805/258-2663) RELEASE: 98-44 X-38 ATMOSPHERIC VEHICLE COMPLETES FIRST UNPILOTED FLIGHT TEST Development of the X-38, an innovative new spacecraft design planned for use as a future International Space Station emergency crew return "lifeboat," passed a major milestone today with a successful first unpiloted flight test. The first X-38 atmospheric test vehicle was dropped from under the wing of NASA's B-52 aircraft at the Dryden Flight Research Center, Edwards, CA, at 11:30 a.m. EST and completed a descent from a 23,000 foot altitude at 11:38 a.m. EST. The test focused on the use of the X-38's parafoil parachute, which deployed as planned within seconds after the vehicle's release from the B-52 and guided the test craft to landing. "This was a real experimental flight test and the culmination of two years of hard work by a team from the Johnson Space Center and the Dryden Flight Research Center," X- 38 project manager John Muratore said. "We had done everything we could to minimize the unknowns. But the real proof of the concept is a successful flight. We got one of those today, and we plan to do this about 20 more times over the next two years to prove we're ready to fly from space." Atmospheric drop tests of the X-38 will continue for the next two years using three increasingly complex test vehicles. The drop tests will increase in altitude to a height of 50,000 feet and include longer flight times for the test craft prior to deployment of the parafoil. In 2000, an unpiloted space test vehicle is planned to be deployed from a Space Shuttle and descend to a landing. The X-38 crew return vehicle is targeted to begin operations aboard the International Space Station in 2003. "With Johnson and Dryden employees working as a team, we were able to design, outfit and test the vehicle," said Bob Baron, Dryden X-38 project manager. "Using existing NASA infrastructure, such as the Johnson and Dryden control rooms and the B-52 mothership, has provided considerable cost and schedule savings in the development of this prototype X-38 vehicle." Once operational, the X-38 will become the first new human spacecraft designed to return humans from orbit in more than 20 years, and it is being developed at a fraction of the cost of past human space vehicles. The primary application of the new spacecraft would be as an International Space Station "lifeboat," but the project also aims at developing a design that could be easily modified for other uses, such as a possible joint U.S. and international human spacecraft that could be launched on expendable rockets as well as the Space Shuttle. The European Space Agency is cooperating with NASA in the current development work, supplying several components for the planned space test vehicle. The X-38 is being developed with an unprecedented eye toward efficiency, taking advantage of available equipment and already-developed technology for as much as 80 percent of the spacecraft's design. The design uses a lifting body concept originally developed by the Air Force X-24A project in the mid- 1970s. Following the jettison of a deorbit engine module, the X-38 would glide from orbit unpowered like the Space Shuttle and then use the steerable parafoil parachute for its final descent to landing. In the early years of the International Space Station, a Russian Soyuz spacecraft will be attached to the station as a crew return vehicle. But, as the size of the station crew increases, a return vehicle like the X-38, that can accommodate up to seven passengers, will be needed. -end- Hа сегодня все, пока! =SANA=

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