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Дата: 24 октября 1998 (1998-10-24) От: Alexander Bondugin Тема: Antarctica is not shrinking (Forwarded) Привет всем! Вот, свалилось из Internet... European Space Agency Press Release No 36-98 Paris, France 15 October 1998 ANTARCTICA IS NOT SHRINKING EUROPEAN SPACE AGENCY SATELLITES PROVIDE NEW INSIGHT INTO RISING SEA LEVELS Antarctica is not shrinking, the European Space Agency ESA reveals today. This result of the ERS (European Remote Sensing) satellites is reported 16 October 1998 by an international team of scientists in the leading American magazine, SCIENCE (See note). But the same investigation provides evidence that one part of West Antarctica may be rapidly losing its ice to the ocean. The team of British, Dutch and American scientists, led by Professor Duncan Wingham at University College London, based their findings on ERS data collected over five years. The data reveal that most of the ice stored in Antarctica is very stable. The icy continent now looks an unlikely source of rising global sea level this century, making thermal expansion of the ocean due to global warming, and the shrinking of mountain glaciers, more likely causes. Prof. Wingham's team used ERS's radar altimeter instruments to determine if the thickness of the Antarctic Ice Sheet changed over the five-year period from 1992 to 1996. Transmitting over 4,000,000 radar pulses to the surface of the ice, and measuring the time taken for the echoes to return to the satellite, the average change of the height of 63 of the Ice Sheet was measured with an accuracy of 0.5 cm per year. The ice sheet has changed on average by less than 1 cm per year. Using previous measurements of changes in snowfall over the ice sheet, the team concluded that the interior of the Antarctic Ice Sheet had contributed only 1.7 cm to sea level rise this century. Sea level has risen 18 cm over the past 100 years. Previously the accuracy of data could have meant that Antarctica were responsible for a raise or lowering of global sea level by 14 cm in either direction. Speaking today on the importance of the research Professor Duncan Wingham said: "Scientists have never really understood the role that Antarctica has played in this century's rising sea level. Our research makes it likely that the answer is very little." The result supports the view that global warming, leading to a thermal expansion of the ocean and the melting of mountain glaciers, is responsible for rising sea level. Professor Wingham continued, "As a consequence of our research we should be able to produce more accurate predictions of future sea level rises. Indeed it is possible that the consequences of global warming on sea level rise has been underestimated." Professor Wingham and his team also discovered a rapid reduction in thickness in one of West Antarctica's least known drainage basins. The Thwaites Glacier basin was shrinking rapidly at 12 cm per year. The result provides evidence that one of the most hostile regions of Antarctica may be undergoing rapid change. Commenting on the wider importance of the research, ESA's Earth Observation Mission Manager Guy Duchossois said: "Knowledge about sea level rise matters for many million people in coastal areas whose lives depend on dykes that can withstand the forces of nature. ESA will continue to fly satellites that provide the data for a better understanding of our environment. Global warming may have daunting consequences that satellites in space can help to manage." Further information: Franco Bonacina Media Relations, European Space Agency 00 33 1 5369 7713 Patrick Edwards Head of Media Relations 0171 391 1621 Linda Capper British Antarctic Survey 01223 221 448 NOTES TO EDITORS. (i) Antarctic Elevation Change 1992 - 1996, D.J.Wingham et al. Appears in the 16 October 1998 edition of SCIENCE Andrew Yee ayee@nova.astro.utoronto.ca Hа сегодня все, пока! =SANA=

Дата: 24 октября 1998 (1998-10-24) От: Alexander Bondugin Тема: Boeing Changes Delta III Control Software (Forwarded) Привет всем! Вот, свалилось из Internet... The Boeing Company Contact: Walt Rice (714) 896-5171 Communications (714) 896-1301 Delta Launch Hotline: (714) 896-4770 98-076 Boeing Changes Delta III Control Software HUNTINGTON BEACH, Calif., Oct. 15, 1998 -- The Delta III investigation team here completed the cause and corrective action investigation into the Aug. 26 failure of the Boeing Delta III launch vehicle. "The roll instability which led to the Delta III failure can be corrected by a change to our control software," said Clarence Quan, Boeing [NYSE: BA] Delta III investigation chairman. The Delta III control system consists of an onboard computer system which controls the main engine, two vernier engines and three solid-rocket motors (SRMs) with thrust-vector control (TVC) assemblies. When designing the roll aspects of the control system, 56 roll modes were identified. A 4 hertz (cycles per second) roll mode caused the roll instability seen in the Delta III launch. A mode is the characteristic pattern of movement or shape an object takes as it vibrates. "Past flight data with Delta II shows the most significant roll mode at liftoff remains the dominant mode throughout the first phase of flight," Quan said. "This data drove the design of the control system; because the 4 hertz roll mode was not significant at liftoff it was not designed into the control system." The 4 hertz roll mode was caused by the three airlit solid-rocket motors rocking back and forth in unison. As the ground lit SRMs burned and lost weight, the rocking air-lit solids had a greater influence on the vehicle. The mode became significant 40 to 50 seconds into flight. Once the control system recognized the mode, it attempted to correct the roll oscillation. In doing so, the hydraulic fluid used to move the nozzles on the solid-rocket motors with TVCs was depleted. Without the solid-rocket-motor TVC system, the Delta III was unable to maintain control. Approximately 72 seconds after liftoff, the vehicle flew through a wind shear, yawed 25 - 35 degrees, started to breakup and the rocket's automatic destruct system initiated. At this time the investigation team is focusing on the return-to-flight planning for the next Delta III launch, planned for the first quarter of 1999. Dan Collins is leading the Delta III return-to-flight and revalidation team. Clarence Quan and Walt Wilson will continue to lead the senior investigation board. Other former and current senior members of the Delta team will join representatives from NASA, U.S. Air Force Space and Missile Center, Aerospace Corporation, Hughes Space and Communications, as well as a retired vice president from General Dynamics on the senior investigation board. Andrew Yee ayee@nova.astro.utoronto.ca Hа сегодня все, пока! =SANA=

Дата: 24 октября 1998 (1998-10-24) От: Alexander Bondugin Тема: New iceberg breaks off Ronne Ice Shelf in Antarctica (Forwarded) Привет всем! Вот, свалилось из Internet... NOAA 98-69 CONTACT: Patricia Viets, NOAA FOR IMMEDIATE RELEASE: 10/15/98 NEW ICEBERG BREAKS OFF RONNE ICE SHELF IN ANTARCTICA An iceberg larger than the state of Delaware has broken off the Ronne Ice Shelf in Antarctica, the National Ice Center reported today. The iceberg, named A-38, is 92 x 29.9 miles and covers an area roughly 2750.8 square miles. It broke off the second largest ice shelf in Antarctica, located in the southern Weddell Sea. Mary Keller, a scientist at the National Ice Center in Suitland, Md., sighted the iceberg using satellite data. The data are from an instrument on a satellite in the Defense Meteorological Satellite Program -- the Operational Linescan System, which has a spatial resolution of .55 km (.34 miles). These satellites are operated by the Commerce Department's National Oceanic and Atmospheric Administration. The National Ice Center is a tri-agency operational center represented by the U.S. Navy (Department of Defense); the National Oceanic and Atmospheric Administration (Department of Commerce); and the U.S. Coast Guard (Department of Transportation). The National Ice Center's mission is to provide world-wide operational ice analyses for the armed forces of the United States and allied nations, U.S. government agencies, and the private sector. Ice shelves are massive, floating sheets of snow and frozen water that encircle the Antarctic mainland. Scientists at University College London believe that the breaking off, or calving, of icebergs is an important mechanism in the disintegration of ice shelves, and a possible indicator of global warming. Scientists there report that the mechanics of ice shelf fracturing remain poorly understood. A research group at the college is planning to study ice core samples from the Ronne Ice Shelf to learn more about fracture and deformation properties. The last known iceberg of this magnitude to calve off a Southern Hemisphere Ice Shelf was B-9 in the Ross Sea in October 1987. Iceberg names are derived from the Antarctic quadrant in which they were originally sighted. The quadrants are divided counter-clockwise in the following manner: A = 0 to 90 degrees West longitude (Bellinghausen/Weddell Sea) B = 90 West to 180 (Amundsen/Eastern Ross Sea) C = 180 to 90 East (Western Ross Sea/Wildesland) D = 90 East to 0 (Amery/Eastern Weddell Sea) When an iceberg is first sighted, the National Ice Center documents its point of origin. The letter of the quadrant, along with a sequential number, is assigned to the iceberg. For example, A-38 is the 38th iceberg the ice center has found in the Antarctica in Quadrant A. ### Note to Editors: An image of A-38 is on the World Wide Web at: http://www.natice.noaa.gov . Click on Icebergs; then click onto Southern Hemisphere Icebergs. The GIF image of A-38 is located above the weekly iceberg update table. Andrew Yee ayee@nova.astro.utoronto.ca Hа сегодня все, пока! =SANA=

Дата: 24 октября 1998 (1998-10-24) От: Alexander Bondugin Тема: WDC-A R&S Launch Announcement 12968: UHF F/O F9 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 12968 COSPAR/WWAS USSPACECOM NUMBER SPACECRAFT INTERNATIONAL ID (CATALOG NUMBER) LAUNCH DATE,UT UHF F/O F9 1998-058A 25501 20 OCTOBER 1988 DR. JOSEPH H. KING, DIRECTOR, WDC-A-R&S. [PH: (301) 286 7355. E-MAIL: KING@NSSDCA.GSFC.NASA.GOV 20 OCTOBER 1998, 14:00 UT] Further details will be in a forthcoming SPACEWARN Bulletin 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 SPACEWARN home page: http://nssdc.gsfc.nasa.gov/spacewarn/ Hа сегодня все, пока! =SANA=

Дата: 24 октября 1998 (1998-10-24) От: Alexander Bondugin Тема: MGS Aerobraking Update - October 18, 1998 Привет всем! Вот, свалилось из Internet... Mars Global Surveyor Aerobraking Status Report Sunday, October 18 (DOY 286/19:00:00 to DOY 291/19:00:00 UTC) Last Orbit Covered by this Report = 631 Total Phase I Aerobraking orbits accomplished = 180 Total Phase II Aerobraking orbits accomplished = 58 Total Science Phasing orbits accomplished = 290 Apoapsis altitude = 14074 km Apoapsis altitude decrease since start of aerobraking = 39952 km Periapsis altitude = 113.9 km Current Orbit Period = 09:02:37 Orbit Period decrease since start of aerobraking = 35:56:56 Starting Phase II orbit period = 11:38:02 RECENT EVENTS: The spacecraft health continues to be excellent as the 9 hour orbit period is reached in Phase 2 aerobraking. The orbit period has been reduced by 36 minutes over the past 13 drag passes during this reporting period. A periapsis lowering maneuver was executed on the apoapsis portion of orbit 622 to increase the drag pressure by about 10 percent. The 4-orbit running mean has been modified to use the last 5 orbits in the calculation. The current 5-orbit running mean is now 0.276 N/m2. The mean ran slightly over the 0.28 N/m2 upper corridor limit following orbit 628 registering 0.292 N/m2. The peak dynamic pressure on this orbit was recorded as 0.34 N/m2, just under the first alarm limit of 0.35 N/m2. Per Wednesday's reset meeting decision, the flight operations manager exercised discretion and did not order a periapsis raise maneuver based on reliable predictions that the following drag passes would provide less drag force. Navigation predictions are now based on the Wave-3 model which indicates relatively higher atmospheric densities at drag altitudes occurring over 110њ, 230њ and 350њ East longitudes. Sequence P632 will be built today to replace the current P630 sequence that was loaded yesterday. On Friday it was noticed that orbit 625 was executed by the P622 sequence and not the P624 sequence as planned. The planned uplink of the P626 sequence was rejected by flight software due to the target memory area being in use. An unplanned build of sequence P627 was required to take over before the last command of the P622 sequence forced contingency mode entry. An investigation found that the P624 sequence, following successful uplink and initiation, encountered an error and aborted its execution at the same time the P622 sequence should have been canceled. The error was caused by a Send'Two' Word command that was being executed during the same second as another flight software command. A FSW idiosyncrasy does not process commands successfully when Send'XX'Word commands are issued concurrently with other commands. A flight rule will be implemented to prevent this from recurring and checks are being executed to prevent this command configuration. The MAG/ER calibration executed on Wednesday was cut short when an error in the Load and Go sequence caused it's execution to cease. Analysis shows a back-to-back timing constraint violation using PDS (Payload Data Subsystem) commands. This restriction, implemented as a flight rule, was not checked by ground processes and was left undetected. The remainder of the MAG/ER calibration will be performed using NIPCs. A command sequence was generated and loaded to correct the telemetry state left by the aborted calibration successfully. The two incidents have been recorded in ISAs. The -Y solar array yoke continues solid structural performance. Attitude control continues excellent performance with no concerns with momentum management or star processing. The power subsystem reports strong performance with 10.7 % battery discharge depths each orbit. This deficit is being easily replaced by the primary charger with 7 minutes of margin. The minimum MOLA temperature continues to stay above 11.2њC using the shorter 70 minute warming maneuver. The telecommunications subsystem continues solid performance. UPCOMING EVENTS: Periapsis for Orbit 632 DOY292/00:57:45 UTC Periapsis for Orbit 633 DOY292/09:57:32 UTC Periapsis for Orbit 634 DOY292/18:54:35 UTC Periapsis for Orbit 635 DOY293/03:38:39 UTC Periapsis for Orbit 636 DOY293/12:39:13 UTC Periapsis for Orbit 637 DOY293/21:25:28 UTC (Note: MDT = UTC-6 hours DOY292=10/19) SPACECRAFT COMMANDING: There were 32 command files radiated to the S/C during this period. The total files radiated since launch is now 2881. These commands were sent in support of the following activities: MAG/ER & TES NIPCs Nominal drag pass sequences (P619, P622, P624, P626, P627, P630) Nominal aerobraking maneuver sequences (A622) Command Loss Timer resets Express SSR 1A playback Full SCP memory read-out Contingency Mode script update MAG/ER calibration Recovery from aborted calibration test Hа сегодня все, пока! =SANA=

Дата: 24 октября 1998 (1998-10-24) От: Alexander Bondugin Тема: New MGS Image: Cliff-Face In The North Polar Layered Deposits Привет всем! Вот, свалилось из Internet... http://mars.jpl.nasa.gov/mgs/msss/camera/images/10_19_98_polar_release/10_19_9 8_npld_rel/index.htm Mars Global Surveyor Mars Orbiter Camera Mars Orbiter Camera (MOC) High Resolution Images: Detailed View of Cliff-face in the North Polar Layered Deposits Mars Global Surveyor Mars Orbiter Camera Release: MOC2-70A, -70B Mars Global Surveyor Mars Orbiter Camera Image ID: 586335198.46103 P461-3 (A) [Image] 960 KByte GIF image --or-- 270 KByte GIF image (A) Regional and local context of MOC image 46103. The small figure in the upper right corner is a map of the north polar region, centered on the pole with 0њ longitude located in the lower middle of the frame. A small black box within the polar map indicates the location of the Viking Orbiter 2 image used here for local context. The Viking image, 560b60, was taken in March 1978, toward the end of Northern Spring. The thin strip superposed on the Viking image is MOC image 46103, reduced in size to mark its placement relative to the Viking context image. The black box on the MOC image shows the location of the subframe highlighted in (B), below. Illumination is from the left in the Viking image. The 10 kilometer scale bar also represents approximately 6.2 miles. (B) [Image] 625 KByte GIF image --or-- 160 KByte GIF image (B) MOC image 46103 subframe centered on outcrop of layered deposits in the north polar region of Mars. The picture was taken in July 1998, during early Northern Spring. The dark bar represents 600 meters (656 yards or 1,968 feet). Illumination is from the right. You may need to adjust the images for the gamma of your monitor to insure proper viewing. Note: This MOC image is made available in order to share with the public the excitement of new discoveries being made via the Mars Global Surveyor spacecraft. The image may be reproduced only if the image is credited to "Malin Space Science Systems/NASA". Release of this image does not constitute a release of scientific data. The image and its caption should not be referenced in the scientific literature. Full data releases to the scientific community are scheduled by the Mars Global Surveyor Project and NASA Planetary Data System. Typically, data will be released after a 6 month calibration and validation period. Click Here for more information on MGS data release and archiving plans. CAPTION On Earth, geologists use layers of rock to "read" the history of our planet. Where rocks were initially formed as layers of sediment, the historic record of Earth is deciphered by knowing that older layers are found beneath the younger layers. Scientists investigating changes in Earth's climate over the past few million years also use this principle to examine cores of ice from Greenland and Antarctica. Layered rock and layered polar deposits on Mars may also preserve a comparable record of that planet's geologic and environmental history. The martian north and south polar regions are covered by large areas of layered deposits. Since their discovery in the early 1970's, these polar layered deposits have been cited as the best evidence that the martian climate experiences cyclic changes over time. It was proposed that detailed investigation of the polar layers (e.g., by landers and/or human beings) would reveal a climate record of Mars in much the same way that ice cores from Antarctica are used to study past climates on Earth. On January 3, 1999, NASA's Mars Polar Lander and Deep Space 2 Penetrators will launch on a journey to study the upper layers of these deposits in the martian southern hemisphere. Meanwhile, investigation of the north polar layered deposits has advanced significantly this year with the acquisition of MGS data. The Mars Orbiter Laser Altimeter acquired new topographic profiles over the north polar deposits in June and early July, 1998, and dozens of new high resolution images were taken by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) from mid-July to mid-September, 1998. When it was proposed to NASA in 1985, one of the original objectives of MOC was to determine whether the polar layered deposits-- then thought to consist of 10 to 100 layers each between 10 and 100 meters (33 to 330 feet) thick--have more and thinner layers in them. The layers were proposed to have formed by slow accumulation of dust and ice--perhaps only 100 micrometers (0.004 inches) per year. A layer 10 meters (33 feet) thick would take 100,000 years to accumulate, roughly equal to the timescale of climate changes predicted by computer models. The image shown here (B) was taken at 11:52 p.m. PDT on July 30, 1998, near the start of the 461st orbit of Mars Global Surveyor. The picture shows a slope along the edge of the permanent north polar cap of Mars that has dozens of layers exposed in it. The image shows many more layers than were visible to the Viking Orbiters in the 1970s (see (A) above). The layers appear to have different thicknesses (some thinner than 10 meters (33 feet)) and different physical expressions. Some of the layers form steeper slopes than others, suggesting that they are more resistant to erosion. The more resistant layers might indicate that a cement (possibly ice) is present, making those layers stronger. All of the layers appear to have a rough texture that might be the result of erosion and/or redistribution of sediment and polar ice on the slope surface. The presence of many more layers than were seen by Viking is an important and encouraging clue that suggests that future investigation of polar layered deposits by landers and, perhaps some day, by human explorers, will eventually lead to a better understanding of the of the polar regions and the climate history recorded there. Our view of these deposits will be much improved--starting in late March 1999--when the Mapping Phase of the MGS mission begins, and MOC will be able to obtain images with resolutions of 1.5 meters (5 feet) per pixel. ------------------------------------------------------------------------ ------------------------------------------------------------------------ Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. Hа сегодня все, пока! =SANA=

Дата: 24 октября 1998 (1998-10-24) От: Alexander Bondugin Тема: GIS system maps shuttle exhaust cloud (Forwarded) Привет всем! Вот, свалилось из Internet... Purdue University Sources: Bernie Engel, (765) 494-1198; e-mail, engelb@ecn.purdue.edu Ross Hinkle, (407) 867-4188 Writer: Rebecca J. Goetz, (765) 494-0461; e-mail, rjg@aes.purdue.edu Purdue News Service: (765) 494-2096; e-mail, purduenews@uns.purdue.edu October 16, 1998 GIS system maps shuttle exhaust cloud WEST LAFAYETTE, Ind. -- On Oct. 29 the shuttle Discovery will head into space from Florida, but only after a computer-based geographic information system (GIS) assures launch managers that shuttle exhaust won't harm the local wildlife. Bernie Engel, a Purdue University agricultural engineer, helped develop the GIS system for the National Aeronautics and Space Administration. "Right next to the launch area is Merritt Island National Wildlife Refuge, which is visited by more than a million people a year," Engel said. "NASA is very careful about not messing up, not letting harmful deposits accumulate there." A few hours after a shuttle goes up, spent fuel from the solid rocket boosters falls back down. Much of what falls is an acid cloud -- in concentrations low enough that it won't h