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Декабрь 1998


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    Дата: 29 декабря 1998 (1998-12-29) От: Alexander Bondugin Тема: Successful NEAR Flyby Of Eros - Closeup Images Available Привет всем! Вот, свалилось из Internet... NEAR Spacecraft Makes Planned Flyby of Asteroid Eros On Dec. 23, at 1:43 p.m. EST, the NEAR spacecraft made a flyby of Eros designed to provide scientists with detailed data on the asteroid. In a matter of hours, mission operations personnel were able to respond to an aborted scheduled engine burn and program the command sequence that put the spacecraft on a trajectory approximately 2,500 miles (4,100 kilometers) from the surface of the asteroid. Currently (Dec. 23, 3 p.m. EST), the spacecraft is executing the command sequence as planned. Three instruments onboard the spacecraft, the Multispectral Imager, the Near-Infrared Spectrometer, and the Magnetometer, are operating as expected. More than 1,100 images of the asteroid are anticipated, which will provide scientists with valuable information on the size, shape, and surface characteristics of Eros and whether it has any moons. The first photographs will be posted on the NEAR Web site on Dec. 24 between 1:00 - 2:30 p.m. NEAR Sends Back Images of Eros (December 24, 1998, 2 p.m. EST) Despite an aborted engine burn that postponed the January 1999, rendezvous of the NEAR spacecraft with asteroid Eros, mission operations team members were able to quickly upload new commands to the spacecraft, making it possible to obtain valuable information during a December 23, flyby of the asteroid. Science data, including multicolor images, spectral data, and magnetic field measurements taken during the flyby, are now coming into the Applied Physics Laboratory's NEAR Science Data Center. Doppler navigation data and real-time telemetry were collected that will help determine the mass of the asteroid. The flyby gave NEAR Mission Operations an opportunity to test tracking and instrument sequences in preparation of a rendezvous event, says Mission Operations Center Manager Mark Holdridge. "The flight recorders, full of Eros science data, are being played back at the present time. The spacecraft is healthy and doing just fine and it has been confirmed that the flyby pointing and instrument command sequence executed flawlessly to completion." In addition to flyby data processing, team members are also studying data sent by the spacecraft soon after contact with it was reestablished on Dec. 22, following 27 hours of communication blackout to determine the exact nature of the software anomaly that led to the rendezvous burn failure. NEAR and Eros are now traveling in separate orbits around the sun as plans are being made for a rendezvous sometime between August 1999 and April 2000. Images of Eros taken during the flyby are being posted on the NEAR Web site as they are processed. NEAR's First Close-Ups of Eros http://near.jhuapl.edu/iod/000/index.html This montage of the asteroid Eros was assembled from images acquired by the Near Earth Asteroid Rendezvous (NEAR) spacecraft on Dec. 23, as the spacecraft flew by the asteroid at a distance of 2,500 miles (4,100 kilometers) at 1:43 p.m. EST. This montage shows the first nine of 28 views of Eros that were obtained during the flyby. The images were taken between 10:44 AM and 12:44 PM EST as the spacecraft range closed from 7300 miles (11,100) km to 3300 miles (5300 kilometers). During that time, the asteroid completed nearly half of a rotation. The smallest resolved detail is approximately 1650 feet (500 meters) across. A firing of the main engine at 5 PM EST December 20, designed to slow the spacecraft for insertion into orbit around the asteroid, was aborted by the spacecraft. Contact with ground controllers was temporarily lost, but was regained at 8 PM EST December 21 when autonomous spacecraft safety protocols took over and transmitted a signal to the ground. All spacecraft systems appear healthy and operational. Within hours, a flyby observation sequence was developed and uploaded to the spacecraft. Over 1100 images were acquired by the multispectral imager, to determine the size, shape, morphology, rotational state, and color properties of Eros, and to search for small moons. The infrared spectrometer measured spectral properties of the asteroid to determine what minerals are present, and the magnetometer searched for a natural magnetic field. Analysis of the spacecraft radio signal will yield bounds on the asteroid's mass and density. Options for rescheduling firing of the main spacecraft engine are currently being examined, and could lead to Eros rendezvous and orbit insertion as early as mid-1999 or as late as May 2000. Eros is NEAR's second asteroid encountered. On June 27, 1997, NEAR flew by the main-belt asteroid Mathilde at a range of 1212 kilometers (750 miles). Built and managed by The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, NEAR was the first spacecraft launched in NASA's Discovery Program of low-cost, small-scale planetary missions. See the NEAR web page at http://near.jhuapl.edu for more details. Hа сегодня все, пока! =SANA=
    Дата: 29 декабря 1998 (1998-12-29) От: Alexander Bondugin Тема: Lunar Prospector Update - December 21, 1998 Привет всем! Вот, свалилось из Internet... Lunar Prospector Mission Status Report #62 December 21, 1998 The Lunar Prospector spacecraft is operating well and all instruments continue to collect good data. On Saturday, December 19, the spacecraft was placed into a orbit with an average altitude of 40 km. This is a transition orbit, between the nominal mapping orbit (with altitude 100 km) and the extended mission orbit (with altitude 25-30 km), where the gravity model will be verified. The timeline is given below: 353/1740 cmd'd thruster heaters on 353/1811 fired A3/A4 thrusters for 46.8 sec 353/1840 cmd'd thruster heaters on 353/1911 fired A1/A2 thrusters for 150.4 sec 353/1917 cmd'd thruster heater on 353/1937 fired T1 thrusters for 0.65 sec The starting orbit was 77.5 km x 122.5 km. The first burn was at apoapsis to lower periapsis from 77.5 km to 50.5 km. The second burn was at the ascending node to set new periapsis altitude to 25 km at desired argument of periapsis. The resulting orbit was 25 km x 55 km. The gravity field will tend to circularize it over the next few days. The attitude reorientation maneuver was cancelled and the third burn trimmed the spacecraft spin rate back to its nominal value. There were very high winds in the California high desert and there was concern that the antenna (DSS 27) would have to be stowed mid-way during the maneuver, but fortunately the winds stayed below the limits and everything went on time. Eclipses started as predicted at 353/2005 but their length will decrease with time and the season will end before Christmas. Current spacecraft state (0000 GMT 12/21/98): Orbit: 4184 Downlink: 3600 bps Spin Rate: 12.00 rpm Spin Axis Attitude (ecliptic): Latitude: -88.0 deg Longitude: 242 deg Trajectory: Periapsis Alt: 29 km Apoapsis Alt: 52 km Period: 112 min Occultations: 10 minutes Eclipses: 23 minutes Propellant remaining: 17.45 kg Hа сегодня все, пока! =SANA=
    Дата: 29 декабря 1998 (1998-12-29) От: Alexander Bondugin Тема: Mars Climate Orbiter Update - December 23, 1998 Привет всем! Вот, свалилось из Internet... MARS CLIMATE ORBITER MISSION STATUS December 23, 1998 4:00 P.M. (PST) Earlier today Mars Climate Orbiter successfully completed its last planned activity for 1998, in which its two science instruments, the Pressure Modulator Infrared Radiometer (PMIRR) and MARs Color Imager (MARCI), were powered for their first post-launch health check. Preliminary analysis of the telemetry data returned indicated that both instruments are in good operating condition. Further detailed analysis of the health check data will be perfomed over the next few weeks. Data collected onboard the spacecraft from both instruments were transmitted back to Earth over a four and one-half hour period. Due to a minor error discovered in the telemetry system configuration, one of the eight MARCI test images was not returned during the scheduled data playback period. The error has been corrected, and the remaining MARCI data will be transmitted early next week. With the completion of this activity, the flight team is now turning its focus to completion of preparations for launch of the Mars Polar Lander. Following the launch of the lander, scheduled for January 3, 1999, the next planned activity for the orbiter is the development of its second "housekeeping" sequence, followed by a second Trajectory Correction Maneuver in late January. For more information on the Mars Surveyor 98 mission, please visit our website at: http://mars.jpl.nasa.gov/msp98 Hа сегодня все, пока! =SANA=
    Дата: 29 декабря 1998 (1998-12-29) От: Alexander Bondugin Тема: Sky & Telescope News Bulletin - December 24, 1998 Привет всем! Вот, свалилось из Internet... SKY & TELESCOPE'S NEWS BULLETIN DECEMBER 24, 1998 A WAYWARD NEAR After a day of anxious worry, ground controllers tracked down and regained control of the Near Earth Asteroid Rendezvous (NEAR) spacecraft. NEAR fell silent soon after its main rocket was commanded to fire on Sunday, December 20th. The main engine has not been used since July 1997. Because the engine failed to slow NEAR's approach speed, the spacecraft coasted past its main objective, the asteroid 433 Eros, at 1:43 p.m. Eastern Standard Time on December 23rd at about 1 kilometer per second at a distance of 4,100 km. An 11th-hour upload of instructions commanded the on-board camera to take more than 1,100 images and to record data from the near-infrared spectrometer and magnetometer. However, the best possible resolution will be no better than about 500 meters. The first images of the highly elongated object -- measuring about 40 km long and 14 across -- were expected to be released today. According to mission manager Robert Farquhar, reestablishing contact was a tremendous relief, and in retrospect the spacecraft was nearly lost for good. A low-voltage condition on board erased crucial engineering data and thus complicated the recovery effort. Moreover, regaining control of the tumbling craft depleted about 30 kg of maneuvering fuel. Once project engineers understand the nature of Sunday's malfunction, they may redirect the spacecraft to return to Eros and assume an orbit around it as early as mid-1999, though a rendezvous in the year 2000 is also being considered. X-RAY OBSERVATORY RENAMED NASA announced on Monday that the Advanced X-ray Astrophysics Facility (AXAF) -- scheduled for launch aboard the Space Shuttle Columbia no earlier than April 8th -- has been renamed the Chandra X-ray Observatory, in honor of the late Nobel-prizewinning physicist Subrahmanyan Chandrasekhar (1910-95). The name was selected by "Name NASA's Next Great Observatory Contest," which ran from April to June 1998. The two winners -- Camarillo, California, high school physics teacher Jatila van der Veen, and Idaho high school student Tyrel Johnson -- win trips to see Columbia lift off. The AXAF team received more than 6,000 entries, from every state in the United States and more than 60 other countries, each including a short essay justifying the entrant's suggestion. Chandra's scientific accomplishments are numerous. In one sense, he was a successor to Einstein, further developing the great German physicist's theory of general relativity and, in so doing, revealing its elegance and widespread applicability. So it is fitting that the Chandra Observatory should be the successor to the Einstein Observatory, the last major X-ray telescope orbited by U.S. astronomers. ALDEBARAN OCCULTATION On December 30th, the waxing gibbous Moon will occult (cover) the 1st-magnitude star Aldebaran (Alpha Tauri) around sunset for parts of North America. Observers in the Northeast will find the Moon well up in the eastern sky and the Sun just below the horizon when the occultation happens. For Southerners and Midwesterners it happens when the Sun is still shining and the Moon is low, but the event should still be visible with a telescope. For more information and a timetable, see http://www.skypub.com/sights/occultations/lunar/lunar.html. WAIT A SECOND! You'll have to wait an extra second for 1999 to begin on December 31st. The U.S. Naval Observatory will introduce a leap second to keep atomic clocks in pace with Earth's rotation. The 22nd leap second since 1972 will occur at 23 hours 59 minutes and 59 seconds Coordinated Universal Time (UTC), which corresponds to 6:59:59 p.m. Eastern Standard Time. THIS WEEK'S "SKY AT A GLANCE" Some daily events in the changing sky, from the editors of SKY & TELESCOPE. DEC. 27 -- SUNDAY * The Moon (just past first quarter) shines near Saturn this evening. * Saturn's own brightest moon, Titan, can be seen in a small telescope three or four ring-lengths east of Saturn this evening through Thursday evening. DEC. 28 -- MONDAY * Seen in a medium-sized telescope, Jupiter's Great Red Spot should cross Jupiter's central meridian (the imaginary line down the center of Jupiter's disk from pole to pole) around 11:15 p.m. Eastern Standard Time. Lately the spot has been very pale tan. For a list of all predicted Red Spot transit times, see http://www.skypub.com/sights/moonplanets/redspot.html. DEC. 29 -- TUESDAY * Jupiter's Red Spot transits around 7:06 p.m. EST. DEC. 30 -- WEDNESDAY * The waxing gibbous Moon will occult (cover) the 1st-magnitude star Aldebaran (Alpha Tauri) around sunset for parts of North America. Observers in the Northeast will find the Moon well up in the eastern sky and the Sun just below the horizon whent he occultation happens. For Southerners and Midwesterners it happens when the Sun is still shining and the Moon is low, but the event should still be visible with a telescope. For the time, see the table in last January's issue, page 97, or at http://www.skypub.com/sights/occultations/lunar/lunarchart.html. * Mars and the 4.4-magnitude star Theta Virginis are in the same telescopic field before dawn Thursday morning. They appear about 0.2 degree apart. DEC. 31 -- THURSDAY * The shadow of Jupiter's moon Io crosses Jupiter's disk from 7:41 to 9:55 p.m. EST, followed by Io itself from 8:58 to 11:11 p.m. EST. * Jupiter's Red Spot transits the planet's central meridian around 8:45 p.m. EST. JAN. 1 -- FRIDAY * Full Moon (exact at 9:49 p.m. EST). JAN. 2 -- SATURDAY * Jupiter's Red Spot transits around 10:24 p.m. EST. THIS WEEK'S PLANET ROUNDUP MERCURY appears low in the southeast during dawn, getting lower daily. Don't confuse it with Antares, which is to Mercury's right early in the week and to its upper right later in the week. VENUS is very low in the southwest during early dusk. Look about 30 minutes after sunset. MARS, shining at magnitude +1.0 in Virgo, rises around 1 a.m. and is high in the south by dawn. Spica is the star below it. JUPITER, magnitude -2.3, is the big, bright "star" high in the south-southwest at dusk. It gets lower in the southwest later in the evening and sets around 10:30 p.m. SATURN, magnitude +0.2, is the yellowish "star" far to Jupiter's upper left. The two planets appear 35 degrees apart, on opposite ends of dim Pisces. URANUS, NEPTUNE, and PLUTO are hidden behind the glare of the Sun. (All descriptions that relate to the horizon or zenith are written for the world's midnorthern latitudes. Descriptions that also depend on longitude are for North America. Eastern Standard Time, EST, equals Universal Time minus 5 hours.) More details, sky maps, and news of other celestial events appear each month in SKY & TELESCOPE, the essential magazine of astronomy. See our enormous Web site at http://www.skypub.com/. Clear skies! SKY & TELESCOPE, P.O. Box 9111, Belmont, MA 02478 * 617-864-7360 (voice) Copyright 1998 Sky Publishing Corporation. S&T's Weekly News Bulletin and Sky at a Glance stargazing calendar are provided as a service to the astronomical community by the editors of SKY & TELESCOPE magazine. Widespread electronic distribution is encouraged as long as these paragraphs are included. But the text of the bulletin and calendar may not be published in any other form without permission from Sky Publishing (contact permissions@skypub.com or phone 617-864-7360). Updates of astronomical news, including active links to related Internet resources, are available via SKY & TELESCOPE's site on the World Wide Web at http://www.skypub.com/. In response to numerous requests, and in cooperation with the Astronomical League (http://www.mcs.net/~bstevens/al/) and the American Association of Amateur Astronomers (http://www.corvus.com/), S&T's Weekly News Bulletin and Sky at a Glance are available via electronic mailing list too. For a free subscription, send e-mail to skyline@corvus.com and put the word "join" on the first line of the body of the message. To unsubscribe, send e-mail to skyline@corvus.com and put the word "unjoin" on the first line of the body of the message. SKY & TELESCOPE, the Essential Magazine of Astronomy, is read by more than 200,000 enthusiasts each month. It is available on newsstands worldwide. For subscription information, or for a free copy of our catalog of fine astronomy books and products, please contact Sky Publishing Corp., 49 Bay State Rd., Cambridge, MA 02138-1200, U.S.A. Phone: 800-253-0245 (U.S. and Canada); 617-864-7360 (International). Fax: 617-864-6117. E-mail: custserv@skypub.com. WWW: http://www.skypub.com/. Clear skies! Hа сегодня все, пока! =SANA=
    Дата: 29 декабря 1998 (1998-12-29) От: Alexander Bondugin Тема: NASA выбирает программы исследований для японской экспедиции Привет всем! Вот, свалилось из Internet... NASA выбирает программы исследований для японской экспедиции Solar-B NASA объявила список из трех научных программ, которые будут реализовываться в ходе экспедиции по исследованию Солнца Solar-B Японского института космоса и астронавтики (Japan's Institute of Space and Astronautical Science, ISAS), старт которой запланирован на 2004 г. В международной миссии Solar-B кроме Японии примут участие США и Великобритания. Основной целью миссии Solar-B является исследование Солнечной короны и связи между тонкой структурой магнитного поля на поверхности Солнца, фотосферой и динамическими процессами, происходящими в короне. NASA для участия в этой экспедиции выбрало 3 программы: Разработка инструментария для оптического телескопа диаметром 50 см (устройства формирования изображения с широкополосным и узкополосным фильтрами и спектрополяриметр). Рентгеновский телескоп для исследования атмосферы Солнца, температура которой составляет миллионы градусов. Спектрометр дальнего УФ диапазона. Источник: InfoArt News Agency Hа сегодня все, пока! =SANA=
    Дата: 29 декабря 1998 (1998-12-29) От: Alexander Bondugin Тема: Ионный двигатель от Hughes готов к работе в дальнем космосе Привет всем! Вот, свалилось из Internet... Ионный двигатель от Hughes готов к работе в дальнем космосе [Business Wire] Объявлено об успешном завершении испытаний ионного двигателя, установленного на борту исследовательского космического корабля New Millennium Deep Space 1. Теперь он может стать основным двигателем для будущих научных космических экспедиций NASA. Создателем ионного двигателя является Hughes Electron Dynamics - подразделение корпорации Hughes Electronics. После включения 24 ноября ионный двигатель проработал более 500 часов, и теперь Deep Space 1 находится на расстоянии более 9,5 млн км от Земли. Исследования в области ионных двигателей были начаты в Hughes еще в 60-х годах. В качестве топлива для них испытывались пары цезия и ртути, но в итоге для этих целей был выбран газ ксенон. Коммерческие ксеноновые ионные двигатели системы XIPS от Hughes уже используются в спутниках связи HS 702 и HS 601HP. Такой двигатель установлен и на борту телекоммуникационного спутника PAS-6B, запущенного 21 декабря. Источник: InfoArt News Agency Hа сегодня все, пока! =SANA=
    Дата: 29 декабря 1998 (1998-12-29) От: Alexander Bondugin Тема: Globalstar заключает контракт на запуск спутников с Arianespace Привет всем! Вот, свалилось из Internet... Globalstar заключает контракт на запуск спутников с Arianespace [Business Wire] Компания Globalstar заключила контракт на запуск 6 своих спутников с французской компанией Arianespace. Спутники Globalstar будут выведены на орбиту ракетой-носителем Ariane 4. Запуск планируется произвести в сентябре 1999 г. с космодрома Куру во Французской Гвиане. Ранее Globalstar объявила о намерении использовать для запуска своих спутников ракеты "Союз" и Delta, каждая из которых должна была выводить на орбиту за раз по 4 спутника. Всего таким образом предполагается запустить 32 спутника, коммерческая эксплуатация которых начнется в третьем квартале 1999 г. К декабрю 1999 г. Globalstar предполагает запустить все 52 спутника своей сети глобальной мобильной связи, 48 из которых будут находиться в рабочем режиме, а 4 будут запасными. Источник: InfoArt News Agency Hа сегодня все, пока! =SANA=

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