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Дата: 12 ноября 1998 (1998-11-12)
От: Alexander Bondugin
Тема: Европейское космическое агентство готовится к полету на Марс
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Европейское космическое агентство готовится к полету на Марс
[SpaceViews] Европейское космическое агентство (ESA) утвердило
планы разработки проекта Mars Express, который включает и
орбитальный и спускаемый на поверхность Марса аппараты. Экспедиция
на Марс запланирована на 2003 г.
Все 14 стран участниц Комитета научных программ ESA одобрили
концепцию миссии, стоимость которой составит 150 млн евро (175 млн
дол.). По заявлению директора ESA по науке Роджера Бонне (Roger
Bonnet), это будет одна из самых дешевых и оригинальных экспедиций на
Марс.
Старт Mars Express запланирован на июнь 2003 г. Для запуска будет
использована российская ракета "Союз". К Марсу корабль прилетит к
Рождеству 2003 г. Hа космическом корабле будет установлено 7 блоков
научной аппаратуры, некоторые из них будут дублировать те, что были
потеряны при аварии российского корабля "Марс-96" в ноябре 1996 г. В
состав аппаратуры войдут фотокамера высокого разрешения, несколько
спектрографов и радар, способный обнаруживать объекты в толще земли.
Этот радар будет использован для исследования воды, скрытого под
марсианской поверхностью, которая находится там в виде рек, озер,
ледников и вечной мерзлоты.
Mars Express понесет и спускаемый аппарат Beagle 2 весом 60 кг, на
котором будут установлены фотокамера и инструменты для исследования
марсианского грунта и горных пород с целью определения прошлого этой
планеты. Установка остального оборудования будет зависеть от
финансовых возможностей разработчиков.
Источник: InfoArt News Agency
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=SANA=
Дата: 12 ноября 1998 (1998-11-12)
От: Alexander Bondugin
Тема: NASA завершает испытания ракетного двигателя на атмосферном воздухе
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NASA завершает испытания ракетного двигателя на атмосферном
воздухе
[NASA] Hациональное управление по аэронавтике и исследованию
космического пространства США(NASA) успешно завершило двухлетние
наземные испытания принципиально нового ракетного двигателя,
который может существенно изменить будущее космонавтики - этот
двигатель "дышит" кислородом воздуха. По заявлению разработчиков, они
готовы продемонстрировать работу нового двигателя в полете.
С таким двигателем весь космический корабль может быть
использован неоднократно и после приземления он будет готов к полету
уже через несколько дней, что существенно удешевит космические
путешествия и откроет ворота в космос для многих стран мира. Часть
полетного времени двигатель будет брать кислород непосредственно из
атмосферного воздуха, что позволит сократить запасы газа на борту
корабля. Соответственно и весить ракета с таким двигателем будет
меньше. Для начального разгона двигателя будут использоваться
специальные ракеты, мощность которых составит около 15% от мощности
современных ракет-носителей. После того как космический корабль
достигнет удвоенной скорости звука разгоняющие ракеты отделяются, и
двигатель переходит на атмосферный кислород. После разгона до
10-кратной скорости звука включается обычная система вывода
космического корабля на орбиту.
По мнению NASA, при использовании таких двигателей запуск
космического корабля удешевится настолько, что полет в космос станет
доступен и для туристов. Цель NASA - снизить затраты на запуск одного
фунта веса космического корабля с 10 тыс. дол. (около 22 тыс. дол. на
килограмм) до нескольких сотен долларов.
В создании воздушного ракетного двигателя принимали участие
компании Aerojet, Rocketdyne, Astrox, Университеты Пеннсильвании и
Алабамы.
Источник: InfoArt News Agency
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=SANA=
Дата: 12 ноября 1998 (1998-11-12)
От: Alexander Bondugin
Тема: Выход в открытый космос на станции "Мир" прошел успешно
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Выход в открытый космос на станции "Мир" прошел успешно
10 ноября в 22 часа 25 минут космонавты 26-ой экспедиции на
станции "Мир" Геннадий Падалка и Сергей Авдеев совершили выход в
открытый космос для установки на внешней поверхности орбитального
комплекса научной аппаратуры и оборудования. Космонавты провели в
открытом космосе 6 часов - практически полный рабочий день. Объем
работ был довольно большим, так что пришлось шевелиться. В общей
сложности космонавты установили на станции 17 блоков с
оборудованием, самым крупным из которых была солнечная батарея
нового типа. По словам разработчиков эта двухсекционная батарея
является практически вечной, во всяком случае они гарантируют
несколько десятков лет ее безотказной работы. Основной целью ее
установки является изучение поведения новых материалов в открытом
космосе. Была испытана и новая система защиты скафандров от внешнего
космического излучения и выхлопных газов орбитальной станции.
Установлен российско-французский датчик-ловушка космических
частиц. Он пройдет проверку боем уже 17 ноября - именно тогда станция
попадет в метеорный поток Леонид, а такое событие в окрестности Земли
происходит раз в 33 года. Станция войдет в поток Леонид 17 ноября в 22
часа по московскому времени. В течение часа частицы будут
бомбардировать станцию. По мнению ученых никакого ущерба станции
нанесено не будет (частицы очень малы), но тем не менее экипаж во
время прохождения метеорного потока будет на всякий случай находиться
в спускаемом аппарате, чтобы в случае необходимости быстро вернуться
на Землю.
Часть оборудования была установлена в рамках программы
разработки Международной космической станции. Кроме того
космонавты в буквальном смысле слова вручную запустили на орбиту
макет первого искусственного спутника Земли размером втрое меньше
оригинала. Hачинка этого спутника была собрана российскими и
францускими школьниками, он в течение нескольких минут передавал в
космическое пространство несколько фраз на русском, французском и
английском языках. К сожалению, космонавтам не удалось высвободить
место на поверхности станции для российского прибора,
предназначенного для измерения различных излучений.
Источник: InfoArt News Agency
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=SANA=
Дата: 12 ноября 1998 (1998-11-12)
От: Alexander Bondugin
Тема: Leonid Meteor Shower Prospects for UK and Europe (Forwarded)
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Royal Astronomical Society
For immediate release: 10 November 1998
Ref. PN 98/23
Issued by:
Dr Jacqueline Mitton
RAS Public Relations Officer
Office & home phone: Cambridge ((0)1223) 564914
Mobile phone: 0370 386133
FAX: Cambridge ((0)1223) 572892
E-mail: jmitton@dial.pipex.com
and
Peter Bond
Space Science Advisor
Phone: (0)1483-268672
Fax: (0)1483-274047
E-mail: 100604.1111@compuserve.com
Leonid Meteor Shower Prospects for UK and Europe
Professional and amateur skywatchers worldwide are awaiting the night of
17th/18th November with considerable anticipation because of the possibility
that a spectacular meteor shower will take place. But what can we really
expect to see in the UK and rest of Europe?
According to the best data available, Europe is likely to experience a good
meteor shower, but not a truly exceptional one -- perhaps up to 100 meteors
per hour if we are lucky. The best time to look will be between 1 a.m. and
dawn in the early hours of 18th November. A storm of many thousands of
meteors per hour could occur, but it is much more likely to be seen in the
Far East -- China, Thailand, Japan -- than in Europe.
Forecasting Metoer Showers
Predictions of a meteor storm in 1998 are based on the fact that exceptional
displays of the Leonid meteors -- so-called because they appear to radiate
from a point in the sky within the constellation Leo -- tend to recur every
33 years or so. There is not always a great storm, however, such as the one
in 1966 when observers in parts of the USA for a short time saw meteors at
a rate of 40 per second.
But forecasting meteor showers is not a precise business, unlike predicting
eclipses, for example, for which the exact times and circumstances can be
calculated in advance. The time when a meteor shower will peak, and the
maximum rate at which meteors will appear to rain down, can never be
anticipated with great certainty. They are something of a celestial lottery.
For that reason, it is well worth looking out for meteors in the early hours
of the 18th, if skies are clear, even from the UK. There is a slim chance of
something exceptional, but a modest display at least is on the cards, and
meteors are easy to observe. They are best seen with the naked eye and,
during a shower, they can streak across almost any part of the sky, as long
as the radiant point is above the horizon.
If a Leonid storm takes place, it is unlikely to last more than an hour or
so, but the gentler background shower carries on for a day or two. According
to the experts the expected peak time of any storm is most likely to be
about 7.45 p.m. (GMT). If this is correct, the storm would be finished
several hours before the constellation Leo rises above the horizon in the
UK.
What Are Meteors?
Meteors are caused by small fragments of material, mostly no larger than a
grain of sand, which burn up as they enter Earth's atmosphere at high speed --
around 71 kilometres (45 miles) per second in the case of the Leonids.
Leonid meteors are dust particles that have come off Comet Tempel-Tuttle.
Most of this dust is still following the comet fairly closely in space. The
comet takes 33 years to complete an orbit around the Sun, and planet Earth
ploughs through its main dust cloud when the comet returns to our vicinity
every 33 years. In the years when this happens, a strong shower or storm
takes place. In the years in between, a very small number of Leonid meteors
are seen in mid-November.
Some meteor showers produce about the same rate of meteors around the same
date every year. Regular annual showers happen when the dust from a comet
has spread around the whole of the comet's orbit, something that takes place
gradually over a long period of time. An example is the Orionids, a shower
in late October each year caused by dust from Halley's Comet.
Looking ahead to 1999, Comet Tempel-Tuttle will still be relatively nearby
and some astronomers are predicting that the Leonid meteor display could be
better next year than this. If that were to happen, then Europe is expected
to be the ideal location.
Do The Leonids Present Any Hazards?
Most of the Leonids weigh about 1 millionth of a gram -- not much more than
a particle of cigarette smoke. Normally, objects this size would pose no
threat to spacecraft. However, when they are travelling many times faster
than a bullet from a high velocity rifle, the threat increases significantly.
Since the velocity of the meteor impacts is affected by a spacecraft's
motion as it orbits the Earth, hits could occur at any speed between 65 and
80 km (40 and 50 miles) per second. These could result in some physical
damage in sensitive areas as well as electrical short circuits, plasma
discharges, and computer malfunctions, which may be sufficiently serious to
disable a satellite. A form of sand-blasting can erode outer surfaces such
as thermal blankets, mirrors and solar cells. Large impacting particles may
even knock a satellite out of its normal position, as happened to the
European Space Agency's Giotto spacecraft during its 1986 flyby of Halley's
Comet.
"These microparticles could penetrate a fairly weak spacecraft skin," said
Professor Tony McDonnell of the Unit for Space Sciences and Astrophysics at
the University of Kent in Canterbury. However, the most likely form of
damage is to vulnerable power systems. "Perhaps a handful of satellites
could have unusual electrical anomalies," said McDonnell.
Past evidence suggests that the risks are fairly low. During the past four
decades, only one spacecraft, the European Space Agency's Olympus satellite,
is known to have been disabled by a (Perseid) meteor. Furthermore, no
spacecraft were damaged by the 1966 Leonid storm. On the other hand, there
are now more than 500 spacecraft orbiting the Earth, over 10 times as many
as in the mid-1960s.
"The biggest uncertainty is the hourly rate (of arrival)," said Professor
McDonnell. "If this reaches 150,000 per hour, there will be all sorts of
damage, but there may only be 1,800 per hour."
While the probability of any satellite being hit is thought to be less than
0.1%, many spacecraft operators are taking no chances. The Space Shuttle
mission that carried John Glenn was deliberately timed to avoid the Leonid
shower. Cosmonauts on the Mir space station do not have the luxury of
choosing their flight window. While the Mir station presents a large target
for the Leonids, no serious damage is expected. However, the two crewmen may
play safe by moving into the Soyuz lifeboat at the peak of the shower.
Fortunately, the direction from which the particles approach the Earth is
almost perpendicular to the direction of the Sun. This means that the chance
of a direct hit will be substantially reduced since most satellites will
already have their solar panels aligned edge-on to the shower.
Further damage-limitation measures have been recommended by the European
Space Operations Centre operated by the European Space Agency. These include
turning spacecraft so that their most vulnerable systems are not in the
direct line of fire; switching off high voltage systems; and putting a team
of ground controllers on alert in case of emergencies.
In the case of the Hubble Space Telescope, its all-important mirror will be
turned away from the shower during observations of distant galaxies. Most of
the scientific instruments on the European ERS-1 and ERS-2 Earth observation
satellites and the Solar and Heliospheric Observatory (SOHO) will be powered
down and placed in 'sleep' mode during the shower. SOHO and the American
Advanced Composition Explorer (ACE), which are located 1.5 million km
sunward of the Earth, will be particularly at risk since the main stream of
meteors is expected to pass much closer to them than any of their
Earth-orbiting brethren. Indeed, the trail of Leonids will actually travel
between the Earth and these two solar observatories.
More Information about the Leonid Meteors may be found at the following Web
Sites:
Leonid '98 Meteor Outburst Mission Homepage (P. Jenniskens - NASA)
http://www-space.arc.nasa.gov/~leonid/1998.html
Leonid Information for the Beginning and Advanced Meteor Enthusiast
(G. Kronk)
http://medicine.wustl.edu/~kronkg/leonids.html
SKY Online's Meteor Page (Sky & Telescope magazine)
http://www.skypub.com/sights/meteors/meteors.html
Visual Material
Sky & Telescope magazine (based in Boston, USA) has available for
distribution:
* still images from the 1966 Leonid storm,
* artistic renderings
* video of the 1997 Perseid and Geminid meteor showers
* a broadcast-quality, 1-minute animation of why the Leonids occur by
artist Don Davis.
Anyone wanting these for reproduction or broadcast can contact Irene
Szewczuk (irenes@skypub.com, phone 00 1 617-864-7360 x127) or Kelly Beatty
(kbeatty@skypub.com, phone 00 1 617-864-7360 x148). Fax for both is
00 1 617-576-0336.
Andrew Yee
ayee@nova.astro.utoronto.ca
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=SANA=
Дата: 12 ноября 1998 (1998-11-12)
От: Alexander Bondugin
Тема: NEAR Weekly Report for Nov. 6, 1998
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NEAR WEEKLY REPORT
November 6, 1998
MISSION OPERATIONS:
The NEAR spacecraft state/configuration has remained nominal (Flight
Computer #1 and Attitude Interface Unit #1 active).
The Magnetometer and XGRS instruments remained on throughout this
reporting period. The MSI and NIS were successfully powered up in
preparation for the Eros Monochrome Light Curve on November 5 and
NIS/MSI rotation Sequence Dry Run on November 9. Today's track should
indicate how successful the Eros Monochrome Light Curve was. It should
be noted this includes the first images of Eros taken by NEAR.
Due to problems at DSN station 34, data recorded and played back from
98:303-00:55:03 to 98:303-20:31:43 was not recovered at the DSN station.
Attempts to replay the data from the station produced data of a quality
to low to be processed. This playback occurred during an unattended
(MOC) playback. Data for the time period in question is
non-recoverable.
DSN 54 track on Wednesday November 4 was a "no go". The station
reported problems at start of track and remained "red" the entire track.
No data automatically dumped from the spacecraft via time tagged
commands during this ATTENDED track was recovered by the DSN.
Fortunately, an UNATTENDED track with station 25 followed the 54 track.
The NEAR team manned the UNATTENDED track and successfully issued
contingency commands to replay the data a second time. This time the
data was retrieved from the DSN. No net data loss resulted.
Upcoming Spacecraft Activities:
November 9: NIS/MSI Rotation Sequence Dry Run
November 18: Fancy Momentum Dump Test #2
November 19: Monochrome Light Curve of Eros
November 19: NIS Cal Target Observation
November 20: Eros Optical Navigation A (16 frames)
Debra Fletcher
240-228-8274/Washington
443-778-8274/Baltimore
Fax: 240-228-3237
Email: debra.fletcher@jhuapl.edu
Bldg.-Rm.: 2-155
The Johns Hopkins University
Applied Physics Laboratory
11100 Johns Hopkins Road
Laurel, MD 20723-6099
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=SANA=
Дата: 12 ноября 1998 (1998-11-12)
От: Alexander Bondugin
Тема: Goddard spacecraft prepared for encounter with Leonid meteor storm (Fo
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Mark Hess/Jim Sahli
Goddard Space Flight Center Nov. 9, 1998
Greenbelt, MD 20771
(Phone: 301-286-8955)
RELEASE NO: 98-184
GODDARD SPACECRAFT PREPARED FOR ENCOUNTER WITH LEONID METEOR STORM
Flight controllers are laying plans to prepare an orbiting fleet of 22
Goddard spacecraft for the upcoming Leonid meteor storm, predicted to be the
fiercest in more than three decades.
The annual Leonid shower -- this year a storm -- is expected to be unusually
intense because the Earth is crossing Comet Tempel-Tuttle's orbital path at
a time when the comet has recently passed by. This happens once every 33
years when Tempel-Tuttle makes its closest approach to the Sun. The Sun's
radiation boils bits of dust and sand off the comet, littering its path with
debris.
Where possible, controllers will change the orientation of satellites to
reduce the possibility that one of these tiny particles (1 to 100 microns in
size, or about the size of a small sand grain) will strike and disable a
spacecraft. However, Leonid storms pose a greater than usual threat to
spacecraft not only because of the many tiny meteors (thousands per hour)
hitting our atmosphere, but also the tremendous velocities of the particles.
As the Earth moves across the comet's trail, Leonid particles will enter the
planet's atmosphere. Like two freight trains hurtling at one another on the
same track, the distance between the massive debris cloud and the Earth
closes at a mind-boggling 45 miles per second, or over 200 times the speed
of sound. In contrast, Perseid meteors reach speeds of about 37 miles per
second, and typical daily meteors achieve velocities of about 12 miles per
second.
On spacecraft where it is practicable, high voltage systems that supply
instruments will be turned off, or ramped down, to safeguard against the
potential for electrical damage as a result of the satellite's plunge into
the debris cloud. The tiny meteors can hit the spacecraft like a sandblaster
and disintegrate, creating a cloud of electrically charged plasma. Under the
right conditions, this plasma cloud can set off a chain reaction causing a
massive short circuit. The loss of the European Space Agency's Olympus
communications satellite in 1993 was attributed to a strike from the Perseid
shower, and the resulting plasma discharge that zapped the spacecraft's
delicate electronics.
The 22 NASA spacecraft under Goddard's control -- from the 24,500 pound
Hubble Space Telescope to the 25-year old, 800 pound IMP-8 satellite -- will
be continuously monitored during the peak of the storm, and some maneuvered
to provide the greatest protection possible from debris.
"Each individual mission and project team reviewed its procedure for dealing
with this annual phenomena, and has a specific implementation plan for the
Leonid meteor storm," said Philip E. Liebrecht, Associate Director for
Networks and Mission Services. "Each spacecraft has an operating plan that
balances the risk of taking specific defensive measures against the risk of
taking no action. We've had independent review teams assess our plans, and I
think we are doing everything prudent and practicable to ensure the safety
of our spacecraft."
The Leonid meteor shower arrives every November. It takes its name from the
constellation Leo, the area of the sky where the meteors appear to
originate. The shower's small particles are completely vaporized high in the
Earth's atmosphere, and present no danger to the Earth's surface or to
aircraft.
Historically, the most active Leonid showers occur during the first two
years following the comet's closest approach to the Sun. This last occurred
on Feb. 28, 1998. This year's outburst is projected to be less severe than
that observed in the last 33-year cycle, which occurred in 1966. The peak
time for the Leonid meteor storm will be Nov. 17, sometime between 11:43 a.m
and 5:43 p.m. Eastern Standard Time.
For the past several weeks, engineers at Goddard have been reviewing the
status of all the spacecraft under their control and developing ways to
reduce exposure to the meteor storm. In general, the health of these
spacecraft will be monitored before, during and after the storm, and
commands to a number of the spacecraft will be stopped or curtailed during
this period.
The Hubble Space Telescope will be maneuvered so that its mirrors face away
from the storm. Its solar arrays will be rotated so only the edges are
exposed to oncoming particles. Controllers won't turn Hubble off during the
storm, but rather use the 10-hour period that Hubble is maintained in this
attitude to take a long-exposure picture (for more on this, check out
http://www.stsci.edu/ftp/proposer/leonid.html).
Some spacecraft, like the Tropical Rainfall Measuring Mission, are already
in the ideal orientation for the storm, and only an adjustment to position
the solar arrays "edge on" to the storm will be needed. The Rossi X-ray
Timing Explorer's instruments will be turned off to protect the spacecraft's
high voltage devices from a potential massive short circuit similar to what
happened to Olympus.
For the Advanced Composition Explorer, the solar arrays will be rotated, and
high voltage supplies for instruments will be ramped down. Since the center
of the Leonid stream is closer to the L-1 orbit (1 million miles from the
Earth toward the Sun) than to Earth, ACE will see an even more intense storm
than Earth-orbiting satellites.
Risk reduction procedures will be followed for other spacecraft including
the Extreme Ultraviolet Explorer, Compton Gamma Ray Observatory, Upper
Atmosphere Research Satellite, Total Ozone Mapping Spectrometer, Fast
Auroral Snapshot, Solar Anomalous Magn