Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://www.astrolib.ru/rsn/1999/01/11/
Дата изменения: Unknown
Дата индексирования: Sat Apr 9 23:36:43 2016
Кодировка: Windows-1251
Поисковые слова: пппппппппппппппппппппппрпрпрпрпрпрпрпрпрпрпрпрпрпрпрп
Электронная библиотека астронома-любителя. Книги по астрономии, телескопостроению, оптике.
Дата: 11 января 1999 (1999-01-11)
От: Alexander Bondugin
Тема: SpaceViews - 1 January 1999 [1/6]
Привет всем!
Вот, свалилось из Internet...
S P A C E V I E W S
Issue 1999.01.01
1999 January 1
http://www.spaceviews.com/1999/01/
*** News ***
NEAR Thruster Abort Delays Eros Rendezvous
Private Investors to Keep Mir in Orbit, Russia Says
SOHO in Safe Mode
Shuttle Chief Warns About Safety of Orbiters
Lunar Prospector in Lower Orbit
Nozomi Spacecraft on Its Way to Mars
Contradictory Findings on Accelerating Universe
NASA Gives AXAF Observatory New Name
Ariane, Long March, Proton Launches Successful
SpaceViews Event Horizon
Other News
*** Articles ***
Shooting for the Moon
Editor's Note: With this issue we are changing our publishing schedule.
Instead of sending out issues twice a month, we will be sending out issues
four times a month, on the 1st, 8th, 15th, and 22nd of each month. This
will serve you in two ways. By publishing more frequently the news
articles you receive will be more timely. Also, by spreading out the
content normally found in each issue into more issues, we'll make the size
of each issue more manageable, especially for those users whose mail
accounts place limits on the size of mail messages. As always, each issue
and the latest news are available on our Web site, http://www.spaceviews.com.
If you have any questions or comments about this change, please contact me
at jeff@spaceviews.com.
-- Jeff Foust
Editor, SpaceViews
*** News ***
NEAR Thruster Abort Delays Eros Rendezvous
An aborted thruster firing by the Near Earth Asteroid
Rendezvous (NEAR) spacecraft on December 20 will delay the
spacecraft's arrival at the asteroid Eros by over a year.
NEAR was scheduled to fire its thrusters for 20 minutes at 5
pm EST (2200 UT) December 20, the first of four thruster burns that
would have put the spacecraft in orbit around Eros by mid-January.
However, contact with NEAR was lost around the time of the thruster
burn and not reestablished for more than one day.
When contact with NEAR was reestablished, controllers found
that the burn had been aborted. Engineers believe the burn was
aborted when certain safety limits in the spacecraft's autonomous
control system were violated during the settling burn, a brief firing
of attitude control thrusters before the main thruster burn.
The delay in reestablishing contact with NEAR meant that the
other thruster burns necessary for a January arrival at Eros could not
be carried out. On December 30 NASA announced plans for a thruster
burn on January 3 that will put NEAR into an orbit that will bring it
back to Eros in mid-February of 2000.
While disappointed with the delay arriving at Eros, mission
managers were able to offer something of a consolation prize to
scientists and others involved with the mission. NEAR performed a
flyby of Eros on December 23, passing within 4,100 km (2,500 mi.) on
December 23.
NEAR returned about 1,100 images of the asteroid during the
flyby, showing features as small as 500 meters (1,650 feet) across.
NEAR's infrared spectrometer and magnetometer also collected data on
the composition of Eros and the existance of any magnetic fields
around the asteroid.
"The abort lost us time but the flyby gave us valuable
information about Eros' shape and mass that we wouldn't have had --
information that will help us during our orbital phase a little more
than a year from now," NEAR project manager Thomas Coughlin said.
Private Investors to Keep Mir in Orbit, Russia Says
Private investors have been found to keep the Russian space
station Mir in orbit through the year 2001, officials with the company
that operates the station announced Wednesday, December 23.
Yuri Semionov, president of the Energia company, refused to
name the investors or the amount of money they were contributing.
Russian officials have previously said that it costs $20 million a
month to operate Mir, so the deal could be worth up to $720 million.
Semionov has asked the Russian government to draft guarantees
for the investment, and that the funding agreement would be signed as
soon as those guarantees were ready.
Energia officials and Russian cosmonauts have said on many
occasions that Mir could continue to operate through 2001, despite
past problems with the station and plans to deorbit the station in
mid-1999.
"It is purely a political question that there is pressure for
us to get rid of Mir as soon as possible," veteran cosmonaut Anatoly
Solovyov told Reuters in November. "It is clear why. Who has the
station? We do."
In November the Russian Space Agency asked NASA to change the
plane of the orbit of the International Space Station to that of
Mir's, to enable easy movement of equipment of even entire modules
from Mir to ISS. Russia later dropped the request when NASA showed no
interest in supporting it.
Any plans to keep Mir in orbit beyond mid-1999 could endanger
Russia's participation in the International Space Station. American
analysts and NASA officials have questioned Russia's ability to
maintain both Mir and ISS given the country's serious economic
problems. Also, any effort to prolong Mir's life in orbit may violate
signed ISS agreements between the United States and Russia.
SOHO in Safe Mode
Just two months after the Solar and Heliospheric Observatory
(SOHO) spacecraft had fully recovered from earlier serious problems,
the spacecraft entered a safe mode late Monday, December 21, possibly
from the failure of the last working gyro.
Spacecraft controllers report that SOHO entered a safe mode at
12:49 pm EST (1749 UT) December 21. Preliminary indications are that
the sole working gyro on the spacecraft had failed.
If true, and the gyro cannot be restored, it may be difficult
to impossible for the spacecraft to resume normal operations. No
further information on the spacecraft status was available from
mission control.
A message posted on the SOHO Web site late Tuesday, December
22, stated that no scientific observations will be performed with SOHO
until software to permit gyroless observations can be uploaded. No
date was set for observations to resume.
Scientists and engineers had just celebrated the complete
restoration of SOHO in October, when after nearly four months of
effort they were able to bring SOHO back to normal after an accident
crippled the spacecraft.
SOHO started tumbling June 24, a problem traced to the human
error by ground controllers when they tried using a switched-off gyro
to orient the spacecraft. SOHO remained out of contact until early
August. Engineers worked to bring SOHO's systems back online, stop
the tumbling, and check out the scientific instruments.
Although many predicted that only some of SOHO's instruments
could be brought back online, all instruments were eventually
restored. "I tip my hat to the engineers who built this spacecraft
and these sensitive but robust instruments," Bernhard Fleck, the ESA
project scientist for SOHO, said in October.
The joint NASA/ESA SOHO spacecraft was launched in December
1995. It completed its primary mission in April 1998 and entered an
extended mission to monitor the Sun as it entered the peak of its
11-year activity cycle.
Hа сегодня все, пока!
=SANA=
Дата: 11 января 1999 (1999-01-11)
От: Alexander Bondugin
Тема: SpaceViews - 1 January 1999 [2/6]
Привет всем!
Вот, свалилось из Internet...
Shuttle Chief Warns About Safety of Orbiters
The manager of NASA's space shuttle program has expressed
concern about a number of recent incidents that affected the safety of
shuttle orbiters and has reminded the shuttle workforce to be more
vigilant about safety.
In a memo dated November 20 but published publicly earlier
this week on the NASA Watch Web site, shuttle manager Tommy Holloway
noted three incidents within the past 13 months that could have led to
serious accidents with the shuttle.
"History tells us that all major events are preceded by a
number of smaller, less significant, and less observed events which
provided insight and avoidance opportunities," Holloway said in the
memo to shuttle workers. "As we observe these events, we realize the
importance of being alert for these 'wake- up' calls and of taking
timely action to respond to them."
The first of the three incidents took place in November 1997,
when the shuttle Atlantis was ferried from Florida to
California atop a 747 for upgrades. A washer for one of the bolts
used to secure the shuttle was missing. According to Holloway only
"the high level of structural margin in the design" prevented an
accident that could have destroyed the shuttle and 747 and killed the
747 flight crew.
In June, a pressure sensor for one of the main engines on the
shuttle Discovery failed 20 seconds into the flight. A broken
piece of test equipment inadvertently left in place was later blamed
for the failure. Had the sensor failed later in the launch, Holloway
said, the engine could have shut down, forcing an abort and a landing
attempt in Spain or North Africa.
In October, the door to the drag chute compartment fell off
seconds before Discovery lifted off on flight STS-95. The door
bounced off one of the main engines nozzles after it fell off; had it
done so differently it could have damaged the nozzle and even caused
an "uncontained failure" of the engine.
Holloway followed up the report of the near-accidents with
eight pieces of advice for shuttle workers, ranging from sharing
information with coworkers to taking time to do the job right.
"Cutting corners and hurrying to do a job are sure ways to fail," he
warned. "If you don't think you have the time to do it right, take
time out!"
"We are in for a very challenging and dynamic period,"
Holloway said, noting that the shuttle will be called upon for the
assembly of the International Space Station, among other planned
missions. "Learning from history, I believe that rigorous application
of these steps will decrease the probability of a Space Shuttle
incident to improbable."
Lunar Prospector in Lower Orbit
Flight controllers have recently maneuvered the Lunar
Prospector spacecraft into a new lower orbit, in preparations for
putting the spacecraft into a very low orbit for detailed studies of
the lunar surface.
On December 19 controllers fired Lunar Prospector's thrusters
to move the spacecraft from its previous 100-km (62-mi.) orbit into a
lower 40-km (25-mi.) orbit above the lunar surface. There were no
problems reported with the maneuver.
Prospector's new orbit will be a temporary one. In January
the orbit will be further lowered by controllers, eventually placing
the spacecraft into an orbit 25-30 km (16-19 mi.) above the Moon. That
maneuver will end Prospector's year-long primary mission and begin its
extended mission.
During the extended mission, expected to last into mid-1999,
Prospector will conduct high-resolution studies of regions of the
Moon. Those studies will include efforts to better define the regions
of the lunar poles where water ice may be hidden.
During the extended mission scientists will also continue to
study the Moon's magnetic field, including detailing regions of the
Moon with unusually strong magnetic fields. Spacecraft instruments
will also study the composition of the moon with greater resolution.
"Lunar Prospector's instruments have gathered such superior
data that we have far exceeded our primary mission objectives," said
Sylvia Cox, Lunar Prospector mission manager. "This success raises our
expectations about getting an even closer look at the lunar surface,
collecting data at higher resolutions, and gaining further insights
about our closest celestial neighbor."
The extended mission will end when Prospector runs out of fuel
needed to maintain its orbit through the Moon's notoriously "lumpy"
gravitational field. The spacecraft will then crash to the surface.
Nozomi Spacecraft on Its Way to Mars
The Japanese spacecraft Nozomi completed last week a series of
Earth and Moon swingbys needed to send the spacecraft towards Mars,
but extra propellant needed to complete the gravity assists may affect
the future of the mission.
Nozomi entered a trans-Mars trajectory with a 7-minute
thruster burn during an Earth flyby early December 20. That flyby had
been preceded by lunar flybys September 24 and December 18.
Mission officials expressed concern about two
course-correction thruster firings on December 21. The burns were
longer than expected to compensate for "insufficient acceleration"
during the Earth flyby. The impact those extra burns on the rest of
the mission are under investigation.
Nozomi, Japanese for "hope", is the first mission to Mars by
anyone other than the United States or the former Soviet Union/Russia.
the $80-million spacecraft will orbit the Red Planet and study its
magnetic fields, atmosphere, and ionosphere. The spacecraft is
scheduled to arrive at Mars in October 1999.
Nozomi was launched July 4 on a Japanese M-V booster. The
booster is not powerful enough to launch the spacecraft on a direct
Mars trajectory, so controllers used a series of gravity assists and
thruster burns to build up velocity. At the time of launch the
spacecraft was named "Planet-B"; it received its current name shortly
after launch.
Contradictory Findings on Accelerating Universe
The discovery that the expansion of the universe may be
accelerating, and not slowing down as once thought, was named the top
science story of 1998 by the journal Science Thursday, December 17.
However, data released just one day later contradicts those
earlier findings by showing that the universe's expansion is slowing
down as predicted by theory.
Work by two separate international research groups showed that
the rate of expansion of the universe appears to be accelerating.
Astronomers measured the Doppler redshift of distant supernovae and
compared the light with similar, nearby supernovae to determine the
distances to the distant objects, and hence the expansion rate.
Most astronomers believed that the results would show that the
rate of expansion had decreased since the Big Bang some 15-20 billion
years ago. Instead, they found that the rate of expansion was
increasing, meaning galaxies were flying away from each other at
higher rates now than ever before. It also means that there is far
less mass than necessary to ever stop the expansion.
The results have strong implications for theories of the Big
Bang. Inflation theory, the leading theory to explain the sudden
growth of the universe a tiny fraction of a second after the Big Bang,
requires a universe with just enough mass to stop its expansion, or
more than what recent observations show.
The acceleration also implies that an unknown force is at work
to cause galaxies to speed up. A leading explanation is the
"cosmological constant", a term introduced into general relativity by
Albert Einstein to prevent the expansion of the universe, which his
theories predicted. Einstein later retracted the constant, calling it
his "greatest blunder."
Jeffrey Peterson, an astronomer at Carnegie Mellon University,
announced at an astrophysics conference in Paris December 18 findings
that contradicted earlier results using data from the Viper Telescope,
an submillimeter-wavelength telescope located in Antarctica.
Peterson reported that observations of distant gas clouds
showed that their angular size -- about one-half of a degree of arc --
was exactly that predicted for a universe whose rate of expansion is
slowing as predicted by inflation theory.
"These findings indicate that the material of the universe was
given just the right kick by the Big Bang to expand forever, never
collapsing, but also never becoming so dilute that gravity can be
ignored," Peterson said.
"This delicate balance is hard to understand unless inflation
theory, or something akin to it, is correct," he concluded.
Hа сегодня все, пока!
=SANA=
Дата: 11 января 1999 (1999-01-11)
От: Alexander Bondugin
Тема: SpaceViews - 1 January 1999 [3/6]
Привет всем!
Вот, свалилось из Internet...
NASA Gives AXAF Observatory New Name
NASA's Advanced X-Ray Astrophysics Facility (AXAF), now
scheduled for launch in April of 1999, will be named after a famed
astronomer, the space agency announced Monday, December 21.
AXAF will now be known as the Chandra X-Ray Observatory after
Subrahmanyan Chandrasekhar, a late Nobel-winning astrophysicist.
Chandrasekhar was known to friends and colleagues as "Chandra", a word
that also means "Moon" or "luminous" in Sanskrit.
"Chandrasekhar made fundamental contributions to the theory of
black holes and other phenomena that the Chandra X-ray Observatory
will study," said NASA administrator Dan Goldin. "His life and work
exemplify the excellence that we can hope to achieve with this great
observatory."
Chandrasekhar was born in India and moved to the United States
in the mid-1930s, when he joined the faculty of the University of
Chicago. He won the Nobel Prize in physics in 1983 for work completed
much earlier in his career on the physical processes that control the
structure and evolution of stars. He remained at the University of
Chicago until his death in 1995.
"Chandra's work on the mass limit of white dwarfs really set
the stage for our understanding of violent events in the evolution of
stars," said Chicago astronomy professor Peter Vandervoort. "His work
lays the foundation for the modern understanding of neutron stars and
black holes that will come from the data collected by the Chandra
Observatory."
The name was selected from among 6,000 entries submitted by
students and teachers from all 50 states and 61 countries. Fifty-nine
entires suggested the name Chandra; of those, two people, an Idaho
student and a California physics teacher, won trips to see the Chandra
Observatory launch.
That launch has now been scheduled for no earlier than April
8, 1999, NASA announced the same day as the new name for the
telescope. The Chandra Observatory will be carried into orbit on the
shuttle Columbia on mission STS-93.
The launch, once scheduled for August 1998, was pushed back to
December a year ago because of problems with the assembly and testing
of the spacecraft. The launch was delayed again in October because of
electrical problems with the spacecraft and plans to conduct a
thorough review of the spacecraft before shipping it to Florida from
the California facilities of TRW, assemblers of the spacecraft.
The April launch date is contingent on shipping the spacecraft
to Florida on or before January 28 and a successful independent review
in mid-February of the spacecraft's control center in Cambridge,
Massachusetts.
When launched, the Chandra Observatory will fly in a
highly-elliptical orbit that will permit X-ray observations free from
the Earth's atmosphere, which absorbs X-rays, and the Van Allen
radiation belts, which also interfere with observations. It will
provide observations of X-ray sources, including black holes and
supernovae, 25 times sharper than previous X-ray missions.
Ariane, Long March, Proton Launches Successful
Launches of satellites ranging from replacement Iridium
satellites to Russian global positioning satellites on three different
boosters were successful in late December.
A Long March LM-2C/SD lifted off at approximately 6:30 am EST
(1130 UT) Saturday, December 19, from the Taiyuan launch center in
eastern China. Its payload, two Iridium satellites, successfully
reached orbit shortly after launch.
The satellites will be placed in plane 2, one of 6 orbital
planes used by Iridium satellites. The two satellites will serve as
on-orbit replacements for the existing satellites in the plane. The
constellation of 66 operational satellites entered commercial service
November 1, providing cellular phone service to nearly any point on
the Earth.
An Ariane 42L lifted off at 8:08 pm EST Monday, December 21
(0108 UT December 22) from the Ariane launch facility in Kourou. The
launch, the second one this month and the 11th overall this year, was
a success and its payload, the PAS-6B comsat for PanAmSat, was placed
into orbit.
PAS-6B will be used to provide direct TV services to Latin
America. Half of its 32 Ku-band transponders will be used to provide
broadcasting for Brazil while the other half will be used for the rest
of Latin America.
A Proton with a Blok-D upper stage lifted off from Baikonur
Cosmodrome in Kazakhstan December 30 at 1:35 pm EST (1835 UT). The
launch placed three Uragan satellites, named Kosmos 2362, 2363, and
2364, into orbit.
The three satellites will form part of Russia's Glonass
(Global Navigation Satellite System), similar to the United States'
Global Positioning System. The three satellites launched Wednesday
will all orbit in the same plane 19,000 km (11,780 mi.) above the
Earth. The Glonass system now has 21 of the 24 satellites necessary
for full operations.
SpaceViews Event Horizon
January 3 Delta 2 launch of the Mars Polar Lander spacecraft,
from Cape Canaveral, Florida at 3:21 pm EST (2021 UT)
January 3 Near Earth Asteroid Rendezvous (NEAR) spacecraft
thruster burn
January 13 Atlas 2AS launch of the JCSAT-6 comsat, from Cape
Canaveral, Florida at 7:40 pm EST (0040 UT Jan. 14)
January 14 Delta 2 launch of the Argos, Sunsat, and Oersted
satellites from Vandenberg AFB, California, at
5:58 am EST (1058 UT)
Hа сегодня все, пока!
=SANA=
Дата: 11 января 1999 (1999-01-11)
От: Alexander Bondugin
