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Электронная библиотека астронома-любителя. Книги по астрономии, телескопостроению, оптике.
Дата: 19 мая 1998 (1998-05-19)
От: Alexander Bondugin
Тема: SpaceViews Update - 1998 May 15 [1/7]
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S P A C E V I E W S U P D A T E
1998 May 15
http://www.seds.org/spaceviews/980515/
*** Top Stories ***
HGS-1 Rounds Moon in Salvage Effort
Goldin Says Russian-Built Service Module a Mistake
Activists Outraged Over "BitFlip" Silencing
*** Technology ***
Columbia Lands Safely
NASA Nixes Neurolab Reflight
Study Says Station Launch Failures Likely
Proton and Titan Launches Successful
*** Policy ***
Mir Deorbit Burn Delayed
Report: Protocols Needed for Reporting Threatening Asteroids
Japan Questions Need for Small Launcher
*** Science ***
Scientists Puzzled by Brilliant Cosmic Burst
Did Deadly Dust Do in the Dinosaurs?
Is "Deep Impact" Real or Just Reel?
Black Hole Feeds on Colliding Galaxy
*** CyberSpace ***
Space Day
John Glenn: Three Orbits to History
ProSpace
Rocketry.Org
*** Space Capsules ***
SpaceViews Event Horizon
Other News
*** Top Stories ***
HGS-1 Rounds Moon in Salvage Effort
The HGS-1 satellite became the first commercial spacecraft to go
around the Moon Wednesday, May 13, when it swung around the Moon in an
effort to place the communications satellite into a geosynchronous
orbit.
The spacecraft came within 6,290 km (3,883 mi.) of the lunar
surface at 3:50pm EDT (1950 UT) May 13. It had been occulted -- hidden
from view of the Earth -- by the Moon from approximately 2:50pm to
3:20pm EDT (1850 to 1920 UT).
HGS-1 is now on a return trajectory to the Earth and will arrive
on May 16. The first thruster burn in a series to nudge the spacecraft
into geosynchronous orbit is planned for about 11pm EDT May 16 (0300 UT
May 17). Hughes officials said the spacecraft will be tracked by ground
stations, optical telescopes, and radars prior to arrival, to confirm
its orbit.
The spacecraft, originally named AsiaSat 3, was launched
Christmas Day 1997 on a Russian Proton rocket. However, the upper stage
of the Proton failed, stranding the spacecraft in an elliptical,
inclined transfer orbit, without enough fuel on the spacecraft itself to
reach the proper orbit.
Hughes started the rescue of the satellite with a series of
burns in April and early May that gradually raised its orbit. The final
burn, on May 7, raised its orbit such that it crossed the Moon's orbit
at the time the Moon was passing by, allowing engineers to use the
Moon's gravity to adjust the orbit.
While Hughes officials said they did not "seriously consider"
this kind of salvage operation until late February, one industry insider
told SpaceViews May 4 that the idea had its genesis outside of Hughes,
about a month before.
Rex Ridenoure of Microcosm told SpaceViews that Ed Belbruno, of
Innovative Orbital Design, suggested a trajectory that used the Moon to
salvage the satellite, and following some analysis and validation at
Microcosm, Ridenoure passed that information on to Hughes in
mid-January.
Ridenoure said that the approach Belbruno and he suggested was
more radical than what Hughes eventually adopted, sending the spacecraft
beyond the Moon and using the Moon for flybys on the way out and/or
back. A wide variety of novel orbit-transfer techniques such as this
were developed by Belbruno during the past decade. Their proposal would
have saved about one-third of the stationkeeping fuel on the spacecraft,
while the Hughes approach will use nearly all the fuel.
Ridenoure believes the conditions in this situation were
"supersaturated" to allow an innovative solution like a lunar flyby to
work. "We provided that idea to them," Ridenoure said, "and everything
fell into place."
Goldin Says Russian-Built Service Module a Mistake
NASA Administrator Dan Goldin admitted in a Congressional
hearing Wednesday, May 6, that assigning a key module of the
International Space Station to Russia was an error that has seriously
hurt the project.
"In retrospect, I wish that we built the... module," Goldin told
the House Science Committee during a hearing on the International Space
Station.
Goldin was referring to the Service Module, a key component of
the station. Originally scheduled for launch in early 1998, the launch
date has slipped first to the end of 1998 and now to March or April of
1999 as assembly of the module falls further behind schedule.
Goldin was more critical of Russian participation in the project
than in past Congressional appearances. "I'm very frustrated and angry
at the leadership in Russia who doesn't do what they say they are going
to do," he said.
Goldin said NASA is working on a new timeline for the assembly
of the station and expects to have it completed by June 15 -- one month
later than what NASA Associate Administrator Joe Rothenberg promised in
another Congressional hearing in March.
The new timeline, Goldin said, will include contingency plans
for moving forward on the station without key Russian components. That
timeline will be approved at a "Heads of Agencies" meeting scheduled for
the end of May in Florida.
Goldin also noted the agency was planning a response to the Cost
Assessment and Validation study, also known as the Chabrow report after
committee chairman Jay Chabrow, that was released last month. Goldin
said the key area of difference between NASA's internal studies and the
Chabrow report is the estimate of the appropriate level of reserve
funding needed for the program. The response is due out by early June.
Goldin's change of attitude towards the Russians appeared to
temper Congressional reaction to the situation, including key critics
like House Science Committee chairman James Sensenbrenner (R-WI).
Sensenbrenner was more critical of the Clinton Administration,
criticizing the President for not sending up an official from the Office
of Management and Budget to the hearing.
In a separate press release, the National Space Society also
called on President Clinton to become more involved with the station.
"Since [1993], it appears as if the Administration has been sitting on
the sidelines while a series of problems -- some in NASA's control and
many not -- have developed," NSS executive director Pat Dasch said. "It
is now incumbent upon the White House to step onto the playing field and
provide the necessary leadership to deal with Russian delays."
Goldin said Clinton is expected to discuss the status of the
station with Russian president Boris Yeltsin when the two meet during a
summit of industrialized nations later this month in England.
Hа сегодня все, пока!
=SANA=
Дата: 19 мая 1998 (1998-05-19)
От: Alexander Bondugin
Тема: SpaceViews Update - 1998 May 15 [2/7]
Привет всем!
Вот, свалилось из Internet...
Activists Outraged Over "BitFlip" Silencing
Outrage was the mood of many space activists after NASA and
Boeing allegedly silenced an employee who had been providing unofficial
updates on the status of the International Space Station.
The employee, known only by the pseudonym "BitFlip", had
provided weekly updates on the development of the station for over a
year, first on Usenet, then on the NASA Watch Web site.
A Florida Today article published May 5 identified BitFlip as
Tom Hancock, a systems and software specialist who works for Boeing in
Huntsville, Alabama.
BitFlip, who posted from an America Online address at home and
apparently used no NASA or corporate resources to send out his messages,
provided "unvarnished truth", good and bad, about the status of the
station, information that NASA or prime contractor Boeing rarely
provided on a timely basis.
However, space policy analyst Rich Kolker reported last week
that BitFlip's identity has been uncovered by NASA and forwarded on to
Boeing, his employer, who questioned him for several hours.
According to Kolker, BitFlip was not fired, but was prohibited
from posting any further reports on the space station.
"They handed me a piece of paper and said I can't publish
anything without their approval," BitFlip told Florida Today. "I'm not
going to post anything like I did before. I feel if I do, I might as
well clean out my desk."
The move was met with strong opposition by many space advocates.
"I think what NASA and the contractor has done is totally, completely
inappropriate," Kolker said in a posting in the Houston Chronicle's
Space Forum. "One does not give up the protections of the First
Amendment when one goes to work for the space program."
"What's amazing is that Bit has been and is a tremendous
supporter of ISS," Kolker added. "All he's doing is providing
information, something NASA by law... is required to provide."
"BitFlip posted nothing proprietary, confidential, or
classified," said Keith Cowing, editor of the NASA Watch Web site where
BitFlip's reports had been posted in past months. "Indeed this
information could have been gathered by any one of a thousand people on
the shop floor or in the offices at NASA."
Cowing reacted by removing most of the information from the
front page of his site and turning the background black in protest.
"There will be no NASA Watch for at least 24 hours - perhaps longer," he
wrote on the page late in the day May 4.
A number of comments to Cowing added to the NASA Watch Web site
by readers showed strong disagreement with the move by NASA and Boeing
to silence BitFlip.
There has been no public comment on the situation by NASA or
Boeing officials.
*** Technology ***
Columbia Lands Safely
The space shuttle Columbia landed safely at the Kennedy Space
Center in Florida Sunday afternoon, May 3, with a faulty power unit
having no effect on the landing.
Columbia landed at 12:09pm EDT (1609 UT) on May 3, as scheduled.
The landing was without problems as Columbia glided to a safe landing at
KSC's Runway 33.
There was some initial concern yesterday about the failure of
one of the shuttle's three Auxiliary Power Units (APUs), which provide
power for the shuttle's flaps, rudder, and other control surfaces needed
during landing. The cooling unit on APU 3 malfunctioned, overheating
the unit.
However, the shuttle can be controlled normally with only two
APUs functioning, and can still be controlled, albeit sluggishly, with
only one operating. The other two units operated normally.
Mission controllers decided Saturday to turn on APU 3 at about
six minutes before landing, so that all three units would be operating
in the final, crucial maneuvers before landing. An APU can operate for
10-12 minutes before overheating, NASA officials said.
The landing brought the mission to an end just a couple hours
shy of 16 days after launch. Mission controllers had considered
extending the mission by a day but decided on April 30 not to, when
weather forecasts called for an increased chance of poor weather on
Monday and Tuesday.
NASA was still mulling the possibility of reflying Columbia this
August on the same Neurolab mission at the time of landing, but dropped
the idea a few days later.
NASA Nixes Neurolab Reflight
NASA decided Tuesday, May 5, not to refly the shuttle Columbia
this summer on the Neurolab mission, opening up a gap in the shuttle
schedule for 1998 that could last up to five months.
NASA had considered reflying the Neurolab mission in August to
conduct more tests on the effects of weightlessness on the nervous
system. However, officials said it was more important to retain
flexibility in the shuttle schedule.
The current schedule calls for the launch of Discovery on
mission STS-91 on June 2. The nearly 10-day mission will feature the
final docking of the shuttle with the Russian space station Mir, picking
up Mir astronaut Andy Thomas.
After that the next flight will take place no earlier than
September 3, when Endeavour blasts off on STS-88, the first shuttle
mission dedicated to the International Space Station. The mission,
which will attach the Unity docking node to the FGB module launched by
Russia, may be further delayed until late in the year, NASA officials
admitted, depending on the status of the Russian-built Service Module.
If STS-88 is delayed into November the next shuttle mission
would then become STS-95, the launch of Discovery on a 16-day mission
that will feature the second space flight of Senator John Glenn. STS-95
is scheduled for an October 29 launch.
A long delay for STS-88 would mean over four and a half months
between the landing of STS-91 on June 12 and the launch of STS-95
October 29. The delay between missions would be one of the longest in
recent years for the shuttle program.
Last year NASA had planned two launches in the summer: STS-88 in
July and STS-93, the launch of Columbia carrying the AXAF X-ray
astronomy satellite, in August. However, STS-88 has been pushed back by
space station delays and STS-93 has been pushed back to at least
December 3 because of delays assembling AXAF.
STS-96, the launch of Endeavour on the second space station
mission, had been scheduled for December 9, but will likely be pushed
back to early 1999 at the earliest.
Hа сегодня все, пока!
=SANA=
Дата: 19 мая 1998 (1998-05-19)
От: Alexander Bondugin
Тема: SpaceViews Update - 1998 May 15 [3/7]
Привет всем!
Вот, свалилось из Internet...
Study Says Station Launch Failures Likely
A study published in the current issue of the British science
weekly New Scientist concludes that the failure of one or more launches
of equipment or supplies necessary to assemble the International Space
Station is almost inevitable.
The study, performed by the magazine itself, uses simple
probability techniques to show that there is a 99.5% chance that at
least one of the 93 American and Russian launches planned during the
station's assembly will fail, and that the most likely outcome is the
failure of five launches.
The figure includes 48 launches of supplies on Russian boosters,
12 launches of station hardware on Russian boosters, and 33 American
space shuttle missions.
The magazine noted that a failure of one of the 48 supply
launches would not be critical to the station, but even removing those
launches leaves a 73.6% chance of a launch failure, the magazine
concluded.
Launch failures include the destruction of the booster during
launch, placing the payload in an inaccessible orbit, and other failures
that would prevent the cargo carried by the booster from reaching the
station.
The failure of certain launches, particularly of key modules or
other segments of the station, could hold up the entire station assembly
process for two to three years until a replacement could be assembled
and launched.
"It really depends on what element fails and where in the
sequence you are," Michael Hawes, NASA's chief engineer for the station,
told New Scientist. "You might have a full delay of the manufacturing
time -- maybe two to three years."
The study assumed the odds of a successful shuttle launch at 99%
and a Russian Proton or Soyuz launch at 92%. The odds of a successful
set of launches was found by taking those odds to the power of the
number of launches -- 0.99^33 for the shuttle and 0.92^60 for the
Russian boosters -- and multiplying the results. The odds of at least
one failure came from simply taking 1 minus the successful odds.
Proton and Titan Launches Successful
A Russian Proton booster successfully launched an American
communications satellite earlier this month, while two generations of
Titan boosters launched government payloads in early May.
The Proton launched the EchoStar-4 satellite at 7:45pm EDT (2345
UT) May 7 from the Baikonur Cosmodrome in Kazakhstan. The launch
proceeded without any problems reported.
The satellite, owned by Colorado-based EchoStar Communications,
will augment existing direct TV broadcasts on EchoStar's DISH Network.
The satellite was built by Lockheed Martin Missiles and Space Company.
The Titan 4B Centaur launched a classified military satellite
from Pad 40 at Cape Canaveral at 9:38pm EDT (0138 UT) Friday, May 8.
The launch was reported as a success by officials with the Air Force and
Lockheed Martin, who built the Titan booster.
The Air Force described the Titan's payload as classified and
would not comment on its contents. Civilian observers, however, believe
the Titan booster carried a satellite into orbit capable of
eavesdropping on radio and telephone communications.
A refurbished Titan II lifted off from Vandenberg AFB,
California, at 11:52am EDT (1552 UT) Wednesday, May 13. The launch was
a success, placing a weather spacecraft into a polar orbit 830 km (515
mi.) above the Earth.
The Titan II's payload, the NOAA-K satellite, is the latest
model of the Television Infrared Observation Satellite (TIROS), a series
of weather satellites developed for NASA and the National Oceanic and
Atmospheric Administration (NOAA) dating back to the early 1960s.
*** Policy ***
Mir Deorbit Burn Delayed
The Russian Space Agency has decided to postpone the beginning
of the Mir deorbiting procedure by a month, while a key Russian space
official suggested the deorbiting might be delayed further because of
problems with the International Space Station.
The Russian Space Agency announced May 8 that the first burns to
lower the orbit of Mir, originally scheduled for late May, would be
postponed until the end of June. Deputy flight director Viktor Blagov
told the Itar-Tass news agency that it would be "too costly" to begin
the deorbiting procedure before the space shuttle Discovery arrived at
Mir June 5.
A Progress resupply spacecraft, scheduled for launch later this
month from Baikonur, Kazakhstan, will bring extra fuel needed to begin
the maneuver.
Under current plans the station's orbit will be gradually
lowered from 400 km (250 mi.) to 150 km (93 mi.) before the station is
abandoned and allowed to burn up in the Earth's atmosphere at the end of
1999.
However, Blagov hinted to Reuters that the life of Mir may be
extended because of delays with the International Space Station (ISS).
"If the Alpha station continues to be delayed, Mir will continue to
fly," he told Reuters, using the old term "Alpha" to refer to ISS. "As
soon as Alpha flies, we'll take measures."
Blagov's statement seems to fly in the face of recent NASA
statements calling for Russia to deorbit Mir as soon as possible so it
can devote its full attention to ISS. In Congressional hearings earlier
this week, NASA Administrator Dan Goldin said Russia does not have the
number of launch vehicles needed to support both Mir and ISS.
Goldin's statements at that hearing, which were unusually
critical of Russian efforts, were called "unpleasant" by Russian Space
Agency officials. "What our colleague said is extremely regrettable and
unpleasant," said Alexei Krasnov, the Russia Space Agency's deputy head
of international cooperation, who also spoke at the hearing.
Meanwhile, Russia may be planning changes to their contribution
to ISS. The Interfax news agency reported May 8 that officials were
considering modifications to the modules they plan to contribute to the
space station, reducing the number of modules but refitting the
remaining modules so they serve the same purposes as before.
The report hinted that modifications could include changes to
the Functional Cargo Block (known by its Russian acronym FGB), which has
already been completed and is scheduled for launch on a Proton booster
in late summer or fall.
Hа сегодня все, пока!
=SANA=
Дата: 19 мая 1998 (1998-05-19)
От: Alexander Bondugin
Тема: SpaceViews Update - 1998 May 15 [4/7]
Привет всем!
Вот, свалилось из Internet...
Report: Protocols Needed for Reporting Threatening Asteroids
NASA and astronomers need to develop a protocol for
communicating information about potentially threatening asteroids and
comets to avoid false alarms in the future, a National Research Council
report announced Wednesday, May 13.
The report also recommended increased efforts for telescopic
studies of asteroids and comets, laboratory investigations, and more
spacecraft missions, including possibly human missions to near-Earth
objects.
Meanwhile, a Los Angeles Times article Thursday, May 14 reported
that astronomers receiving NASA funds have agreed to keep the discovery
of any potentially threatening asteroid secret for 72 hours, to allow
time for the threat to be confirmed and avoid fiascoes such as the one
two months ago.
The Committee on Planetary and Lunar Exploration (COMPLEX)
started the report before the announcement in March that asteroid 1997
XF11 would pass near the Earth in 2028, a claim that was retracted a day
later after a new orbit for the asteroid was calculated using
newly-discovered data. However, the dangers of such false alarms was a
key focus of the report.
The committee noted that several new telescopes and instruments
coming on line in the near future will dramatically increase the rate of
asteroid discoveries. "With the flood of discoveries expected within
the next decade also will come the risk of false alarms," the report
noted.
This increased risk requires NASA, astronomers, and other groups
like the International Astronomical Union to develop a series of
protocols to communicate news of potentially hazardous objects among
themselves and with the public, the committee concluded.
According to the Times, astronomers have agreed to keep
discoveries to themselves for 48 hours before reporting them to NASA,
who will keep them secret for an additional 24 hours. The time is
supposed to allow for additional data to come in and confirm -- or
reject -- any hazard the asteroid might pose.
Some astronomers have expressed skepticism at the proposal,
noting that the rapid dissemination of information is vital to allow
other astronomers to observe the asteroid and provide data that could
refine its orbit. Moreover, the proposal does not apply to amateur
astronomers and others who do not receive NASA funding.
The COMPLEX report, "The Exploration of Near-Earth Objects",
also suggested that increased attention be given to several areas of
research related to near-Earth objects.
The committee recommended that asteroid and comet observations
get "routine or priority access" to existing telescopes, or have
telescopes dedicated solely to such observations. Such access is
required because fast-moving near-Earth objects can appear and disappear
from view within a few days.
More laboratory work is also needed to better understand the
composition of asteroid and comets, the committee noted. Such research
could explain why the physical characteristics of the most common
varieties of asteroids and meteorites, which come from asteroids, do not
match.
The report also recommended additional missions to asteroid and
comets to perform up-close studies of them, and to return samples of
them to the Earth.
Human missions to near-Earth asteroids should be strongly
considered, the report noted. "Because missions to these asteroids
represent deep-space exploration with moderate technical challenges,
they would be the least-expensive next step in human exploration of
space," the report noted, "and could provide the experience and
technology needed for fruitful missions to Mars and beyond."
The report requested that NASA conduct additional research on
the specific technical requirements for such a mission, which would last
from six to 12 months.
Japan Questions Need for Small Launcher
A Japanese government agency has questioned the need for the
country's space agency to develop a small booster, noting it has no
market and would cost several times more than foreign competitors.
Aviation Week, reporting in its May 11 issue, said the
Management and Coordination Agency (MCA), a branch of the Japanese
government similar to the U.S. General Accounting Office, suggested that
development of the J-1 launcher be dropped unless the development cost
of the project can be reduced.
The J-1, used only once to date, was designed to launch payloads
of up to 1,000 kg (2,200 lbs.) into low-Earth orbit. The cost of a J-1
is currently $36 million, and is expected to fall to $26 million by
2000, but would still be much higher than foreign launch vehicles with
similar capabilities.
The MCA recommended that unless costs can fall to "competitive
levels" by 2004 or 2005, the National Space Development Agency (NASDA)
should drop the project.
Currently only one future J-1 launch, of the Oicets experimental
communications satellite in the year 2000, is scheduled. No commercial
launches of the J-1 are foreseen at current prices, Aviation Week
reported.
Hа сегодня все, пока!
=SANA=
Дата: 19 мая 1998 (1998-05-19)
От: Alexander Bondugin
Тема: SpaceViews Update - 1998 May 15 [5/7]
Привет всем!
Вот, свалилось из Internet...
*** Science ***
Scientists Puzzled by Brilliant Cosmic Burst
Astrophysicists are pondering the possible causes for a massive
gamma-ray burst witnessed last December that, for a few seconds, was as
bright as the rest of the universe combined.
In a paper published in the May 7 issue of the British journal
Nature, a team of astronomers from the California Institute of
Technology report on a brilliant burst detected by satellites in
mid-December that cannot be explained by most gamma-ray burst theories.
The short-lived burst, lasting only a few seconds, was detected
December 14 by the Italian-Dutch BeppoSAX satellite as well as NASA's
Compton Gamma Ray Observatory. The decline of the burst was later
tracked in X-rays by BeppoSAX and NASA's Rossi X-Ray Timing Explorer,
and in visible light by several telescopes on the ground and the Hubble
Space Telescope.
Key observations were performed by Caltech astronomers at the
Keck Observatory in Hawaii, where they were able in February to detect
the faint, distant galaxy that hosted the burst. They determined that
the galaxy was about 12 billion light years away.
Using the observations of the burst and the measurement of its
distance, the Caltech team, led by professors George Djorgovski and
Shrivinas Kulkarni, determined the massive amount of energy released by
the burst.
"For about one or two seconds, this burst was as luminous as all
the rest of the entire universe," Djorgovski said.
The amount of energy released by the burst was hundreds of times
larger than that from a supernova explosion and equal to what the entire
Milky Way galaxy radiates over the course of a few centuries.
A mechanism that can provide such massive amounts of energy in a
short period of time is not readily apparent to astronomers. "Most of
the theoretical models used to explain these bursts cannot explain this
much energy," Kulkarni said.
Kulkarni added that some theories that involve rotating black
holes as the source of the bursts, could explain the bursts. "On the
other hand, this is such an extreme phenomena that it is possible we are
dealing with something completely unanticipated and even more exotic,"
he said.
Gamma-ray bursts have defied any easy explanation since their
discovery by satellites in the 1960s. Over 100 theories have been
advanced to explain their existence, but few work to the satisfaction of
most astrophysicists.
Did Deadly Dust Do in the Dinosaurs?
Variations in the amount of dust the Earth passes through in its
orbit may have triggered a decline in the population of the dinosaurs
thousands of years before a giant impact killed them off, researchers
reported Friday, May 7.
Stanley Dermott of the University of Florida and Stephen
Kortenkamp of the Carnegie Institution reported in the May 7 issue of
the journal Science that the amount of interplanetary dust the Earth's
atmosphere absorbs can vary over a 100,000-year cycle.
Scientists had known about the 100,000-year cycle in the Earth's
climate, known as the Milankovich Cycle, and had blamed it on changes in
the eccentricity of the Earth's orbit.
However, Dermott and Kortenkamp found that the variations in
eccentricity are too small to account for the observed changes in
climate, but that the variations could account for changes in the amount
of dust absorbed by the Earth by a much as a factor of three.
The Earth currently gains about 30 million kilograms (66 million
pounds) of dust a year, based on data collected by NASA's Long Duration
Exposure Facility (LDEF) satellite that orbited in the 1980s.
The dust acts like dust thrown into the atmosphere by volcanoes,
in that it blocks out sunlight and cools the Earth. However, according
to Kortenkamp, interplanetary dust is much more long-lived in the
atmosphere than volcanic dust.
"The influx of interplanetary dust could remain at high levels
for extended periods -- several hundred thousand years -- and therefore
any associated cooling would also persist for this length of time," he
said.
This fact, Dermott and Kortenkamp believe, could explain why
dinosaur populations appeared to be dying out before the Chicxulub
impact 65 million years ago that wiped them out. The impacting object
may have been in an orbit that crossed the Earth's for some time, and
the Earth may have passed through its debris train a number of times,
collecting extra amounts of dust.
That dust could have triggered a cooling phase that started to
kill off the dinosaurs before the asteroid or comet struck the Earth.
"While the issue is controversial, there are groups of paleontologists
who have found evidence suggesting some mass extinctions were gradual,
lasting for hundreds of thousands of years," Kortenkamp said.
Is "Deep Impact" Real or Just Reel?
This weekend millions of Americans will see the premiere of
Steven Spielberg's disaster epic Deep Impact, which features the Earth
threatened by the impact of a comet. A question on the minds of many
moviegoers will be, "Just how realistic is this?"
Not bad, scientists say.
During the filming of the movie, producers employed a number of
consultants, including former Johnson Space Center director Gerry
Griffin, to check the science of the movie, from the effects of an
impact to how astronauts attempting to deflect the comet would work in
space.
Most recently, scientists and computer experts at Sandia
National Labs in Albuquerque used the world's fastest computer to
simulate an impact similar to the one threatened in the movie. Their
"teraflops supercomputer", capable of performing more than one trillion
calculations a second, modeled an impact off the coast of New York.
In their model, a 1.4-km (0.85-mi.) diameter comet strikes the
Atlantic Ocean 40 km (25 mi.) south of Brooklyn. The computer simulated
the effects by dividing a 310 square kilometer (120 sq. mi.) region into
100 million separate cubes, and used the laws of physics to take into
account the effects of the impact in each cube over time.
The results? Within five seconds a superheated plume of water,
earth, and other debris, at temperatures of more than 5,000 degrees
Celsius (9,000 degrees Fahrenheit) incinerates much of Long Island.
Eventually the impact destroys all of the New York City area and even
much of New England, and creates a global cloud that could trigger a
"nuclear winter".
How does Spielberg's version of such an impact stack up? "The
movie makers didn't have the benefit of the world's fastest computer,"
said Arthurine Breckenridge of Sandia, "but they produced superior
visuals that appear remarkably realistic."
Breckenridge did quibble with one aspect of the version seen in
previews of the movie. The vapor cloud produced by the impact would not
be symmetric, she said, but "is initially asymmetric, sending more
material in the direction of the ricochet."
Scientists at Sandia have been using supercomputers to model the
effects of asteroid and comet impacts for some time and have made the
models more realistic, said Mark Boslough. "It's almost like doing an
experiment -- one you could never do. One you would never want to do."
Hа сегодня все, пока!
=SANA=
Дата: 19 мая 1998 (1998-05-19)
От: Alexander Bondugin
Тема: SpaceViews Update - 1998 May 15 [6/7]
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Black Hole Feeds on Colliding Galaxy
Astronomers using the Hubble Space Telescope have seen an
unprecedented -- and bizarre -- event: a supermassive black hole at the
center of a galaxy, feeding on another, smaller galaxy that's colliding
with the larger galaxy.
An international team of astronomers who released the Hubble
images May 14 say the unprecedented event observed in the Centaurus A
galaxy (NGC 5128) may have been far more common in the early universe.
The galaxy, located 10 million light-years from the Earth, is
the closest "active" galaxy to our own galaxy. The peculiar galaxy was
long believed to be the result of the collision of a larger elliptical
galaxy with a smaller spiral one.
Using Hubble's infrared camera, astronomers were able to peer
through lanes of dust that blocked the center of the galaxy at visible
wavelengths of light. In the center astronomers saw a disk of hot gas
swirling around the suspected black hole.
However, unlike a typical black hole believed to be in the
centers of many galaxies, the disk was oriented at an angle to the black
hole's axis, as shown by high-speed jets of material ejected along the
axis. The disk appears to wobble as it rotates around the black hole,
while the black hole itself is not aligned with the rest of the galaxy.
"We have found a complicated situation of a disk within a disk
within a disk, all pointing in different directions," said Ethan
Schreier of the Space Telescope Science Institute in Baltimore and head
of the team of astronomers who studied the Hubble images.
"This black hole is doing its own thing," he said. "Aside from
receiving fresh fuel from a devoured galaxy, it may be oblivious to the
rest of the galaxy and the collision."
The mass of the black hole is not known but may be up to one
billion times the mass of the Sun, compacted into a region no larger
than the solar system.
Schreier and his colleagues plan analysis of new Hubble images
as well as data from ground-based telescopes in an effort to better
understand how supermassive black holes are affected by galaxy
collisions.
*** CyberSpace ***
Space Day
Next Thursday, May 21, will be the second annual Space Day, a
time to educate the public about the benefits of space. The Space Day
Web site is an integral part of this effort, with information about
events planned for the day. One of those events will be a day-long
Webcast from the site, featuring interviews with John Glenn,
teacher/astronaut Barbara Morgan, astronomer David Levy, and others.
Other information on the site includes how to plan a Space Day event,
teacher information, and games.
http://www.spaceday.com/
John Glenn: Three Orbits to History
"John Glenn: Three Orbits to History" is a beautifully-designed
Web site which recounts the early days of the Space Race, from the
launch of Sputnik through Glenn's historic flight. The site
incorporates a wide range of multimedia elements to enhance the
educational and entertainment experience. As Glenn prepares for his
second spaceflight on the shuttle this far (for far more than three
orbits!) it's worthwhile to peruse this site to get some background on
the era and on Glenn himself.
http://www.capstonestudio.com/mercury/
ProSpace
While space-related Web sites tend to focus on the scientific or
technical aspects of space exploration, a key aspect (or necessary evil)
of expanding our presence in space is in the political arena. ProSpace,
which bills itself as the "Citizen's Space Lobby", is working to open
the space frontier though its support of key programs and legislation.
Its Web site is filled with information about the current status of
bills and programs, from background issues on space policy to
legislative alerts. There is also information on becoming a space
activist, from contacting your representatives to participating in
events like ProSpace's "March Storm" lobbying effort.
http://www.prospace.org/
Rocketry.Org
Amateur rocketry is more than just sticking a D-motor into the
tail of a cardboard tube and lighting it off these days. Amateur and
experimental rocketry efforts have produced some impressive efforts in
recent years, and it will be only a matter of time before these rockets
make it into space. Rocketry.Org is a large collection of material on
this subject, with introductory information, resource directories, a
bookstore, contest information (like the $250,000 CATS Prize for the
first private rocket to launch 2 kg above 200 km altitude), and more.
It's an excellent resource for anyone, beginners seeking an introduction
to the subject, to experts looking for specific information.
http://www.rocketry.org/
*** Space Capsules ***
SpaceViews Event Horizon
May 15 Launch of a Delta II carrying five Iridium satellites
from Vandenberg Air Force Base, California.
May 15 Launch of the Progress M-40 resupply spacecraft for Mir,
on a Soyuz booster from Baikonur, Kazakhstan.
May 19 Long March 3B launch of the Chinastar-1 communications
satellite from Xichang, China
May 20 Athena launch of the Ikonos-1 satellite from Vandenberg
Air Force Base, California.
May 21-25 International Space Development Conference, Milwaukee,
Wisconsin.
June 2 Launch of the shuttle Discovery on mission STS-91, the
final Shuttle-Mir docking mission, from Kennedy Space
Center, Florida.
Hа сегодня все, пока!
=SANA=
Дата: 19 мая 1998 (1998-05-19)
От: Alexander Bondugin
Тема: SpaceViews Update - 1998 May 15 [7/7]
Привет всем!
Вот, свалилось из Internet...
Other News
One Launch Site, No Waiting: The U.S. Army is offering its missile
range at Kwajalein atoll in the central Pacific as a launch site, but
commercial launch providers aren't interested right now, Space News
reports. The site, about 3,500 km (2,170 mi.) west of Hawaii, is
located near the equator and thus would be an ideal location for
launching geosynchronous communications satellites. The Army currently
uses the site to track ICBM test launches from Vandenberg Air Force Base
and to location missile defense systems, and is interested in using
commercial launch fees to offset the costs of operating the base.
However, commercial launch providers haven't shown much interest, likely
because they would have to build their own launch sites and support
facilities.
Spacehab's New Shuttle Module: Spacehab is privately developing a new
module for use in the shuttle's cargo bay that would aid the shuttle's
ability to reboost the International Space Station. The Docking Double
Module, based on Spacehab's existing shuttle lab module, would
reposition the docking airlock to the rear of the shuttle's cargo bay,
allowing for more efficient use of the shuttle's thrusters to reboost
the station. Spacehab is taking a risk developing the $35-40 million
module, since none of the ISS member nations have agreed in writing to
use the module. In a separate deal, Spacehab acquired the rights May 7
to the Wake Shield Facility (WSF), a free-flying satellite flown on
several shuttle missions to test the development of ultra-pure
semiconductor films. Spacehab made the deal with the WSF's developers,
the University of Houston.
SpaceDev Makes Financing Deal: SpaceDev announced Thursday, May 14,
that it had reached an agreement with investment banking company J. P.
Carey of Atlanta to raise $900,000 in near-term funding for NEAP, the
company's Near-Earth Asteroid Prospector mission. SpaceDev said the
funding will go to filling several key positions, including NEAP program
manager and spacecraft engineer. The company earlier reported that
seven principal investigators from universities and government centers
had filed notices of intent (NOIs) with NASA, announcing their intent to
submit proposals for funding instruments that would be flown on NEAP.
Each successful proposal would earn SpaceDev $10-12 million.
Boeing Wins Ellipso Contact: Mobile Communications Holdings, Inc. (MCHI)
awarded a contract to Boeing earlier this month to build the
17-satellite Ellipso global communications system. Ellipso, an
innovative constellation of 10 spacecraft in elliptical orbits and seven
in equatorial orbits, will provide global voice communications by 2002.
MCHI has earlier worked with Orbital Science Corporation on Ellipso, but
that deal fell through in March when Boeing offered MCHI a better deal,
Aviation Week reported. OSC instead announced it will build the
12-satellite Ecco system for CCI International. Ecco will provide
mobile telephone services in a band around the Equator.
NASA and the Net: NASA won the Tenagra Award in Online Public Relations
Success for its Mars Pathfinder Web site in a ceremony May 8. "By
placing a wide spectrum of informational resources up and online
incredibly quickly, and doing it in an extremely interactive fashion,
the Mars Pathfinder online effort became the defining Internet public
relations event of 1997," the award citation noted. The award is one of
several handed out each year by the Tenagra Corporation, a Houston-based
Internet marketing and consulting firm... Defense Week reported than
hackers from the National Security Agency will attempt to break into
NASA computers this week, in a test of the space agency's computer
security. NASA computers have been the subject of computer attacks in
the past... Internet pioneer Vincent Cerf is working with NASA to
develop ways to extend Internet networking into deep space, Inter@ctive
Week magazine reported in its May 4 issue. Cerf reportedly is a strong
believer in space colonization and thinks it's only a matter of time
before humans are living on other worlds -- and want to send e-mail.
This has been the May 15, 1998, issue of SpaceViews Update.
SpaceViews Update is also availble on the World Wide web from the
SpaceViews home page:
http://www.spaceviews.com/
or via anonymous FTP from ftp.seds.org:
/pub/info/newsletters/spaceviews/update/980515.txt
For editorial questions and article submissions for SpaceViews or
Spaceviews Update, contact the editor, Jeff Foust, at jeff@spaceviews.com.
For questions about the SpaceViews mailing list, please contact
spaceviews-approval@nss.org.
____ | "SpaceViews" (tm) -by Boston Chapter
// \ // | of the National Space Society (NSS)
// (O) // | Dedicated to the establishment
// \___// | of a spacefaring civilization.
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