Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: O'Neil Named Manager Of 2003, 2005 Mars Sample Return Missions
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MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov
Contact: Diane Ainsworth
FOR IMMEDIATE RELEASE December 17, 1998
O'NEIL NAMED MANAGER OF 2003, 2005 MARS SAMPLE RETURN MISSIONS
William J. O'Neil, who served as project manager of NASA's Galileo
mission to Jupiter at the Jet Propulsion Laboratory, Pasadena, CA from 1990
to 1998, has been named manager of the agency's first two Mars sample return
missions, scheduled for launches in 2003 and 2005.
O'Neil, who was appointed in mid-November, had served as the chief
technologist for the Mars exploration program in the interim, overseeing all
aspects of technology development and implementation for NASA's long-range
program of robotic exploration of Mars. This summer he led a comprehensive
effort at JPL to redesign the architecture of the Mars sample return
missions to determine the best approach for these first-ever missions.
Prior to his appointment as Galileo project manager, he served as the
Galileo science and mission design manager during the spacecraft's
development phase. The Galileo spacecraft is continuing its extended science
mission to study Jupiter's major moons, atmosphere and magnetosphere.
Galileo became the first spacecraft to orbit an outer planet and penetrate
its atmosphere. On its circuitous route to Jupiter, the spacecraft also
became the first to perform close-up asteroid studies when it flew past the
asteroids Gaspra and Ida.
O'Neil's past assignments have included work, in the mid- 1960s, as a
trajectory design and navigation engineer for the Lunar Surveyor project,
which became the first robotic spacecraft to soft-land on the surface of the
moon. He also served as navigation chief on the 1971 Mariner mission to
Mars, the first U.S. spacecraft to orbit another planet, and navigation
chief for the Viking mission to perform the first soft-landings on the
surface of Mars.
Before joining JPL in 1963, O'Neil was as an aerospace engineer
working in 1960 at the Boeing Airplane Company in Renton, Washington. From
1961 to 1963, he was an employee of Lockheed Missiles and Space Company in
Sunnyvale, CA.
O'Neil earned his bachelor of science degree with distinction in
aeronautical engineering in 1961 from Purdue University, West Lafayette,
Indiana, and his master of science degree in aerospace engineering in 1967
from the University of Southern California.
O'Neil is the recipient of NASA's highest award, the Distinguished
Service Medal, and Purdue University's Distinguished Alumni Award. He also
holds an honorary doctorate from the University of Padova, Italy, home of
the Galileo spacecraft's namesake, 16th century astronomer Galileo Galilei.
O'Neil resides with his wife in Sierra Madre, CA, and has three adult
children.
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=SANA=
Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: Cassini Update - December 18, 1998
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Cassini Significant Events
for 12/11/98 - 12/17/98
Spacecraft Status:
The most recent spacecraft status is from the DSN tracking pass on
Thursday, 12/17, over the Goldstone tracking station. The Cassini
spacecraft is in an excellent state of health and is executing the Cruise
11 sequence normally. The Cassini spacecraft is presently traveling at a
speed of approximately 66,338 kilometers/hour relative to the sun and has
traveled approximately 1.079 billion kilometers since launch on
October 15, 1997.
Spacecraft Activity Summary:
On Friday, 12/11, the Solid State Recorder (SSR-B) record and playback
pointers were reset as planned.
On Sunday, 12/13, two planned of the three possible components of Periodic
Engineering Maintenance were performed. All activities were nominal;the
third component is planned for next week.
On Wednesday, 12/16, routine maintenance was performed on the Solid State
Recorder (SSR-B) flight software partitions.
On Thursday, 12/17, an Instrument Flight Software update was performed for
MIMI in preparation for Instrument Checkout.
Upcoming events:
Activities scheduled for the week of 12/18-12/24 include SSR Pointer
Reset, Periodic Engineering Maintenance (Reaction Wheel Portion), and
Instrument Flight Software update for CDA, CIRS and RPWS on 12/18, Probe
Checkout, SSR Pointer Resets, and Flight Software update for CAPS and INMS
on 12/21, and reset of the PSA (Probe Support Avionics) Prime status
following Probe Checkout on 12/22.
Cassini Outreach
Jet Propulsion Laboratory
California Institute of Technology
National Aeronautics and Space Administration
Pasadena, Calif. 91109.
Telephone (818) 354-5011
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=SANA=
Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: NEAR Update - December 18, 1998
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NEAR Mission Status Reports - http://near.jhuapl.edu
NEAR WEEKLY REPORT December 18, 1998
MISSION OPERATIONS:
All systems are "GO" for Rendezvous Burn 1 on 12/20/98 at 5:00 p.m.
EST.
The NEAR spacecraft state/configuration has remained nominal (Flight
Computer#1 and Attitude Interface Unit #1 active) throughout this
reporting period.
The MSI, MAG, NIS, and XGRS instruments have remained on during this
reporting period. The NLR will remain off until 1/21/99.
All activities planned for this period were successfully conducted
including:
Daily repeating Eros Optical Navigation Images
NIS SDC Test 1
NIS SDC Test 2
MSI/NIS Eros Mono Light curve 3
Preparations for the upcoming rendezvous burn this Sunday (12/20)
continue on schedule. All commands for Rendezvous Burn 1, and
Contingency Burn 1A, are loaded on the spacecraft and enabled. A
short test pressurization of the propulsion system will execute today
at 2:00 p.m. EST, followed 4 hours later by a longer pressurization
test.
A change to the mission timeline to turn off the MAG, XGRS, and NIS
instruments from 12/19 through 12/30 has been made to provide
additional power margin for the upcoming rendezvous burns.
24 hour/day monitoring of the spacecraft has begun. This will
continue for the next two months.
All science and engineering data was recovered from the spacecraft for
this reporting period.
Upcoming Spacecraft Activities:
December 19: XGRS, MAG, NIS OFF
December 20: Rendezvous Burn 1- 5:00 p.m. EST
December 21: OpNav B, repeated every 8 hours until Rendezvous
Burn 4
December 23: MSI/NIS Mono Light Curve 4
December 23: MSI/NIS Mono Light Curve 5
December 27: Eros Satellite Search A
December 28: Rendezvous Burn 2
December 29: Rendezvous Burn 3 (optional cleanup burn)
December 30: XGRS, MAG, NIS ON
Debra Fletcher
The Johns Hopkins University
Applied Physics Laboratory
Bldg.-Rm.: 2-155
11100 Johns Hopkins Road
Laurel, MD 20723-6099
240-228-8274/Washington
443-778-8274/Baltimore
Fax: 240-228-3237
Email: debra.fletcher@jhuapl.edu
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=SANA=
Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: Sky & Telescope News Bulletin - December 18, 1998
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SKY & TELESCOPE'S NEWS BULLETIN
DECEMBER 18, 1998
COSMOLOGICAL TOP STORY OF THE YEAR
The discovery that the expansion of the universe is actually accelerating
has been named the 1998 "Breakthrough of the Year" by the journal
*Science.* As described by Ann K. Finkbeiner in the September issue of *Sky
& Telescope* (page 38), astronomers with the Supernova Cosmology Project
and the High-Z Supernova Search Team unexpectedly found that the universe
seems to be accelerating, as if driven by some kind of "antigravity" force
(termed the cosmological constant). Additional analysis continues to
support this idea. Virginia Trimble summarizes this and other significant
astronomical findings from the past year in the February issue of *Sky &
Telescope,* now in the mail to subscribers.
GEMINID RECAP
Normally one of the year's most rewarding and dependable meteor showers,
the Geminids are often likened to August's popular Perseid shower. The 1998
Geminids, however, were destined to be measured against November's Leonid
fireball show. Initial accounts suggest the Geminids gave a solid
performance. This year's Geminids favored observers in Hawaii, where the
radiant was high overhead during the peak on the 14th. Observing from the
Big Island, Jaimie and Bill Perry lost count at 100 per hour as meteors
began to arrive at a rate of one every two to three seconds and streaked
all over the sky. Meanwhile in Volcano, Hawaii, *Sky & Telescope*
contributing editor Stephen James O'Meara monitored the display through
holes in a persistent cloud cover but still managed to see 44 meteors in
one hour. The Geminids share another trait with the Leonids: future levels
of activity are difficult to predict. Next year's Geminid display might
prove even richer as the shower's parent asteroid 3200 Phaethon swings
within 1.2 astronomical units of Earth on October 16th.
A SPACECRAFT BONANZA
All systems are well a week after the December 11th launch of Mars Climate
Orbiter. Flight controllers will command the spacecraft to make its first
-- and largest -- trajectory correction maneuver on Monday, December 21st.
This will direct the craft for an on-time arrival at Mars in September
1999. Shortly afterward, the probe's two scientific instruments will be
checked out. Engineers continue to calibrate the instruments aboard NASA's
Submillimeter Wave Astronomy Satellite (SWAS), launched on December 5th.
SWAS will study the composition of interstellar matter at a wavelength that
cannot be examined from Earth's surface. All things are go with Deep Space 1.
After a two-week run using its ion-propulsion drive, the engine was
turned off so that two instruments -- a plasma experiment and spectrometer
-- could be checked out. Engineers then tested to see how high the drive
could be set before the spacecraft could no longer run the engine with only
solar power and began drawing from its battery. And finally, the Near Earth
Asteroid Rendezvous (NEAR) spacecraft is now only three weeks away from its
historic encounter with asteroid 433 Eros. NEAR will be the first
spacecraft to go into orbit around a minor planet on January 10th. On
December 20th, NEAR will be commanded to make the first of three planned
trajectory corrections to cozy the spacecraft up to the 32-by-13-kilometer
asteroid.
SUN TO MOVE NORTH
The solstice occurs at 8:56 p.m. EST Monday, December 21st. This is when
the Sun is at its farthest south for the year and begins its six-month
return north. In the Northern Hemisphere, winter begins and we get the
year's longest night. In the Southern Hemisphere, summer begins with the
year's longest day.
THIS WEEK'S "SKY AT A GLANCE"
Some daily events in the changing sky, from the editors of SKY &
TELESCOPE.
DEC. 20 -- SUNDAY
* The waxing crescent Moon stands well to the upper left of Venus, low in
the southwestern sky at dusk.
* Some doorstep astronomy: Look low in the east-southeast in early
evening for the bright constellation Orion. It rises higher in the
southeast later in the night. In its middle you'll see a nearly vertical
row of three stars, Orion's Belt. The Belt points upward roughly to the
orange star Aldebaran (look about two fist-widths at arm's length above the
Belt). Higher above Aldebaran and a bit right is the little Pleiades star
cluster, the size of your fingertip at arm's length.
* Mercury is at greatest elongation, shining low in the dawn 22 degrees
from the Sun.
DEC. 21 -- MONDAY
* The solstice occurs at 8:56 p.m. EST. This is when the Sun is at its
farthest south for the year and begins its six-month return north. In the
Northern Hemisphere, winter begins and we get the year's longest night. In
the Southern Hemisphere, summer begins with the year's longest day.
* Early this evening the faint asteroid 245 Vera should occult (cover) a
9th-magnitude star near the Taurus-Gemini border for observers along a
narrow track from Lake Superior through Utah. The occultation, which could
last up to 8 seconds, should come within a few minutes of 6:59 p.m. Central
Standard Time, 5:59 p.m. Mountain Standard Time. Finder charts for this
week's asteroid occultations are in the December Sky & Telescope, page 124,
and at http://www.skypub.com/sights/occultations/occultations.html.
* 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 10:26 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.
* The eclipsing variable star Algol should be in one of its periodic
dimmings, magnitude 3.4 instead of its usual 2.1, for a couple hours
centered on 11:50 p.m. EST. Algol takes several additional hours to fade
and brighten. For all its predicted minima see
http://www.skypub.com/sights/variables/algol.html.
DEC. 22 -- TUESDAY
* Antares is 6 degrees south (lower right) of Mercury Wednesday morning;
look low in the southeast during early dawn. Binoculars will help.
DEC. 23 -- WEDNESDAY
* The faint asteroid 49 Pales should occult a 9.5-magnitude star in
Aquarius for observers in parts of the Southeast. The occultation, which
could last up to 5 seconds, should take place around 7:07 p.m. EST. See
http://www.skypub.com/sights/occultations/occultations.html.
DEC. 24 -- THURSDAY
* Jupiter is the "star" shining to the upper left of the Moon this
evening.
* Jupiter's Red Spot transits around 7:56 p.m. EST.
* Algol should be at minimum light for a couple hours centered on 8:39
p.m. EST.
DEC. 25 -- FRIDAY
* Jupiter shines to the right of the Moon at dusk, and to the Moon's
lower right later in the evening.
DEC. 26 -- SATURDAY
* First-quarter Moon (exact at 5:46 a.m. EST).
* Jupiter's Red Spot should transit around 9:35 p.m. EST.
THIS WEEK'S PLANET ROUNDUP
MERCURY appears low in the southeast during dawn. Look for the dimmer star
Antares to its lower right early in the week and more directly to its 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 +1.2 in Virgo, rises around 1 a.m. and is high
in the south by dawn. Spica is the star below it or to its lower left.
JUPITER, magnitude -2.4, is the big, bright "star" high in the south at
dusk. It gets lower in the southwest later in the evening and sets around
11 p.m.
SATURN, magnitude +0.2, is the yellowish "star" far to Jupiter's left at
dusk and to Jupiter's upper left later in the evening. The two planets
appear 36 degrees apart (about 4 fist-widths at arm's length), on opposite
ends of 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). For 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
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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
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custserv@skypub.com. WWW: http://www.skypub.com/. Clear skies!
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=SANA=
Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: National Science Foundation Telescope Sheds Light On Fate Of Universe
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National Science Foundation
Washington, D.C.
Media contacts: Peter West (703) 306-1070 pwest@nsf.gov
Teresa Thomas (412) 268-3580 ts2h+@andrew.cmu.edu
Embargoed until 7 A.M. EDT, December 18, 1998
NSF PR 98-88
NSF Telescope Sheds Light On Fate Of Universe
Researchers from Carnegie Mellon University, using a National Science
Foundation (NSF) microwave telescope in Antarctica, have made a crucial
measurement of cosmic background radiation that may help science to settle a
fundamental question of whether the universe will expand forever or collapse
back upon itself.
Scientists measured the dimensions of extremely distant gas clouds with the
Viper Telescope, operated by the Center for Astrophysical Research (CARA) in
Antarctica at NSF's Amundsen-Scott South Pole Station. Jeffrey Peterson, a
Carnegie Mellon astrophysicist and the lead scientist on the Viper project,
announced the findings on Dec. 18 in Paris, France at the Symposium on
Relativistic Astrophysics. The biennial meeting attracts the world's foremost
astronomers and astrophysicists. "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," according to Peterson. "This delicate balance is hard to
understand unless inflation theory, or something akin to it, is correct."
Viper is used to make images of the faint structure, an anisotropy, seen in
the sky. Astrophysicists widely accept that if the expansion of the universe
were slowing, the glowing clouds of gas observed with Viper would be, in
astronomical terms, relatively close by and would measure as much as one-half
degree of arc across the sky. The discovery announced this week -- that the
size of extremely distant gas clouds is, indeed, one-half degree on the sky
indicates that the expansion of the universe is slowing at just the rate
predicted by inflation theory.
Inflation theory holds that just after the Big Bang, as the universe expanded
and cooled, it passed through a critical temperature, currently thought to be
100 billion degrees -- which changed the character of the laws of physics. As
the proto-universe passed through this critical temperature threshold, there
was an enormous release of energy, which caused the universe to "inflate,' or
to dramatically increase in size. This inflation process would have caused the
universe to expand with a precise "escape velocity," which would provide an
explanation for the Viper findings. The newly released easurements indicate
that the universe has just such an escape velocity, Peterson stressed. The
anisotropy measurement is just a small part of the data collected from the
telescope, which provides a snapshot of the universe as it was 300,000 years
after the Big Bang, the cataclysmic event that set in motion the forces that
created today's universe.
Previous cosmic background telescopes have been smaller than Viper and have
not been able to focus in fine enough detail to measure the clouds as viper
can. However, the CARA group's work with these earlier prototypes was
critical to the new discovery. Karl Erb, the director of NSF's Office of
Polar Programs, said "This advance is a fitting testament to the vision and
dedication of the CARA scientists whose pioneering work proved that the South
Pole is an ideal site for these delicate measurements." The two-meter Viper
telescope began operation only last February.
Further observations by Viper and other telescopes under development by
CARA's member institutions are planned to verify the newly released result.
Andrew Yee
ayee@nova.astro.utoronto.ca
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=SANA=
Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: A New Earth Observation Satellite for Canada (Forwarded)
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Canadian Space Agency
St. Hubert, Quebec
A New Earth Observation Satellite for Canada -- Government of Canada
Successfully Negotiates RADARSAT-2 Agreement With MacDonald Dettwiler
VANCOUVER, BRITISH COLUMBIA, December 18, 1998 -- John Manley, Industry
Minister and Minister responsible for the Canadian Space Agency (CSA),
announced today the conclusion of successful negotiations with MacDonald
Dettwiler (MDA) of Richmond, B.C., to construct and operate a $305 million
satellite system, RADARSAT-2. It is expected that approximately 300 jobs
will be created during the three-year construction phase of the project.
MDA's estimates also indicate that the total number of jobs created will be
approximately 3,500 person-years over what is expected to be a seven-year
project.
"This project will result in the construction of the world's most advanced
Earth observation satellite, scheduled to be launched in November 2001," said
Minister Manley. "RADARSAT-2 is concrete proof of Canada's commitment to a
vigorous knowledge-based economy through the establishment of public-private
sector partnerships," he added. "High-technology projects like this one
will lead our entry in the next millennium, creating jobs tailored to the new
economy. In fact, this is the largest space contract ever awarded in British
Columbia," he concluded.
RADARSAT-2 is the outcome of a ground-breaking financial and management
arrangement. Under the terms of the agreement, the Government of Canada and
MacDonald Dettwiler will invest $225 million and $80 million respectively for
the construction of this satellite system. CSA's contribution to the system
is considered a pre-payment for future government data requirements. The
government will recuperate its financial input through the provision of
RADARSAT-2 imaging data of equivalent value. MacDonald Dettwiler will be
responsible for all ongoing operations and data commercialization.
"MacDonald Dettwiler is very proud to be the chosen industry partner of the
Canadian Space Agency in building RADARSAT-2," said MacDonald Dettwiler CEO,
Dan Friedmann. "This agreement heralds a new era in the field of Canadian
remote sensing. It enables MacDonald Dettwiler to lead Canada into the
competitive worldwide Earth observation market and into developing a
significant value- added information industry."
The RADARSAT satellites are unlike most remote sensing satellites in that
they are able to collect images through the use of a powerful radar which
provides all-climate, all weather conditions imagery of the Earth to clients.
RADARSAT-2's innovations will build on the successes of RADARSAT-1 and offer
improved quality of data images to meet the growing world demand for Earth
observation information. These images have proven to be effective tools in
the management and monitoring of the global environment in areas of ice
navigation, cartography, geological exploration, maritime surveillance,
disaster relief operations, agriculture and forestry surveillance.
Having captured much of the world's market in Earth observation, MacDonald
Dettwiler has set out to build a major company, capable of delivering a broad
range of information products about the Earth to customers around the world.
MacDonald Dettwiler's mandate is to deliver the information and systems
required to monitor the scope of human activities on our planet. The
Canadian Space Agency is committed to leading the development and application
of space knowledge for the benefit of Canadians and humanity.
-30-
FOR FURTHER INFORMATION PLEASE CONTACT:
Canadian Space Agency
Stephane Corbin
Manager, Media and Public Relations
(450) 926-4350 cell:(514) 917-9509
stephane.corbin@space.gc.ca
http://www.space.gc.ca
or
MacDonald Dettwiler
Michael Harding
Director of Public Relations
(604) 231-2262
mharding@mda.ca
http://www.mda.ca
or
Jennifer Sloan
Press Secretary, Office of the Minister of Industry
(613) 995-9001
Andrew Yee
ayee@nova.astro.utoronto.ca
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=SANA=
Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: Astronomers examine brown dwarf's hazy atmosphere (Forwarded)
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New Mexico State University
Las Cruces, New Mexico
December 15, 1998
Astronomers examine brown dwarf's hazy atmosphere
By Karl Hill
Brown dwarfs, sometimes known as failed stars, have a reputation for being
the dim bulbs of the heavens. That's one reason the first real specimen, a
brown dwarf named Gliese 229B, was discovered only three years ago.
But Gliese 229B presented a puzzle to New Mexico State University astronomer
Mark Marley and his colleagues as they studied the strange new object,
because it seemed even darker than expected.
"Brown dwarfs are supposed to be dim, but it was turning out to be much,
much darker than we would have thought in the optical part of the spectrum,"
Marley said.
In a classic example of the high-tech detective work today's astronomers use
to analyze distant objects, Marley and two colleagues have determined that
the brown dwarf suffers from a malady similar to one Los Angeles is famous
for -- a hazy atmosphere. "The compounds are different, but it's like the
red haze you see when you fly into Los Angeles," he said.
While L.A.'s smog is caused by sunlight reacting with auto emissions and
other particles in the air over the city, the brown dwarf's red haze is
thought to be caused by a different sort of chemical reaction. It appears
that gases in the brown dwarf's atmosphere, primarily methane, react with
light from a nearby star that Gl229B orbits, causing them to form more
complicated molecules that clump together to form extremely small drops,
Marley said -- drops about one-hundredth the size of those that form clouds
in the Earth's atmosphere. The drops tend to block the visible light from
the brown dwarf but are transparent in other parts of the spectrum, he said.
Results of the analysis of Gl229B's atmosphere were published in the Dec. 11
issue of Science, the weekly journal of the American Association for the
Advancement of Science. The article was written by Caitlin Griffith of
Northern Arizona University's Department of Physics and Astronomy, Roger
Yelle of Boston University's Center for Space Physics, and Marley, a
planetary scientist in NMSU's Department of Astronomy.
Solving this particular mystery about this particular brown dwarf, Marley
said, adds to scientists' understanding of the universe around us. Since
Gliese 229B was discovered, by a team of Cal Tech and Johns Hopkins
scientists, "there are now dozens of brown dwarfs that have been discovered,
and it's important to understand what their spectra can tell us about them,"
Marley said. "If these guys turn out to be a common part of the universe, we
have to get a basic understanding of what's going on in their atmospheres,
how hot they are, what they're made of."
Brown dwarfs are too small and cool to be stars and too massive to be
planets. Scientists believe they form the same way stars do, but never
accumulate enough mass to sustain nuclear fusion at their cores. They seem
to share some characteristics with giant planets like Jupiter.
Drawing on his research on Jupiter and other planets, Marley has developed
computer models that help astronomers examine newly discovered objects such
as brown dwarfs and planets orbiting stars beyond our solar system. His
collaborators on the latest brown dwarf project have models that complement
his. Using data obtained by the Keck Telescope in Hawaii, they found that
Gliese 229B fit their models in most respects, but not in the optical part
of the spectrum.
The optical part of the spectrum includes light waves that are visible to
the human eye, plus a section of the spectrum between visible light and the
infrared region that is not visible to the human eye. The brown dwarf's
darkness in this part of the spectrum could not be caused by clouds, the
scientists concluded. Its atmosphere is too warm to contain ice clouds like
those on Jupiter and too cool to contain silicate clouds like those on low
mass stars. Also, in parts of the spectrum where the brown dwarf is
brighter, such as the near-infrared part of the spectrum, "the data look
like there are no clouds at all -- a perfectly clear atmosphere," Marley
said.
"So there was this puzzle," he said. "It seemed to be cutting off light in
one region (of the spectrum) but in other areas it looked just fine."
While the astronomers are confident they have solved the puzzle of Gliese
229B's atmosphere, by analysis of its spectrum and an understanding of how
different particles scatter light, the results don't necessarily apply to
other brown dwarfs, Marley said.
"Most of the other brown dwarfs that have been discovered are isolated," he
said. Gliese 229B is orbiting a nearby star, and ultraviolet light from the
star is a factor in the chemical reaction in the brown dwarf's atmosphere.
"And this one is still the coldest one so far," he added -- another factor
in the atmospheric makeup.
Andrew Yee
ayee@nova.astro.utoronto.ca
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=SANA=
Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: Researchers Searching for Light from E.T. (Forwarded)
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Harvard University
3 December 1998
Researchers Searching for Light from E.T.
By Maria Cristina Caballero and John Lenger, Harvard Gazette
If E.T. won't call, maybe he'll shine a light on us instead.
That's the hope of Harvard researchers involved in the search for
extraterrestrial intelligence (SETI) who have unveiled a new experiment
that
involves scanning the heavens for flashes of laser light.
Professor of Physics Paul Horowitz's laboratory recently installed the
experiment at the Harvard-Smithsonian Oak Ridge Observatory in Harvard,
Mass. The optical SETI (or OSETI) experiment has occasionally registered
a signal similar to what one would expect if another civilization's laser
were aimed at us. None of those signals has shown the regular repetitions
that could indicate an intelligent hand behind them; but then, the
researchers have just begun looking. Though such searches for laser lights
from beyond our solar system have been done before, in an isolated and
sporadic way, the Harvard experiment is the first broad-based and systematic
search.
Horowitz has had his ears to the skies for interstellar radio messages for
the past 20 years. He directs Harvard's BETA project, which for the past
three years has searched 600 million channels for radio signals broadcast by
an intelligent civilization. Before BETA there was META, an 8.4
million-channel searching device that went on-line in 1985 and was supported
in part by funds from E.T. director Steven Spielberg. While BETA continues
its radio-wave search in full force, collecting the equivalent of a compact
disc's worth of data every two seconds, none of the radio signals collected
has yet been shown to be of intelligent origin. "After 20 years, maybe it's
time to try something else," Horowitz says.
The idea of analyzing light flashes from distant parts of the galaxy is not
a new one, Horowitz explains. Charles Townes, who shared the Nobel Prize in
Physics in 1964 for his work on masers and lasers, first raised the idea in
a paper co-authored with R.N. Schwartz, "Interstellar and Interplanetary
Communication by Optical Masers," that was published in the journal Nature
in April 1961. But technology developed just within the past five years
finally made it a viable project. "This is very much an experiment of the
'90s," Horowitz says.
The beauty of the new experiment, Horowitz explains, is that flashes of
concentrated light are easy to detect and show up as distinct from other
sources of illumination. If, for instance, Earthlings aim a high-intensity
pulsed laser at a distant star, anyone watching from that star with a
moderate-sized telescope will suddenly see a flash 1,000 times brighter
than the light of our Sun -- "an efficient interstellar beacon."
And since the brightness of starlight and laser light both decrease at the
same rate, that particular high-intensity laser beam shot from Earth would
always be 1,000 times brighter than the light from our Sun, no matter how
far it travels.
Reversing the direction, any extraterrestrial flash pointed the way of Earth
would be easily distinguishable from the light of a distant star. That could
make pulsed light the preferred method for communicating across galactic
distances instead of radio waves. If you remember childhood games involving
walkie-talkies and messages communicated by flashlight beams, you'll recall
that flashlight beams were much more reliable than static-filled
walkie-talkie transmissions, if not as dramatic.
Horowitz, who has long been an optimist regarding the idea of
extraterrestrial civilizations, cautions, however, that, "Maybe they're
using 'zeta rays' to communicate, and the problem is we haven't discovered
zeta rays yet."
Still, the elegance and simplicity of the new laser-detection experiment is
appealing. BETA took four years to build (at a cost of hundreds of thousands
of dollars), involves enough high-end computer equipment to fill a large
truck, and uses an 84-foot radio telescope. The OSETI equipment, funded by
the Planetary Society, the SETI Institute, and the Bosack-Kruger Charitable
Foundation, was put together in three months by Horowitz and fellow
researchers Jonathan Wolff, Chip Coldwell, and Costas Papaliolios at a cost
of less than $10,000.
"It fit in the back seat of my Corolla," Horowitz says, describing the
monitoring device as being as big as a box "for a large loaf of bread." It
uses leftover light from a 61-inch telescope that already was engaged in a
survey of 2,500 nearby solar-type stars, an experiment run by researchers
Joe Caruso, David Latham, Robert Stefanik, and Joe Zajac.
The simplicity of the new OSETI equipment means the experiment could easily
be duplicated elsewhere. Researchers at the University of California at
Berkeley, who have done some preliminary looking, are setting up an optical
SETI experiment along the same lines, and their experiment will be
operational soon.
A more detailed description of Harvard's optical SETI experiment is on-line
at http://mc.harvard.edu/hgroup.html, and contains a call for the SETI
research community "to consider alternative OSETI strategies -- choice of
wavelength, pulse widths and repetition rates, revisit times, etc. -- in an
attempt to identify a particularly compelling a priori strategy, involving
both sender and receiver, that could be the basis for major Earth-based
OSETI receiving efforts in the near term."
Optical SETI is an added tool for searching the heavens that has emerged
just as the more traditional searches of radio frequencies are getting
tougher. Darren Leigh, a recent Harvard Ph.D. in applied physics who
oversees the BETA project, says that cellular phones in particular have made
it harder to hear signals from outer space. As satellite transmissions
increase, Leigh says, we are confronted by the possibility that our interest
in talking with each other might mean less chance of hearing a call from
extraterrestrials.
Horowitz is optimistic about the optical SETI project, but 20 years of
waiting have made him cautious. "I'll be excited when we get results," he
says.
PHOTO CAPTIONS:
[http://www.news.harvard.edu/science/current_stories/3.Dec.98/
seti.3.dec.98.html]
[Image 1]
Part of the experiment's crew poses with the telescope being used for the
SETI experiment. From left to right are researchers Costas Papaliolios,
Chip Coldwell, Paul Horowitz, and Jonathan Wolff. A more detailed
description of Harvard's optical SETI experiment is online
[http://mc.harvard.edu/hgroup.html].
[Image 2]
The OSETI equipment fit in Horowitz's Corolla; Jonathan Wolff (above) built
most of the device.
Andrew Yee
ayee@nova.astro.utoronto.ca
Hа сегодня все, пока!
=SANA=
Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: Latest NEAR news not good
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From mission control center ...
Update on Aborted Burn
At 5:20 p.m. today, Dec. 21, the NEAR mission team is still trying to
reestablish communications with the spacecraft. Communications ceased at about
5:10 p.m. EST, Sunday, Dec. 20, during the first of four rendezvous burns that
would put the spacecraft at optimum speed and location for a Jan. 10, 1999,
rendezvous with asteroid 433 Eros.
Doppler data collected at about 5:40 p.m. Dec. 20, leads team members to
believe that the spacecraft was transmitting at that time. Around-the-clock
strategy sessions are being held to correct the problem. If communications are
not established by midnight tonight it is highly unlikely that the spacecraft
will go into orbit on January 10.
Because of the robust nature of the spacecraft design many alternatives are
available to the team to ensure that the mission can weather schedule changes
and still yield significant science return. Those alternatives will be reviewed
once communications have been reestablished.
Hа сегодня все, пока!
=SANA=
Дата: 22 декабря 1998 (1998-12-22)
От: Alexander Bondugin
Тема: Mars Climate Orbiter Update - December 21, 1998
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MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov
Mars Climate Orbiter Mission Status
December 21, 1998
Mars Climate Orbiter successfully completed its first
trajectory correction maneuver at 1:33 p.m. Pacific Standard Time
today to fine-tune its flight path. This maneuver removed a bias
intentionally set by the vehicle that was designed to prevent the
third stage of the Delta II launch vehicle from tagging along and
colliding with Mars. It also removed a small launch injection
error, putting the orbiter on course for its capture into orbit
around Mars on September 23, 1999.
The spacecraft began the turn to align its thrusters to the
desired direction at 1:19 p.m. PST, fired the thrusters for 2.8
minutes, then turned back to its original orientation so that its
solar panels would continue to generate electrical power. The
maneuver changed the spacecraft's velocity by just 19.1 meters
per second (42.7 miles per hour). This very slight change in
flight course and velocity indicated the high degree of accuracy
achieved during launch on December 11.
Now on its way to Mars, the orbiter is in excellent health.
An onboard software program recently uplinked to the spacecraft
is regulating its thermal control and power requirements, as well
as monitoring other subsystems. A health check of the Mars Color
Imager and opening of the cooler door on the Pressure Modulator
Infrared Radiometer are planned for Wednesday, December 23.
Mars Climate Orbiter is currently about 2.87 million
kilometers (1.75 million miles) from Earth, traveling at a
velocity of about 11,950 kilometers per hour (7,290 miles per
hour) relative to Earth.
#####
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