Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: Dan Goldin, Hillary Rodham Clinton Join Trans-Atlantic Classroom
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Roderic Olvera Young
Headquarters, Washington, DC May 11, 1998
(Phone: 202/358-4726)
NOTE TO EDITORS: N98-33
NASA ADMINISTRATOR GOLDIN IN WASHINGTON, DC, AND
FIRST LADY IN PARIS JOIN TRANS-ATLANTIC CLASSROOM
Using the Internet, First Lady Hillary Rodham Clinton and
students at the Ecole Nationale de Chimie, Physique et Biologie in
Paris will talk to NASA Administrator Daniel S. Goldin and
students at Kramer Middle School in Washington, DC. The American
and French space agencies at 9:00 a.m. EDT, Wednesday, May 13,
will connect students in Washington, DC, New York, and Paris.
Students will share groundwater and vegetation data collected
using the CERES satellite and lead each other on tours of their
respective cities.
Building on extensive cooperation in space research, NASA and
the Centre National d'Etudies Spatiales (CNES) are forging an
international educational program that capitalizes on the wonder
and excitement of space. The First Lady and Goldin also seek to
address recent studies that show U.S. students lagging behind in
science and mathematics.
Event: First Lady Hillary Rodham Clinton and NASA Administrator
Join Students in Trans-Atlantic Internet Classroom
Where: Kramer Middle School, 1700 Q St., SE, Washington, DC
Principal, Nancy Berry
202/645-3520
When: Wednesday, May 13, 1998
9 am to 10 am EDT
-end-
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: WDC-A R&S Launch Announcement 12939: NOAA-K
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COSPAR/ISES
WORLD WARNING AGENCY FOR SATELLITES
WORLD DATA CENTER-A FOR R & S, NASA/GSFC
CODE 633, GREENBELT, MARYLAND, 20771. USA
SPACEWARN 12939
COSPAR/WWAS USSPACECOM NUMBER
SPACECRAFT INTERNATIONAL ID (CATALOG NUMBER) LAUNCH DATE,UT
NOAA-K 1998-030A 25338 13 MAY 1998
DR. JOSEPH H. KING, DIRECTOR, WDC-A-R&S.
[PH: (301) 286 7355.
E-MAIL: KING@NSSDCA.GSFC.NASA.GOV
14 MAY 1998, 14:00 UT]
Further details will be in the next SPACEWARN Bulletin
Dr. Edwin V. Bell, II
_/ _/ _/_/_/ _/_/_/ _/_/_/ _/_/ Mail Code 633
_/_/ _/ _/ _/ _/ _/ _/ _/ NASA Goddard Space
_/ _/ _/ _/_/ _/_/ _/ _/ _/ Flight Center
_/ _/_/ _/ _/ _/ _/ _/ _/ Greenbelt, MD 20771
_/ _/ _/_/_/ _/_/_/ _/_/_/ _/_/ +1-301-286-1187
ed.bell@gsfc.nasa.gov
SPACEWARN home page: http://nssdc.gsfc.nasa.gov/spacewarn/
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: Hughes Satellite Orbits Moon, Heads Back To Earth
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HUGHES GLOBAL SERVICES, INC.
Communications and Customer Relations
P.O. Box 92919 (S10/S323)
Los Angeles, CA 90009
Media Relations (310) 364-6363
Investor Relations (310) 662-9688
www.hughesglobal.com
HUGHES SATELLITE ORBITS MOON, HEADS BACK TO EARTH
LOS ANGELES, May 13, 1998 -- The HGS-1 spacecraft became the first
commercial communications satellite to orbit the moon, passing behind it at
noon PDT today to grab a boost from lunar gravity and hurtle back toward
Earth.
Engineers at the Hughes Mission Control Center in El Segundo, Calif., will
begin braking maneuvers Saturday to guide the arriving spacecraft into orbit
around the equator.
HGS-1 is a high-power satellite built by Hughes Space and Communications
Company of Los Angeles, and owned by its subsidiary, Hughes Global Services,
Inc. (HGS). It was designed to provide television and other
telecommunications services for Asia and neighboring regions.
During launch last Christmas Day, however, the rocket that was carrying it
malfunctioned, leaving the satellite in an unusable, highly inclined,
elliptical orbit. The original owner of the spacecraft filed an insurance
claim, and the insurers declared the mission a total loss for its original
purposes.
Hughes scientists and engineers weren't ready to give up on the fully
functional satellite, however. They devised a salvage mission using the
moon's gravity to reposition the satellite into a usable circular orbit
22,300 miles above the equator, called geosynchronous orbit. It is the first
known lunar mission involving a communications satellite and the first lunar
mission financed by a non-governmental entity. If Hughes can put the HS
601HP model satellite into a useful revenue-generating orbit, it has agreed
to share profits with the insurers.
HGS-1 began its lunar encounter at 11:52 a.m. PDT today. Occultation -- the
period during which it was behind the moon and out of radio contact with
ground controllers -- lasted until 12:20 p.m. The satellite came within
3,883 miles of the moon's surface -- called perilune -- at 12:55 p.m. It's
now on a 3-day return trip to Earth.
Over the next three days, Hughes controllers will prepare the satellite for
a retro burn that will slow HGS-1 as it approaches geosynchronous orbit. The
spacecraft is expected to execute the maneuvers around 8 p.m. PDT Saturday.
Controllers are using satellite ground stations, optical telescopes and
radar facilities around the world to track the spacecraft.
Hughes began the mission April 10, firing the satellite's onboard rocket
motor several times to raise its altitude. The 12th firing was May 7, giving
HGS-1 its final kick toward the moon.
Hughes Space and Communications, a unit of Hughes Electronics Corporation,
has been building communications and scientific spacecraft and instruments
for more than 35 years. It is the world leader in manufacturing commercial
geostationary communications satellites. Hughes Global Services packages
commercial satellite services for government and military customers. HGS
also works with other Hughes Electronics companies to provide end-to-end
solutions for underserved commercial markets. PanAmSat Corporation, of which
Hughes Electronics is the majority owner, has been providing critical
command and tracking support for the mission through its teleport in
Fillmore, Calif. The earnings of Hughes Electronics are used to calculate
the earnings per share attributable to GMH (NYSE symbol) common stock.
###
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: SJI's Sky And Space Update - May 1, 1998
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SAN JUAN INSTITUTE'S SKY AND SPACE UPDATE
Summary information about the night sky and recent findings and events
in solar system exploration and science. Updated every 2 weeks.
LAST UPDATED: FRI. MAY 1, 1998
Prepared by: Dr. Bruce Betts and Andre Bormanis
OBJECTS TO LOOK FOR IN THE NIGHT SKY (MID-NORTHERN LATITUDES)
MERCURY is visible just before dawn low in the east-northeast, looking
like a dim star.
VENUS is visible in the east in the pre-dawn sky, looking like an
extremely bright star.
MARS, not visible in the night sky, passes through conjunction with the
Sun on May 12.
JUPITER lies to the upper right of Venus before dawn, looking like a
bright star.
SATURN is just barely visible above the eastern horizon before dawn, to
the lower left of Venus, looking like a pale yellow star. It lies within
one degree of Mercury on the mornings of May 12 and May 13.
THE MOON
First Quarter Moon occurs May 3 at 2:04 a.m. PDT (UT - 7 hours).
Full Moon occurs May 11 at 6:29 a.m. PDT. This month's full Moon is
called the Milk or Planting Moon and the Moon of the Shedding Ponies.
THE IRIDIUM FLASH
A new family of communication satellites built by Motorola is producing
an interesting night-sky phenomenon. The Iridium satellite constellation
will eventually consist of 66 satellites orbiting the Earth in six
evenly-spaced orbital planes (about 50 of the satellites have been launched
so far). The satellites are designed to provide world-wide digital
communication services.
As the satellites circle the Earth, their antenna arrays occasionally
turn at an angle that flashes a beam of sunlight toward the ground. These
so-called "Iridium flashes" are sometimes, for a few seconds, significantly
brighter than the planet Venus! Several times a week, from any given
location, Iridium flashes of varying brightness should be visible just after
dusk or just before dawn.
The timing and brightness of the flashes strongly depends on your
geographic location. You can find out when flashes will be visible in your
area on the World Wide Web. Point your web browser to
http://www.gsoc.dlr.de/satvis/. The site will prompt you for the name of
your city, or your latitude and longitude.
EUROPA DAY
A "Day on Europa" will take place on May 20 and 21, sponsored by the
Jet Propulsion Lab in Pasadena, CA, including the Galileo mission currently
in orbit around Jupiter. Europa Day will be a series of free public and
educational activities focusing on current and future exploration of Europa,
and its potential for an ocean of water under its icy crust, and that
ocean's potential for life. A panel discussion held at Caltech on May 21
will be available on the Internet via video on the Internet and via
satellite broadcast. There are also numerous events scheduled across the
U.S. For additional details, see:
http://www.jpl.nasa.gov/galileo/europaday/
PLANETARY SPACECRAFT UPDATE
CASSINI: The Cassini spacecraft passed within 284 kilometers of the
planet Venus on Sunday, Apr. 26. Cassini used this close encounter with the
second planet from the Sun to increase its speed in a maneuver called a
'gravity assist.' As Cassini zoomed past Venus, the planet's gravitational
pull acted like a slingshot, giving the spacecraft additional momentum. The
encounter increased the speed of Cassini by some 26,000 kilometers per hour.
Cassini pointed several of its science instruments toward Venus during
its Sunday fly-by. All instruments functioned as expected. A second Venus
fly-by is scheduled for Jun. 24 of next year, to be followed by an Earth
gravity assist in Aug. 1999, and a Jupiter assist in the year 2000. By
stealing a little of each planet's orbital momentum, Cassini will be able to
cover the 3.5 billion kilometer journey to Saturn in just 7 years. Cassini
is currently traveling at 140,000 kilometers per hour.
SOHO: Data from the SOHO (Solar and Heliospheric Observatory)
spacecraft suggest that the Sun sometimes ejects blobs of hot solar plasma
into space in 'spasms' that resemble human coughing, and also experiences
'solar tornadoes.'
SOHO's Large Angle Spectrometric Coronograph monitors the Sun's tenuous
outer atmosphere, called the corona. Using this instrument, scientists have
observed that large-scale eruptions of solar gas, called coronal mass
ejections, can trigger a chain reaction that leads to a series of plasma
ejections. This process is similar to the muscular spasms in the human
throat that trigger fits of coughing.
Electrical engineers are particularly interested in coronal mass
ejections because these clouds of electrically charged particles travel
through space and occasionally interact with the Earth's magnetic field.
These interactions frequently disrupt electrical distribution grids on the
ground, triggering power failures. Coronal mass ejections can also damage
Earth orbiting satellites.
SOHO also observed eruptions of solar plasma that formed twisting,
funnel-shaped vortices above the solar photosphere. These tornado-like
structures featured shear velocities clocked at 536,000 kilometers per hour
-- a thousand times the velocity of winds in the most ferocious tornadoes on
Earth.
SOHO, launched in 1995, is a joint mission of NASA and the European
Space Agency (ESA). For more information on current U.S. and other
planetary science missions, see the NASA website http://www.jpl.nasa.gov.
For more information on ESA missions, see the ESA website
http://www.esrin.esa.it/.
THESE WEEKS IN SPACE HISTORY
MAY 1, 1949: Neptune's moon Nereid was discovered by American
astronomer Gerard Kuiper.
MAY 5, 1961: Alan Shepard becomes the first American in space during a
fifteen minute sub-orbital flight.
RANDOM SPACE FACT
William Herschel, who discovered Uranus in 1781, tried unsuccessfully to
name his discovery "Georgian Sidus" after King George III; instead, the
planet was named by Johann Bode in 1781 for the father of Saturn.
*****************************************************************************
The San Juan Institute (SJI) is a 501(c)(3) non-profit corporation
headquartered in San Juan Capistrano, CA with divisions there and in Tucson,
AZ. SJI carries out research and education in planetary and Earth sciences
and astronomy, with funding provided by government grants and private
donations, which are always needed. Partial funding for the SSU has been
provided by NASA's Office of Space Science.
San Juan Capistrano Research Institute Ph: 714-240-2010, Fax: 714-240-0482
31882 Camino Capistrano, Suite 107 Email: educate@sji.org
San Juan Capistrano, CA 92675 Web site: http://www.sji.org
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: Hubble Provides Multiple Views Of How To Feed A Black Hole
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May 14, 1998
CONTACT: Douglas Isbell
Headquarters, Washington, DC
(Phone: 202/358-1753)
Ray Villard
Space Telescope Science Institute, Baltimore, MD
(Phone: 410/338-4514)
PRESS RELEASE: STScI-PR98-14
HUBBLE PROVIDES MULTIPLE VIEWS OF HOW TO FEED A BLACK HOLE
Astronomers have obtained an unprecedented look at the nearest example
of galactic cannibalism -- a massive black hole hidden at the center of a
nearby giant galaxy that is feeding on a smaller galaxy in a spectacular
collision. Such fireworks were common in the early universe, as galaxies
formed and evolved, but are rare today.
Although the cause-and-effect relationships are not yet clear, the views
provided by complementary images from two instruments aboard NASA's
Hubble Space Telescope are giving astronomers new insights into the
powerful forces being exerted in this complex maelstrom. Researchers
believe these forces may even have shifted the axis of the massive black
hole from its expected orientation.
The Hubble wide-field camera visible image of the merged Centaurus A
galaxy, also called NGC 5128, shows in sharp clarity a dramatic dark
lane of dust girdling the galaxy. Blue clusters of newborn stars are
clearly resolved, and silhouettes of dust filaments are interspersed with
blazing orange-glowing gas. Located only 10 million light-years away,
this peculiar-looking galaxy contains the closest active galactic nucleus
to Earth and has long been considered an example of an elliptical galaxy
disrupted by a recent collision with a smaller companion spiral galaxy.
Using the infrared vision of Hubble, astronomers have penetrated this
wall of dust for the first time to see a twisted disk of hot gas swept up
in the black hole's gravitational whirlpool. The suspected black hole is
so dense it contains the mass of perhaps a billion stars, compacted into
a small region of space not much larger than our Solar System.
Resolving features as small as seven light-years across, Hubble has shown
astronomers that the hot gas disk is tilted in a different direction from the
black hole's axis -- like a wobbly wheel around an axle. The black hole's
axis is identified by the orientation of a high-speed jet of material,
glowing
in X-rays and radio frequencies, blasted from the black hole at 1/100th the
speed of light.
This gas disk presumably fueling the black hole may have formed so
recently it is not yet aligned to the black hole's spin axis, or it may
simply be influenced more by the galaxy's gravitational tug than by
the black hole's.
"This black hole is doing its own thing. Aside from receiving fresh fuel
from a devoured galaxy, it may be oblivious to the rest of the galaxy and
the collision," said Ethan Schreier of the Space Telescope Science
Institute, Baltimore, MD. Schreier and an international team of
co-investigators used Hubble's Near Infrared Camera and Multi-Object
Spectrometer to probe deeper into the galaxy's mysterious heart than
anyone has before.
The hot gas disk viewed by Hubble investigators is perpendicular to the
galaxy's outer dust belt, while the black hole's own internal accretion
disk of superhot gas falling into it is tilted approximately diagonally to
these axes.
"We have found a complicated situation of a disk within a disk within
a disk, all pointing in different directions," Schreier said. It is not clear
if the black hole was always present in the host galaxy or belonged to
the spiral galaxy that fell into the core, or if it is the product of the
merger of a pair of smaller black holes that lived in the two
once-separate galaxies.
Having an active galaxy just 10 million light-years away from Earth
rather than hundreds of millions or billions of light-years distant
offers astronomers a unique laboratory for understanding the elusive
details of the behavior of supermassive black holes as fueled by galaxy
collisions.
"Though Hubble has seen hot gas disks around black holes in other
galaxies, the infrared camera has for the first time allowed us to peer
at this relatively nearby, very active, but obscured black hole region,"
Schreier added.
The team of astronomers is awaiting further Hubble data to continue its
study of the disk, as well as ground-based spectroscopic observations to
measure the velocity of entrapped material around the black hole. This
will allow the astronomers to better calculate the black hole's mass.
The current results are scheduled to appear in the June 1, 1998 issue of
Astrophysical Journal Letters.
Images and further information related to these results are available on the
Internet at the following URLs:
http://oposite.stsci.edu/1998/14
http://oposite.stsci.edu/pubinfo/latest.html or
http://oposite.stsci.edu/pubinfo/pictures.html
GIF and JPEG images are available via anonymous ftp to oposite.stsci.edu
in /pubinfo/jpeg/9814a.jpg, /pubinfo/jpeg/9814.jpg, /pubinfo/gif/9814a.gif
and /pubinfo/gif/9814b.gif.
The Space Telescope Science Institute is operated by the Association of
Universities for Research in Astronomy, Inc. (AURA) for NASA, under
contract with the Goddard Space Flight Center, Greenbelt, MD.
The Hubble Space Telescope is a project of international cooperation
between NASA and the European Space Agency (ESA).
*************************************
PHOTO CAPTIONS:
EMBARGOED UNTIL: 1:00 P.M. (EDT) MAY 14, 1998
PHOTO NO.: STScI-PRC98-14a
TURBULENT CAULDRON OF STARBIRTH IN
NEARBY ACTIVE GALAXY
NASA's Hubble Space Telescope offers a stunning unprecedented
close-up view of a turbulent firestorm of starbirth along a nearly edge-on
dust disk girdling Centaurus A, the nearest active galaxy to Earth.
A ground-based telescopic view (upper left insert) shows that the dust
lane girdles the entire elliptical galaxy. This lane has long been
considered the dust remnant of a smaller spiral galaxy that merged
with the large elliptical galaxy. The spiral galaxy deposited its gas
and dust into the elliptical galaxy, and the shock of the collision
compressed interstellar gas, precipitating a flurry of star formation.
Resembling looming storm clouds, dark filaments of dust mixed with
cold hydrogen gas are silhouetted against the incandescent yellow-orange
glow from hot gas and stars behind it.
Brilliant clusters of young blue stars lie along the edge of the dark
dust rift. Outside the rift the sky is filled with the soft hazy glow of the
galaxy's much older resident population of red giant and red dwarf stars.
The dusty disk is tilted nearly edge-on, its inclination estimated to be only
10 or 20 degrees from our line-of-sight. The dust lane has not yet had
enough time since the recent merger to settle down into a flat disk. At this
oblique angle, bends and warps in the dust lane cause us to see a rippled
"washboard" structure.
The picture is a mosaic of two Hubble Space Telescope images taken with
the Wide Field Planetary Camera 2, on Aug. 1, 1997 and Jan. 10, 1998.
The approximately natural color is assembled from images taken in blue,
green and red light. Details as small as seven light-years across can be
resolved. The blue color is due to the light from extremely hot, newborn
stars. The reddish-yellow color is due in part to hot gas, in part to older
stars in the elliptical galaxy and in part to scattering of blue light by
dust
-- the same effect that produces brilliant orange sunsets on Earth.
Centaurus A (NGC 5128) Fast Facts:
Right Ascension: 13: 25.5 (hours : minutes)
Declination: -43 : 01 (degrees : minutes)
Apparent Magnitude: 7.0
Apparent Diameter: 18.2 (arc minutes)
Distance: 10 million light-years
Constellation: Centaurus (southern sky)
Hubble image credit: E.J. Schreier, (STScI) and NASA
Team members are: E.J. Schreier, A. Marconi, D. Axon,
N. Caon, and D. Macchetto (STScI)
Groundbased image credit: NOAO
*****************************************************
EMBARGOED UNTIL: 1:00 P.M. (EDT) May 14, 1998
PHOTO NO.: STScI-PRC98-14b
CENTAURUS A: THE INSIDE STORY
Astronomers have used NASA's Hubble Space Telescope to probe the
core of the nearest active galaxy to Earth, Centaurus A.
[UPPER LEFT] - A close-up high resolution Wide Field Planetary Camera 2
image of the dramatic dust disk which is thought to be the remnant of a
smaller spiral galaxy that merged with the large elliptical galaxy. The shock
of the collision compressed interstellar gas, precipitating a flurry of star
formation and giving the material a fleecy pattern. Dark filaments of dust
mixed with cold hydrogen gas are silhouetted against the incandescent
yellow-orange glow from stars behind it.
[LOWER RIGHT] - Hubble's Near Infrared Camera and Multi-Object
Spectrometer was used to peer past the dust to discover a tilted disk of
hot gas at the galaxy's center (white bar running diagonally across
image center). This 130 light-year diameter disk encircles a suspected
black hole which may be one billion times the mass of our Sun. The disk
feeds material to presumably an inner, unresolved accretion disk that
is made up of gas entrapped by the black hole. The red blobs near the
disk are glowing gas clouds which have been heated up and ionized by
the powerful radiation from the active nucleus.
The false-color NICMOS image was taken on Aug. 11, 1997 at a
wavelength of 1.87 microns ("Paschen alpha"), characteristic of
ionized Hydrogen.
Centaurus A (NGC 5128) Fast Facts
Right Ascension: 13 : 25.5 (hours : minutes)
Declination: -43 : 01 (degrees : minutes)
Apparent Magnitude: 7.0
Apparent Diameter: 18.2 (arc minutes)
Distance: 10 million light-years
Constellation: Centaurus (southern sky)
Credit: E.J. Schreier, (STScI) and NASA
Team members are: Ethan J. Schreier, Alessandro Marconi,
David J. Axon, Nicola Caon, Duccio Macchetto ( STScI),
Alessandro Capetti - (Osservatorio Astronomico di Torino, Italy),
James H. Hough, Stuart Young ( University of Hertfordshire, UK), and
Chris Packham (Isaac Newton Group, Islas Canarias, SPAIN)
***********************************************************
ASTROFILE:
KEY EVENTS IN THE HISTORY OF CENTAURUS A
1847: Sir John Herschel was the first to report observations of what we now
know as NGC 5128, or its radio name Centaurus A. In his "Outlines of
Astronomy," published in 1849, Herschel described it as "two semi-ovals
of elliptically formed nebula appearing to be cut asunder and separated
by a broad obscure band parallel to the larger axis of the nebula, in
the midst of which a faint streak of light parallel to the sides of the
cut appears."
1848-1949: Despite Herschel's observation, astronomers paid little
attention to Centaurus A for about 100 years because they considered it
another one of those nebulous, fuzzy objects originally thought to be in
our own galaxy. Even Edwin Hubble called it a nebulous object. Later
astronomers with more powerful telescopes identified many of these
objects as galaxies. Centaurus A also was largely ignored because of the
lack of large optical telescopes in the southern hemisphere, where this
galaxy can be seen.
1949: Astronomers had just developed another technique to study
celestial objects besides optical light: special instruments to collect
radio waves. Using an 80-foot radio antenna at Dover Heights, Australia
and radio waves reflected off the nearby sea, astronomers John Bolton,
G. Stanley, and Bruce Slee were the first to identify Centaurus A as a
powerful radio galaxy. Radio waves from Centaurus A were among the
first to be linked to an extragalactic object.
1954: Studying Centaurus A with telescopes at Palomar Observatory in
California, Walter Baade and Rudolph Minkowski confirmed that it is a
galaxy. The pair also proposed that the peculiar structure of Centaurus
A - with a bar of dark dust bisecting the galaxy - is the result of a
merger between two galaxies, a giant elliptical and a small spiral.
1969-1971: Stuart Bowyer, using a sounding rocket, detected X-rays
emanating from Centaurus A. In late 1970, the UHURU satellite
confirmed that the X-rays were indeed associated with the galaxy.
In 1971, Bill Kunkel and Hale Bradt used a telescope at the
Cerro Tololo Inter-American Observatory (CTIO) in Chile to observe
infrared light originating from a compact source in the galaxy's core.
X-ray observations in the early 1970s with the Astronomical
Netherlands Satellite (ANS) and the Orbiting Solar Observatory
(OSO-7) showed changes in the intensity of X-ray emissions.
Significant changes over a very short time indicated that the
emission source was confined to a small region of space. The results
suggested that a black hole could be the culprit.
1975: Looking at the galaxy in visible light with a CTIO telescope,
Victor Blanco discovered a faint jet out in the galaxy. He also noted
blue stellar objects in this region.
1975-76: Using information from the SIGMA satellite and high-flying
research balloons, Josh Grindlay and R.D. Hall detected gamma ray
emissions which were probably coming from the nucleus.
Late 1970s: John Graham, using a CTIO telescope, found a series of
faint shells of gas in the outer regions of the galaxy. These shells
could have been produced by collisions of gas from a galaxy merger.
1979: Using the Einstein Observatory, Ethan Schreier discovered an
X-ray jet emanating from the nucleus of Centaurus. A. Working with
Eric Feigelson and Jack Burns, Schreier used the Very Large Array in
New Mexico to find the jet's radio counterpart.
1981: With the Einstein Observatory, Schreier and Feigelson also
observed extended X-ray emissions in the galaxy, including ridges of
emissions along the north and south edges of the dust lane.
1996: Schreier used the Hubble Space Telescope's Wide Field and
Planetary Camera 2 (WFPC2) to study the dust lane's polarization
properties and the distribution of young stars along its northern edge.
The young, blue stars provided further proof that Centaurus A,
an elliptical galaxy, merged with a spiral galaxy. Elliptical galaxies
such as Centaurus A would not have had enough dust and gas to
form clusters of new stars.
1997: Kenneth Kellermann, Anton Zensus, and Marshall Cohen, using
the Very Long Baseline Array (VLBA) in New Mexico, observed that
the core of Centaurus A is only 10 light-days across, making it the
smallest known extragalactic radio source. They also noted that the
energy produced by this source varies in intensity every day. This core
has a mass of about 100 million suns.
1997-98: Schreier used WFPC2 to further examine the nucleus and the
bright, young stars. Since WFPC2 cannot peer through the dusty core,
Schreier and Alessandro Marconi turned to the Hubble telescope's Near
Infrared Camera and Multi-Object Spectrometer (NICMOS) to explore
the core. They found a very compact nucleus and also discovered a
central, warped disk. The disk could have been warped by a collision
with another galaxy.
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: Galileo Update - May 14, 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
Galileo Europa Mission Status
May 14, 1998
The Galileo spacecraft has spent the week processing and
transmitting to Earth pictures and science information gathered
during its March 29 flyby of Jupiter's moon Europa. The material
had been stored on the spacecraft's onboard tape recorder.
Some of the information would have been transmitted last
week, but it was delayed in the name of science when the Galileo
team gave up some antenna time at the Deep Space Network's 70-
meter (230-foot) antenna in Canberra, Australia. The antenna was
needed to support radio frequency observations of a newly
identified gamma ray burst.
Included in this week's batch of information transmitted to
Earth by Galileo are two images of a region of Europa notable for
its dark spots. Together, these images provide a stereo
topographic view of the area. Another observation measures the
varying light intensities on Europa, information which helps
scientists identify different surface materials. An observation
from Galileo's near-infrared spectrometer should provide more
information on the materials that make up the region of Europa
which has dark spots and pull-apart wedge sections.
The spacecraft is sending back previously recorded
information that will beef up knowledge of the interaction
between Jupiter's magnetic and electric fields and Europa.
Last week, the Galileo team modified the spacecraft's
onboard attitude control software. However, the adjustment did
not change the gyroscope's behavior as the team had hoped. A
second modification was made Wednesday, May 13, and early tests
indicate that the procedure was a success. Another gyro
performance test is scheduled this Friday, May 15, and the
Galileo team expects it will confirm that the attitude control
system is now performing as planned. The attitude control system
has been behaving anomalously since the spacecraft's closest
flyby to Europa last December 16. The Galileo team has been able
to operate the spacecraft in such a way that the anomaly has had
very little effect on the spacecraft's performance. Nonetheless,
engineers continue to analyze the situation, which they believe
is related to the spacecraft's repeated exposure to Jupiter's
strong radiation.
Galileo's next Europa flyby will take place on May 31, 1998,
at an altitude of 2,521 kilometers (1,566 miles). The spacecraft
successfully completed its primary mission in December 1997 and
is now in its two-year extension, the Galileo Europa Mission.
Current plans include four more Europa flybys after the May
encounter, four Callisto flybys, and one or two of Io, depending
on spacecraft health.
#####
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: Mars Surveyor 98 Update - May 15, 1998
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1998 MARS SURVEYOR PROJECT STATUS REPORT
May 15, 1998
John McNamee
Mars Surveyor 98 Project Manager
Orbiter integration and test activities are proceeding on schedule.
Mission system testing of the mapping phase is in progress. The Mars Color
Imager (MARCI) flight instrument has been removed from the orbiter to allow
upgrading of the color filter array. Troubleshooting of the various
Pressure Modulator InfraRed Radiometer (PMIRR) anomalies continues. The
PMIRR chopper motor is scheduled for removal from the instrument on May 19
for troubleshooting at the vendor (Honeywell).
Lander integration and test activities are proceeding on schedule. The
lander was moved into the thermal vacuum chamber on May 11 and chamber pump
down for cruise configuration thermal vacuum testing will begin on May 16.
For more information on the Mars Surveyor 98 mission, please visit this
website:
http://mars.jpl.nasa.gov/msp98/
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: WDC-A R&S Launch Announcement 12940: Progress M-39
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COSPAR/ISES
WORLD WARNING AGENCY FOR SATELLITES
WORLD DATA CENTER-A FOR R & S, NASA/GSFC
CODE 633, GREENBELT, MARYLAND, 20771. USA
SPACEWARN 12940
COSPAR/WWAS USSPACECOM NUMBER
SPACECRAFT INTERNATIONAL ID (CATALOG NUMBER) LAUNCH DATE,UT
PROGRESS M-39 1998-031A 25340 15 MAY 1998
DR. JOSEPH H. KING, DIRECTOR, WDC-A-R&S.
[PH: (301) 286 7355.
E-MAIL: KING@NSSDCA.GSFC.NASA.GOV
15 MAY 1998, 15:45 UT]
Further details will be in the next SPACEWARN Bulletin
Dr. Edwin V. Bell, II
_/ _/ _/_/_/ _/_/_/ _/_/_/ _/_/ Mail Code 633
_/_/ _/ _/ _/ _/ _/ _/ _/ NASA Goddard Space
_/ _/ _/ _/_/ _/_/ _/ _/ _/ Flight Center
_/ _/_/ _/ _/ _/ _/ _/ _/ Greenbelt, MD 20771
_/ _/ _/_/_/ _/_/_/ _/_/_/ _/_/ +1-301-286-1187
ed.bell@gsfc.nasa.gov
SPACEWARN home page: http://nssdc.gsfc.nasa.gov/spacewarn/
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: Cassini Update - May 15, 1998
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CASSINI SIGNIFICANT EVENTS FOR WEEK ENDING 05/15/98
Spacecraft Status:
The Cassini spacecraft is presently traveling at a speed of
approximately 142,000 kilometers/hour (~88,000 mph) relative to the sun
and has traveled approximately 607 million kilometers (~377 million
miles) since launch on October 15, 1997.
The most recent Spacecraft status is from the DSN tracking pass on
Wednesday, 05/13, over Goldstone. The Cassini spacecraft is in an
excellent state of health and has successfully completed execution of
the C7 sequence. The C8 sequence is now on board and is executing
nominally.
Inertial attitude control is being maintained using the spacecraft's
hydrazine thrusters (RCS system). The spacecraft continues to fly in a
High Gain Antenna-to-Sun attitude. It will maintain the HGA-to-Sun
attitude, except for planned trajectory correction maneuvers, for the
first 14 months of flight.
Communication with Earth during early cruise is via one of the
spacecraft's two low-gain antennas; the antenna selected depends on the
relative geometry of the Sun, Earth and the spacecraft. The downlink
telemetry rate is presently 40 bps.
For the next several months, due to increasing range from Earth and relatively
high angles with respect to the Low Gain Antenna boresight, the DSN tracking
passes for Cassini will be dedicated either to command and telemetry (for
spacecraft activities and health monitoring) or to Navigation ranging data (for
orbit determination). This approach manages the available telecommunications
signal strength, directing it to either command/telemetry or Navigation,
according to plan. Telecommunications performance will improve again
this Fall.
Spacecraft Activity Summary:
On Friday, 05/08, Stellar Reference Unit A (SRU-A) Decontamination activities
were successfully concluded. Decontamination results were very similar to
those
observed on SRU-B when its radiator was decontaminated in mid-March. SRU-A was
powered off at the end of the activity; SRU-B remains on as the prime unit.
Also on Friday, an SSR double bit error (DBE) was repaired in a non-software
portion of one of the Flight Software (FSW) partitions using the standard
"partition copy" procedure. This procedure is scheduled whenever the
sequenced DBE repair, which only repairs DBEs in the FSW-containing portions,
identifies a DBE in the unused portion of the FSW partition. Such a DBE
had been identified during the SSR partition maintenance activity which
occurred on May 1.
Finally on Friday, the Radio & Plasma Wave Science (RPWS) Instrument was turned
off following confirmation of the successful playback of the RPWS Venus-1 flyby
data. Data had been preserved in instrument memory, until its receipt on Earth
had been assured, by keeping the RPWS in the "sleep" state from April 26 till
May 1. Results of the Venus-1 observations will be reported separately.
On Saturday, 05/09, there were no changes to spacecraft configuration.
On Sunday, 05/10, the Cruise 8 sequence began executing on board the
spacecraft.
On Monday, 05/11, the Solid State Recorder (SSR) record and playback pointers
were reset, according to plan. This housekeeping activity, done approximately
weekly, maximizes the amount of time that recorded engineering data is
available
for playback to the ground should an anomaly occur on the spacecraft.
Also on Monday, a housekeeping activity was performed which reads out a set of
AACS Attitude Estimator (ATE) measurements not available in regular engineering
telemetry. This ATE telemetry allows ground controllers to track the normal
functioning of the attitude estimator software on the spacecraft. The readout
is scheduled approximately every 2-4 weeks, over an available DSN telemetry
pass.
On Tuesday, 05/12, there were no changes to spacecraft configuration.
On Wednesday, 05/13, the Solid State Recorder (SSR) record and playback
pointers were reset, according to plan.
Also on Wednesday, a maintenance activity was performed on the SSR Flight
Software Partitions. This activity, performed approximately every 2 weeks,
repairs any SSR double bit errors (DBEs) which have occurred in the
code-containing portions of the Flight Software partitions during the preceding
period.
On Thursday, 05/14, there were no changes to spacecraft configuration.
Upcoming events:
Activities scheduled for the week of 5/15 - 5/21 include an SSR Pointer
Reset (05/20).
DSN Coverage:
Over the past week Cassini had 4 scheduled DSN tracks, occurring from
05/08 through 5/13. In the coming week there will be 2 DSN passes.
Hа сегодня все, пока!
=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: Sky & Telescope News Bulletin - May 15, 1998
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SKY & TELESCOPE'S NEWS BULLETIN
MAY 15, 1998
A BLACK HOLE FOR CENTAURUS A
Centaurus A, an oddball elliptical galaxy known for a monstrous dust lane
sweeping across its face, has been scrutinized by the Hubble Space
Telescope. Images were presented at a NASA press conference on Thursday
showing unprecedented detail in the dust lane. But Hubble's Near Infrared
Camera and Multi-Object Spectrometer (NICMOS) probed deeper, piercing the
dust and revealing two powerful radio jets emerging from the core, which
astronomers believe indicates that a massive black hole lurks there.
Astronomers expected NICMOS to show a dusty disk of gas feeding the black
hole and oriented perpendicular to the jets, but instead they found a disk
at a skewed angle. Perhaps new material is falling toward the black hole
from different directions than before, creating the tilted disk that feeds
into a smaller, unseen disk with the proper orientation.
SUPERNOVA IN M96
Italian astronomer Mirko Villi spied a "new" star -- a supernova -- on CCD
images taken on May 9th of the spiral galaxy M96 in Leo. Images taken as
recently as April 21st show no object at the star's position. Supernova
1998bu was announced the following day on IAU Circular 6899. The exploding
star is located a little less than 1 arcminute north and slightly east of
the galaxy's center. Brightness estimates range from visual magnitude 11.8
to 12.5, placing it within reach of amateur telescopes. Leo is well placed
-- high in the west-southwest -- in the evening sky.
NAMES FOR NEW MOONS
The discoverers of the newest satellites of Uranus have suggested naming
them Caliban and Sycorax. Philip Nicholson (Cornell University) and his
colleagues found the new moons on images taken last September. Following
the guidelines for satellite names for the planet, Caliban and Sycorax are
characters in Shakespeare's play "The Tempest." The astronomers expect the
names to be approved by the International Astronomical Union.
COMET STONEHOUSE
Comet Stonehouse (1998 H1) is hanging in there at about 11th magnitude.
Viewing should be easier now that the Moon is moving out of the evening
sky. The comet is well placed in the sky for observers in the Northern
Hemisphere. Comet Stonehouse is in Canes Venatici during the upcoming week,
just under the handle of the Big Dipper, and is thus visible throughout the
night and is highest in the sky before midnight. Here are positions for
Comet Stonehouse at 0 hours Universal Time in 2000.0 coordinates:
R.A. Dec.
May 16 13h 32 +43.0 deg.
18 13 23 +44.3
20 13 15 +45.4
COMET SOHO
Comet SOHO (1998 J1) is drawing away from the Sun, but moving such that it
will soon set with the Sun as seen from midnorthern latitudes. So far,
there have been only negative observations -- people have tried and failed
to see it. By the end of the month, Comet SOHO will be well away from the
Sun and may still be visible to the unaided eye, but only from the Southern
Hemisphere. Here are 2000.0 coordinates for the coming week:
R.A. Dec.
May 16 4h 43m +15.1 deg.
18 5 01 +10.9
20 5 17 + 6.7
THIS WEEK'S "SKY AT A GLANCE"
Some daily events in the changing sky, from the editors of SKY & TELESCOPE.
MAY 17 -- SUNDAY
* The Big Dipper is nearly overhead in the north during evening around this
time of year.
MAY 18 -- MONDAY
* Last-quarter Moon (exact at 12:35 a.m. Eastern Daylight Time Tuesday
morning).
MAY 19 -- TUESDAY
* The red long-period variable star R Hydrae should be at maximum light
this week, visible to the naked eye at magnitude 4.5.
MAY 20 -- WEDNESDAY
* During dawn Thursday, look east to see Jupiter at the upper right of the
waning crescent Moon. Brighter Venus is far to the Moon's lower left.
MAY 21 -- THURSDAY
* Venus is lower left of the Moon at dawn Friday. Dim Saturn is to Venus's
lower left.
MAY 22 -- FRIDAY
* The star Spica shines fairly high in the south shortly after dark at
this time of year. Look off to its lower right, by about 1 1/2 fist-widths at
arm's length, for the little sail-shaped constellation Corvus, the Crow.
MAY 23 -- SATURDAY
* The brightest star high in the southeast after dark at this time of year
is Arcturus, tinted pale yellowish orange. It's far to the upper left of
Spica. Arcturus is probably the oldest thing most people ever see. It is an
orange giant star about 10 billion years old, more than twice the age of our
Sun, Earth, and solar system.
THIS WEEK'S PLANET ROUNDUP
MERCURY is disappearing into the glare of sunrise, to the lower left of dim
Saturn and bright Venus low in the east at dawn.
VENUS shines low in the east during dawn, with Jupiter to its upper right.
Venus and Jupiter are 23 degrees apart on the morning of May 17th. They're
separating by about 1 degree per day.
MARS is hidden behind the glare of the Sun.
JUPITER is in the southeast during dawn, to the upper right of Venus; see
above.
SATURN is low in the east at dawn, to the lower left of bright Venus -- and
closing in on it daily. They'll have a close conjunction on May 28th and 29th.
URANUS and NEPTUNE, magnitudes 6 and 8, respectively, are in Capricornus in
the south-southeast before dawn. See the finder chart in the May Sky &
Telescope, page 96.
PLUTO, magnitude 13.7, is near the Ophiuchus-Scorpius border. It's well up
in the southeast by 11 p.m. See the finder chart in the May Sky & Telescope,
page 97. The finder charts for Uranus, Neptune, and Pluto are also at
http://www.skypub.com/whatsup/urnepl98.html.
(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 Daylight Time, EDT, equals Universal Time
minus 4 hours.)
More details, sky maps, and news of other celestial events appear each month
in SKY & TELESCOPE, the essential magazine of astronomy. See our Web site at
http://www.skypub.com/. Clear skies!
SKY & TELESCOPE, P.O. Box 9111, Belmont, MA 02178 * 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). Illustrated versions,
including active links to related Internet resources, are available via SKY
Online on the World Wide Web at http://www.skypub.com/.
In response to numerous requests, and in cooperation with the Astronomical
League (http://www.mcs.net/~bstevens/al/) and the American Association of
Amateur Astronomers (http://www.corvus.com/), S&T's Weekly News Bulletin and
Sky at a Glance are available via electronic mailing list too. For a free
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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
astronomy books and products, please contact Sky Publishing Corp., P.O. Box
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custserv@skypub.com. SKY Online: http://www.skypub.com/. Clear skies!
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: * SpaceNews 18-May-98 *
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SB NEWS @ AMSAT $SPC0518
* SpaceNews 18-May-98 *
BID: $SPC0518
=========
SpaceNews
=========
MONDAY MAY 18, 1998
SpaceNews originates at KD2BD in Wall Township, New Jersey, USA. It
is published every week and is made available for non-commercial use.
* LMCC DEMANDS 70-CM BAND FOR COMMERCIAL USE *
The Land Mobile Communications Council has issued a demand to the FCC that
it immediately reallocate of most of the 70 centimeter Amateur band over
to private mobile operations with private land mobile designated as the
primary user.
Technically the document is nothing more than a formal rule making request
to the FCC that has been designated RM 9267. In reality it is more a demand
by the LMCC for the FCC to immediately reallocate 420 to 430 MHz and 440 to
450 MHz away from the federal government and over to the Private Mobile Radio
Service on a primary basis. The Land Mobile Communications Council is also
asking for new allocations at 1390 to 1400 MHz, 1427-1432 MHz, and 1670 to
1675 MHz. It is also demanding a walloping 85 MHz at 960 to 1215 MHz and
it wants all of this turned over to the Private Mobile Radio Service no
later than 2010.
But LMCC is not willing to wait until 2010 to take over the 70 centimeter
band even though this is the second most popular of the Amateur radio
services' VHF and UHF allocations. Amateur Radio is a secondary user of
420 to 450 MHz. There are thousands of FM repeaters operating from 440 to
450 MHz and a variety of modes on the air every day in the 420 to 430 MHz
segment. While the Land Mobile Communications Council petition indicates
that it is willing to permit Amateur Radio to retain some sort of secondary
status, this would be only on a non-interfereing basis with the new commercial
interests.
Experts say that the best way to kill RM 9267 is though a massive letter
writing campaign to the FCC. A campaign that outlines the specific use of
the band by Amateur Radio Interests -- informational filings that detail how
every hertz of 420 to 430 and 440 to 450 MHz is utilized on a day to day
basis by hams.
The commentary cutoff date on RM 9267 is June 1st. This leaves precious
little time for radio amateurs around the nation to react. Those responding
must be certain to reference RM 9267 at the top of their letter. Send
comments to the Secretary, Federal Communications Commission, Washington DC,
20554.
[Info via Newsline 1082 released 1998-May-08 from Bill Pasternak, WA6ITF]
* OSCAR-11 NEWS *
During the period 1998-Apr-16 to 1998-May-15, good signals have been
received from UoSAT-OSCAR-11 via the 145.826 MHz beacon. It has been
an uneventful period.
Telemetry has shown that the battery voltage has tended to rather low,
mostly around 13.5 volts, with values between 13.3 and 14.0 volts recorded.
No explanations of the changed power supply currents (as reported last
month) have been received, therefore these values will now be regarded
as nominal.
The internal temperatures have remained fairly constant at around 5C and
3C for battery and telemetry electronics respectively.
A single WOD survey of channels 1, 2, 3, 61 (magnetometers) dated
1998-Mar-19 has been transmitted by the satellite. A quick plot of this
WOD showed reasonable agreement with the theoretical field and nominal
attitude. Anyone using this survey should note the unusual starting
time of 16:00:05 UTC.
Three reports of the OSCAR-11 Mode-S beacon have been received from
Fernando CX6DD, Gary N4OLN, and Steve HB9FMX/G4KAM. Of special interest
is the equipment used by CX6DD. This a modified MMDS commercial TV antenna,
model 130194, made by California Amplifier Inc. The device which is known
as an LNBY, consists of a 23 element antenna, 60 cm long, where each element
is a 4.5 cm disc, and an integrated down converter which forms the remainder
of the antenna. There is sufficient space inside the unit to allow a cheap
surplus HC-6 crystal to be used instead of the original HC-49 type. A
8.8125 MHz crystal would give an IF in the 145 MHz band. An ICOM 821H and
FODTRACK software completed the system. The audio file that Fernando sent
showed excellent reception. The price of the antenna (in Uruguay) was
US $190. Further details can be found on the California Amplifier web
site http://www.calamp.com/ (Use the search facility to find 130194).
The operating schedule is unchanged.
ASCII status (210 seconds)
ASCII bulletin (60 seconds)
BINARY SEU (30 seconds)
ASCII TLM (90 seconds)
ASCII WOD (120 seconds)
ASCII bulletin (60 seconds)
BINARY ENG (30 seconds)
The ASCII bulletin is currently a static message, detailing modes and
frequencies of all the amateur radio satellites.
There are additional status blocks after each bulletin is transmitted,
and between ASCII TLM and WOD.
The Mode-S beacon is ON transmitting an unmodulated carrier, but telemetry
indicates that it has partially failed, and delivering half power. This
beacon is a useful test source for those testing Mode-S converters, prior
to the launch of P3-D. It is considerably weaker than DOVE-OSCAR-17, which
should be used for initial testing. Any reports of reception of the 2401 MHz
beacon would be most welcome, and should be directed to Clive Wallis at:
g3cwv@amsat.org.
The 435.025 MHz beacon is normally OFF. However it can sometimes be heard
when the satellite is being commanded by ground control, ie. within range
of Guildford, UK. When the 435 MHz beacon is transmitting, the 145 MHz
beacon is normally OFF. The data transmitted is mainly binary.
In response to many requests for information about methods of decoding
OSCAR-11 signals, Clive Wallis has added a package of hardware information
to his OSCAR-11 web site.
Another recent addition is a new page for miscellaneous topics such as
tracking, eclipses, and orbital decay. The first addition to this new page
is a package for evaluating satellite eclipses, as described in OSCAR News
April 1998, page 29. The other item in this new page is a program OZFORM.BAS
for generating a table of Keplerian elements from the NASA 2-line format.
The format of the output is similar to that published in every issue of
OSCAR News.
The web site also contains some software for capturing data and decoding
ASCII telemetry and WOD. There is an archive of raw data (mainly WOD) for
analysis, which is continually being expanded as new data is captured.
Also included are some audio files, including 10-second examples of each
type of data transmitted by OSCAR-11. There are also examples of Mode-S
reception. All the audio files are zipped so that they can be played
off-line. These should help listeners identify the various types of
data, and give an indication of the signal quality required for
successful decoding.
Clive's OSCAR-11 Web Site may be accessed by connecting to the following URL:
http://www.users.zetnet.co.uk/clivew/
[Info via Clive Wallis, G3CWV (g3cwv@amsat.org)]
* FUJI-OSCAR-29 NEWS *
On 1998-May-14, the FO-29 command station released a new announcement
indicating that software reloading was in progress, adn had reached the
40 percent completion point. A new announcement is expected to be released
on 1998-May-29.
[Info via Kazu Sakamoto, JJ1WTK]
* FEEDBACK/INPUT WELCOMED *
Comments and input for SpaceNews should be directed to the editor (John,
KD2BD) via any of the paths listed below:
WWW : http://www.njin.net/~magliaco/
PACKET : KD2BD @ KS4HR.NJ.USA.NA
INTERNET : kd2bd@amsat.org, magliaco@email.njin.net
SATELLITE : AMSAT-OSCAR-16, LUSAT-OSCAR-19, KITSAT-OSCAR-25
<<=- SpaceNews: The first amateur newsletter read in space! -=>>
<<=- Serving the planet for 10 years -=>>
/EX
-=-=-=-=-=-=-=-=-=-=-=-=- John A. Magliacane, KD2BD -=-=-=-=-=-=-=-=-=-=-=-=-
Internet : kd2bd@amsat.org | Voice : +1.732.224.2948
Satellite : AO-16, LO-19, KO-25 | Morse : -.- -.. ..--- -... -..
Packet : KD2BD @ KS4HR.NJ.USA.NA | WWW : http://www.njin.net/~magliaco/
Video : 426.250 MHz/439.250 MHz | FAX : +1.732.224.2060
-=-=-=-=-=-=-=-= Linux/GNU: Because Money Can't Buy Freedom -=-=-=-=-=-=-=-=-
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=SANA=
Дата: 18 мая 1998 (1998-05-18)
От: Alexander Bondugin
Тема: The Mars Microphone: Ready To Go
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The Mars Microphone: Ready To Go
by Greg Delory
Ever wonder what it sounds like on Mars? When the next lander in NASA's
program to explore the Red Planet touches down in 1999, we will all have
the chance to find out. Onboard the Mars Polar Lander will be a small
recording device, the Mars Microphone, whose job is to sample sound while
the rest of the probe studies the soil, weather, and atmospheric dust.
The idea for the Mars Microphone started with Janet Luhmann of the
University of California, Berkeley and David Juergens of the Jet Propulsion
Laboratory, who proposed to the Planetary Society that a sound-recording
device would be easy to include on a Mars mission. Society Executive
Director Louis Friedman investigated the possibility of incorporating a
microphone in the Mars Polar Lander mission.
At that time, mission planners had just selected a Russian instrument to be
put aboard the spacecraft (the first Russian instrument included on a US
planetary mission). Under the direction of Viacheslav Linkin of the Space
Research Institute in Moscow, the lidar will use a laser to study the
distribution of dust in the Martian atmosphere. Linkin offered a place on
the lidar for the microphone, which could operate without requiring any
mass, power, volume, or data-rate adjustments on the lander.
Friedman and Society President Carl Sagan then requested NASA approval to
include the microphone in the Mars Polar Lander payload, stipulating that
there would be no cost to NASA. NASA Associate Administrator for Space
Science Wes Huntress agreed.
The Planetary Society formed a team with the Space Sciences Laboratory at
Berkeley, and together we developed a low-cost implementation plan that
enabled us to build the instrument with funding solely by the Planetary
Society.
The Mars Microphone will be the first instrument funded by a membership
organization to fly to another world. It was designed, constructed, and
tested under Luhmann's direction at the Space Sciences Laboratory.
Are There Sounds on Mars?
Given that sound waves need an atmospheric medium through which to travel,
many people are surprised to learn that any sounds at all can be heard on
Mars. The atmospheric pressure on the surface of the Red Planet is small,
amounting to around 0.1 percent of the Earth's sea level pressure. But even
at Mars' low pressure, acoustic signals within the frequency range of the
human ear can be detected. And while the atmosphere of Mars is very
different from Earth's, consisting mostly of carbon dioxide, there are
similarities between these environments that should make the sound data
worthwhile.
For example, there is weather on Mars, including winds, sandstorms, and
dust devils, which are little tornadoes caused by local weather patterns.
The Mars Microphone may be able to hear these winds and perhaps even a type
of lightning within sandstorms. The microphone will also record noises made
by the lander, such as the sound of the robotic arm digging for soil
samples.
However, the most exciting sounds are likely to be ones that we don't even
know about yet. Experience has demonstrated that whenever a new instrument
is developed and flown in space, we learn something new about
extraterrestrial environments, and therein lies the true spirit of the
Mars Microphone concept.
The instrument will bring the public closer to Mars exploration. The sounds
picked up by the Mars Microphone will be available on a World Wide Web page
during the mission so that anyone will be able to hear for themselves what
it sounds like on Mars.
Building and Testing on a Shoestring
The Mars Microphone is a small device, roughly 5 centimeters on a side and
one centimeter thick (2 x 2 x 0.5 inches), weighing less than 50 grams (1.8
ounces) and using a small amount of power, less than 0.1 watt during its
most active times. In addition to the microphone, the instrument contains
digital electronics to acquire and store sound samples. Because the rate at
which we can acquire data will be limited, it will take several days, maybe
even a week, to retrieve one 10-second sound clip. The device has internal
memory, similar to the RAM in your home computer, which will store sounds
for transmission to Earth along with other lander data.
In the construction of the Mars Microphone, we relied on commercial,
off-the-shelf technology, meaning that very few of the components were
developed specifically for this mission. Most are readily available
commercially. Our sound processor chip, for example, is also used in
talking toys and educational computers that listen and respond to spoken
words. The microphone itself is typically used in hearing aids. The entire
program, including design, construction, and testing, cost roughly $50,000,
a bargain for an instrument on a planetary probe.
The Mars Microphone has since passed several tests to show it can withstand
the rigors of a planetary mission. Radiation levels in space and on Mars
are higher than what we are used to on Earth, and, like humans, the
electronic components in the microphone are sensitive to radiation damage.
We exposed the microphone and the sound processor chip to levels of
radiation that they would receive during the mission, and there were no
failures or degradation of performance. We also conducted thermal tests
with temperature ranges of -100 to +20 degrees Celsius (about -150 to +70
degrees Fahrenheit), and detected no malfunctions.
Finally, we performed pressure tests to ensure that the microphone could
actually hear noises at the low pressures of the Martian atmosphere.
Although sound level diminishes substantially with decreased pressures, we
were still able to hear sounds by increasing the gain of the amplifiers
within the microphone.
The microphone was integrated onto the Mars Polar Lander last October at
Lockheed Martin in Denver, Colorado. We verified that the microphone worked
properly on the lander and even listened to the technicians conversing as
they tended to the craft.
The next phase of testing will occur this summer, when the entire lander
plus microphone will undergo thermal and vacuum tests to simulate the
journey through space and operations on the Martian surface. During this
time the microphone will practice listening to the movements of the
lander's robotic arm.
For the latest on the Mars Microphone project and more details about the
experiment, visit the Mars Microphone home page at
http://sprg.ssl.berkeley.edu/marsmic.
Greg Delory is a Postdoctoral Physicist at the Space Sciences Laboratory of
the University of California, Berkeley.
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