Дата: 02 февраля 1999 (1999-02-02)
От: Alexander Bondugin
Тема: Today On Galileo - January 30, 1999
Привет всем!
Вот, свалилось из Internet...
TODAY ON GALILEO
Saturday, 30 January 1999
Today at 4 pm PST [see Note 1], Galileo starts the eighth encounter of
the Galileo Europa Mission. The encounter features a close flyby of
Jupiter's icy moon Europa, the ninth in a series that started with the
last flyby of Galileo's primary mission. This flyby is also the last
Europa flyby of the Galileo Europa Mission, and will occur tomorrow,
Sunday, just after 6 pm PST. The spacecraft will be executing
encounter commands through next Wednesday, but most of the encounter
activity takes place on Sunday and Monday. During this time, the
spacecraft is approximately 836 million kilometers (519 million miles)
from Earth. At that distance, it takes radio signals approximately 46
1/2 minutes to travel from the spacecraft to Earth.
To kick off the encounter, the fields and particles instruments resume
their survey of the inner portions of Jupiter's vast magnetosphere.
This survey has been repeated for almost every encounter of Galileo's
mission at Jupiter, allowing scientists to study the long term
variations in the plasma, dust, and electric and magnetic fields that
comprise the magnetosphere. The survey is scheduled to continue
through Monday.
Four remote sensing observations are performed today--two by the
near-infrared mapping spectrometer and two by the ultraviolet
spectrometer. Both near-infrared observations are designed to obtain
measurements of the composition and thermal properties of Jupiter's
atmosphere. Similar observations have been repeated during previous
orbits, allowing the science community to map variations over time. By
looking at the same location on Jupiter at different times, with
different viewing geometries, it is possible to extract information on
the properties of Jupiter's cloud layers. The depths of the different
cloud layers, and their thickness, can be assessed in this way.
The ultraviolet spectrometer takes the encounter's first look at
Europa. Its first observation gathers measurements of Europa's surface
that will give scientists clues as to how the surface has been affected
by external phenomena such as meteors and high-energy particles which
bombard the surface. In the second observation, the instrument will
look for atmospheric emissions, which might be due to venting. Such
outgassing events are an expected feature of ice volcanism. If
detected, they would provide scientists with indirect evidence of
internal activity within Europa, and would strengthen the case for
liquid water there.
For more information on the Galileo spacecraft and its mission to
Jupiter, please visit the Galileo home page:
http://www.jpl.nasa.gov/galileo
Note 1. All times listed correspond to the Pacific Time zone
(currently standard time) and spacecraft event time. Radio signals
indicating that an event has occurred on the spacecraft reach the Earth
33 to 50 minutes later, depending on the time of year. Currently, this
time is 46 1/2 minutes. Currently, Pacific Standard Time (PST) is 8
hours behind Greenwich Meridian Time (GMT).
Hа сегодня все, пока!
=SANA=
Дата: 02 февраля 1999 (1999-02-02)
От: Alexander Bondugin
Тема: TRW-Built TOMS Spacecraft Restored To Normal Operation; SpacecraftAlre
Привет всем!
Вот, свалилось из Internet...
TRW Inc.
CONTACT: TRW Inc.
Sally Koris, 310/812-4721
TRW-Built TOMS Spacecraft Restored To Normal Operation; Spacecraft Already
Exceeds Design Life By 25 Percent
REDONDO BEACH, Calif., Jan. 25, 1999 -- TRW engineers, supporting their
counterparts at NASA's Goddard Space Flight Center and NASA's satellite
tracking networks, devised a clever solution that recovered the agency's
only satellite dedicated to ozone mapping from a near-fatal emergency.
Based on detailed knowledge of the Total Ozone Mapping System
(TOMS)-Earth Probe satellite, built by TRW, engineers last month came up
with the idea to bypass the fuel-depleted propulsion system and use
magnetic torque rods to restore the spacecraft to its normal
Earth-pointing orientation.
"The dedicated efforts of an industry/government team brought back
online a critical environmental tool," said Joanne Maguire, vice president
and general manager, TRW Space & Laser Programs Division. "TOMS has
already exceeded its two-year design life by 25 percent, and as a result
of this fix, will continue its mission of supplying daily measurements of
the global ozone layer to scientists around the world.
"The robust spacecraft design enabled engineers to devise a solution
that required a one-byte patch to the software code," Maguire continued.
"It is stunning in its simplicity, and yet solved a problem of great
complexity. The solution is based on the recognition that torque rods,
which balance out small disturbances in the attitude of the spacecraft,
could be used to re-establish the orientation of a satellite."
The emergency occurred in mid-December and is believed to have been
caused by a single event upset (SEU). SEUs occur in space when a high
energy particle hits the spacecraft electronics, disrupting the
spacecraft's computer operations.
In this case, TOMS went into a "safehold" mode. In the safehold mode,
the spacecraft is programmed to point toward the Sun so the solar panels
get power. The satellite is then stabilized by being automatically
commanded to spin at three degrees per second.
When TOMS thrusters fired to begin spinning the spacecraft, unexpected
residual gyroscopic forces of the spacecraft caused it to wobble. This led
to the continuous firing of thrusters as it tried to compensate for the
wobble, exhausting the onboard fuel. The spacecraft was rotating in the
Sun-line at a rate of approximately 15 degrees per second.
So engineers modified, or "patched," the control software to allow the
spacecraft to de-spin itself and then recover its operational status using
the magnetic torque rods. This patch was validated first on the ground,
using a table-top version of the spacecraft computer.
Because the magnetic torque rods exert such small torques on the
spacecraft, the de-spin maneuver from the initial 15 degrees per second
to approximately three degrees per second required three days, completing
very early on New Year's Day. A subsequent one-and-a-half day maneuver
brought the satellite back to its operational "science mode" status.
"This recovery could only have been accomplished by the kind of
dedicated people that work our projects, both government and industry,"
said Michael Luther, deputy associate administrator, Office of Earth
Sciences, NASA headquarters.
The satellite was launched in July 1996 from Vandenberg Air Force
Base, Calif. TRW built the 650-pound satellite and integrated the TOMS-EP
instrument as a part of NASA's Earth Science enterprise initiative to
gather data on the global environment.
The ozone layer, at the outer reaches of the Earth's atmosphere,
protects life on Earth from the deadly radiation of space. Scientists use
TOMS-EP data in conjunction with the atmospheric chemistry measurements
from other satellites to understand the processes that drive the global
creation, destruction and distribution of the Earth's ozone layer.
In December 1997, NASA directed the boost of TOMS into a higher orbit
to fill the void left by the loss of the Advanced Earth Observing
Satellite (ADEOS). The higher altitude widened the coverage of the TOMS
instrument and exerted less atmospheric drag on the TRW-built satellite.
The reboost orbit enabled the satellite to provide ozone measurements
for three additional years, or at least until the next satellite with a
Total Ozone Mapping Spectrometer is launched.
TRW Space & Electronics Group builds communications, scientific and
defense spacecraft for military, civil and commercial customers, and
produces, integrates and tests payloads; develops advanced space
instruments; and integrates experiments into spacecraft.
It is an operating unit of TRW Inc., which provides advanced
technology products and services for the automotive, space-and-defense,
and information-technology markets worldwide.
Andrew Yee
ayee@nova.astro.utoronto.ca
Hа сегодня все, пока!
=SANA=
Дата: 02 февраля 1999 (1999-02-02)
От: Alexander Bondugin
Тема: U.Washington astronomy professor's Stardust quest set for launchSaturd
Привет всем!
Вот, свалилось из Internet...
University of Washington
FROM: Vince Stricherz
206-543-2580
vinces@u.washington.edu
FOR IMMEDIATE RELEASE: Feb. 1, 1999
UW astronomy professor's Stardust quest set for launch Saturday
It's a moment University of Washington astronomy professor Donald Brownlee
has been awaiting for nearly two decades. If all goes as planned, that
moment will arrive Saturday afternoon when a Boeing Delta II rocket, with
"University of Washington" emblazoned on the side, sends a desk-sized
spacecraft on a seven-year journey to rendezvous with a comet.
Stardust is scheduled to launch from Cape Canaveral, Fla., at 1:07 p.m. PST,
and UWTV will provide live coverage. The mission, selected in 1995 by NASA
as part of its Discovery series, aims to capture particles from comet Wild 2
(pronounced Vilt 2) and return them to Earth for analysis in laboratories at
the UW, NASA and around the world. There's much to be learned, Brownlee
said.
"People have long suspected that comets played a role in the origin of life.
No one really knows this because no one knows how life began. But we do know
that comets are the most carbon-rich materials in the solar system, and we
know they're full of organic compounds and they fall on the Earth all the
time. Even now we have tens of thousands of tons of comet particles landing
on the Earth every year," he said.
Even though microscopic comet particles blanket open spaces such as parks
and football stadiums every year, those particles don't tell the same story
as ones collected from a comet such as Wild 2, Brownlee said. That's because
Wild 2 only recently started orbiting close enough to the sun to make the
mission feasible, so there hasn't been time enough for the sun's heat to
destroy the characteristics of particles that have been preserved in a
cryogenic deep freeze of space for billions of year.
In 1980, Brownlee and NASA first considered a mission to capture comet
particles. In that case, the target would have been Halley's comet, but the
idea proved unworkable. Various technological advances and a bit of
celestial luck changed that. Before 1974, Wild 2 traveled outside the orbit
of Jupiter. But a close encounter with Jupiter that year altered the comet's
trajectory, bringing it close enough to make Stardust possible. The
spacecraft's encounter with the comet in early 2004 will take place just
outside the orbit of Mars, 242 million miles from Earth on the other side of
the sun.
The mission is the first since Apollo 17 in 1972 to return extraterrestrial
samples to Earth, and it is the first to bring back samples from beyond the
orbit of the moon. Scientists will study the returned comet particles in the
hope of understanding how life evolved on Earth. The planet probably was
formed without water and without carbon or nitrogen, the building blocks of
life. "The building blocks of life have long been thought to have come from
further out in the solar system, out further away from the sun, and these
would be materials from asteroids and comets," Brownlee said.
Stardust will have journeyed 3.1 billion miles before it parachutes into the
Utah desert in early 2006. During its encounter with Wild 2, a
tennis-racquet shaped collector, sheathed with a wispy substance called
aerogel, will be extended to collect comet grains when the spacecraft is
within 100 miles of the comet's icy core. A high-power antenna will transmit
close-up pictures, and sensitive equipment will gather data about the comet.
The mission is a collaboration of the UW, NASA, NASA's Jet Propulsion
Laboratory at the California Institute of Technology in Pasadena, Calif.,
and Lockheed Martin Astronautics in Denver. Other key members of the team
are The Boeing Co., Germany's Max-Planck-Institut fЭr extraterrestrische
Physik, the NASA Ames Research Center and the University of Chicago.
Brownlee expects information gathered by Stardust to shed light on how the
solar system and the universe evolved. The mission also could have
implications on astrobiology, the search for life beyond Earth. The UW this
fall will begin the first doctoral program in astrobiology to train people
to look for life on other celestial bodies, such as Mars and Europa, a moon
of Jupiter.
"From the astrobiology standpoint, we're interested in what kind of organic
materials actually exist and how much there is and whether this played a
role (in the formation of life)," Brownlee said. "Now this may be an
impossible problem. We can study astrobiology and we can investigate how
life might have formed, but no one was there taking notes when life formed.
"You have things ... before there was life and things after there was life
but the real records aren't there," he said. "But by insight on this, you
can at least look at what the starting materials were. So that's what
Stardust is going to do, look at the starting materials, what was around in
the solar system before life existed on Earth."
The name "Stardust" seemed appropriate because of the nature of the project
and the fact that people can relate to that name, Brownlee said. A recent
radio interview ended with a few bars of the song "Woodstock" by Joni
Mitchell, which includes the lyrics: "We are stardust, we are golden, we are
2 billion-year-old carbon." That's an appropriate thought, Brownlee said.
"Comets are a vehicle that brings organic materials to the Earth. Many of
the carbon atoms in our bodies were in comets early in the history of the
solar system. So one of the bylines of the Stardust mission is that we are
stardust. Our bodies are actually made of stardust."
Science aside, there's a hint of romanticism about this mission. That's why,
come Saturday, it won't be "Woodstock" but instead the soft strains of Hoagy
Carmichael's "Stardust" drifting through the launch area.
###
Additional information is available at http://stardust.jpl.nasa.gov or at
http://www.washington.edu/newsroom/stardust/stardust.html
Andrew Yee
ayee@nova.astro.utoronto.ca
Hа сегодня все, пока!
=SANA=
Дата: 02 февраля 1999 (1999-02-02)
От: Alexander Bondugin
Тема: planetary map FAQ
Привет всем!
Вот, свалилось из Internet...
PLANETARY MAPS: (this article is in the public domain)
A list of maps of all mapped solar system bodies except Earth, 58 by October
1998. If there are many maps (e.g. Mars) a general purpose global map is
listed, subdivided if necessary: relief maps (usually with placenames),
topography (contours), geological maps... If not (e.g. Deimos) the best
available map is listed. Some (e.g. Comet Encke) are simple diagrams of
possible surface features ('sketch' under map type). A few interesting
books are listed at the end. Questions, errors or omissions: please
contact me (Phil Stooke) at: pjstooke@julian.uwo.ca.
For IAU definitions of North, longitudes, prime meridians etc. see Chapter
5 of PLANETARY MAPPING (see below) and further references in that chapter.
References: USGS = U.S. Geological Survey. Order by I-number from USGS
Map Sales, Box 25286, Denver, Colorado USA 80225. About $4 / sheet (some
in list are sets of several sheets). Call Customer Service: (303) 236-7477
for price and ordering details. Details also at their website:
wwwflag.wr.usgs.gov/USGSFlag/Space/GEOMAP/PGM_home.html
NASA Tech. Memo. 4395 (Indexes of Maps of Planets and Satellites 1992) by J.
Inge
and R. Batson is the best guide to sheet maps. Most Apollo-era Moon maps
(LAC, LTO)
are out of print, but some (+ NASA CD-ROMS) may be found at NSSDC: National
Space
Science Data Center, Goddard Space Flight Center, Greenbelt, Maryland USA
20771.
NSSDC now has a WWW interface into their inventory of available planetary
maps
(Moon, Mars, Mercury only): http://nssdc.gsfc.nasa.gov/nmc/map.html
Edmund Scientific: 101 E.Gloucester Pike, Barrington, NJ 08007-1380, USA.
Virtual Reality Labs: 2341 Ganador Ct., San Luis Obispo, CA 93401, USA.
Other maps are in books and journals. Bibliographic data are abbreviated
but there should be enough detail to find the item. My maps and digital
shape models of small bodies are available on the WWW at:
www.uwo.ca/geog/faculty/stooke.htm
BODY MAP TYPE REFERENCE
Sun outline L'Astronomie (Astr.Soc.France) (prior to 1996)
Mercury relief USGS maps I-1149,1171,1822
geology USGS maps I-1199,1233,1408,1409,1658,1659,1660,
2015,2148, + NASA ATLAS OF THE SOLAR SYSTEM
atlas Davies et al. ATLAS OF MERCURY, NASA SP-423, 1978
globe USGS (out of print- see at Cornell U. or LPI)
Venus relief USGS map I-2444
topogr USGS maps I-1324,1562,2041 + GxDR CD-ROM from NSSDC
geology USGS map I-2059 (Venera 15/16 data)
digital VENUS EXPLORER CD-ROM, Virtual Reality Labs Inc.
atlas ATLAS POVERKHNOSTI VENERY, Russia, 1989
globe Sky Publishing (ads in Sky & Telescope)
online http://www-pdsimage.jpl.nasa.gov/PDS/public/
magellan/midrcd_query.html
Moon relief USGS maps I-1218,1326,2276
topogr NSSDC: LAC maps (earthside), LTO maps (Apollo zone)
+ Smith et al.,J.GEO.RES.102:1591-1611,1997
(global)
geology USGS maps I-703,948,1034,1047,1062,1162,
+ Wilhelms, USGS Professional Paper 1348, 1987
atlas LUNAR ORBITER PHOTO ATLAS, NASA SP-206, 1971
+ A. Rukl, ATLAS OF THE MOON, Hamlyn, 1990
globe Replogle Globes (via Sky Publ., ads in SKY+TEL.)
online http://www.nrl.navy.mil/clementine/clib
digital CLEM. BASEMAP CD-ROMs (set of 15), from NSSDC
Mars relief USGS maps I-1618,2179, Edmund Scientific Mars Map
topogr USGS map I-2160 + MDIM CD-ROM, disk 7, from NSSDC
geology USGS map I-1802
digital MDIM CD-ROMs, disks 1-6, available from NSSDC
+ MARS EXPLORER CD-ROM, Virtual Reality Labs Inc.
atlas Batson et al., ATLAS OF MARS, NASA SP-438, 1979
globe Sky Publishing (ads in SKY+TELESCOPE)
online http://ic-www.arc.nasa.gov/ic/projects/
bayes-group/Atlas/Mars
Phobos relief Greeley+Batson, NASA ATLAS SOL.SYST. Cambr.U.Pr.
1996
topogr Thomas, ICARUS, 105:326-344, 1993 (+ photomosaic)
globe Max Planck Inst. Phys+Astrophys., 1988 (see at LPI)
Deimos outline Thomas, ICARUS, 40: 223-243, 1979
topogr Thomas, ICARUS, 105:326-344, 1993 (+ photomosaic)
Jupiter mosaics Smith et al., SCIENCE 206:927-950, 1979 (Voyager)
mosaics Hammel+, SCIENCE 267:1288-1296, 1995 (HST, SL9
sites)
Amalthea rel,topo Stooke, EARTH,MOON,PLANETS 64:187-197, 1994
Io relief USGS map I-1713
topogr Gaskell+Synnott,GEOPHYS.RES.LET. 15:581-584, 1988
geology USGS map I-2209
colour Burns+, SATELLITES, U.Ariz.Pr.,1986, Pl.2
(Voyager)
colour ASTRONOMY v.25:p.28, 1997 (Galileo mosaic)
Europa relief USGS maps I-1241,1493,1499
geology SATELLITES OF JUPITER,Ch.14, U.Arizona Press, 1982
Ganymede relief USGS map I-2331
geology USGS maps I-1934,1966,2289,2328,2388,2459,2497,2534
Callisto relief USGS maps I-1239,2035
geology USGS map I-2581
Saturn mosaics Sromovsky+, J.GEOPH.RES.88:8650-8666, 1983
(Voyager)
mosaics Westphal et al., ICARUS 100:485-498, 1992 (HST)
mosaics Godfrey, ICARUS 76:335-356, 1988 (N. Pole)
Prometheus rel,topo Stooke, EARTH,MOON,PLANETS, 62: 199-221, 1993
Pandora rel,topo Stooke, EARTH,MOON,PLANETS, 62: 199-221, 1993
Janus rel,topo Stooke+Lumsdon, EARTH,MOON,PLAN. 62:223-237, 1993
Epimetheus rel,topo Stooke, EARTH,MOON,PLANETS, 63: 67-83, 1993
Mimas relief USGS maps I-1489,2155
geology Croft, NASA TECH.MEM. 4300, 95-97, 1991
Enceladus relief USGS maps I-1485,2156
geology Kargel+Pozio, ICARUS 119:385-404, 1996
Tethys relief USGS maps I-1487,2157
geology Moore+Ahern, J.GEOPHYS.RES. 88:A577-A584, 1983
Dione relief USGS maps I-1488,2158
geology Moore, ICARUS, 59:205-220, 1984
Rhea relief USGS maps I-1484,1921
geology Moore et al., J. GEOPHYS.RESEARCH 90:C785-C795,
1985
Titan albedo Smith et al., ICARUS 119:336-349, 1996
Hyperion rel,topo Stooke, EARTH, MOON & PLANETS 74:61-83, 1996
Iapetus relief USGS maps I-1486,2159
geology Croft, NASA TECH. MEMO 4300, 101-103, 1991
Phoebe albedo Thomas et al., J. GEOPHYS. RESEARCH 88:8736-8742,
1983
+ Simonelli et al. ICARUS, submitted 1998.
Uranus magnetic Connerney et al., J. GEOPHYS. RESEARCH
92:15329-15336, 1987
Puck outline Stooke, LUN.PLANET.SCI. XXV, 1349-1350, 1994
Miranda relief USGS map I-1920
topogr Wu, LUNAR PLANET.SCI XVIII, 1110-1111, 1987
geology Croft & Soderblom, URANUS, U. Arizona Press, 1991
Ariel relief USGS map I-1920
geology Croft & Soderblom, URANUS, U. Arizona Press, 1991
Umbriel relief USGS map I-1920
geology Croft & Soderblom, URANUS, U. Arizona Press, 1991
Titania relief USGS map I-1920
geology Croft & Soderblom, URANUS, U. Arizona Press, 1991
Oberon relief USGS map I-1920
geology Croft+Soderblom, URANUS, U. Arizona Press, 1991
Neptune mosaics Smith et al., SCIENCE 246:1422-1449, 1989
Larissa relief Stooke, EARTH, MOON & PLANETS, 65:31-54, 1994
Proteus rel,topo Stooke, EARTH, MOON & PLANETS, 65:31-54, 1994
Triton relief USGS maps I-2153,2154,2275
geology Croft et al., NEPTUNE & TRITON, U. Arizona Press,
1995
Pluto albedo Stern et al., ASTRONOMICAL JOURNAL 113:827-843,
1997
Charon albedo Buie et al., ICARUS, 97:211-227, 1992
4 Vesta albedo Binzel et al., ICARUS, 128:95-103, 1997
topogr Thomas et al., SCIENCE, 277:1492-1495, 1997
15 Eunomia sketch Reed et al., ICARUS, 125:446-454, 1997
29 Amphitrite sketch Barucci et al., ASTEROIDS, COMETS, METEORITES II,
89-92, 1986
43 Ariadne sketch Detal et al., ASTRON.ASTROPHYS. 281:269-280, 1994
243 Ida geology Belton et al., SCIENCE, 265:1543-1547, 1994
+ Stooke, LPSC XXVIII, 1385-1386, 1997
topogr Thomas et al., ICARUS, 120:20-32, 1996
243(1) Dactyl outline Veverka et al., ICARUS, 120:200-211, 1996
253 Mathilde outline Thomas et al.., ICARUS, submitted, 1998
433 Eros topogr Mitchell et el., ICARUS, 131:4-14, 1998
532 Herculina sketch Taylor et al., ICARUS, 69:354-369, 1987
624 Hektor sketch Hartmann+Cruikshank, ICARUS, 36:353-366, 1978
951 Gaspra rel,topo Stooke, EARTH, MOON & PLANETS, 75:53-75, 1997
1620 Geographos outline Stooke, LPSC XXVIII, 1387-1388, 1997
4179 Toutatis relief Hudson & Ostro, SCIENCE, 270:84-86, 1995
outline Stooke, LPSC XXVII, 1283-1284, 1996
4769 Castalia relief Hudson & Ostro, SCIENCE, 263:940-943, 1994
+ Stooke, CANADIAN GEOGRAPHER, in press, 1998
topogr Scheeres et al., ICARUS, 121:67-87, 1996
Comet Encke sketch Sekanina, ASTRONOMICAL JOURNAL 96:1455-1475, 1988
Comet Halley outline Moehlmann+,COMETS IN THE POST-HALLEY ERA, p.764,
Kluwer 1991
rel,topo Stooke & Abergel, ASTRON.ASTROPHYS 248:656-668,
1991
+ Stooke, LPSC XXVIII, 1387-1388, 1997
Swift-Tuttle sketch Sekanina, ASTRONOMICAL JOURNAL 86:1741-1773, 1981
Com.Tempel-2 sketch Sekanina, ASTRONOMICAL JOURNAL 102:350-388, 1991
Interesting books: (no single book has maps of all bodies listed above)
NASA ATLAS OF SOLAR SYSTEM, Greeley & Batson (eds), Cambridge U.Press, 1996
ATLAS PLANET ZEMNOI GRUPPA...(atlas of terrestrial planets), Russia, 1992
PLANETARY MAPPING, Greeley & Batson (eds), Cambridge U. Press, 1990
PLANETARY LANDSCAPES, Greeley, Cambridge U. Press, 2nd ed. 1994
MAPPING OF THE MOON, Kopal & Carder, D.Reidel Co., 1974
MARS AND ITS SATELLITES, J. Blunck, Exposition Press, 1982 (ed. 2)
Interesting websites with planetary maps:
Pele.wr.usgs.gov (U.S. Geological Survey, outer planet satellite maps)
Maps.jpl.nasa.gov (David Seal's planetary map site, very useful)
www.uwo.ca/geog/faculty/stooke.htm (my small body maps)
(and link from my links page to Calvin Hamilton's Views of the Solar System
- excellent resource)
Hа сегодня все, пока!
=SANA=
сайт служит астрономическому сообществу с 2005 года