PLEASE NOTE:
*
CCNet 106/2003 - 17 November 2003
ASTEROID IMPACT RISK FURTHER REDUCED
---------------------------------------
A new survey revises down the likelihood of a massive asteroid
hitting the Earth
by 20-30%. We're only due to collide with rocks larger than one
kilometre across
roughly once every 600,000 years, it concludes "There was a
lot of error in our
previous estimates," says astronomer Alan Harris of the
German space agency, DLR.
"It's all because near-Earth asteroids are somewhat brighter
than we thought".
--Tom Clarke, Nature, 14 November 2003
Data from Ulysses show that the solar wind originates in holes in
the sun's corona,
and the speed of the solar wind varies inversely with coronal
temperature. "This
was completely unexpected. Theorists had predicted the opposite.
Now all models of
the sun and the solar wind will have to explain this
observation."
--Louis Lanzerotti, New Jersey Institute
of Technology/Bell Labs, 14 November 2003
(1) ASTEROID IMPACT RISK FURTHER REDUCED
Nature, 14 November 2003
(2) KECK OBSERVATIONS OF NEAR-EARTH ASTEROIDS IN THE THERMAL
INFRARED
Icarus, Volume 166, Issue 1 , November 2003,
Pages 116-130
(3) SEISMOLOGISTS MODEL UNLIKELY IMPACT TSUNAMI
Santa Cruz Sentinel, 16 November 2003
(4) "NO ONE REALLY KNOWS HOT SUN'S MAGNETIC FIELD IS FORMED
AND WHY IT CHANGES AS IT DOES"
Oliver Manuel <oess@umr.edu>
(5) U.S. AIR FORCE KEEPS A WARY EYE ON FEROCIOUS SPACE STORM
Andrew Yee <ayee@nova.astro.utoronto.ca>
(6) WHO WILL CONQUER THE MOON AND REAP ITS RICHES?
Space.com, 14 November 2003
(7) AND FINALLY: SIGNALS FROM SPACE ENABLE EARTHQUAKE DETECTION
Andrew Yee <ayee@nova.astro.utoronto.ca>
======
(1) ASTEROID IMPACT RISK FURTHER REDUCED
Nature, 14 November 2003
http://www.nature.com/nsu/031110/031110-14.html
TOM CLARKE
A new survey revises down the likelihood of a massive asteroid
hitting the Earth by 20-30%.
We're only due to collide with rocks larger than one kilometre
across roughly once every
600,000 years, it concludes (1).
"There was a lot of error in our previous estimates,"
says astronomer Alan Harris of the
German space agency, DLR. "It's all because near-Earth
asteroids are somewhat brighter than
we thought".
Near-Earth asteroids, or NEAs, are too small and too far away to
measure directly, so
astronomers approximate their size from how much light they
reflect. But reflectiveness
varies among asteroids of the same dimensions, thanks to
different rock types or dust
coatings, says Harris.
So instead his team used infrared detectors on the powerful Keck
telescope at Mauna Kea in
Hawaii to calculate the warmth of 20 NEAs - or how much energy
each absorbs.
Objects either reflect or absorb the light that reaches them. So
subtracting an asteroid's
warmth from the total light that falls on it from the Sun gives a
better measure of how
reflective it is, and hence how large, the researchers argue.
Applying the results of the sample to the 2,200 known NEAs,
suggests that around 1,090 are
more than a kilometre across. Previous estimates put the number
between 1,200 and 1,300.
The analysis doesn't change the chance of an asteroid hitting the
Earth, points out astronomer
Iwan Williams of Queen Mary University of London, UK. "But
assuming that there are fewer
large asteroids, the damage will be less," he says.
References
Delbó, M., Harris, A. W., Binzel, R. P., Pravec, P. &
Davies, J. K. Keck observations of near-Earth asteroids in the
thermal infrared. Icarus, 166, 116 - 130,
doi:10.1016/j.icarus.2003.07.002 (2003). |Article|
© Nature News Service / Macmillan Magazines Ltd 2003
===========
(2) KECK OBSERVATIONS OF NEAR-EARTH ASTEROIDS IN THE THERMAL
INFRARED
Icarus, Volume 166, Issue 1 , November 2003, Pages 116-130
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WGF-49KH00F-3&_coverDate=11%2F30%2F2003&_alid=128117419&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6821&_sort=d&view=c&_acct=C000043031&_version=1&_urlVersion=0&_userid=777686&md5=946b475fb807a0c30386294afd40aadd
Marco Delbóa, 1, Alan W. Harris, , a, Richard P. Binzelb, Petr
Pravecc and John K. Daviesd
a DLR Institute of Planetary Research, Rutherfordstrasse 2,
12489, Berlin, Germany
b Department of Earth, Atmospheric, and Planetary Sciences, MIT,
Cambridge, MA 02139, USA
c Astronomical Institute, Academy of Sciences of the Czech
Republic, CZ-25165, Ondejov, Czech Republic
d Astronomy Technology Centre, Royal Observatory Edinburgh,
Blackford Hill, Edinburgh EH9 3HJ, UK
Received 12 May 2003; revised 9 July 2003. Available
online 22 September 2003.
Abstract
We present the results of thermal-infrared observations of 20
near-Earth asteroids (NEAs) obtained in the period March
2000-February 2002 with the 10-m Keck-I telescope on Mauna Kea,
Hawaii. The measured fluxes have been fitted with thermal-model
emission continua to determine sizes and albedos. This work
increases the number of NEAs having measured albedos by 35%. The
spread of albedos derived is very large (pv=0.02-0.55); the mean
value is 0.25, which is much higher than that of observed
main-belt asteroids. In most cases the albedos are in the ranges
expected for the spectral types, although some exceptions are
evident. Our results are consistent with a trend of increasing
albedo with decreasing size for S-type asteroids with diameters
below 20 km. A number of objects are found to have unexpectedly
low apparent color temperatures, which may reflect unusual
thermal properties. However, the results from our limited sample
suggest that high thermal-inertia, regolith-free objects may be
uncommon, even amongst NEAs with diameters of less than 1 km. We
discuss the significance of our results in the light of
information on these NEAs taken from the literature and the
uncertainties inherent in applying thermal models to near-Earth
asteroids.
Copyright © 2003 Elsevier Inc. All rights reserved.
=============
(3) SEISMOLOGISTS MODEL UNLIKELY IMPACT TSUNAMI
Santa Cruz Sentinel, 16 November 2003
http://www.santacruzsentinel.com/archive/2003/November/16/local/stories/09local.htm
By AMY COOMBS
SANTA CRUZ - Imagine a tsunami that could wipe out Santa Cruz.
Steven Ward has.
Ward, Ph.D., a seismologist at the UC Santa Cruz Institute of
Geophysics and Planetary Physics, and his colleagues have
developed computer-simulation programs to model the potential
impact of an asteroid crashing into the ocean, resulting in
300-foot high waves.
The modeling comes in the wake of NASA predictions that a large
asteroid known as 1950DA will crash into Earth on March 16, 2880.
The odds that the asteroid will hit earth, scientists say, are
roughly one-in-1000.
Ward says collisions of this magnitude have happened in the past.
"There are 100 known craters (from asteroid crashes) on
land," says Ward. "As the ocean covers two-thirds of
the planet, we can expect there have been at least this many
asteroid- ocean collisions in the past."
Because collisions of this magnitude, though rare, are a real
possibility, Ward and his colleagues are studying the potential
impact on coastal regions.
Ward's models suggest that the impact, if an asteroid like the
ones that have previously hit Earth slams into the Atlantic
Ocean, could create waves that travel at more than 500 miles an
hour.
The results of Ward's computer modeling appeared in the June
issue of the "Geophysical Journal International."
Ward says that if a collision were to occur in the Pacific Ocean,
coastal towns like Santa Cruz could be completely submerged.
Scientists do not know where 1950DA, if it collides with Earth,
would land, nor what the impact would be.
They also say efforts to detect asteroids approaching Earth can
only identify a small percentage of the ones that actually will.
Many more asteroids await discovery, and of those found, some are
difficult to keep an eye on.
After its initial discovery, 1950DA disappeared. It wasn't
re-discovered until 2000, nearly 50 years later.
Most incoming rocks and boulders burn up in the Earth's
atmosphere before they hit land, and no one needs to lose sleep
over the possibility of a meteor-sparked tidal wave.
Instead, Ward says, the Monterey Bay Area is more likely to
experience a tsunami as a result of a landslide or earthquake.
Ward says that Santa Cruz has earthquakes big enough to cause a
tsunami every 50 years or so, which could cause large waves to
head ashore.
There was a tsunami associated with the 1989 earthquake. However,
it was small and barely noticeable.
Ward thinks that an earthquake of a magnitude 7.5 could cause a
15-foot tsunami to reach the Santa Cruz shoreline in a matter of
minutes under certain conditions.
"It's as if a giant stood in the sea and picked up the ocean
floor, tilting it and causing the water to run toward the
coast," he said.
The effect is sometimes more like a flash flood than a
Hollywood-style tidal wave, he explained. It's not a single,
giant wave that crashes on top of houses and buildings but water
that begins to flow in and never stops. Sometimes the water flows
in at 30 miles an hour, and sometimes it doesn't stop for 20 or
30 minutes.
There are no documented cases of a tsunami hitting Santa Cruz
after a local underwater landslide. However, Santa Cruz has been
hit by tsunamis caused by earthquakes.
In 1946 an elderly man was killed by a wave while walking around
the point from Cowell Beach from a 7.5-magnitude earthquake off
the coast of Alaska. A Santa Cruz restaurant located at the
entrance of the Municipal Wharf reported that water levels rose
up to its floorboards.
Offshore earthquakes along the Pacific Rim have caused multiple
tsunamis in Hawaii, where local beaches have sirens that warn
beach-goers to move to higher ground when a tsunami is thought to
be on the way.
In 1965, an earthquake with a magnitude of 9.5 - the largest
earthquake every recorded - occurred off the coast of Chili,
breaking nearly 600 miles of coastline. The quake caused 20 feet
of uplift and sent 10-foot high tsunamis towards Japan.
Steven Ward's Web site is www.es.ucsc.edu/~ward
Copyright 2003, Santa Cruz Sentinel
==========
(4) "NO ONE REALLY KNOWS HOT SUN'S MAGNETIC FIELD IS FORMED
AND WHY IT CHANGES AS IT DOES"
Oliver Manuel <oess@umr.edu>
Dear Benny,
This quote (from a NASA news release) demonstrates the current
state
of understanding about the origin of solar magnetic fields and
solar
eruptions.
The complete report is below.
With kind regards,
Oliver
---------
Date: Fri, 14 Nov 2003 14:11:25 -0500
From: "STEPHEN P. MARAN" <hrsmaran@eclair.gsfc.nasa.gov>
Subject: BELL LABS/NJIT: FIRST 3-D SOLAR STORMS OBSERVATIONS
BELL LABS/ NJIT JOINT NEWS RELEASE
For more information, please contact:
Gale Scott
New Jersey Institute of Technology
(973) 596 3438
gscott@njit.edu
Saswato Das
Lucent Technologies' Bell Labs
(908) 582 4824
srdas@lucent.com
SCIENTISTS REPORT FIRST-EVER 3-D OBSERVATIONS OF SOLAR STORMS
USING ULYSSES SPACECRAFT
New Jersey Institute of Technology/Bell Labs physicist Louis
Lanzerotti
was participated in international team that studied the unquiet
sun when
it was most active and found interesting phenomena
FOR RELEASE: FRIDAY, NOVEMBER 14, 2003
Newark, NJ-The sun's surface is a violent and turbulent place,
where
a fiery tempest always blows. Scientists are reporting in the
journal
Science today that they have finally succeeded in getting a good
three-dimensional view of it.
"The sun is huffing and puffing and blowing off steam,"
said Louis
Lanzerotti, a member of an international team that used the
Ulysses
spacecraft to make the first-ever 3-D study of our parent star
during
solar maximum, the peak of the sun's 11-year activity
cycle. "Ulysses
gave us a chance to observe the sun from unique vantage points to
better understand solar storms and their consequences."
Scientists have been trying to understand solar weather for
years, in
an effort to better predict terrestrial consequences of solar
storms.
Solar storms sometimes severely disrupt wireless telephone calls,
satellite communications and electric power grids on Earth.
Ulysses, launched in 1990 by the shuttle Discovery as a joint
mission
of NASA and the European Space Agency, has an orbit that takes it
over the solar poles, giving scientists a chance to look at the
sun
from all angles.
"No other spacecraft can do that," said Lanzerotti, a
solar physicist
who divides his time between Lucent Technologies' Bell Labs,
which he
joined in 1965 and where he is now a consultant, and the New
Jersey
Institute of Technology, where he is a distinguished research
professor at the Center for Solar Terrestrial Research.
"Many space
missions have observed the sun near its equator, but only Ulysses
has
traveled from the solar equator to above the sun's polar
caps."
Ulysses began its first solar orbit in 1992 and completed it in
1998,
a period when solar activity was at a minimum. But during the
second
orbit, begun in 1998, the sun was at its most turbulent.
The scientists report that, during this period, huge explosions
on
the sun hurled vast amounts of solar material into space.
Called
coronal mass ejections, since the sun's outermost layer -- the
corona
-- throws them off, these swirling, boiling plumes travel out
from
the sun and are thought to be caused by the severest of solar
gales.
"We just had a coronal mass ejection last week,"
Lanzerotti noted.
"These are some of the most violent phenomena associated
with the
sun. We were able to look at a few that happened around the
recent
solar maximum."
The team also got to observe the solar wind - the stream of
charged
particles that are emitted by the sun. The solar wind
blows out a
giant bubble called the heliosphere within the interstellar
medium,
the dilute gas and dust that fills the space between stars. The
sun's
influence extends far beyond the orbits of the outer planets and
the
vast reservoir of periodic comets known as the Kuiper Belt
because
the solar wind fills the heliosphere and exerts an outward
pressure
on the interstellar medium. (The boundary between the heliosphere
and
the interstellar medium is the true edge of the solar system, a
place
where a lot of interesting physical phenomena take place.
Last week,
a separate team of scientists, of which Lanzerotti is also a
member,
reported in the journal Nature that Voyager 1 has reached the
edge of
the solar system.)
Data from Ulysses show that the solar wind originates in holes in
the
sun's corona, and the speed of the solar wind varies inversely
with
coronal temperature.
"This was completely unexpected," said
Lanzerotti. "Theorists had
predicted the opposite. Now all models of the sun and the solar
wind
will have to explain this observation."
Another surprising finding based on Ulysses' data is that the
sun's
magnetic field originates from a magnet that seems to be
perpendicular to the sun's axis of rotation (instead of being
parallel
to it, as is the case with Earth).
"At solar maximum, the sun's polar cap magnetic fields
reverse
direction or sign," said Edward Smith of NASA's Jet
Propulsion Lab at
the California Institute of Technology, who is the US project
scientist for the Ulysses mission. "Inward fields become
outward and
vice versa. Ulysses observations show that during this reversal,
the
Sun's magnetic poles are located near the solar equator instead
of in
the polar caps."
The sun has a powerful magnetic field -- the needle of a compass
placed on the sun's surface would be deflected so strongly that
it
would require Herculean strength to push it back. It is thought
that
solar activity is strongly related to changes in the sun's
magnetic
field.
"We knew that the sun's magnetic field was dynamic and
variable,"
said Lanzerotti. "But this shows that we still have a lot of
understanding to do. No one really knows how it is formed and why
it
changes as it does."
Other members of the scientific team were: R.G. Marsden (European
project scientist) and M. Landgraf of the European Space Agency
in
the Netherlands; A. Balogh of Imperial College, London; G.
Gloeckler of the University of Maryland; J. Geiss of the
International Space Science Institute in Switzerland; D. J.
McComas
of Southwest Research Institute; R.B. McKibben of the University
of
New Hampshire; R. J. MacDowall of NASA Goddard Space Flight
Center;
and N. Krupp and H. Krueger of the Max Planck Institutes in
Germany.
The team's paper, "The Sun and Heliosphere at Solar
Maximum,"
appears in the November 14, 2003 issue of Science on page 1165.
About NJIT
NJIT, located in Newark, New Jersey, is a public, scientific and
technological research university enrolling more than 8,800
students. The university offers bachelor's, master's and
doctoral
degrees to students in 80 degree programs throughout
its six
colleges: Newark College of Engineering, New Jersey School of
Architecture, College of Science and Liberal Arts, School of
Management, Albert Dorman Honors College and College of Computing
Sciences. The division of continuing professional education
offers adults eLearning, off campus degrees and short courses.
Expertise and research initiatives include architecture and
building science, applied mathematics, biomedical engineering,
environmental engineering and science, information technology,
manufacturing, materials, microelectronics, multimedia,
telecommunications, transportation and solar astrophysics.
NJIT
ranks in the top tier of U.S. News & World Report's list of
national doctoral universities.
About Lucent Technologies' Bell Labs
Bell Labs is the leading source of new communications
technologies.
It has generated more than 30,000 patents since 1925 and has
played
a pivotal role in inventing or perfecting key communications
technologies, including transistors, digital networking and
signal
processing, lasers and fiber-optic communications systems,
communications satellites, cellular telephony, electronic
switching
of calls, touch-tone dialing, and modems. Bell Labs
scientists
have received six Nobel Prizes in Physics, nine U.S. National
Medals of Science and eight U.S. National Medals of Technology.
For
more information about Bell Labs, visit its Web site at
http://www.bell-labs.com.
Lucent Technologies (NYSE: LU), headquartered in Murray Hill,
N.J.,
USA, designs and delivers networks for the world's largest
communications service providers. Backed by Bell Labs
research and
development, Lucent relies on its strengths in mobility, optical,
data and voice networking technologies as well as software and
services to develop next-generation networks. The company's
systems,
services and software are designed to help customers quickly
deploy
and better manage their networks and create new,
revenue-generating
services that help businesses and consumers. For more information
on Lucent Technologies, visit its Web site at http://www.lucent.com.
===============
(5) U.S. AIR FORCE KEEPS A WARY EYE ON FEROCIOUS SPACE STORM
Andrew Yee <ayee@nova.astro.utoronto.ca>
Public Affairs
Air Force Research Laboratory
CONTACT: John Brownlee
PHONE: (505) 846-4704
November 3, 2003
VS RELEASE NO. 03-28
Air Force Keeps a Wary Eye on Ferocious Space Storms
HANSCOM AIR FORCE BASE, MA -- If you plan to orbit the Earth this
week, be sure
to pack plenty of sunscreen. Two whopping solar flares -- among
recorded
history's worst 20 -- have blasted the Earth's protective
magnetosphere with
potent clouds of solar radiation and energized particles from the
sun, leaving
in their wake the potential for fried satellites and scrambled
circuits on the
ground. Not good news for electronically-dependant military and
civilian
telecommunication operations.
But instead of merely complaining about this "weather"
in space, solar
physicists at the Air Force Research Laboratory's (AFRL) Space
Weather Center of
Excellence outside Boston are actually doing something about it.
And they rely
on one of their most recent space-based tools, the Solar Mass
Ejection Imager
(SMEI), to track the sun's activity.
Also known as coronal mass ejections, or CMEs, solar eruptions
are incompletely
understood yet natural phenomena that occur periodically -- often
in 11-year
cycles -- and with varying levels of intensity. They trigger
geomagnetic storms
-- this week's first one rated at G5, the highest possible --
harmful to
spacecraft and communications, increase radiation exposure for
astronauts and
high-flying aircraft, and damage ground-based power grids and
subsystems. Such
storms have impaired U.S. communication satellites in the past
and blacked-out
power stations in Canada. This week's solar assault forced some
air traffic
controllers to alter aircraft flight plans due to disrupted radio
transmissions
and crippled two Japanese satellites. If CMEs were better
understood and more
accurately anticipated, steps might then be taken to mitigate
their disruptive
effects, such as temporarily shutting down satellites and
switching off power
systems. SMEI is now beginning to help shed some light on the yet
hidden
mysteries behind solar storms and their effects on advanced
technology.
For its solar reconnaissance mission, SMEI uses first-of-a-kind
cameras aboard
Coriolis, a DoD Space Test Program spacecraft. Launched just nine
months ago,
SMEI and its highly sensitive cameras reached orbit just in time
to study how
such violent storms behave. Built as a proof-of-concept
experiment to detect,
track and forecast CMEs, SMEI has now detected many of the sun's
radiation-laden
eruptions.
"An Earth-bound CME looks like a broad, bright,
outward-moving ring with the sun
at its center, or a halo," said AFRL geophysicist David
Webb. "Our SMEI cameras
have detected two of them within the last week, which were part
of a series of
major events centered around two huge sunspot groups on the
sun," he added. An
image of the first event in this series appears in Figure 1. Fig.
2 shows two
white light images of the Sun showing the motion of the sunspots
over 5 days.
SMEI, in a sun-synchronous polar orbit around the Earth, can
detect even fast,
Earth-bound CMEs up to a day before their arrival, providing
valuable early
warning of an impending storm unobtainable until now. Warning
time is truly of
the essence here, given that one solar eruption this week took
only took 19
hours to reach the Earth. Seeing CMEs in this distance range
(20-180 degrees
from the sun) is a new capability that along with other space
environment
sensors promises to greatly enhance the space weather "big
picture."
"Although the jury is still out on what impact all this
recent solar activity
has had on satellites and ground communications, we expect that
SMEI, only in
its first year of operation, will better enable us to predict
future solar
events and provide earlier warning of incoming CMEs," he
said. "Then we can take
preventative measures to protect sensitive electronics, in space
as well as on
the ground."
IMAGE CAPTIONS:
[Figure 1:
http://www.vs.afrl.af.mil/News/images/03-28-A.jpg
(62KB)]
Partial field of view of SMEI camera 3 on Oct. 29 at 02:10 UT.
The + sign
denotes the Sun's position and the dark circle is an excluded
zone around the
Sun. This is a difference image of the previous orbit subtracted
from the
present one. Arrows point to bright/dark arcs to the upper right
and the bright
structure to the lower left that are parts of the halo CME.
Black/white areas
are contamination by particles in Earth orbit.
[Figure 2:
http://www.vs.afrl.af.mil/News/images/03-28-B.jpg
(43KB)]
White light images of the Sun on Oct. 23 and 28, both at 00:00
UT. From SOHO MDI
instrument.
========
(6) WHO WILL CONQUER THE MOON AND REAP ITS RICHES?
Space.com, 14 November 2003
http://www.space.com/businesstechnology/technology/space_resources_031114.html
Extraterrestrial Resources: 'Living off the Land'
By Leonard David
GOLDEN, Colorado -- Outer space has an endless supply of
resources. Within rocket's reach there are light buckets full of
intense solar energy, at least out to Mars. Then there are
valuable materials on the Moon, as well as on Mars and its moons.
Near Earth asteroids offer yet another mother lode of minerals.
At present, the vast gulf of space prohibits access to these
treasures, but a loosely knit group of like-minded experts
believe that by tapping the rich resources of space, humanity's
foothold on other worlds will be far more secure and long-lived.
Mining specialists, space engineers, and energy strategists were
among those gathered at Space Resources Roundtable V, held here
October 28-30 at the Colorado School of Mines.
Also giving space resource mining its "due diligence"
were lawyers. Turns out you can't leave Earth without them.
Trans-space railroad
If humans are ever to truly spread their wings in space, they
must be nourished and sustained by space resources. That means no
less than "living off the land", severing the supply
umbilical of Mother Earth. It's also tagged as in-situ resource
utilization -- or ISRU in space lingo short speak. Off-world
resources can be transformed into oxygen, propellant, water, as
well as used for construction purposes and to energize power
stations.
As new trade routes flourish in space, space resources,
particularly energy and the systems needed to collect and
distribute it, will grow in importance as their value and uses
begin to be realized. Moreover, commercial opportunities are
expected to exist within this growing domain.
"ISRU really is the stepping stone, a key part of the
development of space," said Gerald Sanders, Chief,
Propulsion and Fluid Systems Branch at NASA's Johnson Space
Center in Houston, Texas. "We can do things at low Earth
orbit bringing materials up from Earth. But once you start
getting any distance away from low Earth orbit, the leveraging
just isn't there," he told SPACE.com .
Sanders envision a progressive build-up of space infrastructure,
akin to a space-based railroad. Part of that trans-space network
of hardware is a depot at the Lagrangian L1 point, along with use
of Moon-made propellant.
In the past, rocketeers have been focused on cutting the costs of
lobbing payloads from Earth into space. In some quarters, that
has evoked a "so cheap to launch, everything can be thrown
away" attitude. But even if launch costs were radically
reduced, Sanders said, not throwing space hardware away makes far
greater sense.
All that translates into reusable and sustainable space
infrastructure.
International bid for the Moon
"The enthusiasm is perennial. We're all infected with the
same dream," said Brad Blair, Ph.D student in mineral
economics at the School of Mines. He acknowledges that the NASA
humans-to-the-Moon program of the late 1960s into the early 1970s
was a certifiable statement of American technical prowess.
In essence, the dusty dozen Apollo moonwalkers were the first
prospectors to site-survey another world.
"Apollo was a grand one but there was a lot of potential
that was left hanging...now left hanging for the last 30 years or
so," Blair said. "We seem to be hooked on this idea of
throwing away infrastructure as soon as we make it in
space," he added.
"It's very interesting right now to realize that there are
two countries with the ability to put humans into space, and the
United States is not one of them," Blair said, noting
China's recent entry into the human spaceflight arena along with
Russia's on-going launch of passenger-carrying Soyuz spacecraft.
Blair senses that there is an "international bid" for
the Moon, driven by such nations as China and India that want to
go the lunar distance in years to come.
Is there a lunar payoff out there?
Finding an economic return on the Moon is critical for any
commercial enterprise to cough up investment money, Blair said.
"All of our research so far indicates that there's still
need for reliance on the government to get that kicked off."
Once an entrepreneur sees a profitable edge to a Moon-derived
product, Blair foresees a stampede towards the door by space
capitalists trying to make the next buck. It's a matter of
getting the process started. NASA has the ability to open those
doors, to reduce the business risk and help spearhead the
economic development of space, he said.
Strategic and economic potential
The concepts for utilizing the Moon's resources continue to
expand, said Michael Duke, the Roundtable's organizer and
Director of the Center for Commercial Applications of Combustion
in Space (CCACS) at the School of Mines.
Duke said that the discovery of hydrogen deposits -- perhaps in
the form of water -- at the lunar poles should be stimulating
NASA and other countries to investigate the strategic and
economic potential of that resource.
Data presented at the Roundtable meeting suggests propellants
produced from lunar ice could be developed commercially, Duke
said. "However, we must first learn more about its location
and concentration."
A surface exploration program to one of the lunar poles should be
undertaken, Duke believes, to better determine just how much ice
is resident there and how tough it would be to mine the material,
then process it to produce fuel. "Lunar propellant can
become a stepping stone for human expansion into the solar
system," he said.
Whether or not water ice is tucked away in niches at the lunar
poles remains debatable, however.
Researchers analyzing data gleaned from NASA's Lunar Prospector
orbiter, as well as the Pentagon's Clementine spacecraft, argue
that hydrogen, likely in the form of water ice, exists in huge
quantities hidden within craters free of the Sun's warming rays.
It was reported at the meeting that there are
"discrepancies" in the data supporting the water ice
idea. Carbon deposits at the lunar poles, rather than
hydrogen/water ice, was offered as one possibility for what has
been detected on the Moon.
Legal landscape
The greatest need -- to prepare not only for Moon mining, but
also digging out resources from Mars -- is not for technological
breakthroughs. Rather, it is for information and clarification.
That's the belief of Leslie Gertsch, Assistant Professor of
Geological Engineering at the Rock Mechanics & Explosives
Research Center at the University of Missouri-Rolla.
It is obvious that fundamental differences exist between the
working conditions on Earth contrasted to the Moon and Mars,
Gertsch said. On the other hand, we shouldn't forget the know-how
gained by humans after more than 10 millennia of extracting
natural resources on our own planet, she noted.
First of all, Gertsch said, the legal landscape for
extraterrestrial resource ownership and extraction must be
clarified. Additionally, there needs to be detailed feedstock
specifications for products that could be made using off-Earth
materials. Obtaining more, and higher resolution data on
prospective deposits needed for space mining -- using both
orbiters and landers -- is critical too. Lastly, achieving and
maintaining the link to the Moon and Mars is key, she said.
Extraterrestrial mining is sure to involve interactions that
won't be discovered until on-the-spot work takes place, Gertsch
said. The effects of gravity, vacuum, even how particles act when
put in a pile or fed through processing machinery...these and
other factors need to be considered in moving space mining into
high gear, she said.
Terrestrial mining and milling are not designed for use on the
Moon or Mars, Gertsch said. "They are doable, but at the
cost of being terribly inefficient. Modifying these processes to
bring their efficiency up to commercial levels will be
non-trivial, but it's not necessary to achieve perfection
beforehand," she reported.
"We need to get out there and try these things out,"
Gertsch advised.
Glass roads
Throughout the three-day meeting, numbers of space mining ideas
were tabled.
For example, Lawrence Taylor, Director, Planetary Geoscience
Institute at the University of Tennessee in Knoxville advanced
the idea of microwave processing of lunar soil.
Taylor, along with colleague Thomas Meek, is studying how lunar
regolith -- the topside blanket of "soil" comprised of
stone, fine powder and rock fragments -- can be sintered and
melted to create a variety of products.
"What's been found really presents us with a fantastic
situation," Taylor explained. First of all, the magnetic
properties of lunar soil are a lot different than ever thought.
Making use of an array of microwaves, working at adjustable
frequencies and power settings, lunar soil can be simply and
effectively sintered to varying depths.
"I can actually put a glass coating on the upper inch or so.
I can make whatever kind of roads you want," Taylor said.
Focused microwaves can blast the lunar soil to also make
shielding, antenna dishes, glass fiber, and other products, such
as solar cells made out of ilmenite. Even an igloo can be made
using the concept, Taylor said.
"It depends on how far you want to stretch your
imagination," Taylor said. The best match of Moon and
microwave processing, in terms of efficiency and soil
composition, is the Apollo 17 landing site - the valley called
Taurus-Littrow.
Master of the space domain
A relatively new legal concept, "telepossession", was
detailed at the Space Resources Roundtable.
Richard Westfall, head of Galactic Mining Industries, Inc. of
Denver, Colorado, suggested that telepossession can be used to
establish title to asteroids accessible from Earth orbit.
The notion is to use robot emissaries to perform tasks that a
hands-on asteroid miner could do at a remote site. That includes
gaining legal domain over a property and establishing a form of
legal possession of the mini-world. Here on Earth, this legal
model has been applied to maritime salvage of a shipwreck using
underwater telerobots.
Westfall proposed creation and use of Telepossession Probes: A
lander and a relay spacecraft.
Rendezvousing with an asteroid in space, the lander performs the
tasks of assaying the space rock, drilling, and turning out a
product. All these lander activities are sent to the relay
spacecraft. This relay craft not only oversees the asteroid's
position and condition 24 hours a day, 365 days a year, but also
collects assay data and transmits this information to Earth
operators.
No doubt the idea of gaining some sort of legal footing on an
asteroid via robots is sure to spark legal beagle-type debates.
"Part of the education process in the international legal
community is to educate people that resources in outer space are
virtually unlimited," noted Wayne White Jr., a space law
consultant in Huntsville, Alabama. "There's more than enough
for everyone," he said.
"We must look at the great frontier of space as the next
place to get our large injection of resources," Westfall
said. "I admit that we might be opening a can of worms. But
you've got to have worms to catch fish," he said.
Copyright 2003, Space.com
===========
(7) AND FINALLY: SIGNALS FROM SPACE ENABLE EARTHQUAKE DETECTION
Andrew Yee <ayee@nova.astro.utoronto.ca>
ESA News
http://www.esa.int
31 October 2003
Signals from space enable earthquake detection
A violent earthquake that cracked highways in Alaska set the sky
shaking as well
as the land, an ESA-backed study has confirmed.
This fact could help improve earthquake detection techniques in
areas lacking
seismic networks, including the ocean floor.
A team from the Institut de Physique du Globe de Paris and the
California
Institute of Technology has successfully used the Global
Positioning System
(GPS) satellite constellation to map disturbances in the
ionosphere following
last November's magnitude 7.9 earthquake in Denali, Alaska.
Their paper has been published in the scientific journal
Geophysical Research
Letters. The research itself was carried out in support of ESA's
Space Weather
Applications Pilot Project, aimed at developing operational
monitoring systems
for space conditions that can influence life here on Earth.
The ionosphere is an atmospheric region filled with charged
particles that
blankets the Earth between altitudes of about 75 to 1000 km. It
has a notable
ability to interfere with radio waves propagating through it.
In the particular case of GPS navigational signals, received on
Earth from
orbiting satellites, fluctuations in the ionosphere -- known as
'ionospheric
scintillations' -- have the potential to cause signal delays,
navigation errors
or in extreme cases several hours of service lockouts at
particular locations.
But while such interference can be an inconvenience for ordinary
GPS users, it
represents a boon for scientists. By measuring even much
smaller-scale shifts in
GPS signal propagation time -- caused by variations in local
electron density as
the signal passes through the ionosphere -- researchers have at
their fingertips
a means of mapping ionospheric fluctuations in near real time.
The French and US team made use of dense networks of hundreds of
fixed GPS
receivers in place across California. These networks were
originally established
to measure small ground movements due to geological activity, but
they can also
be utilised to plot the ionosphere structure across three
dimensions and in fine
detail.
Then when the Denali earthquake occurred on 3 November 2002, the
team had a
chance to use this technique to investigate another distinctive
property of the
ionosphere, its ability to work like a natural amplifier of
seismic waves moving
across the Earth's surface.
There are several different types of seismic waves moving the
ground during an
earthquake, the largest scale and the one that does most of the
movement is
known as a Rayleigh Wave. This type of wave rolls along the
ground up and down
and side-to-side, in the same way as a wave rolls along the
ocean.
Previous research has established that shock waves from Rayleigh
Waves in turn
set up large-scale disturbances in the ionosphere. A one
millimetre peak-to-peak
displacement at ground level can set up oscillations larger than
100 metres at
an altitude of 150 km.
What the team were able to do following the Denali quake was
detect a
distinctive wavefront moving through the ionosphere. "Using
the network allowed
us to observe the propagation of the waves," explained
co-author Vesna Ducic.
"We could also separate the small total electron content
signal from the very
large total electron content variations related to the daily
variation of the
ionosphere."
The team observed a signal two to three times larger than the
noise level,
arriving about 660 to 670 seconds after the arrival of Rayleigh
Waves on the
ground. And because around six GPS satellites are visible to
every ground
receiver they were able to calculate the altitude of maximum
perturbation --
around 290 to 300 km up.
The signals were weak and only sampled every 30 seconds, with a
maximum
resolution of 50 km and the overall noise rate high. But the
ionospheric signal
observed had a clear pattern consistent with models of seismic
behaviour. The
hope is that the technique can be improved in future, and used to
detect
earthquakes in areas without seismic detectors, such as the deep
ocean or near
islands.
"In the framework of Galileo we plan to develop this
research," said Ducic.
"Galileo will double the number of satellites and therefore
will allow much more
precise maps of the ionosphere. We can also foresee that Europe
will develop a
dense network of Galileo/GPS stations that will take part in the
monitoring of
these phenomena.
"ESA, together with the French Ministry of Research and CNES
have already
decided to fund a pre-operational project called SPECTRE --
Service and Products
for Ionosphere Electronic Content and Tropospheric Refractive
index over Europe
from GPS -- devoted to the high-resolution mapping of the
ionosphere. We will be
carrying out mapping above Europe as well as California.
"These investigations will support the French space agency
CNES's DEMETER
(Detection of Electro-Magnetic Emissions Transmitted from
Earthquake Regions)
microsatellite, to be launched in 2004 and devoted to the
detection in the
ionosphere of seismic, volcanic and man-made signals. These ESA
activities will
be performed in the framework of the Space Weather Applications
Pilot Project."
The Space Weather Applications Pilot Project is an ESA initiative
which has
already begun to develop a wide range of application-oriented
services based
around space weather monitoring.
The co-funded services under development -- of which this project
is one -- also
include forecasting disruption to power and communication
systems, and the
provision of early warning to spacecraft operators of the hazards
presented by
increased solar and space weather activities. The hope is that an
a seismic
detection service based on ionospheric measurements may in future
supplement
existing resources in Europe and elsewhere.
Related links
* Geophysical Research Letters
http://www.agu.org/grl/
* Article abstract
http://www.agu.org/pubs/crossref/2003/2003GL017812.shtml
* ESA Space Weather Applications Pilot Project
http://www.estec.esa.nl/wmwww/wma/spweather/esa_initiatives/pilotproject/pilotproject.html
* Institut de Physique du Globe de Paris
http://www.ipgp.jussieu.fr/index2.html
* DEMETER
http://smsc.cnes.fr/DEMETER/
* SPECTRE
http://ganymede.ipgp.jussieu.fr/projets/spectre/
IMAGE CAPTIONS:
[Image 1:
http://www.esa.int/export/esaSA/SEMUPAWLDMD_earth_1.html]
An Alaska Department of Transportation truck sits at the edge of
one of the
large cracks on the Tok Cutoff Highway, near Mentasta, Alaska,
Monday, Nov. 4,
2002, caused by an 7.9 magnitude earthquake on Sunday that rocked
a sparsely
populated area of interior Alaska. Bruce Turner of the West Coast
and Alaska
Tsunami Warning Center in Palmer, Alaska, said the quake hit at
1:13 p.m Alaska
Standard Time and was centered 90 miles south of Fairbanks.
Credits: AP Photo/Alaska Department of Transportation
[Image 2:
http://www.esa.int/export/esaSA/SEMUPAWLDMD_earth_1.html#subhead1]
Solid Earth-atmosphere coupling at teleseismic distances. Adapted
from Calais &
Minster [1995]. Data shown correspond to the vertical
displacement in France
after Izmit earthquake recorded on SSB seismometer (Geoscope,
France) and by the
Francourville Doppler sounding network, at an altitude of about
170 km.
Credits: ESA
[Image 3:
http://www.esa.int/export/esaSA/SEMUPAWLDMD_earth_1.html#subhead3]
Image of the wave front in the ionosphere and its intersection of
signals
between GPS satellites 26 and 29 and California GPS stations. The
wave front can
be detected by measuring the total electron content of the
signals.
Credits: ESA
[Image 4:
http://www.esa.int/export/esaSA/SEMUPAWLDMD_earth_1.html#subhead5]
The figure shows California GPS receivers location and 'piercing
points' for
ionospheric measurements from all receivers in California (SCIGN
+ BARD + IGS
GPS networks). Different satellites are shown in different
colours. The black
star shows the epicentre location for the Denali earthquake. The
piercing point
is the intersection point between the GPS ray path
(receiver-satellite) and a
spherical shell with infinitesimal thickness at the mean altitude
of the peak in
the electron density profile.
Credits: ESA
[Image 5:
http://www.esa.int/export/esaSA/SEMUPAWLDMD_earth_1.html#subhead6]
Galileo's new technology will revolutionise our transport
systems, increasing
safety and improving efficiency; this will make for better
quality of life and
less pollution in our cities. Galileo will also bring benefits in
other aspects
of everyday life, with precision farming raising yields, improved
information
for emergency services speeding up response times, and more
reliable and
accurate time signals underpinning our most vital computer and
communications
networks.
Credits: ESA - J.Huart
[Image 6:
http://www.esa.int/export/esaSA/SEMUPAWLDMD_earth_1.html#subhead8]
The DEMETER (Detection of Electro-Magnetic Emissions Transmitted
from Earthquake
Regions) microsatellite will be launched by the French Space
Agency CNES in
2004. It is designed to detect fluctuations in the ionosphere.
Credits: CNES
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