PLEASE NOTE:
*
CCNet, 34/2003 - 25 March 2003
-------------------------------
"Britain is planning its first solo space science mission in
20 years. Scientists hope to send a satellite into deep space to
study solar influences on climate change. The Earthshine mission
would showcase British expertise and provide vital data on
climate change. Principal investigator Mike Lockwood believes
going it alone will deliver answers more quickly than joining
forces with other nations."
--Helen Briggs, BBC News Online, 24 March 2003
(1) UK SEEKS TO GO IT ALONE IN SPACE
BBC News Online, 24 March 2003
(2) TOO FEW LUNAR METEORITES
Sky & Telescope, 20 March 2003
(3) ISRAEL JOINS INTERNATIONAL EFFORT TO GUARD OUR PLANET AGAINST
COSMIC COLLISIONS
The Jerusalem Post, 20 March 2003
(4) ROSETTA TO PLAY ORBITAL MECHANICS TO REACH COMET
CHURYUMOV-GERASIMENKO
SpaceDaily, 23 March 2003
(5) AND FINALLY: THE COMPLETE IDIOT'S GUIDE TO SURVIVING ANYTHING
Ottawa Citizen, 23 March 2003
==========
(1) UK SEEKS TO GO IT ALONE IN SPACE
>From BBC News Online, 24 March 2003
http://news.bbc.co.uk/1/hi/sci/tech/2880845.stm
By Helen Briggs
Britain is planning its first solo space science mission in 20
years, BBC News Online has learned.
Scientists hope to send a satellite into deep space to study
solar influences on climate change.
The Earthshine mission would showcase British expertise and
provide vital data on climate change.
Principal investigator Mike Lockwood believes going it alone will
deliver answers more quickly than joining forces with other
nations.
"The need is to get the data quickly," he told BBC News
Online. "Science has moved to a point where people are
asking questions now that we can't answer because we don't have
the data."
Maverick opinion
Earthshine strays into the contentious area of the Sun's
influence on climate change.
Evidence suggests that variations in the amount of solar
radiation reaching the Earth, because of changes in the Sun's
activity, may impact on climate.
Most observers believe the solar contribution is minor compared
with humanity's footprint on the planet but a few scientists
argue that it may equal or outweigh human factors.
Dr Lockwood of the Rutherford Appleton Laboratory in Oxfordshire
is keen to stress that he does not take the maverick view.
"I am not out to prove that anthropogenic effects are caused
by the Sun," he said. "This (solar variability) is in
no way a rival to manmade effects."
'Unique view'
The nature and extent of solar influence on climate is not fully
understood, however, which is where Earthshine comes in.
The spacecraft would carry out experiments from a vantage point
about 1.5 million kilometres from the Earth where there is an
uninterrupted view of the Sun.
The spacecraft would have a "unique view" of the
sunlight reflected back out to space by our planet, hence its
name, Earthshine.
Its three scientific instruments would probe cosmic rays and
clouds to test current models of climate change.
"The possibility that current climate models underestimate
the effect of solar variations on climate is probably the single
most contentious issue in climate research at the moment,"
said Dr Myles Allen of the department of physics at Oxford
University.
"The mission has the potential to settle the argument or at
least put an upper figure on how far the models are wrong."
Dr Lockwood estimates that Earthshine would cost about £16m,
which he says is "absolutely tiny" for a space mission.
The Particle Physics and Astronomy Research Council, the Natural
Environment Research Council and the Department of Trade and
Industry are expected to provide funding. The satellite would be
built by the space company, Astrium.
Copyright 2003, BBC
=============
(2) TOO FEW LUNAR METEORITES
>From Sky & Telescope, 20 March 2003
http://skyandtelescope.com/news/current/article_905_1.asp
By J. Kelly Beatty
March 20, 2003 | It's been 20 years since planetary scientists
first realized that chunks of the Moon and Mars were practically
falling into their laps as meteorites. And, while thankful for
the free samples, they've always puzzled over why these two
worlds are represented roughly equally on Earth. To date
collectors have snatched up 24 distinct meteorites from the Moon
(some of which were found in multiple pieces or paired with other
finds) and 28 from Mars.
The puzzle arises because the lunar specimens should outnumber
their Martian counterparts by more than 100 to 1. For one thing,
the Moon's weaker gravity means that a much smaller impact will
accelerate lunar debris to escape velocity, compared to the more
energetic (and thus rarer) blasts necessary to eject something
from Mars. Calculations performed several years ago by Brett
Gladman (University of British Columbia) show that, once launched
into space, a chunk of lunar rock has about a 50-50 chance of
ending up on Earth - 10 times better odds than for an arrival
from Mars.
So why aren't the meteorite-rich tracts of Antarctica and Saharan
Africa littered with more chunks of Tycho and Mare Imbrium? The
answer, according to James N. Head (Raytheon Missile Systems),
may be that most of them have simply disappeared over the past
100,000 years or so, eroded to oblivion by wind and water. Head
says that most meteorites from the Moon should reach Earth within
only about 10,000 years, so if by chance there haven't been any
recent lunar impacts, the arrival rate right now will be in a
deep lull, and the old ones will be mostly gone.
Martian meteorites, by contrast, take an average of roughly 10
million years to make their way here, ensuring a steadier arrival
rate. Long after the most recent wave of lunar rocks are
eradicated by weathering, new messengers from Mars will keep
trickling in - roughly once per month. Notably, four Martian
falls have been witnessed firsthand, whereas no one has seen a
piece of the Moon descending to Earth.
But there's a problem with this scenario. Head's scheme, which he
presented yesterday at the annual Lunar and Planetary Science
Conference, implies that all lunar meteorites should be recent
arrivals, and that's not the case. Of the 13 with
well-established travel times (determined by measuring their
exposure to cosmic rays while in transit), six left the Moon
between 500,000 and 9 million years ago. In fact, notes Kunihiko
Nishizumi (University of California, Berkeley), lunar and Martian
meteorites share the same basic age distribution.
Nonetheless, Head says, to date the census of the two groups is
still "a wash," with 99 percent of the expected lunar
meteorites somehow staying out of collectors' hands. Gladman
agrees, noting that the near-equal numbers of lunar and martian
meteorites "must be a consequence of the finite age of the
[Antarctic] ice sheet combined with transfer dynamics that today
deliver few meteorites from ancient lunar impacts, but a
reasonable flux from larger ancient martian impacts."
Copyright 2003 Sky Publishing Corp.
===============
(3) ISRAEL JOINS INTERNATIONAL EFFORT TO GUARD OUR PLANET AGAINST
COSMIC COLLISIONS
>From The Jerusalem Post, 20 March 2003
About 65 million years ago, the collision of an asteroid about 10
kilometers in diameter with the Earth was apparently responsible
for a thick layer of dust that killed off the dinosaurs, along
with most life forms then in existence. Space researchers,
including those at the Israel Space Agency (ISA), want to keep an
eye on such cosmic vagabonds. The Israeli Knowledge Center on
Celestial Bodies Threatening the Earth was established at Tel
Aviv University recently. Dr. Noah Brosch, director of the
university's Wise Observatory, serves as its director.
The ISA chose TAU and scientists from its academic staff to
create and operate the national knowledge center on "Near
Earth Objects" (NEOs) - space objects liable to collide with
our planet and cause immense damage some day. The NEO center is a
collaboration among the university's department of astronomy and
astrophysics, the department of geophysics and planetary
sciences, and the school of education.
Apart from the major planets, the solar system contains a
population of small bodies called "minor planets"
(asteroids) and comets. The International Astronomical Union
collects information about more than 60,000 such bodies. Most of
them orbit between Mars and Jupiter, while the comets reach
father away. About 500 small bodies are known to approach rather
close to Earth and, in rare cases, could collide with it. The
danger of such impacts is now known to the scientists and to
various governmental agencies. The US Congress charged the
National Aeronautics and Space Administration with identifying
90% of such celestial bodies larger than one kilometer in
diameter by 2008. Other countries initiated similar programs and
now, with the establishment of the new knowledge center, Israel
has joined the global effort.
The center's activities include observations from the Wise
Observatory and others to detect new NEOs and follow-up known
objects, as well as the organization of educational events for
the general public. The first operational phase includes
observations with the existing one-meter telescope. The second
phase will see the introduction of an additional telescope to
search for new asteroids and follow them automatically.
The members of the knowledge center encourage cooperative efforts
with amateur astronomers and the education system. The center's
work plan and NEOs will be discussed on April 13 from 9 a.m. at
TAU's Lev Auditorium. The center operates a dedicated Web site
at: http://spaceguard.tau.ac.il.
Copyright 2003, The Jerusalem Post
============
(4) ROSETTA TO PLAY ORBITAL MECHANICS TO REACH COMET
CHURYUMOV-GERASIMENKO
>From SpaceDaily, 23 March 2003
http://www.spacedaily.com/news/rosetta-03e.html
by Bruce Moomaw
Sacramento - Mar 23, 2003
"SpaceDaily" has now acquired additional information on
the favored new mission plan for Europe's Rosetta
comet-rendezvous spacecraft, whose planned January launch to
comet Wirtanen had to be cancelled due to the disastrous failure
of the immediately preceding launch of its Ariane 5 booster.
While a delayed launch to Wirtanen next January cannot be
completely ruled out, the most probably replacement mission for
the craft is a launch next February . Since this comet's nucleus
is thought to be considerably bigger than Wirtanen's, this will
require considerable replanning of the landing procedure for its
small ejectable comet-nucleus lander (as described in
SpaceDaily's March 20 article).
But simply getting to the comet also requires major redesign of
its flight plan -- and part of this is trying to find new
replacements for the two asteroids Rosetta was supposed to
rapidly fly by for additional science observations during its
circuitous 9-year trip to Wirtanen.
The first of those two asteroids was 4979 Otawara -- only a few
kilometers wide, which may actually be a small chunk of the
third-biggest asteroid Vesta broken loose by an ancient impact.
(Vesta is the only big asteroid with actual flows of volcanic
basalt on its surface; America's "Dawn" spacecraft is
scheduled to visit it in 2010 and spend almost a year orbiting it
for detailed study.)
The second would have been 140 Siwa -- a big "C-type"
asteroid, thought to be made of the same darker
"carbonaceous chondrite" rock that makes up most rocky
bodies in the outer Solar System, which condensed out of the
original solar-orbiting nebula out of which the Solar System
formed at lower temperatures than the silicate rock bodies of the
inner System, and so is much richer in water and even in organic
compounds. (Siwa, at 110 km, would have been the biggest asteroid
yet visited by a spacecraft.)
Those, however, are now out of reach. Rosetta's new flight plan
calls for it to match orbits with comet Churyumov with an even
more complex set of loops around the Sun than its original flight
plan to Wirtanen did. It will still make a gravity-assist flyby
of Mars -- but if the Feb. 2004 launch to Churyumov is chosen, it
will also make three gravity-asist flybys of Earth instead of
only two.
The new plan would involve Rosetta being initially launched into
a near-Earth orbit with a period of exactly one year, allowing it
to return to and fly by Earth at that time to get a boost into a
more elongated orbit that will take it to Mars. (If it misses
this launch window, it can be launched a year later directly from
Earth to Mars -- but since Mars will be farther from the Sun in
its mildly elliptical orbit than it would have been for a launch
last January, such a direct flight to Mars will require a more
powerful booster: either a Russian Proton, or the improved
"Ariane 5 ECA" which failed so disastrously in December
and might not be ready for this mission even by early 2005.)
However it gets to Mars, Rosetta will fly by that planet in Feb.
2007 (making some science observations as it does so) and getting
a gravity-assist boost to further elongate its orbit. It will
then return to Earth to make its second gravity-assist flyby of
our home planet that November, putting itself into a still more
elongated orbit with a period exactly two Earth years long -- so
that it will return once again to make its third and last
gravity-assist flyby of Earth in Nov. 2009, putting itself into a
still more elongated orbit taking it almost as far from the Sun
as Jupiter.
As it sails away from the Sun on that orbit, it will fire a burn
on its main engine in mid-2011, moderately adjusting its path to
help match orbits with Churyumov. Then -- three years later, as
it starts to approach the Sun again -- it will close in on the
comet's nucleus and carry out a months-long string of finer
maneuvers to rendezvous with it after a total journey of about 10
1/2 years (two years longer than the originally planned flight).
Rosetta's planners have already carried out an extensive hunt for
any asteroids it could fly past during this revised series of
loops around the Sun, and have indeed found two. The first is 437
Rhodia, which it would fly past in Sept. 2008 at a speed of about
41,000 km/hour.
Rhodia -- only about 25 km wide -- may be a particularly unusual
asteroid. It is thought to have an albedo higher than that of any
other known asteroid, reflecting fully 56% of the light hitting
it -- which would imply that it is made of some mineral as white
as chalk (possibly a chance extrusion of some white rock like
anorthosite, which formed on a bigger asteroid and was later
broken loose by a collision).
The second asteroid target would be 21 Lutetia, a big asteroid
about 100 km wide which Rosetta would fly past at about 55,000 km
per hour in July 2010. While Lutetia is about the same size as
Siwa, it is definitely odder -- it's one of the biggest of the
so-called "M-class" asteroids, which until recently
have been thought to be made largely of metallic nickel-iron
alloy of the type that makes up many recovered meteorites.
M-class asteroids (tagged, like the other declared classes of
asteroids, by the near-infrared spectra of their rocks as seen
from Earth) are rather uncommon -- they make up only about 4
percent of asteroids. They have been thought to be pieces of the
metal cores that formed at the centers of the dozen or so large
"planetesimals", several hundred km wide, that
orginally formed in the Asteroid Belt, before most of them were
gradually shattered into smaller fragments by repeated collisions
over the eons.
However, more detailed near-IR spectra recently show some signs
that most of the bigger M-class asteroids -- including Lutetia --
may not be metallic at all. Instead, they may be made of silicate
rocks that were exposed to some water during their early history.
Many of the smaller M asteroids -- as well as 16 Psyche, the
biggest of all -- don't seem to show such evidence, and may be
the real thing. If Rosetta does visit Lutetia, its color photos,
close-up IR spectra and magnetic field measurements will likely
settle this question.
There, is, however, a catch. Matching orbits with Churyumov will
require more maneuvering fuel than Wirtanen would have. And so,
in order to take the orbital paths needed to intercept the
asteroids, Rosetta would have to rendezvous with its main comet
target when the comet is closer to the Sun than Wirtanen would
have been -- only 540 million km from the Sun, as opposed to the
600 million km planned for Wirtanen.
Since, as a comet approaches the Sun, the "coma" of gas
and dust boiling off it dramatically increases, as Churyumov
reaches its perihelion it will get much harder for the
comet-orbiting spacecraft and its lander to make their
observations. (Rosetta's design specifications only guarantee its
full operation beyond doubt until the comet approaches within 490
million km of the Sun.) Scientists therefore would very much like
to rendezvous with the comet when it's still 600 million km from
the Sun as originally planned, to prolong their detailed
observation time there. They will thus have to decide which they
prefer: those two asteroid flybys, or as much as six extra months
of time studying Churyumov itself in detail.
They have plenty of time to make that decision, however -- it can
actually delayed until after launch. At any rate, given the
initial alarming indications immediately after the cancellation
of last January's launch that they might be able to find a
workable replacement target for Rosetta at all, ESA scientists
are quite happy even to have such a choice.
Copyright 2003, SpaceDaily
============
(5) AND FINALLY: THE COMPLETE IDIOT'S GUIDE TO SURVIVING ANYTHING
>From Ottawa Citizen, 23 March 2003
The Complete Idiot's Guide to Surviving Anything
By Patrick Sauer and Michael Zimmerman
"Some situations demand more than sensible shoes, a
first-aid kit and the rules Mom taught you," say the authors
of this survival manual. This guide includes tips for all kinds
of situations from avoiding asteroids to battling bears. Notes
survival expert Gregory Davenport in a Foreword: "The will
to survive is the most influential factor in staying alive."
--------------------------------------------------------------------
CCNet is a scholarly electronic network. To
subscribe/unsubscribe, please contact the moderator Benny J
Peiser < b.j.peiser@livjm.ac.uk
>. Information circulated on this network is for scholarly and
educational use only. The attached information may not be copied
or reproduced for
any other purposes without prior permission of the copyright
holders. The fully indexed archive of the CCNet, from February
1997 on, can be found at http://abob.libs.uga.edu/bobk/cccmenu.html.
DISCLAIMER: The opinions, beliefs and viewpoints expressed in the
articles and texts and in other CCNet contributions do not
necessarily reflect the opinions, beliefs and viewpoints of the
moderator of this network.
--------------------------------------------------------------------