Download 1 Marsbugs: The Electronic Astrobiology Newsletter, Volume 12

Marsbugs: The Electronic Astrobiology Newsletter
Volume 12, Number 13, 13 April 2005
Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College,
Batesville, Arkansas 72503-2317, USA. [email protected]
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Page 7
CU STUDY SHOWS EARLY EARTH ATMOSPHERE
HYDROGEN-RICH, FAVORABLE TO LIFE
University of Colorado release
NEW METHOD COULD DETECT ALIEN SPACE
STATIONS
By Tammy Plotner
Page 7
LIFE'S GREATEST INVENTIONS
From New Scientist
WHERE BACTERIA GET THEIR GENES
By Daniel Stolte
Page 7
"BORN-AGAIN" STARS REVEAL HOW THE EARTH
WAS CREATED
University of Manchester release
NASA TESTING HUMAN-ROBOT INTERACTIONS IN
UTAH DESERT
NASA/ARC release 05-22AR
Page 8
REVISED ASTEROID SCALE AIDS UNDERSTANDING OF
IMPACT RISK
By Elizabeth A. Thomson
Page 9
FLYING A SCIENCE LAB TO MARS
By Stephen Hart
Page 11
PERFECT SPOT FOUND FOR MOON BASE
By Robert Roy Britt
Articles and News
Page 1
Page 2
Page 3
Page 4
IS THIS A BROWN DWARF OR AN EXOPLANET? NEW
YOUNG SUB-STELLAR COMPANION IMAGED WITH
THE VLT
European Southern Observatory release 09/05
Page 5
SPACE EXPLORATION OVERHAUL: NEXT FIVE YEARS
"CRITICAL"
By Leonard David
Page 5
DIRECTOR JAMES CAMERON WORKS WITH NASA ON
FUTURE MARS MISSION
By John Kelly
Announcements
Page 11
SEE THE OLDEST THING ON EARTH
By Ryan J. Foley
NASA MAY SILENCE VOYAGERS ON APRIL 15
By Jeff Barbour
Page 5
SURFING THE WAVELENGTHS
By Maggie Turnbull
Page 11
Page 7
EXPERTS EXAMINE THREAD OF LIFE IN THE
UNIVERSE
By Leonard David
Mission Reports
Page 11
MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
CU STUDY SHOWS EARLY EARTH ATMOSPHERE HYDROGENRICH, FAVORABLE TO LIFE
University of Colorado release
6 April 2005
A new University of Colorado at Boulder study indicates Earth in its infancy
probably had substantial quantities of hydrogen in its atmosphere, a surprising
finding that may alter the way many scientists think about how life began on
the planet. Published in the April 7 issue of Science Express, the online
edition of Science Magazine, the study concludes traditional models
estimating hydrogen escape from Earth's atmosphere several billions of years
ago are flawed. The new study indicates up to 40 percent of the early
atmosphere was hydrogen, implying a more favorable climate for the
production of pre-biotic organic compounds like amino acids, and ultimately,
life. The paper was authored by doctoral student Feng Tian, Professor Owen
Toon and Research Associate Alexander Pavlov of CU-Boulder's Laboratory
for Atmospheric and Space Physics with Hans De Sterck of the University of
Waterloo. The study was supported by the NASA Institute of Astrobiology
and NASA's Exobiology Program.
Scientists believe Earth was formed about 4.6 billion years ago, and geologic
evidence indicates life may have begun on Earth roughly a billion years later.
"I didn't expect this result when we began the study," said Tian, a doctoral
student in CU-Boulder's Astrobiology Center at LASP and chief author of the
paper. "If Earth's atmosphere was hydrogen-rich as we have shown, organic
compounds could easily have been produced."
Toon said the premise that early Earth had a CO2-dominated atmosphere long
after its formation has caused many scientists to look for clues to the origin of
life in hydrothermal vents in the sea, fresh-water hot springs or those
delivered to Earth from space via meteorites or dust.
"This study indicates that the carbon dioxide-rich, hydrogen-poor Mars and
Venus-like model of Earth's early atmosphere that scientists have been
working with for the last 25 years is incorrect," said Toon. In such
atmospheres, organic molecules are not produced by photochemical reactions
or electrical discharges.
The team concluded that even if the atmospheric CO2 concentrations were
large, the hydrogen concentrations would have been larger. "In that case, the
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
production of organic compounds with the help of electrical discharge or
photochemical reactions may have been efficient," said Toon.
Jim Scott
Phone: 303-492-3114
Amino acids that likely formed from organic materials in the hydrogen-rich
environment may have accumulated in the oceans or in bays, lakes and
swamps, enhancing potential birthplaces for life, the team reported. The new
study indicates the escape of hydrogen from Earth's early atmosphere was
probably two orders of magnitude slower than scientists previously believed,
said Tian. The lower escape rate is based in part on the new estimates for past
temperatures in the highest reaches of Earth's atmosphere some 5,000 miles in
altitude where it meets the space environment.
Read the original news release at
http://www.colorado.edu/news/releases/2005/156.html.
While previous calculations assumed Earth's temperature at the top of the
atmosphere to be well over 1,500 degrees F several billion years ago, the new
mathematical models show temperatures would have been twice as cool back
then. The new calculations involve supersonic flows of gas escaping from
Earth's upper atmosphere as a planetary wind, according to the study.
"There seems to have been a blind assumption for years that atmospheric
hydrogen was escaping from Earth three or four billion years ago as
efficiently as it is today," said Pavlov. "We show the escape was limited
considerably back then by low temperatures in the upper atmosphere and the
supply of energy from the sun."
Despite somewhat higher ultraviolet radiation levels from the sun in Earth's
infancy, the escape rate of hydrogen would have remained low, Tian said.
The escaping hydrogen would have been balanced by hydrogen being vented
by Earth's volcanoes several billion years ago, making it a major component
of the atmosphere.
Left: Stanley Miller's classic "primordial soup" experimental setup, with
a simulated ocean, lightning and broth of hydrogen, methane,
ammonia and water. Right: University of Chicago graduate student,
Stanley Miller, 1953. Image credit: University of Chicago.
In 1953, University of Chicago graduate student Stanley Miller sent an
electrical current through a chamber containing methane, ammonia, hydrogen
and water, yielding amino acids, considered to be the building blocks of life.
"I think this study makes the experiments by Miller and others relevant
again," Toon said. "In this new scenario, organics can be produced efficiently
in the early atmosphere, leading us back to the organic-rich soup-in-the-ocean
concept."
In the new CU-Boulder scenario, it is a hydrogen and CO2-dominated
atmosphere that leads to the production of organic molecules, not the methane
and ammonia atmosphere used in Miller's experiment, Toon said. Tian and
other team members said the research effort will continue. The duration of the
hydrogen-rich atmosphere on early Earth still is unknown, they said.
Journal reference:
F. Tian, O. B. Toon, A. A. Pavlov and H. De Sterck, 2005. A hydrogen-rich
early Earth atmosphere.
Published online April 7 2005;
10.1126/science.1106983
(Science
Express
Reports).
http://www.sciencemag.org/cgi/content/abstract/1106983v1.
Contacts:
Owen Toon
Phone: 303-492-1534
Feng Tian
Phone: 303-492-2413
Alexander Pavlov
Phone: 303-492-4765
2
An additional article on this subject is available at
http://www.astrobio.net/news/article1515.html.
WHERE BACTERIA GET THEIR GENES
By Daniel Stolte
University of Arizona release
7 April 2005
Bacteria acquired up to 90 percent of their genetic material from distantly
related bacteria species, according to new research from The University of
Arizona in Tucson. The finding has important biomedical implications
because such gene-swapping, or lateral gene transfer, is the way many
pathogenic bacteria pick up antibiotic resistance or become more virulent.
"To maintain effective treatments and develop new antibiotics, it's important
to monitor the rates and patterns of lateral gene transfer," said team member
Howard Ochman, a UA professor of biochemistry and molecular biophysics
and a member of UA's BIO5 Institute.
The research also solves a long-standing evolutionary puzzle. Many scientists
have argued that drawing traditional family trees does not make sense for
bacteria, because their genomes represent a mix of genetic material from their
parental cells and from other species of bacteria. Ochman and his colleagues'
work shows that bacterial lineages can still be traced by considering only the
"traditional" forms of genetic inheritance. The widespread exchange of genes
does not blur the line of descent because the acquired genes get lost from the
genome at a later point or, if they do persist, the bacteria then transmit them to
their offspring.
Being able to classify bacteria is crucial for medicine, Ochman said. "If you
go to the doctor with strep throat he can be pretty certain that it's the result of
an infection with a species of Streptococcus and can therefore prescribe an
appropriate antibiotic. If you couldn't classify bacteria because they have
genes from all over, doctors wouldn't be able to do this."
The research report is published in the current issue of PLoS Biology,
available on http://www.plosbiology.org. Ochman's coauthors are Nancy
Moran, UA Regents' Professor of ecology and evolutionary biology and BIO5
member, and Emmanuelle Lerat, now at Universite Claude Bernard (Lyon,
France) and Vincent Daubin, now at the Centre National de la Recherche
Scientifique (CNRS) in France. The research was funded by the Department
of Energy and the National Science Foundation.
Lateral gene transfer, unique to the bacterial world, has long been recognized
as common. But until now scientists did not know which of a bacterium's
genes came from lateral gene transfer and which had been inherited from its
parent. In their study, the scientists focused on the best-studied group of
bacteria, the Gamma-Proteobacteria. It includes many human pathogens,
including Salmonella, Shigella, pathogenic E. coli, and Pseudomonas.
Ochman's team compared the bacterial species by analyzing their genomic
sequence data. The researchers then computed family trees, taking into
account the acquired genes, and matched the trees to an established reference
tree. For all genes, the match was about 95 percent. This showed that the
widespread mechanism of lateral gene transfer does not interfere with the
traditional approach of using family trees to infer relationships. Ochman's
team found that only 205 genes of Gamma-Proteobacteria's approximately
7,205 genes are shared by all species. The vast majority of genes found in the
group come from lateral gene transfer. "Most of these occur in one or a few
species only," Ochman said. "But these are the genes that make bacteria
different from each other."
Most commonly, genes are transmitted by bacteriophages, viruses that
specifically hijack bacteria cells. Like tiny syringes, phages inject their own
genetic material into the host cell, forcing it to produce new phages. During
such an event, genes from the bacterial genome can be incorporated into the
newly made phages. They inject their newly modified genetic load into other
bacteria. This way, bacteriophages act as shuttles, taking up DNA from one
bacterium and dumping it into another. Bacteria can also make contact by
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
tiny connection tubes through which they exchange pieces of DNA. They can
also take up genetic material from the environment.
Ochman thinks the team's findings will stir new research in bacterial
evolution. "It should be exciting to see whether gene transfer has been so
widespread in other groups of bacteria, too."
3
"BORN-AGAIN" STARS REVEAL HOW THE EARTH WAS
CREATED
University of Manchester release
7 April 2005
Scientists at The University of Manchester have unveiled new research which
shows how exploding stars may have helped to create the earth. The
discovery was made during a unique research project examining how some
dead stars re-ignite and come back to life. Professor Albert Zijlstra's study of
Sakurai's Object—the only star which has been observed re-igniting in
modern times—has led him to conclude that 5% of the carbon on earth may
have been come from stardust expelled by stars exploding back to life.
"Up to 0.1% of the total mass of the star, which is equivalent to 300 times the
mass of the earth, can be expelled when a star re-ignites," says Professor
Zijlstra. "This discovery not only gives us a new understanding of where the
natural material that made up the earth came from, but also leads us to believe
that part of the carbon in the universe could have come from these events."
Lateral gene transfer (LGT) and genome evolution in γ-Proteobacteria.
Only a small proportion of genes have been retained since the
common ancestor of γ-proteobacteria (in red). Under the assumption
that ancestral and contemporary genome sizes are similar, most of the
genes present in this ancestral genome (in white) have been replaced
by nonhomologous genes (yellow to green), usually via LGT from
organisms outside of this clade. Once a new gene is acquired, its
transmission follows vertical inheritance. The abundance of genes
unique to a species (in blue) indicates that these bacteria (with the
exception of the endosymbionts) constantly acquire new genes, most
of which do not persist long-term within lineages. (Numbers of proteincoding genes, excluding those corresponding to known IS elements
and phages, are in parentheses for each genome). From Lerat
E, Daubin V, Ochman H, Moran NA (2005) Evolutionary Origins of
Genomic Repertoires in Bacteria. PLoS Biol 3(5): e130.
Journal reference:
E. Lerat, V. Daubin, H. Ochman and N. A. Moran, 2005. Evolutionary
origins of genomic repertoires in bacteria. PLoS Biology, May 2005, Volume
3, Issue 5, e130. http://www.plosbiology.org.
Radio/optical images of Sakurai's Object. The color image
shows nebula ejected thousands of years ago. Contours
indicate radio emissions. Inset is Hubble Space Telescope
image showing the central part of the region with contours
indicating radio emission. Image credit: Hajduk et al.,
NRAO/AUI/NSF, ESO, StSci, NASA.
Stars die when they have used up most of their hydrogen. For the Sun, this
will happen in about 4.5 billion years. But some stars will experience a brief
rebirth when their helium suddenly ignites, and the remaining hydrogen in
their outer envelope is drawn into the helium shell. After the explosive reignition, the star will expand to giant proportions—expelling tons of carbon in
the process—before rapidly burning out again.
"We expect that some 25% of all stars will experience such a re-ignition, but
this is an extremely rare occurrence, and we will probably only see it happen
once every hundred years or so", says Professor Zijlstra.
Related Web sites:
Howard Ochman,
http://www.biochem.arizona.edu/dept/ppl/Profiles/ochman.htm
Nancy Moran, http://eebweb.arizona.edu/Faculty/Bios/moran.html
BIO5 Institute, http://www.bio5.org
Contacts:
Daniel Stolte, UA News Services
Phone: 520-626-4407
Howard Ochman
Phone: 520-626-8355
E-mail: [email protected]
Nancy Moran
Phone: 520-621-3581
E-mail: [email protected]
Left: Spectacular gas remnants from exploding star. Right: Our Milky
Way galaxy is packed with 400 billion stars and perhaps even more
planets. Image credits: NASA/Hubble.
Incredibly, the earth's formation was not the main focus of Professor Zijlstra's
research, which sought to establish a better understanding of why Sakurai's
Object had re-ignited. Computer simulations had predicted a series of events
that would follow such a re-ignition, but the star didn't follow the script—
events moved 100 times more quickly than the simulations predicted.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
"Sakurai's Object went through the first phases of this sequence in just a few
years—100 times faster than we expected—so we had to revise our models.
We've now produced a new theoretical model of how this process works, and
the observations have provided the first evidence supporting our new model,"
Zijlstra said.
"It's important to understand this process. Sakurai's Object has ejected a large
amount of carbon into space, both in the form of gas and dust grains. These
will find their way into regions of space where new stars form, and the dust
grains may become incorporated in new planets. Our results suggest this
source for cosmic carbon may be far more important than previously
suspected," Zijlstra added.
Zijlstra's findings will be presented in the April 8 issue of the prestigious
journal, Science.
Journal references:
M. Hajduk et al., 2005. The real-time stellar evolution of Sakurai's Object.
Science, 308(5719):231-233.
http://www.sciencemag.org/cgi/content/short/308/5719/231.
M. Asplund, 2005. Enhanced: A stellar swan-song. Science, 308(5719):210211. http://www.sciencemag.org/cgi/content/summary/308/5719/210.
Read the original news release at
http://www.manchester.ac.uk/press/title,20449,en.htm.
An additional article on this subject is available at
http://www.astrobio.net/news/article1518.html.
IS THIS A BROWN DWARF OR AN EXOPLANET? NEW YOUNG
SUB-STELLAR COMPANION IMAGED WITH THE VLT
European Southern Observatory release 09/05
7 April 2005
Since the discovery in 1995 of the first planet orbiting a normal star other than
the Sun, there are now more than 150 candidates of these so-called exoplanets
known. Most of them are detected by indirect methods, based either on
variations of the radial velocity or the dimming of the star as the planet passes
in front of it. Astronomers would, however, prefer to obtain a direct image of
an exoplanet, allowing them to better characterize the object's physical nature.
This is an exceedingly difficult task, as the planet is generally hidden in the
"glare" of its host star.
4
Based on this approach, it might well be that last year's detection of a feeble
speck of light next to the young brown dwarf 2M1207 by an international
team of astronomers using the ESO Very Large Telescope is the long-sought
bona-fide image of an exoplanet. A recent report based on data from the
Hubble Space Telescope seems to confirm this result. The even more recent
observations made with the Spitzer Space Telescope of the warm infrared
glows of two previously detected "hot Jupiter" planets is another interesting
result in this context. This wealth of new results, obtained in the time span of
a few months, illustrates perfectly the dynamic of this field of research.
Now, a different team of astronomers [1] has possibly made another important
breakthrough in this field by finding a tiny companion to a young star. Since
several years these scientists have conducted a search for planets and lowmass objects, in particular around stars still in their formation process—socalled T-Tauri stars—using both the direct imaging and the radial velocity
techniques. One of the objects on their list is GQ Lupi, a young T-Tauri star,
located in the Lupus I (the Wolf) cloud, a region of star formation about 400
or 500 light-years away. The star GQ Lupi is apparently a very young object
still surrounded by a disc, with an age between 100,000 and 2 million years.
The astronomers observed GQ Lupi on 25 June 2004 with the adaptive optics
instrument NACO attached to Yepun, the fourth 8.2-m Unit Telescope of the
Very Large Telescope located on top of Cerro Paranal (Chile). The
instrument's adaptive optics (AO) overcomes the distortion induced by
atmospheric turbulence, producing extremely sharp near-infrared images.
As ESO PR Photo 10a/05 shows, the series of NACO exposures clearly reveal
the presence of the tiny companion, located in the close vicinity of the star.
This newly found object is only 0.7 arcsecond away, and would have been
overlooked without the use of the adaptive optics capabilities of NACO.
At the distance of GQ Lupi, the separation between the star and its feeble
companion is about 100 astronomical units (or 100 times the distance between
the Sun and the Earth). This is roughly 2.5 times the distance between Pluto
and the Sun. The companion, called GQ Lupi B or GQ Lupi b [2], is roughly
250 times fainter than GQ Lupi A as seen in this series of image. Further
images obtained with NACO in August and September confirmed the
presence and the position of this companion.
The astronomers then uncovered that the star had been previously observed by
the Subaru telescope as well as by the Hubble Space Telescope. They
retrieved the corresponding images from the data archives of these facilities
for further analysis. The older images, taken in July 2002 and April 1999,
respectively, also showed the presence of the companion, giving the
astronomers the possibility of precisely measuring the position of the two
objects over a period of several years. This in turn allowed them to determine
if the stars move together in the sky—as should be expected if they are
gravitationally bound together—or if the smaller object is only a background
object, just aligned by chance.
From their measurements, the astronomers found that the separation between
the two objects did not change over the five-year period covered by the
observations (see ESO PR Photo 10b/05). For the scientists this is a clear
proof that both objects are moving in the same direction in the sky.
"If the faint object would be a background object", says Ralph Neuhäuser of
the University of Jena (Germany) and leader of the team, "we would see a
change in separation as GQ Lup would be moving in the sky. From 1999 to
2004, the separation would have changed by 0.15 arcsec, while we are
confident that the change is a least 20 times smaller."
ESO PR Photo 10a/05 shows the VLT NACO image, taken in the Ksband, of GQ Lupi. The feeble point of light to the right of the star is the
newly found cold companion. It is 250 times fainter than the star itself
and it located 0.73 arcsecond west. At the distance of GQ Lupi, this
corresponds to a distance of roughly 100 astronomical units. North is
up and East is to the left.
To partly overcome this problem, astronomers study very young objects.
Indeed, sub-stellar objects are much hotter and brighter when young and
therefore can be more easily detected than older objects of similar mass.
To further probe the physical nature of the newly discovered object, the
astronomers used NACO on the VLT to take a series of spectra. These
showed the typical signature of a very cool object, in particular the presence
of water and CO bands. Taking into account the infrared colours and the
spectral data available, atmospheric model calculations point to a temperature
between 1,600 and 2,500 degrees and a radius that is twice as large as Jupiter
(see PR Photo 10c/05). According to this, GQ Lupi B is thus a cold and rather
small object.
But what is the nature of this faint object? Is it a bona-fide exoplanet or is it a
brown dwarf, those "failed" stars that are not massive enough to centrally
produce major nuclear reactions? Although the borderline between the two is
still a matter of debate, one way to distinguish between the two is by their
mass (as this is also done between brown dwarfs and stars): (giant) planets are
lighter than about 13 Jupiter-masses (the critical mass needed to ignite
deuterium fusion), brown dwarfs are heavier.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
What about GQ Lupi b? Unfortunately, the new observations do not provide a
direct estimate of the mass of the object. Thus the astronomers must rely on
comparison with theoretical models of such objects. But this is not as easy as
it sounds. If, as astronomers generally accept, GQ Lupi A and B formed
simultaneously, the newly found object is very young. The problem is that for
such very young objects, traditional theoretical models are probably not
applicable. If they are used, however, they provide an estimate of the mass of
the object that lies somewhere between 3 to 42 Jupiter-masses, i.e.
encompassing both the planet and the brown dwarf domains.
5
GQ Lupi A turns out to be a planet, it would be called GQ Lupi b, while if it is
a brown dwarf, it would be identified as GQ lupi B. Given the present
uncertainty, we have therefore used both denominations in this press release,
as did the authors in the original scientific paper.
Contact:
Ralph Neuhäuser
Astrophysikalisches Institut
University of Jena, Germany
Phone: +49 36 41 94 75 00
Email: [email protected]
Read the original news release at http://www.eso.org/outreach/press-rel/pr2005/pr-09-05.html.
Ann additional article on this subject is available at
http://www.astrobio.net/news/article1520.html.
SPACE EXPLORATION OVERHAUL: NEXT FIVE YEARS
"CRITICAL"
By Leonard David
From Space.com
8 April 2005
ESO PR Photo 10c/05 shows the NACO spectrum of the companion of
GQ Lupi (thick line, bottom) in the near-infrared (around the Ks-band at
2.2 microns). For comparison, the spectrum of a young M8 brown
dwarf (top, in red) and of a L2 brown dwarf (second line, in brown) are
shown. Also presented is the spectrum calculated using theoretical
models for an object having a temperature of 2,000 degrees. This
theoretical spectrum compares well with the observed one.
These early phases in brown dwarf and planet formation are essentially
unknown territory for models. It is very difficult to model the early collapse
of the gas clouds given the conditions around the forming parent star. One set
of models, specifically tailored to model the very young objects, provide
masses as low as one to two Jupiter-masses. But as Ralph Neuhäuser points
out "these new models still need to be calibrated, before the mass of such
companions can be determined confidently".
The astronomers also stress that from the comparison between their
VLT/NACO spectra and the theoretical models of co-author Peter Hauschildt
from Hamburg University (Germany), they arrive at the conclusion that the
best fit is obtained for an object having roughly 2 Jupiter radii and 2 Jupiter
masses. If this result holds, GQ Lupi b would thus be the youngest and
lightest exoplanet to have been imaged.
Further observations are still required to precisely determine the nature of GQ
Lupi B. If the two objects are indeed bound, then the smallest object will
need more than 1,000 years to complete an orbit around its host star. This is
of course too long to wait but the effect of the orbital motion might possibly
be detectable—as a tiny change in the separation between the two objects—in
a few years. The team therefore plans to perform regular observations of this
object using NACO on the VLT, in order to detect this motion. No doubt that
in the mean time, further progress on the theoretical side will be achieved and
that many sensational discoveries in this field will be made.
Journal reference:
The research presented in this ESO Press Release is published in a Letter to
the Editor accepted for publication by Astronomy and Astrophysics
("Evidence for a co-moving sub-stellar companion of GQ Lup" by R.
Neuhäuser
et
al.)
and
available
in
PDF
form
at
http://www.edpsciences.org/articles/aa/pdf/forthpdf/aagj061_forth.pdf.
Notes:
[1]: The team is composed of Ralph Neuhäuser, Günther Wuchterl, Markus
Mugrauer, and Ana Bedalov (University of Jena, Germany), Eike Guenther
(Thüringer Landessternwarte Tautenburg, Germany), and Peter Hauschildt
(Hamburger Sternwarte, Germany).
[2]: In the astronomical literature, the convention is to put capitals for stars
member of multiple systems, but small letters for planets. If the companion to
After decades of sending probes across the void of interplanetary space,
officials are now reshaping how solar system exploration is accomplished.
The renovation is due in large measure to the visionary Moon, Mars and
beyond directive given to NASA by U.S. President George W. Bush just more
than a year ago. While money and mandate are in a state of near-rendezvous,
the melding of space science objectives with human exploration goals is still
to be fully played out, as is the prospect of broader international collaboration.
"The scientific exploration agenda NASA has been pursuing for the past
decade or so is bearing enormous fruit, providing key early inputs to how
NASA implements the vision," said James Garvin, NASA Chief Scientist in
Washington, DC. "Initial robotic steps in the vision implementation will
inform and guide future decisions that will ultimately steer how human beings
explore the Moon and Mars."
Read the full article at
http://www.space.com/missionlaunches/050408_space_science.html.
DIRECTOR JAMES CAMERON WORKS WITH NASA ON FUTURE
MARS MISSION
By John Kelly
From Florida Today and Space.com
9 February 2005
The maker of legendary movies Titanic, Aliens and The Terminator is no
longer limiting his zest for extracurricular exploration to the depths of the
ocean. Nowadays, James Cameron is spending more of his "spare" time
involved in NASA's bid to send human explorers deeper into the solar system.
He's always been a space nut. He says he cried when, at 15 years old, he
watched shuttle Columbia launch for the first time. He cried again the first
time he saw—in person—a shuttle blast off from Kennedy Space Center, and
felt the vibrations of the sound wave slam into his chest and move right
through him. Now, however, he's not just dreaming and watching from the
sidelines. He's trying to help.
Read the full article at
http://www.space.com/entertainment/ft_cameron_mars_050209.html.
SURFING THE WAVELENGTHS
By Maggie Turnbull
From Astrobiology Magazine
11 April 2005
Maggie Turnbull, an astronomer with the Carnegie Institution, has spent
many years thinking about what kind of stars could harbor Earth-like planets.
Her database of potentially habitable star systems could be used as a target
list for NASA's upcoming Terrestrial Planet Finder (TPF) mission. Turnbull
presented a talk, "Remote Sensing of Life and Habitable Worlds: Habstars,
Earthshine and TPF," at a NASA Forum for Astrobiology Research on March
14, 2005. This edited transcript of the lecture is part one of a four-part series.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
6
Mars?" "Are terrestrial planets common at all, or is it more common to have
massive eccentric Jupiters?"
Left: Artist concept of star system, HD70642. Image credit: John
Rowe animation. Right: Scene from a moon orbiting the extra-solar
planet in orbit around the star HD70642. Image credit: David A. Hardy,
astroart.org © pparc.ac.uk.
To what extent is the universe alive? As soon as we ask that question, a
million more questions pop up: "What is life?" "How does life originate?"
"Could life be originating on Earth now, and if not, why not?" "Where is life
found?" "Can life spread between planets or even between stellar systems?"
"If life can travel between stellar systems, do we have relatives among the
stars?" "Are there other technological civilizations out there?"
Those are too many questions for me to try to answer right now, but I will
address the question, "Are there habitable terrestrial planets orbiting nearby
stars?" That immediately leads us to ask, "What is a habitable planet?" All
life on Earth depends on the availability of liquid water, so I'll just say that a
habitable planet is one that has liquid water on its surface.
So the habitable zone will be that location around a star where an Earth-like
planet will be at the right temperature so that it will have liquid water on its
surface. Around our sun, the habitable zone extends from about 0.7 AU out to
about 1.5 AU. (1 AU is the distance between the Earth and the sun.) For
other stars, we'll just scale that as the square root of the luminosity of the star.
The first mission objective of the Terrestrial Planet Finder is to hone in on the
zone where a terrestrial planet could have liquid water on its surface, and
directly image any terrestrial planets in that zone. We want to see these
planets with our own eyes. We want to take a picture, and see a little dot.
The goal is to image planets in a habitable zone that have at least half Earth's
surface area. We want to be able to image planets somewhere between the
size of Mars and Earth, or larger.
Left: HD 28185 b was the first exoplanet discovered with a circular
orbit within its star's habitable zone. Image credit: STScI Digitized Sky
Survey. Right: Comparison of Mars, Venus and Earth in water bands,
showing the clear presence of water on Earth uniquely. Saturn's moon
Titan has perhaps the highest atmospheric content for methane with
other primordial elements. Image credit: NASA Workshop, Pale Blue
Dot.
The Terrestrial Planet Finder originally was envisioned as a mid-infrared
mission, because it was thought that mid-infrared wavelengths would be the
best way to search for extrasolar Earths around nearby stars. In the midinfrared, planets emit their own light, while the light from the star is tailing
off, so the contrast shown for the mid-infrared is better than in the optical.
At the shorter optical wavelengths, the Earth's spectrum mirrors the Sun—it's
just reflecting sunlight. As we get into the mid-infrared, the Earth starts
emitting its own light, because it has a temperature of 300 degrees Kelvin
(80°F). That heat translates into light in the mid-infrared. So a planet's midinfrared light can give us a handle on the temperature of the planet, and tell us
if that temperature is right for liquid water at the surface.
Earth as seen by the departing Voyager spacecraft: a tiny, pale blue
dot. Image credit: NASA.
In a universe brimming with stars, the search is on to discover whether
life exists elsewhere. Image credit: NASA/STScI/ESA.
The second goal of TPF is to characterize the atmospheres of any planets we
find for indicators of life. The third goal is to do comparative planetology, so
that when we have a database of planetary systems in the solar neighborhood,
we can ask questions like, "How common are terrestrial planets?" "How
diverse are they?" "How common is it to have a habitable terrestrial planet?"
"Is liquid water a common thing, or do most planets look like Venus or
Also in the mid-infrared, we can see some exciting signatures, such as carbon
dioxide, water, and ozone. Since ozone is a proxy for molecular oxygen, it's
an indicator of life. Spectra in the infrared taken by the Galileo spacecraft of
Mars, Earth, and Venus showed that the three planets look fairly similar. But
Earth had two indicators of habitability and life, namely, water and ozone.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
The Earth is one-ten-billionth as bright as the sun in the optical. In the midinfrared, it's only a factor of one million, so it's not quite as bad. But still, if
you take the Earth-sun system, and put it at 10 parsecs distance—about 30
light years away—there will be an angular separation between the two of 100
milliarcseconds. That's very small. So even looking in the mid-infrared—
with the planet being one millionth as bright as the sun at 100 milliarcseconds
at 10 parsecs—that's not easy.
In order to do high resolution imaging in the mid-infrared, we need to have a
very long baseline, which means we need to either have a huge telescope, or
we need to somehow fly an interferometer in formation. That technology is
more advanced than what we'll have over the next ten years.
So the first mission will be TPF-C, a coronagraph that is slated for launch in
2014, and it will operate at optical wavelengths. The key issue here is that we
need to suppress the light of the star so that we can see the light of the
planet—planets are very much fainter than the star.
For the optical, we don't have observations that are analogous to the Galileo
infrared observations. We've got lots of satellite observations of Earth in the
optical wavelengths, but the low-flying satellites only see a small footprint of
ground at a time. We don't have satellite observations that have the whole
spectrum of the visible Earth all summed up in one pixel.
So to get those spectra, we have to observe them from the ground. Luckily,
we can do that by looking at the moon, by pointing our telescopes at where
"Earthshine" lights up the dark portion of the thin crescent moon. The way
this works is, the sun shines on the Earth, the Earth shines on the moon, and
that light reflects off the moon and goes back to the Earth and into our
telescope. The dark portion of the moon shows the spectrum of the whole
Earth, all summed up together.
Sunlight reflecting off the bright crescent of the moon also goes into our
telescope as we observe it on the ground. We just take our dark moon
spectrum and divide it by our bright moon spectrum, and what we have left
over is the spectrum of the Earth. In the Earth's optical spectrum, we see
Rayleigh scattering in the blue part of the spectra—we're seeing the blue sky
of our planet. We also have signs of oxygen, ozone, and water. We may even
be able to see signs of vegetation in the optical.
The interesting thing about observing the Earth in the optical is that you can
see all the way through Earth's atmosphere to the ground. The light that
reflects back contains the spectrum of whatever is on the ground of that
planet, whether it's oceans, or soil, or plants. And plants happen to have a
very distinctive spectrum that could be observable even across stellar
distances.
All land plants have pretty much the same spectral signature—they're very
dark in the optical, where 10 percent of the light that strikes them gets
reflected. For the most part, in the optical, they absorb just about all of the
photons that fall on them, which makes them good photosynthesizers. They
become strongly reflective in the near-infrared, where they reflect 70 percent
of the light that falls on them. This "vegetation edge" is a distinctive spectral
feature that allows satellites to map the health, density and even different
species of plants on Earth.
Now, you could ask how relevant this is to the search for life elsewhere. Do
we really expect Earth-like plants to be on other terrestrial planets? It's not
reasonable to expect that, but life does have a way of exploiting whatever
energy source is available. So life on the surface of a planet should be
expected to be photosynthetic. It's going to absorb very strongly in some
wavelength range where the atmosphere of the planet is transparent and where
the star is emitting a lot of energy.
Is it just a coincidence that plants on Earth become strongly reflecting in the
infrared? Or is that useful to the plant biologically, for instance, for cooling
purposes? If it is biologically advantageous to reject photons that are not
energetically useful rather than absorbing them, and to strongly absorb those
wavelength ranges where you can do something with the energy, then we
should not be surprised if photosynthetic life on other planets also has a strong
spectral "edge" feature.
Read the original article at http://www.astrobio.net/news/article1519.html.
7
EXPERTS EXAMINE THREAD OF LIFE IN THE UNIVERSE
By Leonard David
From Space.com
11 April 2005
Consider it nothing short of the cosmic quest for all time: Understanding the
origin, evolution, distribution, and fate of life on Earth and in the Universe.
That’s a tall order, but within the sights of experts gathering here this week to
take part in the 2005 Biennial Meeting of the NASA Astrobiology Institute.
From the formation and evolution of habitable worlds to the origins of life,
extra-solar planets, and future exploration technologies and strategies—
dedicated scientists are tackling big questions in a big universe.
Read the full article at
http://www.space.com/searchforlife/050411_astrobio_nasa.html.
NEW METHOD COULD DETECT ALIEN SPACE STATIONS
By Tammy Plotner
From Universe Today
11 April 2005
Since the beginning of astronomical observation, science has been viewing
light on a curve. In a galaxy filled with thousands of eclipsing binary stars,
we've refined our skills by measuring the brightness or intensity of so-called
variable star as a function of time. The result is known as a "light curve".
Through this type of study, we've discovered size, distance and orbital speed
of stellar bodies and refined our ability to detect planetary bodies orbiting
distant suns. Here on Earth, most of the time it's impossible for us to resolve
such small objects even with the most powerful of telescopes, because their
size is less than one pixel in the detector. But new research should let us
determine the shape of an object, like a ringed planet, or an orbiting alien
space station.
Read the full article at
http://www.universetoday.com/am/publish/alien_space_stations.html.
LIFE'S GREATEST INVENTIONS
From New Scientist
11 April 2005
Evolution's methods are blind, brutish and aimless, yet it has fashioned some
of the most exquisite machines in the known universe. And every now and
then, it stumbles across a truly stunning innovation that rewrites the rules of
life. From the eye and the brain to language and sex, New Scientist reveals the
Top Ten at http://www.newscientist.com/channel/life/mg18624941.700.
NASA TESTING HUMAN-ROBOT INTERACTIONS IN UTAH
DESERT
NASA/ARC release 05-22AR
12 April 2005
Two NASA robots and two geologists are now simulating an expedition to
another planet during a field test expected to continue until April 15 in Utah's
Southeast Desert, near Hanksville. During the ongoing "Mobile Agents
Project", NASA engineers are working to improve human-robot interactions
to help NASA accomplish its Vision for Space Exploration to return to the
moon and venture to Mars. The wheeled robots are attempting to help the
astronaut team to maintain connection with a wireless computer network.
"As you look at NASA's exploration vision to return to the moon and go on to
Mars, human-robotic cooperation will be vital to achieve that vision," said
Eugene Tu, deputy director for the Exploration Technology Directorate at
NASA Ames Research Center in California's Silicon Valley.
"One of our biggest problems is to break out of preconceived notions rooted in
science fiction or existing robotic technology," said Bill Clancey, principal
investigator for the Mobile Agent project. "By building and testing
prototypes, we can test design concepts."
During the field exercise, the researchers' objective is to develop ways to
enable robots to take the initiative to work together to help a team of
astronauts. Scientists and engineers from NASA Ames and NASA Johnson
Space Center, Houston, are taking part in the test. Prototype "Extravehicular
Activity (EVA) Robotic Assistants", developed at NASA Johnson, will follow
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
geologists and respond to voice commands at the Mars Society's Mars Desert
Research Station.
8
Publication-size images are available at
http://www.marssociety.org/MDRS/fs04/.
Contacts:
John Bluck
NASA Ames Research Center, Moffett Field, CA
Phone: 650-604-5026 or 604-9000
E-mail: [email protected]
Kelly Humphries
NASA Johnson Space Center, Houston, TX
Phone: 281-483-5111
REVISED ASTEROID SCALE AIDS UNDERSTANDING OF IMPACT
RISK
By Elizabeth A. Thomson
Massachusetts Institute of Technology release
12 April 2005
A group huddles around [the robot] Thibodeaux in the wind;
explanations provided by Bill Vreugde and Ed Herrera. Image credit:
Mars Society.
According to NASA scientists, human-robotic interactions can best be
improved using in-situ experiments, during which people and robots cooperate
to do research. Scientists plan to examine the interacting constraints of
landscape, distance, work coordination and other factors to suggest what new
tools and methods are needed to refine existing technology. This process will
bring together the remote science team, mission support, the habitat and its
crew, robots, computer networks and astronauts to simulate planetary surface
exploration.
A team that includes about 20 people has placed equipment in and around the
Mars Desert Research Station. Team members are using prototype tools,
including a wireless computer network, the voice-commanded robots and
voice-commanded mission control communication services that partly
automate the role of the kind of communications used during the Apollo
missions to the moon in the late 1960s and early 1970s.
Astronomers led by an MIT professor have revised the scale used to assess the
threat of asteroids and comets colliding with Earth to better communicate
those risks with the public. The overall goal is to provide easy-to-understand
information to assuage concerns about a potential doomsday collision with our
planet. The Torino scale, a risk-assessment system similar to the Richter scale
used for earthquakes, was adopted by a working group of the International
Astronomical Union (IAU) in 1999 at a meeting in Torino, Italy. On the
scale, zero means virtually no chance of collision, while 10 means certain
global catastrophe.
"The idea was to create a simple system conveying clear, consistent
information about near-Earth objects [NEOs]," or asteroids and comets that
appear to be heading toward the planet, said Richard Binzel, a professor in
MIT's Department of Earth, Atmospheric and Planetary Sciences and the
creator of the scale. Some critics, however, said that the original Torino scale
was actually scaring people, "the opposite of what was intended," said Binzel,
hence the revisions.
"For a newly discovered NEO, the revised scale still ranks the impact hazard
from 0 to 10, and the calculations that determine the hazard level are still
exactly the same," Binzel said. The difference is that the wording for each
category now better describes the attention or response merited for each.
For example, in the original scale NEOs of level 2-4 were described as
"meriting concern." The revised scale describes objects with those rankings as
"meriting attention by astronomers"—not necessarily the public.
Equally important in the revisions, says Binzel, "is the emphasis on how
continued tracking of an object is almost always likely to reduce the hazard
level to 0, once sufficient data are obtained." The general process of
classifying NEO hazards is roughly analogous to hurricane forecasting.
Predictions of a storm's path are updated as more and more tracking data are
collected.
According to Dr. Donald K. Yeomans, manager of NASA's Near Earth Object
Program Office, "The revisions in the Torino Scale should go a long way
toward assuring the public that while we cannot always immediately rule out
Earth impacts for recently discovered near-Earth objects, additional
observations will almost certainly allow us to do so."
Mobile Agents team plans first reconnaissance "EVA" for Boudreaux, the
robot. Image credit: Mars Society.
Researchers are continuing to conduct a series of human-robot simulated
geology missions to scout new terrain during multiple days. These
simulations also involve the remote science team. Scientists are making audio
and video recordings of the activities. Researchers later will evaluate the data
to learn about human-robot interactions including voice commands and work
preferences. From analysis of the recordings and other data, investigators can
assess equipment, software and procedures. Scientists can then write new
requirements and specifications to improve human-robot interactions and
cooperation.
The highest Torino level ever given an asteroid was a 4 last December, with a
2 percent chance of hitting Earth in 2029. And after extended tracking of the
asteroid's orbit, it was reclassified to level 1, effectively removing any chance
of collision, "the outcome emphasized by level 4 as being most likely," Binzel
said.
"It is just a matter of the scale becoming more well known and understood.
Just as there is little or no reason for public concern over a magnitude 3
earthquake, there is little cause for public attention for NEO close encounters
having low values on the Torino scale." He notes that an object must reach
level 8 on the scale before there is a certainty of an impact capable of causing
even localized destruction.
The Torino scale was developed because astronomers are spotting more and
more NEOs through projects like the Lincoln Near Earth Asteroid Research
project at MIT's Lincoln Laboratory. "There's no increase in the number of
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
asteroids out there or how frequently they encounter our planet.
changed is our awareness of them," Binzel notes.
What's
9
FLYING A SCIENCE LAB TO MARS
By Stephen Hart
From Astrobiology Magazine
13 April 2005
Even before the Mars Science Lander (MSL) touches down descending from
its hovering mother ship like a baby spider from an egg case the first of a slew
of cameras will have started recording, capturing and storing high-resolution
video of the landing area. The MSL landing will represent a first, says Frank
Palluconi, MSL project scientist. After entering the Mars atmosphere like
Viking and MER but with a potential landing zone about one fourth the size
he says, MSL will show its stuff. "It completes the descent down to the tenmeter [33-foot] level, or so, where the descent vehicle hovers, and it lowers
the rover on a tether down to the surface. By that time, the rover has erected
its wheels, so it lands on its mobility system. And then the tether is cut and
the descent stage flies away and is no longer used. It crashes."
In addition to the obvious advantages of such a soft landing, hovering and the
tether drop are possible to model mathematically, unlike the airbag landing the
MER vehicles used. Tethered descent is also scalable, Palluconi says,
whereas the much smaller MERs were pushing the envelope of the airbag
system's capability.
Left: Artist conception of Mars long-range science laboratory. Image
credit: NASA/JPL. Right: Sundown on Mars, Pathfinder mission.
Image credit: NASA/JPL.
Eyes on Mars
As a result, astronomers debated whether they should keep potential NEO
collisions secret or "be completely open with what we know when we know
it," Binzel said. The IAU working group, of which Binzel is secretary,
resoundingly decided on the latter.
The revised wording of the scale was published last fall in a chapter of
Mitigation of Hazardous Comets and Asteroids (Cambridge University Press).
The revisions were undertaken through consultation with astronomers
worldwide for nearly a year before being published.
Binzel concludes that "the chance of something hitting the Earth and having a
major impact is very unlikely. But although unlikely, it is still not impossible.
The only way to be certain of no asteroid impacts in the forecast is to keep
looking."
For more information on the revised Torino scale, go to
http://neo.jpl.nasa.gov/torino_scale.html. A version of this article appeared in
the April 13, 2005 issue of MIT Tech Talk (Volume 49, Number 24,
http://web.mit.edu/newsoffice/techtalk-info.html).
Contact:
Elizabeth A. Thomson, MIT News Office
Phone: 617-258-5402
E-mail: [email protected]
Read the original news release at
http://web.mit.edu/newsoffice/2005/torino.html.
An additional article on this subject is available at
http://www.universetoday.com/am/publish/torino_scale_revised.html.
Shooting will begin as soon as the heat shield drops from the MSL descent
stage. The Mars Descent Imager will take video in megapixel resolution,
comparable to modern consumer digital video cameras. Aimed straight down,
this camera will provide a spider's eye view of the landing area a very wide
angle at first and continue shooting until the rover touches down on Mars.
Landing videos will be transmitted to Earth by the rover when it becomes
fully functional. This visual information, showing the landing area and its
surroundings in fine detail, along with the fact that the rover will land on its
wheels no tricky navigation off of a landing vehicle needed will allow project
scientists to begin working the rover much sooner.
Once the rover's mast rises and all systems are go, the real work will begin.
As with MER, a mast-mounted, two-eyed camera system will feature
prominently. The MastCam, like the descent imager and an arm-mounted
close-up camera, is being designed and built by Malin Space Science Systems
in San Diego, CA. All three rely on similar full-color, high-resolution
subsystems. MastCam takes the basic setup found on the MERs twin cameras
that will allow scientists to assemble 3D images and refines it considerably.
MastCam has twin 10x optical zoom lenses, the same power as found in highend consumer digital cameras on Earth. This will allow the camera to take not
only wide-angle panoramas but also zoom in and focus on fist-sized rocks a
kilometer (0.6 miles) away.
MastCam also shoots high definition video, a first for Mars. Both stills and
video will be captured in full color, just like with earthbound digital cameras.
In addition, MastCam will use a variety of specialized filters. Several
members of the Malin Space Science Systems scientific team contributed to
the various camera designs, including director James Cameron (Titanic, The
Abyss, Aliens), a co-investigator on the MastCam science team.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
10
In addition, ChemCam will be able to do some chemical analysis of small
parts of rock samples, before they are crushed and transported to MSL's
internal analytical instruments.
"I think this instrument is going to see a lot of use," Wiens says, "because we
can take a lot of data rapidly. So one of the great things is that we can get a
much larger database of rock samples than some of the in situ techniques. I
think it's going to be an exciting instrument to build and fly."
Schematic of major mission events during entry, descent
and landing. Image credit: NASA/JPL/Cornell University/
Dan Maas.
Palluconi sees MSL as an intermediary step between MER and the direct
search for life on Mars. "I would regard MSL as being kind of a transition
mission between the more conventional aspects of planetary exploration,
which involve geology and geophysics and, in the case of Mars because of its
atmosphere, the climate and weather to ones in the future which will make
direct searches for life. So the overall objective of MSL is to make a
habitability assessment of the area that the vehicle lands in on Mars."
The near future
Photograph, vaporize, analyze
The MSL mast will also hold a unique hybrid optical instrument, never before
flown to Mars. Called the ChemCam, this telescopic tool takes close-ups at a
distance with a field of view of about 30 cm (1 foot) at ten meters (33 feet)
distance. But that's just the first step for ChemCam. In step two eerily
reminiscent of the heat rays described in War of the Worlds a powerful laser
will focus through the same telescope at the target. The laser can heat a spot
about a millimeter (0.04 inches) in diameter to nearly ten thousand degrees
Celsius (18 thousand degrees Fahrenheit). The heat blows away dust, breaks
off molecules, breaks up the molecules and even breaks apart atoms in the
rocky target.
Empty nest view back to landing petal from the mobile
Opportunity rover, which has ventured to the crater's rim.
Image credit: NASA/JPL.
As a result, the target emits a spark of light. ChemCam can analyze the
spark's spectrum, identifying what elements carbon or silicon, for example the
target contained. Called Laser-Induced Breakdown Spectroscopy, or LIBS,
this technique is widely used on Earth but will be a first for Mars, says Roger
C. Wiens, a planetary scientist at Los Alamos National Laboratory and the
principal investigator on the ChemCam project. "LIBS is being used in a
number of facets on earth. For example, a company that makes aluminum
uses it to check the composition of their aluminum alloy in the molten state."
Going into space is a different story. Seven years in the making, ChemCam
will make MSL much faster than MER at choosing targets, Wiens says. "The
Opportunity rover landed in a small crater and here in front of us sat a rock
outcrop, which is the first one we had seen on Mars up close and personal.
And it was less than ten meters away. [With the ChemCam] we could have
immediately analyzed that rock before actually even driving the rover off the
pad, and told them that here sits a sedimentary rock outcrop right in front of
you. Instead, it took a number of days, and they drove up to the rock and
actually sampled it with the contact instruments before they really determined
that it was a sedimentary rock outcrop." With its long optical reach,
ChemCam can analyze objects out of reach of the rover's mechanical arm,
even overhead.
Small scout landers are one consideration for future "scout" missions.
The mission has two goals. One is to study the geologic history of
water, the key to unlocking the story of past climate change. Two is to
search for evidence of a habitable zone that may exist in the ice-soil
boundary, the "biological paydirt." Image credit: NASA JPL.
Because NASA decided only in December 2004, which of many scientific
instruments proposed for MSL will actually fly, all of the scientists whose
projects were chosen are scrambling to put the finishing touches on their
instruments. "The mission is in phase A, which is a definition phase, so it's
really the earliest formal phase of the mission," Palluconi says. "Right now
the principle work on the science side is figuring out where to place the
instruments on the rover, how to meet their thermal needs, how to ensure that
they have the fields of view they need and that their other requirements are
met. Of course, the vehicle itself is being designed at the same time and the
design is being refined. So there's quite a bit of work to do and we're probably
just about a year away from the preliminary design review, which on the 2009
launch schedule would occur next February."
Some aspects of the Mars Science Laboratory remain up in the air. Many of
the MSL scientific instruments require plenty of power. The proposed source
of that power, a radioisotope power supply, requires presidential approval,
which lies in the future. And in March 2005, NASA began considering the
possibility of flying two MSL rovers in 2011 instead of one in 2009.
Mars Odyssey recently detected water ice near the surface in the high
latitudes, and in 2007 the Phoenix Mars Lander will investigate those regions.
This August, the Mars Reconnaissance Orbiter will be launched. What it
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 13, 13 April 2005
discovers will determine the fate of the Mars Science Laboratory, which is
scheduled for launch in 2009.
11
NASA MAY SILENCE VOYAGERS ON APRIL 15
By Jeff Barbour
From Universe Today
12 April 2005
Today NASA has 55 active mission control teams monitoring ongoing
spacecraft and station missions—13 associated with missions extended
beyond original planning. Soon there may be seven less. By October of this
year, we could be turning a deaf ear to data collected by one of the most
successful NASA programs of all times. For even as Voyager 1 and 2 are
poised to enter the interstellar realm, budget-minders in our nation's capital
may have already sealed the fate on a pair of craft that could provide
important information about our solar system—and beyond—for the next 15
years.
In this artist rendition, the Phoenix lander is shown on the arctic plains
of Mars just as it has begun to dig a trench through the upper soil
layer. The polar water ice cap is shown in the far distance. This
rendition of the Phoenix lander was created by artist Corby Waste of
the Jet Propulsion Laboratory.
...If you are an American citizen, please call, write, e-mail, or hand-deliver a
message to your congressional representatives. Tell them that the last word
sent by Voyager I and Voyager II shall not go unheard. Tell them that
humanity must not orphan its children—be they human, or technological. Tell
them that long-after some boondoggle project funded by taxpayer dollars in
support of parochial interests has fallen by the way-side, Voyager I and II will
continue to be our emissaries to the Universe. And if you are a World citizen
please petition your local government to speak plainly to the leadership of the
United States telling them that the entire world has entrusted its hearts and
minds to the continued expansion of humankind's presence in the Cosmos.
Voyager 1 and Voyager 2 are on a mission for us all.
Read the full article at
http://www.universetoday.com/am/publish/nasa_silence_voyagers.html.
Read the original article at http://www.astrobio.net/news/article1521.html.
MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
31 March - 6 April 2005
PERFECT SPOT FOUND FOR MOON BASE
By Robert Roy Britt
From Space.com
13 April 2005
The following new images taken by the Mars Orbiter Camera (MOC) on the
Mars Global Surveyor spacecraft are now available.
Researchers have identified what may be the perfect place for a Moon base, a
crater rim near the lunar north pole that's in near-constant sunlight yet not far
from suspected stores of water ice. Permanently sunlit areas would provide
crucial solar energy for any future Moon settlement, a goal for NASA outlined
last year by President George W. Bush. Such sites would also have resortlike temperatures compared with other lunar locations that fluctuate between
blistering heat and unfathomable cold.
Equally important, in the permanently shadowed depths of craters around the
lunar north pole, water ice may lurk, according to previous but unconfirmed
observations. Melted, it would be vital for drinking. Broken into hydrogen
and oxygen, the water could provide breathable air and be used to make rocket
fuel for a trip to Mars. That fits in neatly with the White House vision of
using the Moon as a stepping stone to Mars.
Read the full article at
http://www.space.com/scienceastronomy/050413_moon_perfect.html.
SEE THE OLDEST THING ON EARTH
By Ryan J. Foley
From Associated Press and LiveScience.com
9 April 2005
A tiny speck of zircon crystal that is barely visible to the eye is believed to be
the oldest known piece of Earth at about 4.4 billion years old. For the first
time ever, the public will have a chance to see the particle Saturday at the
University of Wisconsin-Madison, where researchers in 2001 made the
breakthrough discovery that the early Earth was much cooler than previously
believed based on analysis of the crystal.
To create buzz about an otherwise arcane subject, the university is planning a
daylong celebration of the ancient stone—capped with "The Rock Concert" by
jazz musicians who composed music to try to answer the question: "What
does 4.4 billion years old sound like?"
Read the full article at
http://www.livescience.com/othernews/ap_050409_oldest_thing.html.
Crater with Windstreak (Released 31 March 2005)
http://www.msss.com/mars_images/moc/2005/03/31/
Northern Bands (Released 01 April 2005)
http://www.msss.com/mars_images/moc/2005/04/01/
Crater Streaks (Released 02 April 2005)
http://www.msss.com/mars_images/moc/2005/04/02/
Buttes near Meridiani (Released 03 April 2005)
http://www.msss.com/mars_images/moc/2005/04/03/
Xanthe Valley (Released 04 April 2005)
http://www.msss.com/mars_images/moc/2005/04/04/
Mars at Ls 193 Degrees (Released 05 April 2005)
http://www.msss.com/mars_images/moc/2005/04/05/
Hephaestus Troughs (Released 06 April 2005)
http://www.msss.com/mars_images/moc/2005/04/06/
All of the Mars Global Surveyor images
http://www.msss.com/mars_images/moc/index.html.
are
archived
at
Mars Global Surveyor was launched in November 1996 and has been in Mars
orbit since September 1997. It began its primary mapping mission on March
8, 1999. Mars Global Surveyor is the first mission in a long-term program of
Mars exploration known as the Mars Surveyor Program that is managed by
JPL for NASA's Office of Space Science, Washington, DC. Malin Space
Science Systems (MSSS) and the California Institute of Technology built the
MOC using spare hardware from the Mars Observer mission. MSSS operates
the camera from its facilities in San Diego, CA. The Jet Propulsion
Laboratory's Mars Surveyor Operations Project operates the Mars Global
Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics,
from facilities in Pasadena, CA and Denver, CO.
End Marsbugs, Volume 12, Number 13.