Download 1 Marsbugs: The Electronic Astrobiology Newsletter, Volume 12

Marsbugs: The Electronic Astrobiology Newsletter
Volume 12, Number 14, 19 April 2005
Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College,
Batesville, Arkansas 72503-2317, USA. [email protected]
Marsbugs is published on a weekly to monthly basis as warranted by the number of articles and announcements. Copyright of this compilation exists with the editor,
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editor or by Lyon College. E-mail subscriptions are free, and may be obtained by contacting the editor. Information concerning the scope of this newsletter,
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Articles and News
Announcements
Page 1
EUROPE GOES BACK TO MARS
ESA release 19-2005
Page 8
WASHINGTON DC THINK TANK PUBLISHES ZUBRIN
ANALYSIS OF SPACE PROGRAM
Mars Society release
Page 2
WAYWARD PLANET KNOCKS EXTRASOLAR PLANETS
FOR A LOOP
By Robert Sanders
Page 8
NSBRI POSTDOCTORAL FELLOWSHIP PROGRAM
SOLICITING APPLICATIONS
National Space Biomedical Research Institute release
Page 8
ESP2 ABSTRACT DEADLINE APPROACHING
By Lee Kump
Page 3
Page 4
THE CASSINI MISSION AND ASTROBIOLOGY
By Christopher Chyba
MICHAEL GRIFFIN TAKES THE HELM AS NASA
ADMINISTRATOR
NASA release 05-096
Page 4
MOON WATER
By David H. Levy and Tony Phillips
Page 5
LOW OXYGEN LIKELY MADE "GREAT DYING"
WORSE, GREATLY DELAYED RECOVERY
University of Washington release
Page 6
"ALIEN" LIFE FORMS MAY EXIST ON EARTH STATES
REPORT IN ASTROBIOLOGY JOURNAL
Mary Ann Liebert, Inc. release
Page 6
CRUNCHING THE NUMBERS
By Maggie Turnbull
Page 7
NASA SCIENTIST: "MARS COULD BE BIOLOGICALLY
ALIVE"
By Leonard David
EUROPE GOES BACK TO MARS
ESA release 19-2005
8 April 2005
European space scientists have strongly recommended a mission equipped
with a Rover as the next scientific mission to Mars as part of the European
Space Agency’s Aurora program of planetary exploration. The mission would
conduct a detailed analysis of the martian environment and search for traces of
past or present life. A launch in June 2011, followed by a two year journey,
would arrive on the Red Planet in June 2013. A detailed proposal will be
prepared for consideration by ESA member states at the Agency’s Council
Meeting at Ministerial Level in December 2005.
The recommendation was made by European scientists at an international
space workshop held at Aston University, Birmingham, England on the 6th
and 7th April 2005. The ESA workshop, hosted by the UK’s Particle Physics
and Astronomy Research Council (PPARC), brought together space scientists
and agency officials from Europe, Canada, North America and the
international space community in order to debate robotic mission options up
to 2013 in the first phase of the Aurora program.
Three candidate missions were considered: BeagleNet, ExoMars and its
variant ExoMars-Lite. Consideration was also given to the preparatory
activities needed to develop a sustainable, long-term Mars Exploration
program and how efforts to 2011 address the requirements of a Mars Sample
Return (MSR) mission within an overall Aurora roadmap.
Mission Reports
Page 8
CASSINI SIGNIFICANT EVENTS FOR 7-13 APRIL 2005
NASA/JPL release
Page 11
DART UPDATES
NASA releases
Page 11
DEEP IMPACT MISSION UPDATE
By Maura Rountree-Brown
Page 12
MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
Page 12
MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
Following scientific and technology presentations of each candidate mission
an evaluation process was undertaken by the scientists measured against key
criteria. The outcome and consensus of the workshop recommended a
mission which blended key technologies and objectives from each of the
candidate missions as the first robotic mission in the Aurora program. This
recommendation will form the basis of a detailed proposal by the scientific
community to be considered at the ESA’s Council Meeting at Ministerial
Level in December 2005.
The recommended mission will consist of a Soyuz launcher to deliver a probe
which includes at least one Rover for scientific exploration of the martian
environment. Telecommunications (data relay) between the probe and Earth
will be achieved via NASA orbiting spacecraft. The Rover would be
equipped with a suite of scientific instruments designed to search for traces of
past or present life on Mars; to characterize the shallow subsurface
water/geochemical composition and its vertical distribution profile; and to
identify surface and environmental hazards to future human missions.
Taking into account the exciting and scientifically intriguing results from
ESA’s Mars Express orbiter the recommended mission will also incorporate
instruments to specifically measure seismic phenomena which could be
caused by volcanoes, hydrothermal activity or Marsquakes. The Rover will
also contain a drill capable of penetrating the surface to a depth of 2m and a
Beagle 2 type life marker experiment such as a Gas Analysis Package (GAP)
capable of studying stable isotopes in the atmosphere, rocks, and soil. The
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
2
entry, descent and landing system (EDLS) will utilize key technologies
involving airbags and possibly retrorockets.
To be launched by a Soyuz Fregat 2b vehicle in June 2011 from ESA’s
spaceport at Kourou in French Guiana the probe and Rover would arrive on
the surface of Mars in June 2013 after a two year voyage. Looking beyond
2011 the scientists confirmed their commitment to collaborating in an
international Sample Return Mission in 2016 (which would include sample
acquisition and handling, mobility and planetary protection), as a logical
sequence to the recommended mission in the future roll out of ESA’s Aurora
program.
Commenting on the workshop, Professor Jean Pierre Swings, Chair of ESA's
Exploration Program Advisory Committee, said, "This workshop has brought
an extremely wide range of scientists together from a diverse range of
disciplines to recommend what will be a tremendously exciting mission for
European space. It builds upon the success of ESA’s Mars Express whilst
driving new technologies that will form the foundation for the future
development of the Aurora program".
In terms of UK involvement Dr. Mark Sims, University of Leicester and Chair
of PPARC’s Aurora Advisory Committee was buoyant, "This is a great result
for European planetary exploration with significant involvement for the UK.
The UK community has worked hard to ensure that the Aurora program
reflects the scientific and industrial expertise we have in the UK and the
recommended mission builds upon the heritage of Beagle 2 and Huygens. We
look forward to making major contributions to this scientific mission of
discovery to the Red Planet".
Contacts:
Peter Barratt
PPARC Head of Communications
Phone: +44 [0] 1793 442025
Mobile: + 44 [0]7879 602899
E-mail: [email protected]
Franco Bonacina
European Space Agency
Spokesman and Head of Media Relations Division
Phone: +33 1 5369 7713
Fax: + 33 1 5369 7690
E-mail: [email protected]
Piero Messina
European Space Agency
Aurora Program Communication
Phone: +33 1 5369 7410
Fax: +33 1 5369 7601
Mobile: +33 6 8771 5126
Read the original news release at
http://www.esa.int/esaCP/SEMOBUV797E_index_2.html.
Additional articles on this subject are available at:
http://www.astrobio.net/news/article1522.html
WAYWARD PLANET KNOCKS EXTRASOLAR PLANETS FOR A
LOOP
By Robert Sanders
University of California, Berkeley release
13 April 2005
The peculiar orbits of three planets looping around a faraway star can be
explained only if an unseen fourth planet blundered through and knocked
them out of their circular orbits, according to a new study by researchers at the
University of California, Berkeley, and Northwestern University. The
conclusion is based on computer extrapolations from 13 years of observations
of planet motions around the star Upsilon Andromedae. It suggests that the
non-circular and often highly elliptical orbits of many of the extrasolar planets
discovered to date may be the result of planets scattering off one another. In
such a scenario, the perturbing planet could be shot out of the system entirely
or could be kicked into a far-off orbit, leaving the inner planets with eccentric
orbits.
Artist's rendering of the Upsilon Andromedae planetary
system, where new research suggests the circular orbit of
planets was disrupted by an unseen planet caroming
through the solar system. Image credit: Sylwia Walerys/
Northwestern University.
"This is probably one of the two or three extrasolar systems that have the best
observations and tightest constraints, and it tells a unique story," said Eric
Ford, a Miller postdoctoral fellow at UC Berkeley. "Our explanation is that
the outer planet's original orbit was circular, but it got this sudden kick that
permanently changed its orbit to being highly eccentric. To provide that kick,
we've hypothesized that there was an additional planet that we don't see now.
We believe we now understand how this system works."
If such a planet had caromed through our solar system early in its history, the
researchers noted, the inner planets might not now have such nicely circular
orbits, and, based on current assumptions about the origins of life, Earth's
climate might have fluctuated too much for life to have arisen.
"While the planets in our solar system remain stable for billions of years, that
wasn't the case for the planets orbiting Upsilon Andromedae," Ford said.
"While those planets might have formed similarly to Jupiter and Saturn, their
current orbits were sculpted by a late phase of chaotic and violent
interactions."
According to Ford's colleague, Frederic A. Rasio, associate professor of
physics and astronomy at Northwestern, "Our results show that a simple
mechanism, often called 'planet-planet scattering'—a sort of slingshot effect
due to the sudden gravitational pull between two planets when they come very
near each other—must be responsible for the highly eccentric orbits observed
in the Upsilon Andromedae system. We believe planet-planet scattering
occurred frequently in extrasolar planetary systems, not just this one, resulting
from strong instabilities. So, while planetary systems around other stars may
be common, the kinds of systems that could support life, which, like our solar
system, presumably must remain stable over very long time scales, may not be
so common."
The computer simulations are reported in the April 14 issue of the journal
Nature by Ford, Rasio and Verene Lystad, an undergraduate student majoring
in physics at Northwestern. Ford was a student of Rasio's at the
Massachusetts Institute of Technology before pursuing graduate studies at
Princeton University and arriving at UC Berkeley in 2004.
The planetary system around Upsilon Andromedae is one of the most studied
of the 160-some systems with planets discovered so far outside our own solar
system. The inner planet, a "hot Jupiter" so close to the star that its orbit is
only a few days, was discovered in 1996 by UC Berkeley's Geoff Marcy and
his planet-hunting team. The two outer planets, with elongated orbits that
perturb each other strongly, were discovered in 1999. These three, huge,
Jupiter-like planets around Upsilon Andromedae comprised the first extrasolar
multi-planet system discovered by Doppler spectroscopy.
Because of the unusual nature of the planetary orbits around Upsilon
Andromedae, Marcy and his team have studied it intensely, making nearly
500 observations—10 times more than for most other extrasolar planets that
have been found. These observations, the wobbles in the star's motion
induced by the orbiting planets, allow a very precise charting of the planets'
motions around the star.
"The observations are so precise that we can watch and predict what will
happen for tens of thousands of years in the future," Ford said.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
3
realized there was something much more interesting going on than anyone had
found before."
Understanding what happened during the formation and evolution of Upsilon
Andromedae and other extrasolar planetary systems has major implications
for our own solar system.
Left: The Terestrial Planet Finder will search for
Earth-like planets orbiting 250 of the closest stars.
Image credit: NASA. Right: Artist concept of star
system, HD70642.
Image credit: John Rowe
animation.
"Once you realize that most of the known extrasolar planets have highly
eccentric orbits (like the planets in Upsilon Andromedae), you begin to
wonder if there might be something special about our solar system," Ford
said. "Could violent planet-planet scattering be so common that few planetary
systems remain calm and habitable? Fortunately, astronomers—led by Geoff
Marcy, a professor of astronomy at UC Berkeley—are diligently making the
observations that will eventually answer this exciting question."
Today, while the innermost planet huddles close to the star, the two outer
planets orbit in egg-shaped orbits. Computer simulations of past and future
orbital changes showed, however, that the outer planets are engaged in a
repetitive dance that, once every 7,000 years, brings the orbit of the middle
planet to a circle.
The research was supported by the National Science Foundation and UC
Berkeley's Miller Institute for Basic Research.
"That property of returning to a very circular orbit is quite remarkable and
generally doesn't happen," Ford said. "The natural explanation is that they
were once both in circular orbits, and one got a big kick that caused it to
become eccentric. Then, the subsequent evolution caused the other planet to
grow its eccentricity, but because of the conservation of energy and angular
momentum, it returns periodically to a very nearly circular orbit."
An additional article on this subject is available at
http://www.astrobio.net/news/article1523.html.
Previously, astronomers had proposed two possible scenarios for the
formation of Upsilon Andromedae's planet system, but the observational data
was not yet sufficient to distinguish the two models. Another astronomer,
Renu Malhotra at the University of Arizona, had previously suggested that
planet-planet scattering might have excited the eccentricities in Upsilon
Andromedae. But an alternative explanation claimed that interactions among
the planets and a gas disk surrounding the star could also have produced such
eccentric orbits. By combining additional observational data with new
computer models, Ford and his colleagues were able to show that interactions
with a gas disk would not have produced the observed orbits, but that
interactions with another planet would naturally produce them.
Read the original news release at
http://www.berkeley.edu/news/media/releases/2005/04/13_planet.shtml.
THE CASSINI MISSION AND ASTROBIOLOGY
By Christopher Chyba
From Space.com
14 April 2005
For the past year, the SETI Institute has been one of the lead teams in NASA’s
Astrobiology Institute (NAI), and this week many members of the SETI
Institute have been in Boulder, CO for the biennial meeting of the NAI. The
SETI Institute’s team pulls together a dozen of our scientists and educators in
Life in the Universe research, SETI research, and Education and Public
Outreach to address some of the most important questions in astrobiology.
Chief among these is to understand how the origin and evolution of life
depends upon particular planetary environments, and how, in turn, planetary
environments may themselves be shaped by biology. We are pursuing these
questions by investigating a number of worlds in our own solar system, and by
asking similar questions about worlds orbiting other stars.
"The key distinguishing feature between those theories was that interactions
with an outer disk would cause the orbits to change very slowly, and a strong
interaction with a passing planet would cause the orbits to change very
quickly compared to the 7,000-year time scale for the orbits to evolve," Ford
said. "Because the two hypotheses make different predictions for the
evolution of the system, we can constrain the history of the system based on
the current planetary orbits."
Ford said that as the planets formed inside a disk of gas and dust, the drag on
the planets would have kept their orbits circular. Once the dust and gas
dissipated, however, only an interaction with a passing planet could have
created the particular orbits of the two outer planets observed today. Perhaps,
he noted, the perturbing planet was knocked into the inner planets by
interactions with other planets far from the central star. However it started,
the resulting chaotic interactions would have created a very eccentric orbit for
the third planet, which then also gradually perturbed the second planet's orbit.
Because the outer planet dominates the system, over time it perturbed the
middle planet's orbit enough to deform it slowly into an eccentric orbit as
well, which is what is seen today, although every 7,000 years or so, the middle
planet returns gradually to a circular orbit.
"This is what makes the system so peculiar," said Rasio. "Ordinarily, the
gravitational coupling between two elliptic orbits would never make one go
back to a nearly perfect circle. A circle is very special."
"Originally the main objective of our research was to simulate the Upsilon
Andromedae planetary system, essentially in order to determine whether the
outer two planets lie in the same plane like the planets in the solar system do,"
said Lystad, who started working with Rasio when she was a sophomore and
did many of the computer integrations as part of her senior thesis. "We were
surprised to find that, for many of our simulations, it was difficult to tell
whether the planets were in the same plane due to the fact that the middle
planet's orbit periodically became so very nearly circular. Once we noticed
this strange behavior was present in all of our simulations, we recognized it as
an earmark of a system that had undergone planet-planet scattering. We
Although Titan is unlikely to harbor life as we know it, this large moon
of Saturn may resemble primordial Earth in many ways. Image credit:
NASA/JPL/Space Science Institute.
...Besides Earth, we are paying a great deal of attention to three other worlds
in the solar system. (1) Mars, which once clearly had liquid water on its
surface, and may still have for at least brief periods. The Red Planet may or
may not harbor a subsurface biosphere. (2) Jupiter’s moon Europa, which
almost certainly is host to the solar system’s second ocean, with the possibility
that that ocean hosts at least microbial life, and (3) Saturn’s moon Titan, the
most mysterious of all, and a body that has recently been explored in detail by
the Cassini spacecraft and the Huygens probe.
Read the full article at
http://www.space.com/searchforlife/seti_cassini_050414.html.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
4
MICHAEL GRIFFIN TAKES THE HELM AS NASA
ADMINISTRATOR
NASA release 05-096
14 April 2005
Contact:
Dean Acosta/Bob Jacobs
NASA Headquarters, Washington, DC
Phone: 202-358-1898/1600
Michael D. Griffin reported to work today as NASA's 11th Administrator.
Administrator Griffin becomes the leader of the agency on the day the
Expedition 11 crew is set to launch to the International Space Station. The
Administrator was confirmed late Wednesday night by the U.S. Senate. An
official swearing-in ceremony will be scheduled later.
Additional articles on this subject are available at:
http://www.space.com/news/050414_meet_mike.html
http://www.universetoday.com/am/publish/mike_griffin_takes_helm.html
"I have great confidence in the team that will carry out our nation's exciting,
outward-focused, destination-oriented program," said Griffin. "In the coming
days, I'll be spending a good deal of my time reviewing our progress toward
returning the Space Shuttle safely to flight. I will also be reviewing the
activities of our mission directorates and our various supporting functions. I
share with the agency a great sense of privilege that we have been given the
wonderful opportunity to extend humanity's reach throughout the solar
system."
During his confirmation hearing Tuesday before the U.S. Senate, the
Administrator stated his priorities, consistent with the President's Vision for
Space Exploration will be:

Fly the Space Shuttle as safely as possible until its retirement, not later
than 2010;

Bring a new Crew Exploration Vehicle into service as soon as possible
after the Space Shuttle is retired;

Develop a balanced overall program of science, exploration and
aeronautics at NASA, consistent with the redirection of the human
spaceflight program to focus on exploration;

Complete the International Space Station in a manner consistent with
our international partner commitments and the needs of human
exploration;

Encourage the pursuit of appropriate partnerships with the emerging
commercial space sector;

Establish a lunar return program having the maximum possible utility
for later missions to Mars and other destinations.
MOON WATER
By David H. Levy and Tony Phillips
From NASA Science News
14 April 2005
The first object in the night sky most of us ever saw, the Moon remains a
mystery. Haunted by poets, looked upon by youngsters in love, studied
intensely by astronomers for four centuries, examined by geologists for the
last 50 years, walked upon by twelve humans, this is Earth's satellite. And as
we look towards the Moon with thoughts of setting up a permanent home
there, one new question is paramount: does the Moon have water? Although
none has been definitely detected, recent evidence suggests that it's there.
President George W. Bush nominated Griffin as NASA Administrator in
March, while he was serving as the Space Department Head at Johns Hopkins
University's Applied Physics Laboratory in Baltimore. Griffin was President
and Chief Operating Officer of In-Q-Tel, Inc., before joining Johns Hopkins
in April 2004. He also served in several positions within Orbital Sciences
Corporation, Dulles, VA, including Chief Executive Officer of Magellan
Systems, Inc.
Earlier in his career, Administrator Griffin served as Chief Engineer at NASA
and as Deputy for Technology at the Strategic Defense Initiative
Organization. He has served as an adjunct professor at the University of
Maryland, Johns Hopkins University and George Washington University. He
taught courses in spacecraft design, applied mathematics, guidance and
navigation, compressible flow, computational fluid dynamics, spacecraft
attitude control, astrodynamcis and introductory aerospace engineering. He is
the lead author of more than two dozen technical papers, as well as the
textbook, Space Vehicle Design.
A registered professional engineer in Maryland and California, the
Administrator is a fellow of the American Institute of Aeronautics and
Astronautics (AIAA).
He is a recipient of the NASA Exceptional
Achievement Medal, the AIAA Space Systems Medal and the Department of
Defense Distinguished Public Service Medal, the highest award given to a
non-government employee. He is a certified flight instructor with instrument
and multiengine ratings
He received a bachelor's degree in Physics from Johns Hopkins University; a
master's degree in Aerospace Science from Catholic University of America; a
Ph.D. in Aerospace Engineering from the University of Maryland; a master's
degree in Electrical Engineering from the University of Southern California; a
master's degree in Applied Physics from Johns Hopkins University; a master's
degree in Business Administration from Loyola College; and a master's
degree in Civil Engineering from George Washington University.
For more information about NASA and agency programs on the Internet, visit
http://www.nasa.gov.
The Moon, photographed by amateur astronomer Sylvain Weiller.
Why should there be water on the Moon? Simply for the same reason that
there's water on Earth. A favorite theory is that water, either as water by itself
or as its components of hydrogen and oxygen, was deposited on Earth during
its early history—mostly during a period of "late heavy bombardment" 3.9
billion years ago—by the impacts of comets and asteroids. Because the Moon
shares the same area of space as Earth, it should have received its share of
water as well. However, since it has only a tiny fraction of Earth's gravity,
most of the Moon's water supply should have evaporated and drifted off into
space long ago. Most, but perhaps not all.
In ancient times, observers commonly thought the Moon had abundant
water—in fact, the great lava plains like Mare Imbrium were called maria, or
seas. But when Neil Armstrong and Buzz Aldrin landed on the Moon in 1969,
they stepped out not into the water of the Sea of Tranquillity, but onto basaltic
rock. No one was surprised by that—the idea of lunar maria had been
replaced by lava plains decades earlier.
As preparations were underway in the mid 1960s for the Apollo program,
questions about water on the Moon were barely on the radar screen.
Geologists and astronomers were divided at the time as to whether the lunar
surface was a result of volcanic forces from beneath, or cosmic forces from
above. Grove Carl Gilbert in 1893 already had the answer. That famous
geologist suggested that large asteroidal objects hit the Moon, forming its
craters. Ralph Baldwin articulated the same idea in 1949, and Gene
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
5
Shoemaker revived the idea again around 1960. Shoemaker, almost alone
among geologists of his day, saw the Moon as a fertile subject for field
geology. He saw the craters on the Moon as logical impact sites that were
formed not gradually in eons, but explosively in seconds.
LOW OXYGEN LIKELY MADE "GREAT DYING" WORSE,
GREATLY DELAYED RECOVERY
University of Washington release
14 April 2005
The Apollo flights confirmed that the dominant geological process on the
Moon is impact-related. That discovery, in turn, ushered in a new question.
Since Earth's water was probably delivered largely by comets and asteroids,
could this process have done the same for the Moon? And could some of that
water still be there?
The biggest mass extinction in Earth history some 251 million years ago was
preceded by elevated extinction rates before the main event and was followed
by a delayed recovery that lasted for millions of years. New research by two
University of Washington scientists suggests that a sharp decline in
atmospheric oxygen levels was likely a major reason for both the elevated
extinction rates and the very slow recovery.
Earth's land at the time was still massed in a supercontinent called Pangea,
and most of the land above sea level became uninhabitable because low
oxygen made breathing too difficult for most organisms to survive, said
Raymond Huey, a UW biology professor. What's more, in many cases nearby
populations of the same species were cut off from each other because even
low-altitude passes had insufficient oxygen to allow animals to cross from one
valley to the next. That population fragmentation likely increased the
extinction rate and slowed recovery following the mass extinction, Huey said.
"Biologists have previously thought about the physiological consequences of
low oxygen levels during the late Permian period, but not about these
biogeographical ones," he said.
Hydrogen deposits measured by Lunar Prospector.
In 1994, the SDI-NASA Clementine spacecraft orbited the Moon and mapped
its surface. In one experiment, Clementine beamed radio signals into
shadowed craters near the Moon's south pole. The reflections, received by
antennas on Earth, seemed to come from icy material. That makes sense. If
there is water on the Moon, it's probably hiding in the permanent shadows of
deep, cold craters, safe from vaporizing sunlight, frozen solid. So far so good,
but... the Clementine data were not conclusive, and when astronomers tried to
find ice in the same craters using the giant Arecibo radar in Puerto Rico, they
couldn't. Maybe Clementine was somehow wrong.
In 1998, NASA sent another spacecraft, Lunar Prospector, to check. Using a
device called a neutron spectrometer, Lunar Prospector scanned the Moon's
surface for hydrogen-rich minerals. Once again, polar craters yielded an
intriguing signal: neutron ratios indicated hydrogen. Could it be the "H" in
H2O? Many researchers think so. Lunar Prospector eventually sacrificed
itself to the search. When the spacecraft's primary mission was finished,
NASA decided to crash Prospector near the Moon's south pole, hoping to
liberate a bit of its meager layer of water. Earth's satellite might briefly
become a comet as amounts of water vapor were released.
Lunar Prospector crashed, as planned, and several teams of researchers tried
to detect that cloud, but without success. Either there was no water, or there
was not enough water to be detected by Earth-based telescopes, or the
telescopes were not looking in precisely the right place. In any event, no
water was found from Prospector's impact.
In 2008, NASA plans to send a new spacecraft to the Moon: the Lunar
Reconnaissance Orbiter (LRO), bristling with advanced sensors that can sense
water in at least four different ways. Scientists are hopeful that LRO can
decide the question of Moon water once and for all. Our interest is not just
scientific. If we are indeed to build a base on the Moon, the presence of water
already there would offer a tremendous advantage in building and running it.
It's been 35 years since we first set foot on the Moon. Now ambitious eyes
once again look toward our satellite not just as a place to visit, but as a place
to live.
Read the original article at
http://science.nasa.gov/headlines/y2005/14apr_moonwater.htm.
A depiction of present-day Earth overlaid with simulated atmospheric
oxygen of the early Triassic period. Because oxygen was low, even at
sea level, animals would have been restricted to very low altitudes,
shown in green. Areas shaded red are higher elevations where many
animals could not have found sufficient oxygen and so could not have
lived or even traversed, leaving lowland populations fragmented and
isolated. Image credit: George Wang, UW.
Atmospheric oxygen content, about 21 percent today, was a very rich 30
percent in the early Permian period. However, previous carbon-cycle
modeling by Robert Berner at Yale University has calculated that atmospheric
oxygen began plummeting soon after, reaching about 16 percent at the end of
the Permian and bottoming out at less than 12 percent about 10 million years
into the Triassic period.
"Oxygen dropped from its highest level to its lowest level ever in only 20
million years, which is quite rapid, and animals that once were able to cross
mountain passes quite easily suddenly had their movements severely
restricted," Huey said.
He calculated that when the oxygen level hit 16 percent, breathing at sea level
would have been like trying to breathe at the summit of a 9,200-foot mountain
today. By the early Triassic period, sea-level oxygen content of less than 12
percent would have been the same as it is today in the thin air at 17,400 feet,
higher than any permanent human habitation. That means even animals at sea
level would have been oxygen challenged.
Huey and UW paleontologist Peter Ward are authors of a paper detailing the
work, published in the April 15 edition of the journal Science. The work was
supported by grants from the National Science Foundation and the National
Aeronautics and Space Administration's Astrobiology Institute.
Not only was atmospheric oxygen content dropping at the end of the Permian,
the scientists said, but carbon dioxide levels were rising, leading to global
climate warming.
"Declining oxygen and warming temperatures would have been doubly
stressful for late Permian animals," Huey said. "As the climate warms, body
temperatures and metabolic rates go up. That means oxygen demand is going
up, so animals would face an increased oxygen demand and a reduced supply.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
It would be like forcing athletes to exercise more but giving them less food.
They'd be in trouble."
Ward was lead author of a paper published in Science earlier this year
presenting evidence that extinction rates of land vertebrates were elevated
throughout the late Permian, likely because of climate change, and culminated
in a mass extinction at the end of the Permian. The event, often called "the
Great Dying," was the greatest mass extinction in Earth's history, killing 90
percent of all marine life and nearly three-quarters of land plants and animals.
Ward said paleontologists had previously assumed that Pangea was not just a
supercontinent but also a "superhighway" on which species would have
encountered few roadblocks while moving from one place to another.
However, it appears the greatly reduced oxygen actually created impassable
barriers that affected the ability of animals to move and survive, he said.
"If this is true, then I think we have to go back and look at oxygen and its role
in evolution and how different species developed," Ward said. "You can go
without food for a couple of weeks. You can go without water for a few days.
How long can you go without oxygen, a couple of minutes? There's nothing
with a greater evolutionary effect than oxygen."
Contacts:
Vince Stricherz
Phone: 206-543-2580
E-mail: [email protected]
Raymond Huey
Phone: 206-543-1505
E-mail: [email protected]
Peter Ward
Phone: 206-543-2962
E-mail: [email protected]
Read the original news release at
http://www.uwnews.org/article.asp?articleID=9592.
Additional articles on this subject are available at:
http://www.livescience.com/animalworld/050414_mass_extinction.html
http://www.spacedaily.com/news/life-05z.html
http://www.universetoday.com/am/publish/low_oxygen_great_dying.html
"ALIEN" LIFE FORMS MAY EXIST ON EARTH STATES REPORT
IN ASTROBIOLOGY JOURNAL
Mary Ann Liebert, Inc. release
18 April 2005
"If life readily emerged on Earth shortly after conditions became favorable,
isn't it likely that other genesis events also occurred, creating additional 'alien'
life forms that co-exist with known life?" asks a groundbreaking hypothesis
paper in the April 2005 (Volume 5, Number 2) issue of Astrobiology, a peerreviewed journal published by Mary Ann Liebert, Inc. The paper is available
free online at www.liebertpub.com/ast.
In "Finding a Second Sample of Life on Earth," authors P. C. W. Davies and
Charles Lineweaver propose multiple scenarios for how a second genesis of
life could have occurred. Given that existing life formed under early Earthlike conditions, then logically it would seem possible for alternative life to
have formed on Earth in a similar manner and to have survived to the present
day.
How then to detect a "second sample", and is there evidence for "alien life" on
Earth? Davies, from the Australian Centre for Astrobiology at Macquarie
University (New South Wales), and Lineweaver, from the Planetary Science
Institute at the Australian National University, conclude that life is likely to
have emerged on Earth more than once and, although there are ways to obtain
evidence of alien life, these microorganisms could exist on Earth today and
remain undetected.
"Davies and Lineweaver consider a way to cut the anthropic knot," says
journal Hypothesis Papers editor, Norman H. Sleep, Ph.D., Professor in the
Departments of Geophysics and Geological and Environmental Sciences,
Stanford University. "If the origin of life is easy, a second example of life
may lurk beneath our noses. We have the technology to commence our
search."
6
Astrobiology is an authoritative peer-reviewed journal published bimonthly in
print and online. The Journal provides a forum for scientists seeking to
advance our understanding of life's origins, evolution, distribution and destiny
in the universe. A complete table of contents and a full sample issue may be
viewed online at http://www.liebertpub.com/ast.
Mary Ann Liebert, Inc. is a privately held, fully integrated media company
known for establishing authoritative peer-reviewed journals in many
promising areas of science and biomedical research. Its biotechnology trade
magazine, Genetic Engineering News (GEN), was the first in its field and is
today the industry's most widely read publication worldwide. A complete list
of the firm's 60 journals, books, and newsmagazines is available at
http://www.liebertpub.com/.
Contact:
Paula Masi
Mary Ann Liebert, Inc.
Phone: 914-740-2100 x2163
E-mail: [email protected]
CRUNCHING THE NUMBERS
By Maggie Turnbull
From Astrobiology Magazine
18 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 two of a four-part series.
There are 400 billion stars in the galaxy, and obviously we're not going to
point the Terrestrial Planet Finder at all of them. The TPF science working
group has defined a successful mission as a search for planets around 35
stars—these stars will be our best targets. Then, once that is completed, we'll
look at 130 more stars. So we'll have 165 stars to work with during the TPF
mission lifetime.
It's going to take a lot of observing time to discover a planet in the first place,
and it's going to take even longer to do spectroscopy on a planet once it's been
discovered. So 165 stars is a large task, even though it doesn't sound like
much. But it's not many stars compared to the number of possible targets in
the Galaxy, so we want to choose very wisely, especially considering the
amount of money this mission is going to cost.
I hesitate to mention money, because I want everybody to focus on how TPF
is this fantastic mission. But we're going to be spending somewhere between
12 and 30 million dollars per star that we look at. I personally think it's worth
it, even if we only find an Earth-like planet around just one of those stars. But
given the sheer price tag of each target in this mission, we owe it to the
taxpayers and to ourselves to think very carefully about which stars we look
at.
We should design the core target list of 35 stars so that, when the TPF-C
mission is done, in case we haven't found anything, we can still make a
meaningful scientific statement. We don't want to just look at a smattering of
every different kind of star that's out there, because there really are a lot of
different kinds of stars.
Instead, we should design a core target list to hone in on a particular kind of
star, or at least a small range of stars, that are similar to our own star. Places
where, if there were a planet in the habitable zone, we could live. So, in the
case of not finding anything, we can make a statement that, "X percent of G2V stars of solar metallicity that are thin disk members don't have planets," or
"No more than X percent has an Earth-like planet around it."
But on the other hand, we may not be able to be that picky. We're going to be
up against engineering constraints. But if I put on my scientist hat and say,
"Engineers, you're just going to have to build what I want for this mission,"
then as a scientist I would want to look at Habstars.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
7
habitable zone for about 2 billion years, until the sun becomes a red giant. At
that point, nowhere in the solar system is habitable. The sun spends only
another 1 billion years as a red giant before it starts to lose its outer envelope
and become a planetary nebula.
The number of HabCat stars, as a function of distance for M-type stars
(solid red histogram), K stars (dark-hatched green histogram), G stars
(light-hatched violet histogram), F stars (horizontal-lined yellow
histogram), and all stars (open blue histogram). Inset, Allen Telescope
Array. Image credit: M. Turnbull, J. Tarter.
My definition of a Habstar is a star that has a habitable zone, first of all. That
habitable zone is dynamically stable, meaning that it's not perturbed by giant
planets on eccentric orbits swooping in and out of the habitable zone.
We know now that many stars have giant planet companions. In many of
these systems, the giant planets do not enter the habitable zone. There are a
few giant planet systems where the known planet is in the habitable zone
throughout its entire orbit, and those actually should be top TPF targets. Not
because we'll be able to image any habitable moons those planets might have,
but because the planet itself should be a "can't-miss-it" target. For something
like TPF that's designed to see Earths, we should certainly be able to see giant
planets.
A dynamically stable habitable zone is also not perturbed by any other stellar
companions. Most stars are not single like the sun. Instead, they exist in
binary, triple, or quadruple stellar systems. Could the orbits of those stars
interfere with planets orbiting within the habitable zone? To figure this out,
we have to look at the mass ratio of the various components, the location of
the habitable zone, and the orbit of the second star. I've mapped all that out
for about 15,000 binaries. It turns out that the vast majority of binaries are
perfectly safe places to live for habitable planets.
A Habstar will need to be dynamically stable on a timescale that's comparable
to the timescale of global biosignature production. The Earth didn't have
continents covered with plants and a strong oxygen signature from day one; it
took at least a couple billion years to build up. It wasn't until about 2 billion
years ago that a strong and detectable oxygen signature would have existed on
this planet. If we use a minimum age of 2 billion years, that means we can
eliminate some of the stars in the solar neighborhood from our TPF target list.
A star should have a habitable zone that is spatially static on that same 2
billion year time scale. All stars are variable to some extent, and as they
evolve over time, their luminosity changes. Main sequence stars burn
hydrogen, and as they evolve they get brighter and cooler, and eventually end
up as red giants. The speed at which stars evolve depends on their mass.
Very massive stars evolve quickly into red giants, whereas less massive stars
will remain a main sequence star for a long time, not changing much in
brightness.
To see how this long term evolution of a star affects habitability, let's look at
the sun. When the sun was young, it was fainter, so the habitable zone was
closer to the sun. As the sun has aged, up to today at almost 5 billion years,
the habitable zone has slowly moved outwards. At somewhere between 6 and
7 billion years in age, Earth will no longer be in the habitable zone. We will
be interior to the habitable zone, because the sun will have increased in
luminosity. At that point, the oceans will evaporate into space and we won't
want to live here anymore.
In between 7 and 8 billion years, however, Mars will enter the outer habitable
zone. This doesn't mean that we can just move from Earth to Mars, because
there's a 1 billion year gap where nothing is habitable. Mars will be in the
The Sun, a typical G2V dwarf. G stars are characterized by the
presence of metallic lines and weak hydrogen. Image credit: Harvard
University.
Since higher mass stars evolve more quickly then lower mass stars, then if we
want our targets to have been habitable for 2 billion years or longer, we don't
want stars that are so massive that they evolve all the way to red giants in less
then 2 billion years. So stars that are more massive than about a solar mass
and a half are not good TPF targets. That really limits the mass range for this
mission.
Related to this is the concept of short-term variability. The sun is variable
over days, decades and millennia, in addition to this longer term trend over
billions of years. Those shorter period variability cycles don't seem to impact
biology much. The sun is exceptionally stable, but for other stars with levels
of variability 10 or even 30 times as much as the sun, I don't think that's really
going to make too much of a difference for biology.
Metallicity is a concern. We have seen that, at least for giant planets in very
short period orbits, the likelihood of a planet being present is related to the
metallicity of the star—the heavy metal content of the star itself. Since stars
and planets form out of the same original material, that makes sense. The
Earth is made out of heavy elements—for example, iron—so a star that has
zero metallicity is probably not a good target.
So after we apply all of these cuts, we end up with about 500 scientifically
interesting stars within 30 parsecs. You could go further out in distance if you
wanted to find more stars, but I think 500 is plenty.
Read the original article at http://www.astrobio.net/news/article1526.html.
NASA SCIENTIST: "MARS COULD BE BIOLOGICALLY ALIVE"
By Leonard David
From Space.com
19 April 2005
Evidence for intense local enhancements in methane on Mars has been
bolstered by ground-based observations. The methane, as well as water on
Mars, was detected using state-of-the-art infrared spectrometers stationed atop
Mauna Kea, Hawaii and in Cerro Pachón, Chile.
Scientific teams around the globe are on the trail of methane seeping out of
Mars. And for good reason: the methane could be the result of biological
processes. It could also be an "abiotic" geochemical process, however, or the
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
result of volcanic or hydrothermal activity on the red planet. Many types of
microbes here on Earth produce a signature of methane. Indeed, the tiny
fraction of atmospheric carbon found as methane on our planet is churned out
almost entirely biologically with only a very small contribution from abiotic
processes, scientists say.
Read the full article at
http://www.space.com/scienceastronomy/050419_mars_methane.html.
WASHINGTON DC THINK TANK PUBLISHES ZUBRIN ANALYSIS
OF SPACE PROGRAM
Mars Society release
18 April 2005
An in-depth critique of the space program and a prescription of the radical
steps necessary to make the new Bush administration "Vision for Space
Exploration" real written by Mars Society president Dr. Robert Zubrin has
been published in the Spring 2005 edition of "The New Atlantis," the journal
of the Ethics and Public Policy Center (EPPC). The EPPC is a Washington,
DC science policy think tank with very close links to the Bush administration,
and several EPPC fellows serve the White House as high level advisors.
The Zubrin article, entitled "Getting Space Exploration Right," includes fierce
and systematic criticism of former NASA administrator's non-destination
driven approach of (not) implementing the president's new human space
exploration policy. It also diagnoses the source of the many debacles of the
O'Keefe administration, including the Hubble fiasco, the Orbital Space Plane
and JIMO program failures, and the Columbia disaster. Finally, the article
lays out the technical approach needed for successful implementation of a
human Moon-Mars exploration program.
Together with the appointment of the highly competent, aggressive, and
results oriented Dr. Mike Griffin as new NASA administrator, the publication
by the EPPC of the Zubrin article furnishes strong evidence that the Bush
White House has made a decisive turn towards actually implementing the new
space exploration vision. The New Atlantis article can be read in html online
at http://www.thenewatlantis.com/archive/8/zubrin.htm, or downloaded as a
PDF from http://www.marssociety.org/docs/TNA08-Zubrin.pdf.
An in depth strategy planning session to map plans to win the political and
technical fight for human Moon-Mars exploration will be held at the 8th
International Mars Society Convention, August 11-14, 2005, University of
Colorado, Boulder. Those wishing to present papers on any subject relating to
the exploration or settlement of Mars should submit abstracts of no more than
300 words by May 31, 2005 to [email protected]. Registration is now
open at www.marssociety.org
For further information about the Mars Society, visit our web site at
www.marssociety.org.
NSBRI POSTDOCTORAL FELLOWSHIP PROGRAM SOLICITING
APPLICATIONS
National Space Biomedical Research Institute release
18 April 2005
The National Space Biomedical Research Institute (NSBRI) is soliciting
applications for its Postdoctoral Fellowship Program. Two-year fellowships
are available in any U.S. laboratory carrying out space-related biomedical or
biotechnological research that supports the NSBRI's goals. NSBRI research
addresses and seeks solutions to the various health concerns associated with
long-duration human space exploration.
Applicants must submit proposals with the support of a mentor and institution,
and all proposals will be evaluated by a peer-review panel.
The program is open to U.S. citizens, permanent residents, or persons with
pre-existing visas obtained through their sponsoring institutions. Detailed
program and application submission information is available on the NSBRI
Web site at http://www.nsbri.org/Announcements/rfp05-01.html. Letters of
intent and applications must be submitted through the NSBRI's electronic
proposal submission system. Letters of intent are due May 11, 2005, and the
application deadline is June 28, 2005.
Questions may be directed to:
Gerald Sonnenfeld, Ph.D.
Program Director
8
NSBRI Postdoctoral Fellowship Program
E-mail: [email protected]
Phone: 607-777-4818
ESP2 ABSTRACT DEADLINE APPROACHING
By Lee Kump
Geological Society of America release
19 April 2005
The abstract submission deadline is quickly approaching for the Earth System
Processes 2 meeting in Calgary this coming 8-11 August 2005. The
participation of a diverse array of scientists, like you, who are investigating
how the Earth system works today, how it functioned in the past, and how it
will function in the future, promises to make this one of the best scientific
meetings of its kind to date. Abstracts are due 11:59 PM, Mountain Time,
April 26, 2005.
You must submit your abstract electronically at
http://gsa.confex.com/gsa/2005ESP/index.epl.
To learn more about the meeting, visit our web site at
http://www.geosociety.org/esp2. You'll see that there is an exciting line-up of
plenary speakers including Fred Mackenzie, Dianne Newman, Jerry
Mitrovica, and Stefan Bengtson, as well as theme sessions highlighting the
cutting edge of our science. You can contribute a poster or oral presentation
to any of a number of approved theme sessions, or make a general submission.
We'll work with the accepted abstracts to create additional theme sessions as
needed.
We strongly recommend that you take advantage of your trip to the gateway
of the Canadian Rockies and sign up for one of the many specially designed
field trips offered. Evening activities include two workshops on Earth
systems education K-16 and an out-of-the ordinary conference banquet. Other
social activities, including activities for friends and family members
accompanying you, are being arranged as well.
The discounted Standard Registration deadline is 27 June, 2005.
After this date On-site/Late prices apply. The cancellation/refund deadline is
5 July, 2005. Chris Beaumont, Don Canfield and I are looking forward to
seeing you in Calgary in August!
CASSINI SIGNIFICANT EVENTS FOR 7-13 APRIL 2005
NASA/JPL release
15 April 2005
The most recent spacecraft telemetry was acquired Wednesday from the
Goldstone tracking station. The Cassini spacecraft is in an excellent state of
health and is operating normally. Information on the present position and
speed of the Cassini spacecraft may be found on the "Present Position" web
page located at http://saturn.jpl.nasa.gov/operations/present-position.cfm.
The final science activities in S09 included several magnetospheric boundary
and solar wind campaigns performed by the Magnetospheric and Plasma
Science (MAPS) instruments.
In addition the Composite InfraRed
Spectrometer (CIRS) and Visual and Infrared Mapping Spectrometer (VIMS)
took data for the joint creation of far-IR maps of Saturn.
At the start of this first week of S10 execution, Magnetospheric Imaging
Instrument performed a Solar Wind Magnetospheric Boundary Campaign,
Imaging Science Subsystem (ISS) obtained an ansa movie of the F ring at
high resolution/low phase, Ultraviolet Imaging Spectrograph observed a
Saturn occultation of Delta Orionis, and RADAR performed three separate
polarization measurements of the rings and Saturn. Other atmospheric
observations included VIMS observations of the occultation of Alp CMi by
Saturn and of the high phase limb.
Thursday, April 7:
This is very much a bits-and-pieces kind of day with many events occurring
both in development and operations. It gives a good idea of what a day in the
life of a flight project is like. All teams and offices supported the Cassini
Monthly Management review. Uplink Operations completed radiation of all
files in preparation for the start of S10 execution tomorrow evening. RADAR
performed an engineering test on-board the spacecraft. The files for the S10
Live Inertial Vector Propagator (IVP) update that will execute on April 14
were successfully tested in the Integrated Test Laboratory and the output
products published in the project file repository.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
9
Orbit trim maneuver #21 (OTM-21) was completed this evening. The main
engine burn began at 8:15 PM PST. A "quick look" immediately after the
maneuver showed the burn duration was 37.35 sec long, giving a delta-V of
5.82 m/s. All subsystems reported nominal performance.
Saturn's bright moon Enceladus hovers here, in front of a rings
darkened by Saturn's shadow. Enceladus is 505 kilometers (314
miles) across. This view is from less than one degree beneath the ring
plane. If seen from directly beneath the rings, the planet's giant
shadow would appear as an elongated half-ellipse; the acute viewing
angle makes the shadow look more like a strip here. The dark shadow
first takes a bite out of the rings at the right, where the distant,
outermost ring material appears to taper and fade. Ring features
visible in this image from the outer ring edge inward include: the A ring,
the Cassini Division and the B ring. The C ring is the darker region
that dominates the rings here. The two gaps visible near the center
and below the left of the center are the Titan Gap, about 77,800
kilometers (48,300 miles) from Saturn, and an unnamed gap about
75,800 kilometers (47,100 miles) from the planet. The image was
taken in visible light with the Cassini spacecraft narrow-angle camera
on March 7, 2005, at a distance of approximately 1.1 million kilometers
(650,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or
phase, angle of 30 degrees. The pixel scale is 6 kilometers (4 miles)
per pixel. Image credit: NASA/JPL/Space Science Institute.
Cassini Outreach participated in the National Council for the Teachers of
Mathematics (NCTM) Conference in Anaheim, CA April 6-9, 2005.
Outreach staffed the JPL booth, interacting with math teachers at the
conference. Outreach also attended a variety of professional sessions on
teaching different aspects of mathematics as well as current trends in
mathematics education.
Friday, April 8:
The keys to the spacecraft were officially handed over today by the S09
sequence leads to those leading S10. S10 contains the first multi-day, multivector IVP update, the second live moveable block performed during tour, the
first being for Phoebe in June 2004, four OTMs, one targeted encounter—
Titan 5—and 5 non-targeted encounters of Epimetheus, Mimas, Calypso,
Tethys, and Titan.
Navigation delivered the final Orbit Determination solution for OTM-21. The
command approval meeting, uplink, and execution will occur tomorrow.
Delivery Coordination Meetings were held for the Inertial Vector Propagator
(IVP) V10.6, and E-Kernel Generation software v2.
The Science Operations Plan Update process has concluded for sequence S12.
Output products have been handed off to the sequence developers for next
week's start of the Science and Sequence Update process.
Saturday, April 9:
Cassini offers this lovely comparison between two of Saturn's
satellites, Dione and Tethys, which are similar in size but have very
different surfaces. Extensive systems of bright fractures carve the
surface of Dione (1,118 kilometers, or 695 miles across). The doublepronged feature Carthage Linea points toward the crater Turnus at the
nine o'clock position near the terminator, and Palatine Linea runs
toward the moon's bottom limb near the five o'clock position. In
contrast, the surface of Tethys (1,071 kilometers, or 665 miles across)
appears brighter and more heavily cratered.
The large crater
Penelope is near the eastern limb. The huge rift zone Ithaca Chasma,
which is 3 to 5 kilometers (2 to 3 miles) deep and extends for about
2,000 kilometers (1,200 miles) from north to south across Tethys, is
hidden in shadow just beyond the terminator. For comparison, the
Grand Canyon in Arizona is about 1.5 kilometers (1 mile) deep, and
about 450 kilometers (280 miles) long. The image was taken in visible
light with the Cassini spacecraft narrow-angle camera on March 7,
2005, at a distance of approximately 1.5 million kilometers (908,000
miles) from Tethys and 1.6 million kilometers (994,000 miles) from
Dione. The image scale is 9 kilometers (6 miles) per pixel on Tethys,
and 10 kilometers (6 miles) per pixel on Dione. Image credit:
NASA/JPL/Space Science Institute.
April 9 was an extremely happy day for the Ion and Neutral Mass
Spectrometer (INMS) instrument team as they declared their "unexpected
reboot" problem officially solved. In August of 2003, INMS powered on
during the C39 sequence for the first time since launch in October 1997. Near
the end of this sequence they experienced an unexpected reboot of the
instrument. During the course of the following sequences—C40 and C42—
they again experienced unexpected reboots. In an attempt to debug and gather
information about the problem, three special flight software loads were built
and uplinked between January and March of 2004 during the execution of the
C42 and C43 sequences. As a result of these special flight software "builds",
the INMS engineers were able to determine that the source of the problem had
to do with the interaction with the Bus Interface Unit (BIU). A few patches to
change the way INMS interacts with the BIU were uplinked following this
discovery. Unfortunately, the patches were not successful in fixing the
problem.
It was then decided that adding an ability to interact with the BIU using a
double buffering approach instead of the single buffer approach was the next
option to examine. Within a short period of time this was determined to be a
viable solution. Double buffering could not be built as a patch to flight
software (FSW), so version 9.1 was built, uplinked, and tested during the S04
sequence in September 2004. During the S05 through S08 sequences, this
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
new version of FSW was used routinely and no unexpected resets of the
instrument occurred.
It had been decided previously that INMS would only declare the unexpected
reboot problem resolved if the instrument ran without incident for more than
40 days. It was not until March 2005 during S09 that INMS was able to
acquire a period of time of more than 40 days to be able to perform this test.
This period was selected as it was a time where an unexpected INMS science
loss due to another reset was deemed an acceptable risk. Today, April 9, upon
the conclusion of S09, INMS has successfully run without a reset for over 41
days.
One year and eight months after the initial occurrence of the problem in C39,
the INMS engineering, operations, and science teams have declared victory!
The reboot problem was well documented and publicized. The resolution was
a huge effort by a small and extremely talented group from the University of
Michigan where the INMS Operations Team makes its home. INMS
personnel wish to thank all those at JPL and on the Cassini Flight Team who
assisted along the way with resolving this problem.
10
(MRO) were obtained for all partitions, the actions log, non-interfering, and
interfering error logs. Updated SPICE Rocks SPK & PCK Kernel files have
been released for Science Planning use.
Tuesday, April 12:
The Software Requirements and Certification Review for Cassini Plasma
Spectrometer (CAPS) version 4.1.0 flight software (FSW) was held today.
The FSW was approved with no pending action items. Uplink is currently
scheduled for the May 22/23 time frame. S11 sequence leads and members of
the Spacecraft Operations Office are currently working final uplink dates.
FSW checkout is tentatively planned for May 26/27.
S12 began final sequence development today. In addition, the Live Update
Working group met this morning and decided that a local update was no
longer a feasible option for S12. The current reference trajectory is the best
available baseline for developing the sequence. The team will proceed with
the Live IVP Update strategy as identified in the summary table produced by
the working group. The S12 leads have accepted the proposed live update
schedule.
Wednesday, April 13:
Remember how I said last week that the flight team would be pulling off three
OTMs in 10 days? Well, here is number two. OTM-22 was successfully
completed tonight. This maneuver, also called the "T5 minus 3 day
maneuver," further refines Cassini's trajectory for the 1,025 km flyby of Titan
on April 16. This will be the closest Titan flyby to date.
The reaction control system burn began at 8:55 PM PST. The "quick look"
immediately after the maneuver showed the burn duration was 67.6 sec,
giving a delta-V of approximately 63.5 mm/s. All subsystems are nominal.
Cassini Outreach participated in an astronomy night for disabled students at
Cal State University-Northridge this week. A Braille trail scale model of the
solar system was set up and Cassini outreach led the "solar system walk"
accompanied by an American Sign Language interpreter. A Braille
planisphere, moon and solar system tactiles, and even a tactile Cassini
Spacecraft model were available for the sight impaired. The moon, Saturn
and Jupiter were viewed through wheelchair accessible telescopes provided by
Cassini outreach and the University's observatory. All participants also saw a
planetarium show about the spring night sky.
The ancient and battered surface of Saturn's moon Rhea shows a
notable dark swath of territory near the eastern limb in this image from
Cassini. This view shows principally the Saturn-facing hemisphere on
Rhea (1,528 kilometers, or 949 miles across). North is up and tilted 40
degrees to the right. The image was taken with the Cassini spacecraft
narrow-angle camera on March 7, 2005, through a filter sensitive to
wavelengths of ultraviolet light centered at 338 nanometers. The view
was acquired at a distance of approximately 1.8 million kilometers (1.1
million miles) from Rhea and at a Sun-Rhea-spacecraft, or phase,
angle of 30 degrees. Resolution in the original image was 10
kilometers (7 miles) per pixel. The image has been contrast-enhanced
and magnified by a factor of two to aid visibility. Image credit:
NASA/JPL/Space Science Institute.
Monday, April 11:
A kick-off meeting was held today for the Science Operations Plan Update
(SOPU) process for S13. The S13 process marks the return of SOPU to a 5week activity. S09 through S12 were the first sequences that underwent
advance development in the SOP Implementation (SOPI) process back in May
2002. As SOPI was exercised by the sequence developers, a number of
changes were identified as necessary during SOPU. The S09-S13 products
were archived, and plans were made to extend the S09 through S12 SOPU
process durations to 10 weeks to allow for these additional changes.
Uplink Operations radiated Live Update commands to the spacecraft. The
commands will execute next week on April 14. In addition, memory readouts
The Cassini web site has received a Webby nomination for best science web
site! The Webby Awards is the leading international award event honoring
excellence in Web design, functionality and creativity. Established in 1996
during the web's infancy, the Webbys are presented by The International
Academy of Digital Arts and Sciences, a 500-member body of leading web
experts, business figures, luminaries, visionaries and creative celebrities. The
Ninth Annual Webby Awards Nominees were announced on April 12 and
winners will be unveiled in May 3.
Saturn Observation Campaign and the Old Town Sidewalk Astronomers will
show Saturn, the first quarter moon and Jupiter in Pasadena on Colorado Blvd.
between Fair Oaks and Pasadena Avenue Friday April 15 8:00 - 10:00 PM,
and in Monrovia at Myrtle and Lime streets Saturday night April 16 from 8:00
- 10:00 PM.
The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory,
a division of the California Institute of Technology in Pasadena, manages the
Cassini-Huygens mission for NASA's Science Mission Directorate,
Washington, DC. JPL designed, developed and assembled the Cassini orbiter.
Additional articles on this subject are available at:
http://www.astrobio.net/news/article1524.html
http://www.spacedaily.com/news/saturn-titan-05v.html
http://www.spacedaily.com/news/cassini-05zl.html
http://www.spacedaily.com/news/cassini-05zm.html
http://spaceflightnow.com/cassini/050417enceladus.html
http://www.universetoday.com/am/publish/cassini_titan_flyby_april16.html
http://www.universetoday.com/am/publish/enceladus_hovers_rings.html
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
11
DART UPDATES
NASA releases
On Orbit Anomaly Ends DART Mission Early
NASA release 05-051, 16 April 2005
NASA Launches DART Spacecraft to Demonstrate Automated
Rendezvous Capability
NASA release 05-049, 15 April 2005
The Demonstration of Autonomous Rendezvous Technology (DART)
spacecraft that was successfully launched Friday at 10:25 AM PDT from
Vandenberg Air Force Base, CA, experienced an on orbit anomaly late Friday.
After a successful rendezvous, acquisition of the target spacecraft, and
approach to within approximately 300 feet, DART placed itself in the
retirement phase before completing all planned proximity operations, ending
the mission prematurely.
NASA's Demonstration of Autonomous Rendezvous Technology (DART)
spacecraft successfully launched today at 1:25 PM EDT (10:25 AM PDT)
from Vandenberg Air Force Base, CA, beginning a 24-hour mission to
demonstrate technologies required to locate and autonomously rendezvous
with another craft in space using only computers and sensors. The automated
rendezvous spacecraft was launched on a Pegasus vehicle from the Orbital
Science Corporation's Stargazer L-1011 aircraft. At approximately 40,000
feet over the Pacific Ocean, the Pegasus vehicle was released, boosting the
DART spacecraft into an approximately 472-by-479-mile polar orbit.
Approximately 11 minutes after launch, the spacecraft was delivered to its
initial orbit and successfully completed the on-orbit checkout. DART's
rendezvous target during the 24-hour mission is the Multiple Paths, BeyondLine-of-Sight Communications (MUBLCOM) satellite, an experimental
communications satellite launched in 1999.
NASA is convening a mishap investigation board to determine the reason for
the DART spacecraft anomaly. A teleconference with DART project
managers is scheduled for 11:00 AM PDT. Media who want to participate
must register by calling the DART Newsroom at 805-605-3051.
The DART spacecraft was a flight experiment attempting to establish
autonomous rendezvous capabilities for the U.S. space program. While
previous rendezvous and docking efforts have been piloted by astronauts, the
DART spacecraft completed the rendezvous and acquisition with no human
intervention, relying on a variety of sensors and analyses to complete these
functions.
For more information
http://www.nasa.gov/.
about
DART
on
the
Internet,
visit
Contacts:
Michael Braukus/Kim Newton
Vandenberg Air Force Base, CA
Phone: 805-605-3051
Read the original news release at
http://www.nasa.gov/mission_pages/dart/media/05-051.html.
Additional articles on this subject are available at:
http://www.spacedaily.com/news/robot-05za.html
http://spaceflightnow.com/pegasus/dart/
http://www.universetoday.com/am/publish/dart_mission_failure.html
The launch of the Pegasus rocket from the L-1011 aircraft.
Image credit: NASA.
DART provides a key step in establishing autonomous rendezvous capabilities
for the U.S. space program and will help lay groundwork for future manned
and unmanned launch vehicle missions that use computers to do the "driving"
in space. Future technology applications may aid in cargo delivery, servicing
missions to the International Space Station and other space activities in
support of the Vision for Space Exploration. The DART project, managed by
NASA's Marshall Space Flight Center, is the first demonstration program
selected by NASA's Exploration Systems Mission Directorate to develop
technologies for tomorrow's exploration of the Solar System. The prime
contractor for the mission is Orbital Sciences Corp., of Dulles VA, which also
developed the Pegasus launch vehicle and the MUBLCOM satellite. NASA's
Kennedy Space Center has oversight responsibility for launch integration and
launch services.
A second status report will be issued on Saturday April 16, following
completion of DART's rendezvous and proximity operations phase. For
information about NASA and Agency missions, please visit
http://www.nasa.gov/. For more information about the DART mission, please
visit
http://www.nasa.gov/mission_pages/dart/main/index.html
or
http://www.msfc.nasa.gov/news/dart/. Live information updates during the
DART mission are available through the KSC Virtual Launch Control Center
at http://www.nasa.gov/mission_pages/dart/launch/vlcc.html.
Read the original news release at
http://www.nasa.gov/centers/marshall/news/news/releases/2005/05-049.html.
Contact:
Kim Newton
NASA Marshall Space Flight Center, Huntsville, AL
Phone: 805-605-3051
Cell phone: 256-961-8510
DEEP IMPACT MISSION UPDATE
By Maura Rountree-Brown
NASA/JPL release
The Deep Impact mission team closed the Commission Phase of flight with
the completion of the impactor projectile's checkout activities. During that
phase, the team verified the basic health of all subsystems and tested the
operation of the science instruments. The mission now moves to Cruise
Phase. During the coming months, the team will work toward updating the
attitude control system tables that control the alignment of the spacecraft
instruments, which refines the ability of the spacecraft to accurately point the
onboard instruments at Comet Tempel 1.
The High and Medium Resolution (HRI and MRI) instruments on the flyby
spacecraft are fixed in position so a period of testing and rehearsing takes
place as the team asks the spacecraft to focus on a star and center it. By
updating the software that commands the spacecraft's attitude control, the
team finds the best X and Y axis position for the spacecraft to center on
Comet Tempel 1. It's a little like buying a new camera and then learning how
to take the best pictures by learning the actual parameters of that instrument.
The science team will conduct instrument calibration tests using a set of stars,
further verifying imaging procedures for encounter.
The High Resolution Instrument has not reached perfect focus and the team is
investigating how to bring it to its best performance level. The HRI's current
performance, combined with that of the Medium Resolution imaging and IR
spectrometer on the flyby spacecraft and the Impactor Targeting Sensor on the
projectile, still gives the mission's PI, Dr. Mike A'Hearn the confidence that
images taken of Comet Tempel 1 will be the most detailed of a comet nucleus
ever taken.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 14, 19 April 2005
12
Mars at Ls 193 Degrees (Released 12 April 2005)
http://www.msss.com/mars_images/moc/2005/04/12/
Frosty Crater (Released 13 April 2005)
http://www.msss.com/mars_images/moc/2005/04/13/
All of the Mars Global Surveyor images
http://www.msss.com/mars_images/moc/index.html.
This image shows the first light images taken by the MRI and HRI
instruments on the Deep Impact spacecraft on its way to impact with
Comet Tempel 1 on July 4, 2005. The two telescopes were pointed at
the open star cluster, NGC3532. The left shows the middle portion of
an MRI image. The right is the full HRI image scaled to the field of
view of the MRI (reduced by a factor of 5). The star patterns match
quite well (see Digitized Sky Survey image below) telling us that the
telescopes are operating as expected and are pointed in the same
direction (boresighted). For the technophiles, the boresite alignment is
98 micro-radians, and the rotation around the boresites is about 0.12
degrees. Stars in the MRI image are as faint as mv=12.5 in the 6
second exposure. The HRI is, as expected, out of focus. It was
designed to come into focus after the bakeout heaters are run for
several weeks. Image credit: NASA/Deep Impact.
Read the original mission update at
http://deepimpact.jpl.nasa.gov/mission/update.html.
MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
7-13 April 2005
The following new images taken by the Mars Orbiter Camera (MOC) on the
Mars Global Surveyor spacecraft are now available.
Olympus Flows (Released 07 April 2005)
http://www.msss.com/mars_images/moc/2005/04/07/
Craters and Winds (Released 08 April 2005)
http://www.msss.com/mars_images/moc/2005/04/08/
Martian Fingerprints (Released 09 April 2005)
http://www.msss.com/mars_images/moc/2005/04/09/
North Polar Dunes (Released 10 April 2005)
http://www.msss.com/mars_images/moc/2005/04/10/
Dark-Rimmed Crater (Released 11 April 2005)
http://www.msss.com/mars_images/moc/2005/04/11/
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.
MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
4-8 April 2005
Isolated Northern Dunes (Released 4 April 2005)
http://themis.la.asu.edu/zoom-20050404a.html
North Polar Erg (Released 5 April 2005)
http://themis.la.asu.edu/zoom-20050405a.html
Northern Sand Sea (Released 6 April 2005)
http://themis.la.asu.edu/zoom-20050406a.html
North Polar Erg (Released 7 April 2005)
http://themis.la.asu.edu/zoom-20050407a.html
Dune Variety (Released 8 April 2005)
http://themis.la.asu.edu/zoom-20050408a.html
All of the THEMIS images are archived at http://themis.la.asu.edu/latest.html.
NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission
for NASA's Office of Space Science, Washington, DC. The Thermal
Emission Imaging System (THEMIS) was developed by Arizona State
University, Tempe, in collaboration with Raytheon Santa Barbara Remote
Sensing. The THEMIS investigation is led by Dr. Philip Christensen at
Arizona State University. Lockheed Martin Astronautics, Denver, is the
prime contractor for the Odyssey project, and developed and built the orbiter.
Mission operations are conducted jointly from Lockheed Martin and from
JPL, a division of the California Institute of Technology in Pasadena.
End Marsbugs, Volume 12, Number 14.