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Marsbugs: The Electronic Astrobiology Newsletter
Volume 11, Number 46, 13 December 2004
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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Articles and News
Page 1
Page 2
PROOF POSITIVE: MARS ONCE HAD WATER,
RESEARCHERS CONCLUDE
Texas A&M University release
Page 5
MARS LIFE: TROUBLE WITHOUT THE RUBBLE?
By David Noever
Page 6
LIFE-SWAPPING SCENARIOS FOR EARTH AND MARS
By Leonard David
NASA SLEEP-WAKE SCHEDULING PROTOCOLS MAY
NEED TO BE CHANGED, UNIVERSITY OF PITTSBURGH
RESEARCH SHOWS
University of Pittsburgh Medical Center release
Announcements
Page 2
ON TOP OF TITAN'S MOUNTAIN
By Leslie Mullen
Mission Reports
Page 3
HUNTER OF ALIEN WORLDS SPEAKS AT CORNELL
UNIVERSITY
By Larry Klaes
Page 4
SPACE COOKING: FEEDING ASTRONAUTS ON MARSBOUND MISSIONS
By Tariq Malik
Page 4
SPITZER AND HUBBLE CAPTURE EVOLVING
PLANETARY SYSTEMS
NASA/JPL release 2004-285
Page 5
PROMETHEUS PRE-EMPTED? NEW NUCLEAR FISSION
MISSIONS EVALUATED
By Leonard David
Page 7
LIFTOFF 2005 EXPERIENCE FOR TEACHERS
By Margaret Baguio
Page 7
CASSINI-HUYGENS UPDATES
NASA/ESA releases
Page 10
MARS EXPRESS: THE CHANNELS OF REULL VALLIS
ESA release
Page 11
MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
Page 11
MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
Page 11
MARS RECONNAISSANCE ORBITER: ULTRA-SHARP,
MARS-BOUND HIRISE CAMERA DELIVERED TODAY
By Lori Stiles
PROOF POSITIVE: MARS ONCE HAD WATER, RESEARCHERS
CONCLUDE
Texas A&M University release
meaning ripples of water once flowed over them. There are also mineral
deposits we call blueberries, and on Earth we know these formations only
appear if water is present.
3 December 2004
"So the answer, without a doubt, is yes, liquid water was once on Mars. So
far, we have not seen any evidence that liquid water is currently on Mars."
There is undeniable proof that water once existed on the planet Mars, a team
of researchers has concluded in a series of 11 articles this week in a special
issue of the journal Science. A team of more than 100 scientists from
numerous government agencies and universities, among them Mark Lemmon
of Texas A&M University's College of Geosciences, co-wrote the articles.
Lemmon was the principal author on one article and co-author on three others
describing the work of Spirit and Opportunity, NASA's twin rovers that
landed on Mars in January. The rovers landed in different locations on Mars
and have been sending back data and images for the past 10 months.
The reports in Science focused on results from Opportunity, which is in a
region of Mars called Meridiani Planum, although Lemmon's article and one
other described findings from both rovers regarding Mars' atmosphere. One
of the primary goals of the mission was to learn once and for all if liquid water
ever existed on the red planet. That question has now been answered,
Lemmon reports.
"The conclusion of the entire team, backed by substantial evidence, is that
water was indeed present on Mars," Lemmon says. "The proof is there in
several ways. There are sulfates present on Mars that were left behind when
the water evaporated, plus other salts that show the definite presence of water
long ago.
"Also, Opportunity examined rocks that show evidence of 'cross-bedding,'
The presence of water could mean that life—in some form—existed on Mars.
Lemmon says the atmosphere of Mars contains water, but in miniscule
amounts.
"Even though we are currently seeing frequent clouds with Opportunity, if
you squeezed all of the water out of the atmosphere, it would only be less than
100 microns deep, about the thickness of a human hair," he said.
Because of the lack of water, weather on Mars has a lot to do with dust in the
atmosphere. A small dust storm one month before the rovers landed spread
small amounts of dust around the planet.
"Both rovers saw very dusty skies at first. It was only after the dust settled
after a few months that Spirit could see the rim of the crater it was in, Gusev
Crater, about 40 miles away," Lemmon said.
British scientists have speculated that the British Mars Lander, Beagle 2,
crashed because the atmosphere was thinner than usual as a result of heating
caused by atmospheric dust from the December storm.
"The other key question is when the liquid water was last present on Mars.
Was it a few thousand years ago or billions of years ago?" he points out. "We
know that Mars is about four billion years old. We assume that water was
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
there at any time from one to four billion years ago, but we don't when the last
time water was present."
Lemmon says the rock samples and mineral deposits tend to point to a large
area of water that once existed on Mars, such as a lake or even a sea.
"The marks on some of the rocks and other evidence suggest standing water,"
he says. "But whether this was once an ocean or other large body of water,
we just don't know."
The next phase in the $820 million NASA mission will have Opportunity
examining the heat shield that protected it when it landed, and also have it
travel to another crater. Because the rovers use solar power and sunlight is
currently limited on Mars, the rovers can only cover from 50 to 100 feet on a
good day.
Spirit will continue climbing to the top of Husband Hill, informally named
after the Columbia commander Rick Husband, and the tallest hill in the area.
The rovers are funded by NASA to collect data and send back photos through
March, Lemmon says, but no one knows how long they will keep working.
The rovers were originally designed only to operate through April 2004.
Lemmon is participating in another Mars mission in 2007 called Phoenix,
which will go to Mars' north polar region and dig into a permafrost layer to
search for evidence that Mars was habitable when the permafrost was liquid.
Contact:
Mark Lemmon
Phone: 979-458-8098
Cell phone: 979-777-2831
E-mail: [email protected]
Read the original news release at
http://www.tamu.edu/univrel/aggiedaily/news/stories/04/120304-13.html.
Additional articles on this subject are available at:
http://www.astrobio.net/news/article1333.html
http://www.spacedaily.com/news/mars-water-science-04q.html
NASA SLEEP-WAKE SCHEDULING PROTOCOLS MAY NEED TO
BE CHANGED, UNIVERSITY OF PITTSBURGH RESEARCH
SHOWS
University of Pittsburgh Medical Center release
6 December 2004
New research from the University of Pittsburgh shows the human body has
difficulty adjusting to dramatic time changes such as those experienced by
working shifts or traveling across time zones. The NASA-funded study,
detailed in this month's Aviation, Space and Environmental Medicine, was
designed to examine the protocols the space agency uses to assign sleep-wake
schedules that ensure astronauts are always able to handle their demanding
tasks at peak performance. The findings suggest changes should be made in
the way NASA schedules sleep periods on missions, but also have meaning
for anyone who has had to deal with a significant time change and still
function.
"Many of us find that we have to change our sleep schedule, perhaps to
accommodate work or school start times, or a change in our commute time,"
said Timothy H. Monk, Ph.D., professor of psychiatry at the University of
Pittsburgh School of Medicine and lead author. "We often wonder if we
should make the change all at once, or more gradually over several days or
weeks. This research has the eventual aim of helping us make that decision in
the best way possible."
According to Dr. Monk, early in the history of manned space flight, NASA
realized that it had to have a method for assigning sleep periods to correspond
to astronauts' biological clock rhythms if they were to get enough rest to do
their assignments. "If they scheduled sleep for the wrong time, an astronaut
could end up having disrupted and unrefreshing sleep, leaving them feeling
tired and irritable, and perhaps more apt to make mistakes."
Getting the right amount of sleep at the right time is more complicated in
space than it is on Earth. On Earth, people are used to having time cues tell
their bodies when it is time to sleep or to wake up. The strongest of these is
the 24-hour day-night cycle, which comes from the fact that we live and have
2
evolved on a planet with a 24-hour rotation. Like most animals we have a
biological clock in our head, which is able to keep time, getting us ready for
sleep at night and wakefulness during the day using rhythms with a period of
about 24 hours—referred to as circadian rhythms. In orbit, the sunrise-sunset
cycle lasts for a mere 90 minutes, and after the absence of the natural 24-hour
cycle for three months or more, the biological clock starts to weaken. When
the biological clock gets thrown off balance, sleep and alertness suffer.
Complicating the issue is the need for astronauts to be awake and alert to
undertake sensitive mission goals—say docking with another vessel—at
specific times that may fall during a time at which they are normally asleep.
To reconcile an astronaut's need for sleep with their busy schedules, NASA
originally developed guidelines referred to as "Appendix K." These
guidelines specified how much time had to be set aside for sleep and for the
transitions to and from it. It also specified by how much an astronaut's
bedtime could change from one day to the next. It favored "trickling in"
changes rather gradually, using phase delays to later bedtimes (by up to 2
hours) wherever possible. The concept is similar to the terrestrial example of
the common traveler's advice to move one's bedtime ahead or back a little at a
time in the week before an overseas trip to help minimize jet lag.
"The thought was that mission schedulers could trickle in a series of two-hour
phase delays without incurring any negative consequences as far as sleep
quality and alertness," said Dr. Monk. "However, based on the findings from
this experiment, that assumption might be quite wrong."
The researchers observed participants, who volunteered to spend 16 days on a
"mission" at the University of Pittsburgh's time isolation facilities, and tested
them for alertness, mood and core body temperature—the best standard for
assessing circadian rhythms. At the same time they recorded their sleep to
assess its duration and quality. The experiment involved a series of nine
repeated two-hour delays in bedtime.
During the study Dr. Monk and his colleagues found that the circadian
pacemaker did adjust itself—but only by about one hour per night rather than
the two hours required by NASA's protocol. Because of that, subjects
eventually experienced a massive flattening in the amplitude of their circadian
temperature rhythm indicating that the biological clock was not doing its job
properly. This led to significant disruptions in sleep and lowered alertness
while awake. More research needs to be done before scientists can advise
NASA on how to change its guidelines.
"There is always some cost to performing tasks when we expect to be asleep,
but by the end of the series of experiments, of which this is the first part, we
shall be able to advise NASA which approach—gradual delays, gradual
advances, all at once—will lead to the least disruption of an astronaut's sleep
and alertness," said Dr. Monk.
Co-authors include Daniel J. Buysse, M.D., Bart D. Billy, M.S. and Jean M.
DeGrazia, M.Ed. The National Institute on Aging provided additional
research support.
An additional article on this subject is available at
http://www.spacedaily.com/news/spacetravel-04zzo.html.
ON TOP OF TITAN'S MOUNTAIN
By Leslie Mullen
From Astrobiology Magazine
8 December 2004
When Cassini flew by Saturn's moon Titan on October 26, scientists got a
small taste of the discoveries to come. Astrobiology Magazine editor Leslie
Mullen sat down with Athena Coustenis of the Paris-Meudon Observatory,
and discussed a potential landscape of mountains and lakes on this strange,
smog-filled world.
Astrobiology Magazine (AM): People thought for many years that Titan was
completely covered by a hydrocarbon ocean. When did that change?
Athena Coustenis (AC): When I started out in this field in 1987, Jonathan
Lunine's model of a global hydrocarbon ocean was like the bible to us. His
model was published in 1983, and a global ocean was a very elegant
explanation for why there was methane gas in Titan's atmosphere.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
That outlook changed after observations of Titan were made in the near
infrared. In that wavelength, there are what we call "methane windows,"
regions where you can pierce through Titan's thick smog and see all the way
down to the surface. The near infrared light curve of Titan's surface was not
flat, which it would have been if the whole surface was covered with the same
stuff, like an ocean. Since the surface was not homogeneous, that suggested
that at least some part of Titan's surface was not liquid.
Then in the 1990s came the RADAR echoes, and these readings were more
compatible with a solid surface. Adaptive optics images from the Keck
Observatory, the CFH Telescope in Hawaii and the Very Large Telescope in
Chile, as well as from the Hubble Space Telescope, showed a totally different
surface than we had imagined. The surface of Titan had these strange bright
and dark patches.
3
AM: Like amino acids?
AC: Exactly. We have hydrogen cyanide (HCN) on Titan, and we know
HCN is one of the building blocks that leads to molecules like amino acids.
But have we reached that degree of complexity on Titan? Are there other
nitriles there that are even more complicated? We're looking for them.
Personally, I think their abundance is still very small. I'm not a chemist, but I
know that if the temperature is very low, you don't get the chemical reactions
to behave the same way as on Earth.
On Titan, you have one-hundredth of the sunlight that reaches the Earth. And
that sunlight mostly reaches the upper part of the atmosphere. The surface is
even darker and colder, and chemical reactions aren't going to work as fast as
they did on the early Earth. Maybe these reactions are occurring, but not
enough complex molecules have been produced for us to be able to detect
them.
The CIRS instrument on Cassini can detect large molecules, and it can detect
a very low abundance. Cassini is going to be orbiting Saturn for four years, so
we're hoping CIRS might detect some large molecules during that time.
AM: Are there any internal heat processes on Titan that might help drive
those prebiotic chemical reactions?
AC: That's a good question. I don't think we know at this stage. But in order
to produce a mountain, like the one I was telling you about, you would have to
have some sort of cryovolcanism or tectonics—something to shift the crust
around. The surface of Titan looks young, because of the lack of impact
craters that we've seen. So there may be some processes going on inside the
moon that would explain any topography that we see.
Read the original article at http://www.astrobio.net/news/article1336.html.
Scientists would like to know the origin of the
atmospheric patches imaged on Titan. Image credit:
Hubble Space Telescope/UA Smith.
HUNTER OF ALIEN WORLDS SPEAKS AT CORNELL
UNIVERSITY
By Larry Klaes
From the Ithaca Times
AM: Do we know what these bright and dark patches are?
8 December 2004
AC: Many people think the dark patches are hydrocarbon lakes, and the bright
patches must be a solid material like ice. I think the dark areas could be
hydrocarbon lakes, because their albedo—their reflectivity—is very low. But
I don't think all the dark patches have to be hydrocarbon liquid, because water
ice also is dark at infrared wavelengths.
Geoffrey W. Marcy is Professor of Astronomy at the University of California
at Berkeley. He is also among the first scientists to have discovered planets
around Sun-like stars in our galaxy, leading us one step closer to learning
whether Earth is the only planet with life or just one of many inhabited worlds
in the universe. Marcy visited the campus of Cornell University last week to
participate in the Thomas Gold Lectureship of Astronomy series as the
lecturer for 2004-2005. Marcy's first lecture on November 29, titled "The
Properties of Planetary Systems", was a technical look at the work he and
colleagues have conducted since 1987 investigating 1,330 Sun-like stars in
our region of the Milky Way galaxy for any planets around them.
There are also intermediate regions where the bright and dark appear mixed.
That could be slush, or mud, or something solid but with material in the pores.
I like the idea of a porous surface, because even if the hydrocarbon lakes are
there, they cannot account for the total amount of methane in the atmosphere.
In my opinion, you're going to need a subsurface reservoir.
I think the bright patches are only consistent with hydrocarbon ice. They
cannot be water ice, because water ice is dark in two of the wavelengths we're
looking at. But hydrocarbon ice is bright in all the wavelengths. So the bright
regions could be plateaus or mountains with hydrocarbon ice on top. In order
to get hydrocarbon ice, you have to have a mountain—a high elevation—and
then the hydrocarbon can precipitate on top of that like snow.
AM: But so far, there's no evidence of mountains on Titan.
AC: No, but we've only looked at 0.4 percent of Titan's surface with Cassini.
It would be like if someone was looking at Earth where there was a highway,
and assumed the whole Earth is a highway! So we need to see more of Titan's
surface. The Huygens probe is going to land in an intermediate region, right
between a dark and a bright patch. So maybe when it lands its going to look
off to one side and see a mountain, and then on the other side will be a lake.
It's going to be very interesting.
AM: The Huygens probe will probably tell us more about Titan's chemistry.
How complex do you think that chemistry is?
AC: That's the big question. If you get larger and larger molecules, and more
and more complex ones, then you're getting one step closer to the
macromolecules of life.
Trying to observe a planet around a distant star has been compared to
attempting to detect a firefly sitting on the edge of a search light very far
away. Since it is not possible to detect these worlds from Earth directly,
astronomers watch for "wobbles" in a star's movement caused by the
gravitational pull of any planets around it. For comparison, imagine watching
a person walking an unseen dog on a leash getting yanked around by their pet
while trying to walk in a straight path. You can infer the dog is there by the
way the owner is tugged off their course. Using this method, Marcy and his
team have found almost one hundred exoplanets since 1995. Most are as large
as or larger than the gas giant planet Jupiter of our solar system, which could
hold over one thousand Earths itself. Since the astronomers can only discover
these worlds by their pull on a star, typically only the largest members of
those systems can be found at present. Recently, however, exoplanets of sizes
closer to Saturn and Neptune have been detected.
"There are more Neptunes than Saturns in the galaxy," stated Marcy, basing
this on the number of known exoworlds and projecting the estimate
statistically onto the rest of the stars in the Milky Way.
What Marcy and other astronomers are hoping to find eventually are the
relatively small, rocky worlds—the ones that may be other Earths which could
harbor life. While these celestial bodies are currently too small to detect from
the stellar wobble observations, space satellites planned for the coming
decades, such as the Terrestrial Planet Finder (TPF), could see Earth-like
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
4
worlds and even report on their compositions to determine if any life could
exist on them.
Read the full article at
http://www.space.com/businesstechnology/spacefood_techwed_041208.html
Are we alone?
SPITZER AND HUBBLE CAPTURE EVOLVING PLANETARY
SYSTEMS
NASA/JPL release 2004-285
Professor Marcy's second and final talk in the lecture series came on
December 2. Titled "Planets, Yellowstone, and Prospects for Life in the
Universe," Marcy delved into the underlying reason for his search for alien
worlds: to find out how many stars have their own planetary systems. The
more suns that have worlds circling them, the higher are the chances for life
existing beyond Earth.
Marcy began his examination of the possibility for alien life by starting with
our celestial neighborhood, the worlds of our solar system. He highlighted the
recent findings by the Mars Exploration Rovers (MER) Spirit and Opportunity
that water once flowed across at least some of the Red Planet in the distant
past, increasing the chances for life having been there as well.
9 December 2004
Two of NASA's Great Observatories, the Spitzer Space Telescope and the
Hubble Space Telescope, have provided astronomers an unprecedented look at
dusty planetary debris around stars the size of our Sun. Spitzer has discovered
for the first time dusty discs around mature, Sun-like stars known to have
planets. Hubble captured the most detailed image ever of a brighter disc
circling a much younger Sun-like star. The findings offer "snapshots" of the
process by which our own solar system evolved, from its dusty and chaotic
beginnings to its more settled present-day state.
Another world that has gotten recent headlines is Saturn's largest moon, Titan.
The Cassini probe orbiting that ringed gas giant has also begun to reveal what
Titan looks like under its thick veil of orange clouds. It is a truly alien place,
and though the moon is seemingly too cold for any Earth-type life, Marcy
speculated that some kind of organisms could be there with chemistry far
different from what we know of here, possibly swimming in lakes of liquid
ethane.
Marcy then headed the audience out into the wider galaxy to examine some of
the strange alien worlds he and his team have found in the past decade. Since
the majority of known exoplanets are around the size of Jupiter or larger,
scientists have speculated whether life exists on them. A number of these
planets actually orbit very close to their stars and are presumably so hot that it
is hard to imagine would kind of organisms could survive on them. However,
for those known globes that do orbit at more "reasonable" distances from their
suns, Marcy said that while he "would not bet on life on those worlds as we
know it, I could imagine life that floats in their thick air."
Debris disks around AU Microscopii and HD 107146.
Using his seventeen years of data and discoveries, Marcy estimates that
perhaps twenty billion planetary systems exist in our Milky Way. Combine
that with how hardy life can be on this planet—such as dwelling in hot, acidic
geysers and miles under the ocean—and Marcy thinks that simple life forms
are "common" in our galaxy and probably most others. As for intelligent alien
life, "we must hunt explicitly for extraterrestrial intelligence to find brethren
in the galaxy," said Marcy.
Read the original article at
http://www.zwire.com/site/news.cfm?newsid=13513122&BRD=1395&PAG=
461&dept_id=216620.
SPACE COOKING: FEEDING ASTRONAUTS ON MARS-BOUND
MISSIONS
By Tariq Malik
From Space.com
8 December 2004
While NASA engineers toil away with spacecraft designs to determine
how humans will explore the moon and Mars, other researchers are
developing devices to help future astronauts feed their hunger. Future longduration space crews may need up to 40 different food processing machines to
turn crops such as wheat and tomatoes into edible foods like bread and
cereals, NASA officials estimated.
"As we go on to longer-duration missions, it makes sense to become a little
more self-sufficient with our food," said Michele Perchonok, a food scientist
at NASA's Johnson Space Center (JSC) in Houston, Texas, in a telephone
interview. "The ultimate way of doing that is growing crops and processing
them into food."
But the challenge lies in keeping space food equipment small, light and easy
to maintain during a two-year Mars trip, said Perchonok, the advanced food
technology lead for the National Space Biology Research Institute at JSC.
"Some of the other challenges reside in making sure the food that is produced
is safe, nutritious and acceptable," she added.
"Young stars have huge reservoirs of planet-building materials, while older
ones have only leftover piles of rubble. Hubble saw the reservoirs and
Spitzer, the rubble," said Dr. Charles Beichman of NASA's Jet Propulsion
Laboratory, Pasadena, CA. He is lead author of the Spitzer study. "This
demonstrates how the two telescopes complement each other," he added.
The young star observed by Hubble is 50 million to 250 million years old.
This is old enough to theoretically have gas planets, but young enough that
rocky planets like Earth may still be forming. The six older stars studied by
Spitzer average 4 billion years old, nearly the same age as the Sun. They are
known to have gas planets, and rocky planets may also be present. Prior to
these findings, rings of planetary debris, or "debris discs," around stars the
size of the Sun had rarely been observed, because tphey are fainter and more
difficult to see than those around more massive stars.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
"The new Hubble image gives us the best look so far at reflected light from a
disc around a star the mass of the Sun," said Hubble study lead author, Dr.
David Ardila of the Johns Hopkins University, Baltimore. "Basically, it
shows one of the possible pasts of our own solar system," he said.
Contacts:
Donald Savage
NASA Headquarters, Washington, DC
Phone: 202-358-1727
Debris discs around older stars the same size and age as our Sun, including
those hosting known planets, are even harder to detect. These discs are 10 to
100 times thinner than the ones around young stars. Spitzer's highly sensitive
infrared detectors were able to sense their warm glow for the first time.
Whitney Clavin
Jet Propulsion Laboratory, Pasadena, CA
Phone: 626-395-1877
5
Ray Villard
Space Telescope Science Institute, Baltimore, MD
Phone: 410-338-4514
Additional articles on this subject are available at:
http://www.astrobio.net/news/article1343.html
http://www.space.com/scienceastronomy/planet_formation_041209.html
http://www.universetoday.com/am/publish/planetary_systems_seen_forming.
html
PROMETHEUS PRE-EMPTED? NEW NUCLEAR FISSION
MISSIONS EVALUATED
By Leonard David
From Space.com
10 December 2004
This artist's concept depicts a distant hypothetical solar system, similar in age
to our own. Looking inward from the system's outer fringes, a ring of dusty
debris can be seen, and within it, planets circling a star the size of our Sun.
This debris is all that remains of the planet-forming disc from which the
planets evolved. Planets are formed when dusty material in a large disc
surrounding a young star clumps together. Leftover material is eventually
blown out by solar wind or pushed out by gravitational interactions with
planets. Billions of years later, only an outer disc of debris remains. These
outer debris discs are too faint to be imaged by visible-light telescopes. They
are washed out by the glare of the Sun. However, NASA's Spitzer Space
Telescope can detect their heat, or excess thermal emission, in infrared light.
This allows astronomers to study the aftermath of planet building in distant
solar systems like our own. Image credit: NASA/JPL/T. Pyle/SSC.
"Spitzer has established the first direct link between planets and discs,"
Beichman said. "Now, we can study the relationship between the two." These
studies will help future planet-hunting missions, including NASA's Terrestrial
Planet Finder and the Space Interferometry Mission, predict which stars have
planets. Finding and studying planets around other stars is a key goal of
NASA's exploration mission.
Rocky planets arise out of large clouds of dust that envelop young stars. Dust
particles collide and stick together until a planet eventually forms. Sometimes
the accumulating bodies crash together and shatter. Debris from these
collisions collects into giant doughnut-shaped discs, the centers of which may
be carved out by orbiting planets. With time, the discs fade and a smaller,
stable debris disc, like the comet-filled Kuiper Belt in our own solar system, is
all that is left.
The debris disc imaged by Hubble surrounds the Sun-like star called HD
107146, located 88 light-years away. John Krist, a JPL astronomer, also used
Hubble to capture another disc around a smaller star, a red dwarf called AU
Microscopii, located 32 light-years away and only 12 million years old. The
Hubble view reveals a gap in the disc, where planets may have swept up dust
and cleared a path. The disc around HD 107146 also has an inner gap.
Beichman and his colleagues at JPL and the University of Arizona, Tucson,
used Spitzer to scan 26 older Sun-like stars with known planets, and found six
with Kuiper Belt-like debris discs. The stars range from 50 to 160 light-years
away. Their discs are about 100 times fainter than those recently imaged by
Hubble, and about 100 times brighter than the debris disc around the Sun.
These discs are also punctuated by holes at their centers.
Both Hubble images were taken with the advanced camera for surveys. They
will be published in the Astronomical Journal and the Astrophysical Journal
Letters. The Spitzer observations are from the multiband imaging photometer
and will appear in the Astrophysical Journal. Electronic images and
additional information are available at http://hubblesite.org/news/2004/33 and
http://www.spitzer.caltech.edu.
NASA is reviewing a list of fission-powered missions that could pre-empt the
Jupiter Icy Moons Orbiter (JIMO) effort now being eyed for space travel no
sooner than 2015. A special study team has identified six potential candidate
missions that could be done sooner, have shorter mission durations, and would
be far less difficult to implement.
Read the full article at
http://www.space.com/businesstechnology/technology/jimo_update_041210.h
tml.
MARS LIFE: TROUBLE WITHOUT THE RUBBLE?
By David Noever
From Astrobiology Magazine
10 December 2004
On January 25, Opportunity landed on Mars. The landing site, Meridiani
Planum, was the flattest location scouted in the history of Mars exploration.
Because of the rover's unique mobility, scientists wanted interesting landing
sites with less than ten to twenty percent rock coverage. Rubble was trouble.
But few anticipated what all that flatness would finally deliver—not only for
easy movement of their mobile laboratory, but also for its remarkable science
returns. The rover's story, as detailed in the eleven Science papers this month,
is mainly one about water and salt. But a thread of this adventure includes the
physical landscape itself. It is thus surprising when the flattest spot—Mars
without the rubble—served up pictures of the first bedrock found on another
world.
On earth, bedrock is common in northern New England, particularly Maine
and New Hampshire, the Granite state. But the wind blows around enough
dry dust on Mars to cover what might be exposed bedrock. This debris layer
blankets most of the rest of the planet. Additionally, meteors have pulverized
the martian surface leaving a thick crushed layer. The thing about bedrock is
[that] it is stationery: always has been, always will be, at least as far as
knowing its original location.
Why this is important follows from the preserved geochemistry that such
bedrock shows. Bedrock marks the spot, just because its native location is
known. Bedrock at Meridiani thus becomes the important control experiment
that was missing from previous expeditions. When geologists see bedrock,
then they know they are not studying rocks carried from another place on
Mars. So the first surprise for Opportunity was finding bedrock.
Along with bedrock came sediments, the delicate layering of time-tagged
deposits. Repeated cycles of wet and dry periods can shape these layers into
an intricate record of the planet's history. Such fine laminations also showed
rippling effects at the Opportunity site. Although not exactly like a shoreline,
these thick and thin beds could span up to a meter and may have arisen from
wind-driven water flow in the distant martian past.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
6
One can ask the question: what would a Mars rock feel like? Would it be
heavy or light? Would it crumble when squeezed? In imagining the texture
of the rocks found by the Opportunity rover, the mission team compared them
to spongy sandstone. They were pockmarked, porous, dried and cracked. The
voids and holes in these spongy rocks may have arisen from repeated cycles
of evaporation to harden the surfaces followed by a washing away to dissolve
the more soluble interior portions.
So the story Opportunity told was figuratively a "wash-out"—however, the
role of evaporation had not yet been clarified and another piece of puzzle was
falling into place. Where evaporative layers might deposit chlorine or
bromine, the heavier, less soluble element (chlorine) was found on the bottom
layers. Such dried beds are typically separated like this, since more
concentrated brines come later in the drying and by then, only the most
soluble salts remain as the solution evaporates, thickens and concentrates.
Texture of landing sites. Upper left, the moon; upper
right, Venus; middle left, Pathfinder 1997 Mars; middle
right, Viking 1977 Mars; lower left, airbag imprint in
Eagle Crater, Meridiani Planum 2004; lower right,
airbag drag mark, Meridiani Planum, 2004
Opportunity site. The 1997 Sojourner rover never was
able to travel far from its lander but in any case, the
nearly twenty percent coverage of the ground by large
rocks would have made its traverse challenging if not
impossible. The two Viking landers from 1976-77 had
no roving capabilities but lasted in place for nearly a
decade using nuclear powered generators. This current
generation of rovers is more limited in their expected
lifetimes, owing to dust coverage of their solar panels
and slow mechanical breaks. Image credit: NASA/JPL.
One of the great challenges of doing this kind of remote geology is the lack of
an obvious time scale. The marker between one rhythm to another is
unknown. It may not be annual. But if an inferred timeline presents itself,
just as yearly tree rings are used to date Earth events, then the layers of
sediment tell an important story. So far, the timeline at Meridiani goes
something like this: 600 meters of sediments may have formed in about
250,000 Mars years (or sols, each about 600 days or two earth-years). This
doesn't mean that water flowed on Mars a half-million earth-years ago,
because there is no obvious way to know when any rhythmic cycle might have
started. But simply guessing at the persistence of water and sedimentary
rocks hints at a much warmer and wetter climate than today's.
It would be remarkably useful to know the start and end dates. When did
water stop flowing on Mars? No one knows at the moment.
After finding bedrock and sediments, Opportunity allowed scientists to start
telling the martian story using its many instruments. One chapter that
continues to reveal surprises is the red planet's geochemistry. What are the
rocks and sediment made of? One thing the team was looking for was
minerals that could dissolve in water. On a dry Mars, the salts will be all that
remains after the water leaves.
Examples of soluble salts include traces of chlorine and bromine. Both were
found at Meridiani Planum, along with very high concentrations of sulfates.
So soon after the instruments looked closely at the Opportunity landing site,
the surrounding soil, rocks, and outcrops were found to be salty.
The story was different on the other side of the planet. The Spirit rover had
found something more shaped by lava than brines. A rubble field of volcanic
rocks and inorganic soils was found there, at Gusev crater. The Spirit rocks
were harder to drill and grind than those at Opportunity, since the rubble was
strewn across Gusev crater from past lava flows and meteor strikes. If
Opportunity's site was like a salt-flat, then Spirit's site was like an old lava
field.
A final clue was detection of the mineral jarosite, which requires highly acidic
brine. Taken together, the chemistry of Meridiani was rich in sulfur, iron and
magnesium, while also stratifying deposits in a way consistent with
evaporation and acidity. If a sample of this composition was sought on Earth,
the most likely candidate would be water draining from acid mines. These
mines would be full of polluted areas, turned orange and red from rusting
washouts of iron sulfide ores. Mars, was it the rusting world? Prior to this
mission, the Meridiani plains were compared to the Rust Belt states, those in
the middle north of America (Michigan, Ohio, Pennsylvania). The other
comparison was to the red dirt found in Oklahoma and northern Texas—the
so-called Red River region.
The spherules, blueberries and naming have become important to clues on an
alien landscape. Image credit: NASA/JPL.
"It's an incredibly rich data set," principal investigator for both science
missions, Steve Squyres told Astrobiology Magazine. "The data from the first
90 sols of both landing sites is now out there in the Planetary Data System,
and anybody can access it and do science with it. To a certain extent, it's
going to be very satisfying to just sit back and watch people do science with
this data. We worked very hard to build these rovers, and we've worked very
hard to collect the data."
What does this synopsis hint at for habitability? One thing the Viking probes
found in the 1970's was Mars is rusting. Indeed the soil was considered
highly reactive and oxidizing with the corrosive strength of hydrogen
peroxides. The challenge for life at Meridiani is daunting. To survive
requires tolerance for extreme conditions: supercold, salty and acidic. While
individually not outside the bounds of Earth organisms, the biological hurdle
is a challenging one. A supercold world of acidic brines may have once been
Mars.
Read the original article at http://www.astrobio.net/news/article1341.html.
LIFE-SWAPPING SCENARIOS FOR EARTH AND MARS
By Leonard David
From Space.com
13 December 2004
Evidence is mounting that the time-weathered red planet was once a warm and
water-rich world. And a Mars awash with water gives rise to that globe
possibly being fit for habitation in its past—and perhaps a distant dwelling for
life today. As sensor-laden orbiters circle the planet, NASA's twin Mars
rovers—Spirit and Opportunity—have been tooling about and carrying out
exhaustive ground studies for nearly a year. The Opportunity robot at
Meridiani Planum, for instance, has found telltale signs that water came and
went repeatedly within that stretch of martian real estate. While that
intermittent water at Meridiani Planum is thought to be highly acidic and
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
salty, its ability to sustain life for some period of time cannot be ruled out.
What scientists now see is a Mars different in its first billion years of geologic
history than once thought—and conceivably an extraterrestrial address for
home-grown life.
7
Saturn on 1 July 2004, and began to investigate the ringed planet and its
moons for a mission that will last at least four years.
Read the full article at
http://www.space.com/scienceastronomy/mars_life_041213.html.
LIFTOFF 2005 EXPERIENCE FOR TEACHERS
By Margaret Baguio
Texas Space Grant Consortium release
10 December 2004
Beginning in the summer of 1990, the Texas Space Grant Consortium initiated
a week-long professional development training for teachers. This aerospace
workshop series, called LiftOff, emphasizes science, mathematics, and
technology learning experiences by incorporating a space science theme
supported by NASA missions. Teacher participants are provided with
information, materials, and experiences through hands-on activities and field
trips that will promote space science and enrichment activities for themselves
and others.
Some of the most frequently asked questions about the U.S. space program are
"Why go into space when we have so many problems here on Earth?" and
"What does the space program do for me?" These legitimate questions will be
answered when educators become aware of the vast benefits of the space
program that increase the quality of our daily lives. The applications on Earth
technology needed for space flight have produced thousands of "spin-offs"
that contribute to improving national security, the economy, productivity and
lifestyle. We would be hard pressed to find an area of everyday life that has
not been improved by spin-offs from the space program.
So, the next time someone asks "Why do we go in space" and "What does the
space program do for me?" You will be able to explain it because of LiftOff
2005: NASA Spin-offs, Bringing Space down to Earth! LiftOff 2005
applications are now available online: http://www.tsgc.utexas.edu/liftoff/.
Please let me know if you intend to sponsor a teacher from your state. We
will fax any applications received from your state for your review. Please let
me know if you have questions.
This artist's concept of the Cassini-Huygens orbiter shows the Huygens probe
separating to enter Titan's atmosphere. After separation, the probe drifts for
about three weeks until reaching its destination, Titan. Equipped with a
variety of scientific sensors, the Huygens probe will spend 2-2.5 hours
descending through Titan's dense, murky atmosphere of nitrogen and carbonbased molecules, beaming its findings to the distant Cassini orbiter overhead.
The probe could continue to relay information for up to 30 minutes after it
lands on Titan's frigid surface, after which the orbiter passes beneath the
horizon as seen from the probe. Image credit: NASA/JPL/Caltech.
Contact:
Margaret Baguio
Texas Space Grant Consortium
Education and Outreach Coordinator
3925 W. Braker Lane, Suite 200
Austin, Texas 78759
Phone: 512-471-6922
Fax: 512-471-3585
http://www.tsgc.utexas.edu
E-mail: [email protected]
CASSINI-HUYGENS UPDATES
NASA/ESA releases
Second space Christmas for ESA: Huygens to begin its final journey to
Titan
ESA release 63-2004, 7 December 2004
One year after Mars Express' arrival at Mars, the mighty rules of celestial
mechanics have again set Christmas as the date for a major ESA event in deep
space. At 1.25 billion km from Earth, after a 7-year journey through the Solar
system, ESA's Huygens probe is about to separate from the Cassini orbiter to
enter a ballistic trajectory toward Titan, the largest and most mysterious moon
of Saturn, in order to dive into its atmosphere on 14 January. This will be the
first man-made object to explore in-situ this unique environment, whose
chemistry is assumed to be very similar to that of the early Earth just before
life began, 3.8 billion years ago.
The Cassini-Huygens pair, a joint mission conducted by NASA, ESA and the
Italian space agency (ASI), was launched into space on 15 October 1997.
With the help of several gravity assist maneuvers during flybys of Venus,
Earth and Jupiter, it took almost 7 years for the spacecraft to reach Saturn.
The Cassini orbiter, carrying Huygens on its flank, entered an orbit around
This is a computer-rendered image of Cassini-Huygens during the Saturn
Orbit Insertion (SOI) maneuver, just after the main engine has begun firing.
The spacecraft is moving out of the plane of the page and to the right (firing to
reduce its spacecraft velocity with respect to Saturn) and has just crossed the
ring plane. The SOI maneuver, which is approximately 90 minutes long, will
allow Cassini-Huygens to be captured by Saturn's gravity into a five-month
orbit. Cassini-Huygens's close proximity to the planet after the maneuver
offers a unique opportunity to observe Saturn and its rings at extremely high
resolution. Image credit: NASA/JPL/Caltech/David Seal.
The first distant flyby of Titan took place on 2-3 July 2004. It provided data
on Titan's atmosphere which were confirmed by the data obtained during the
first close flyby on 26 October 2004 at an altitude of 1174 km. These data
were used to validate the entry conditions of the Huygens probe. A second
close flyby of Titan by Cassini-Huygens at an altitude of 1200 km is
scheduled on 13 December and will provide additional data to further validate
the entry conditions of the Huygens probe. On 17 December the orbiter will
be placed on a controlled collision course with Titan in order to release
Huygens on the proper trajectory, and on 21 December (some dates and times
are subject to minor adjustment for operational reasons, except the entry time
on 14 January which is know to within an accuracy of under 2 minutes) all
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
systems will be set up for separation and the Huygens timers will be set to
wake the probe a few hours before its arrival at Titan.
8
Read the original news release at
http://www.esa.int/esaCP/SEMUPZWDE2E_Life_0.html.
Cassini Significant Events for 2-8 December 2004
NASA/JPL release, 10 December 2004
The most recent spacecraft telemetry was acquired from the Madrid tracking
station on Wednesday, December 8. 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.
This image is one of the closest ever taken of Saturn's hazy moon Titan. It
was captured by the Cassini-Huygens Imaging Science Subsystem on 26
October 2004, as the spacecraft flew by Titan. At its closest, Cassini-Huygens
was 1200 kilometers above the moon, 300 times closer than during its first flyby on 3 July 2004. Image credit: NASA/JPL/Space Science Institute.
The Huygens probe is due to separate on the morning of 25 December at
about 05:08 CET. Since the Cassini orbiter will have to achieve precise
pointing for the release, there will be no real-time telemetry available until it
turns back its main antenna toward Earth and beams the recorded data of the
release. It will take over an hour (67 min) for the signals to reach us on Earth.
The final data confirming the separation will be available later on Christmas
Day. After release, Huygens will move away from Cassini at a speed of about
35 cm per second and, to keep on track, will spin on its axis, making about 7
revolutions a minute. Huygens will not communicate with Cassini for the
whole period until after deployment of the main parachute following entry
into Titan's atmosphere. On 28 December Cassini will then maneuver off
collision course to resume its mission and prepare itself to receive Huygens
data, which it will record for later playback to Earth.
Huygens will remain dormant until a few hours before its arrival at Titan on
14 January. The entry into the atmosphere is set for 11:15 CET. Huygens is
planned to complete its descent in about two hours and 15 minutes, beaming
back its science data to the Cassini orbiter for replay to Earth later in the
afternoon. If Huygens, which is designed as an atmospheric probe rather than
a lander, survives touchdown on the surface, it could deliver up to 2 hours of
bonus data before the link with Cassini is lost. Direct radio signals from
Huygens will reach Earth after 67 minutes of interplanetary travel at the speed
of light. An experiment has been set up by radio scientists that will use an
array of radio telescopes around the Pacific to attempt to detect a faint tone
from Huygens. If successful, early detection is not expected before around
11:30 CET.
The European Space Agency owns and manages the Huygens probe and is in
charge of operations of the probe from its control centre in Darmstadt,
Germany. NASA's Jet Propulsion Laboratory in Pasadena, California,
designed, developed and assembled the Cassini orbiter. NASA's Deep Space
Network, also managed by JPL, will be providing communications support via
the Cassini orbiter and relaying it to ESA's control centre in Darmstadt for
processing. The Italian Space Agency provided the high-gain antenna on the
Cassini orbiter, much of the radio system and elements of several of Cassini's
science instruments. The Huygens payload has been provided by teams
including from CNES, DLR, ASI and PPARC, and outside Europe, from
NASA.
Science observations this week focused on the Composite Infrared
Spectrometer (CIRS) integration of the main rings with the mid-infrared focal
planes. This will give the first detailed temperature measurements across the
rings. Additionally, CIRS examined the oxygen compounds H2O and CO2 in
Saturn's stratosphere as a function of latitude. The Imaging Science
Subsystem (ISS) continued to image small satellites for orbit determination,
the Ultraviolet Imaging Spectrograph continued to capture mosaics of Saturn's
magnetosphere, and ISS captured a 3x3 movie of the Saturnian southern
hemisphere in several filters with the Narrow-Angle Camera to measure wind
speeds and map the occurrence of "moist" convection.
On-board activities this week included real time commands for the Cassini
Plasma Spectrometer (CAPS) to restart the master Instrument Expanded
Block (IEB), update the IMS sweep table and IEB for the Titan-B encounter,
and restart actuation after Probe activities in S06. All activities executed as
expected.
Additional real time commanding included a test of the
Magnetometer Subsystem scalar magnetometer, a Cosmic Dust Analyzer
(CDA) RPX calibration, and closing of the main engine cover. The cover will
remain closed until after the Dione flyby on December 14.
The main event this week was the second probe battery depassivation. An
initial assessment indicates that the data looks exactly the same as for the first
depassivation in September of this year. The depassivation sequence lasted
for 35 minutes after which there was a 5-minute pause before the Probe Safing
sequence started. This lasted for 8 minutes and was run to ensure that no
battery remained connected to the Probe power bus. Each battery exhibited
essentially the same behavior during each of the 5 minute depassivation
periods, with voltages starting at ~65V and slowly increasing to ~70V.
Measurements on the bus side showed battery currents ~1.9A with a similar
value being measured from the Cassini line, which indicated an equal sharing
of the busload between battery and Cassini. Bus voltage was rock-solid at
28V. All Probe systems are exhibiting normal behavior.
The Cassini-Huygens program held two reviews on December 2 to support the
mission commitment for the Huygens mission. The first was the Huygens
Probe checkout F16 review. All probe instruments and the probe engineering
systems reported and are nominal and ready to support the probe mission.
The second review was an internal readiness review to assess the program's
total readiness to support mission. All necessary teams, flight products, and
subsystems were reported ready to support the mission. The Mission Risk
Review concluded its activities on December 6 with an updated assessment of
the entry and descent studies. Refined analyses with the latest Titan
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
9
atmosphere models have shown further margin in the heat shield performance.
Residual action items from the November 29 review were closed. The final
report will be presented on December 16.
New details on Iapetus are illuminated by reflected light from Saturn in this
revealing Cassini image. Never-before-seen features on the Saturn-facing
part of Iapetus’ bright trailing hemisphere are visible for the first time,
including many dark spots, and a sharper view of a dark, circular structure
that was first seen at very low resolution by NASA's Voyager 1 in 1980.
Iapetus diameter is 1,436 kilometers (892 miles). The image shows mainly the
night side of Iapetus; part of the far brighter sunlit side appears at the right
and is overexposed due to the long integration time of 180 seconds. Despite
this long exposure time, almost no blurring due to the spacecraft’s motion is
apparent. This technique for imaging the night side of Iapetus will be used
again during a flyby on January 1, 2005, when Cassini will pass 13 times
closer to the icy moon. The image was taken in visible light with the Cassini
spacecraft narrow angle camera on October 22, 2004, at a distance of 1.6
million kilometers (994,000 miles) from Iapetus. The image scale is 9.4
kilometers (5.8 miles) per pixel.
On Tuesday the Navigation Team led a meeting to discuss the impacts of
canceling Orbital Trim Maneuver 7 (OTM). The meeting was attended by
representatives from Program Management, Spacecraft Operations, Science
Planning, and Uplink Operations. It was determined that there was no
compelling reason to perform the maneuver—delivery differences at Titan
with and without the maneuver were negligible, delta-V cost was a "wash",
there was negligible change to instrument pointing, and there was nothing new
that OTM-7 would provide from a spacecraft perspective to make OTM-9 any
more accurate. The decision was made to cancel this maneuver.
As Cassini swung around to the dark side of the planet during its first close
passage after orbit insertion, the intrepid spacecraft spied three ring moons
whizzing around the planet. Visible in this image are: Mimas (398 kilometers,
or 247 miles across) brightest and above center; Janus (181 kilometers, or
112 miles across) second brightest at upper left; and Prometheus (102
kilometers, or 63 miles across) just above the main rings at upper left. The
normally bright B ring appears very dark from this vantage point. Regions
with smaller concentrations of particles, such as the Cassini division (bright
near center) transmit more sunlight and thus are brighter. The image was
taken in visible light with the Cassini spacecraft wide angle camera on
October 27, 2004, at a distance of 757,000 kilometers (470,000miles) from
Saturn. The image scale is about 42 kilometers (26 miles) per pixel.
The Science Operations Plan (SOP) Update process for S09 concluded this
week. A Project Briefing and Waiver Disposition meeting was held and a
handoff package transferred to the Sequence Team leads. S09 has begun the
Sub-Sequence Generation (SSG) phase of SSUP with a kickoff meeting held
on Tuesday. The stripped subsequences were released for teams to populate,
and the SSG Science Allocation Panel meeting was cancelled, as there were
no DSN changes. Official port#1 of the SOP Update process for S10 occurred
last Friday. The products were merged and sent to ACS for the end-to-end
pointing validation. S11 has concluded the Aftermarket process and begins
SOPU next week.
Official port #1 for SOP Implementation of S39/S40 occurred this week along
with Preliminary Port #1 for S41. The team files for S39/S40 were merged
and delivered to ACS for end-to-end-pointing validation. The products for
S41 were merged, the preliminary port analysis performed, and reports
provided to the teams.
Mission Planning has released the Titan-B and Huygens/Titan-C Mission
Descriptions. The Titan-B document provides a brief, concise description of
encounter events, including an estimated playback schedule for all
instruments. Also included is a one-page "quick look" reference sheet.
Updates to the Huygens/Titan-C document include the addition of the Probe
Release timeline and an updated sequence layout chart.
The Titan Orbiter Science Team and Huygens Science Working Team hosted
a Titan-B Preview Meeting with a special Dione preview following. This was
an open meeting for anyone on the project who was interested in a preview of
Tb science, objectives and activities.
A beautiful picture of Mimas against Saturn's rings and shadows was
Astronomy Picture of the Day on December 2. Cassini has an impressive
collection of 131 papers being presented at the Fall AGU meeting next week
in San Francisco, California.
The Science and Sequence Update Process (SSUP) for tour sequence S07
concluded this week. A Final Sequence Integration and Validation (FSIV)
Sequence Change Request (SCR) approval meeting was held with 8 SCRs
dispositioned. Later in the week the fully integrated sequence products were
released, and the final sequence approval meeting was held. Uplink of IEBs
and the background sequence begins on December 11. S07 begins execution
on December 16. Also in SSUP, a PSIV SCR approval meeting was held for
S08, and as well as a Preliminary SCR meeting where 14 SCRs were
approved.
"Cassini Captures Saturn Moon Red-Handed." The Cassini spacecraft has
witnessed Saturn's moon Prometheus snatching particles from one of Saturn's
rings. This and the most recent image advisory may be found on the Cassini
web site at http://Saturn.jpl.nasa.gov.
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.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
10
Distinct flow features can be recognized within impact craters, for example,
the 15-kilometer wide crater in the west (bottom) of the image.
This is a view looking south-east across Promethei Terra, back up Reull Vallis
and the junction with its tributary, Teviot Vallis. The channel seen here is
approximately 20 kilometers wide and has cut into the surrounding plain to a
depth of 1800 meters. Image credit: ESA/DLR/FU Berlin (G. Neukum).
This view of Saturn's outer C ring shows the extreme variations in brightness,
along with the subtle, large-scale wavy variations discovered 24 years ago by
NASA's Voyager spacecraft. The notably dark Maxwell gap (near upper
right) contains the bright, narrow and eccentric Maxwell ringlet, a Saturnian
analog of the narrow Uranian epsilon ring. The gap also contains another
very faint ringlet newly discovered by Cassini. The image was taken with the
Cassini spacecraft narrow angle camera on October 29, 2004, at a distance of
838,000 (521,000 miles) from Saturn. The center of this view shows an area
located approximately 81,300 kilometers (50,500 miles) from the planet. The
image scale is 4.6 kilometers (2.9 miles) per pixel.
Additional articles on this subject are available at:
http://www.astrobio.net/news/article1335.html
http://www.space.com/saturn_rings_041203.html
http://www.spacedaily.com/news/cassini-04zzzzx.html
http://www.spacedaily.com/news/cassini-04zzzzy.html
http://www.spacedaily.com/news/cassini-04zzzzz.html
http://www.spacedaily.com/news/cassini-04zzzzza.html
http://www.spacedaily.com/news/cassini-04zzzzzb.html
http://www.spacedaily.com/news/cassini-04zzzzzc.html
http://spaceflightnow.com/cassini/041208iapetus.html
http://www.universetoday.com/am/publish/huygens_ready_solo.html
http://www.universetoday.com/am/publish/views_iapetus.html
http://www.universetoday.com/am/publish/saturn_c_ring.html
MARS EXPRESS: THE CHANNELS OF REULL VALLIS
ESA release
7 December 2004
These images, taken by the High Resolution Stereo Camera (HRSC) on board
ESA's Mars Express spacecraft, show a region of Reull Vallis in the southern
hemisphere of Mars. The images show an area located at about latitude 42°
South and longitude 102° East. The image was taken with a ground resolution
of about 21 meters per pixel during Mars Express orbit 451 in May 2004.
Reull Vallis is an outflow channel that extends 1500 kilometers across
Promethei Terra in the direction of Hellas Basin. It is approximately 20
kilometers wide and has cut into the surrounding plain to a depth of 1800
meters. It is the major outflow channel in the region and exhibits a high
degree of surface modification, suggesting a complex evolution.
In these images, Reull Vallis extends from the east to the north-west and is
connected to a tributary in the south (Teviot Vallis). Distinct parallel
structures are visible in the channels, possibly caused by glacial flow of loose
debris mixed with ice. Small depressions, located on the flow features, are
probably caused by the sublimation of ice. Numerous impact craters, visible
on the flanks of the valley, have been filled with material from these flows.
Reull Vallis is an outflow channel that extends 1500 kilometres across
Promethei Terra in the direction of Hellas Basin. This Mars Express image
was taken with a ground resolution of about 21 metres per pixel during Mars
Express orbit 451 on 29 May 2004. The image shows an area located at about
latitude 42° South and longitude 102° East. North is to the left. Image credit:
ESA/DLR/FU Berlin (G. Neukum).
There is a clear morphological distinction between the heavily eroded southwest and the plains of the north-east, which have experienced much less
erosion. While most landforms throughout the image have a rounded,
softened appearance, younger structures have a distinctly sharp and raised
morphology. On the southern and western edges of the color image, large
impact craters are visible. Their diameters range from 15 to 35 kilometers.
These craters have heavily eroded rims and are partly filled with material.
Erosion has left distinct, branched gully systems at the edge of the large crater
that is located on the southern edge of the image.
Image resolution has been decreased for use on the internet. The color images
were processed using the HRSC nadir (vertical view) and three color
channels. The perspective views were calculated from the digital terrain
model derived from the stereo channels. The 3D anaglyph image was created
from the nadir channel and one of the stereo channels. Stereoscopic glasses
are needed to view the 3D image.
Read the original news release at
http://www.esa.int/SPECIALS/Mars_Express/SEM1EQWDE2E_0.html.
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
11
MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
6-10 December 2004
Crater in Nighttime IR (Released 6 December 2004)
http://themis.la.asu.edu/zoom-20041206A.html
Nighttime IR Ejecta (Released 7 December 2004)
http://themis.la.asu.edu/zoom-20041207A.html
Dusty Ejecta Blanket (Released 8 December 2004)
http://themis.la.asu.edu/zoom-20041208A.html
Nighttime Wind Streaks (Released 9 December 2004)
http://themis.la.asu.edu/zoom-20041209A.html
Crater at Night (Released 10 December 2004)
http://themis.la.asu.edu/zoom-20041210A.html
This is a view looking down Reull Vallis, west across Promethei Terra in the
direction of Hellas Basin. The channel seen here is approximately 20
kilometers wide and has cut into the surrounding plain to a depth of 1800
meters. Image credit: ESA/DLR/FU Berlin (G. Neukum).
Additional articles on this subject are available at:
http://www.spacedaily.com/news/marsexpress-04zn.html
http://www.universetoday.com/am/publish/channels_reull_vallis.html
MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
2-8 December 2004
The following new images taken by the Mars Orbiter Camera (MOC) on the
Mars Global Surveyor spacecraft are now available.
Lava Flow Features (Released 02 December 2004)
http://www.msss.com/mars_images/moc/2004/12/02/
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.
MARS RECONNAISSANCE ORBITER: ULTRA-SHARP, MARSBOUND HIRISE CAMERA DELIVERED TODAY
By Lori Stiles
University of Arizona release
6 December 2004
The camera that will take thousands of the sharpest, most detailed pictures of
Mars ever produced from an orbiting spacecraft was delivered today for
installation on NASA's Mars Reconnaissance Orbiter.
The Mars
Reconnaissance Orbiter (MRO) will be launched on August 10, 2005,
carrying a payload of six science instruments and a communications relay
package to boost the ongoing exploration of the red planet. The largest
science instrument on the spacecraft will be the University of Arizona's High
Resolution Imaging Science Experiment (HiRISE), a 65 kilogram (145 pound)
camera with a half-meter (20-inch) diameter primary mirror. HiRISE has
been delivered for installation on the MRO spacecraft at Lockheed Martin
Space Systems in Denver, CO. Ball Aerospace & Technologies Corp. of
Boulder, CO, designed, built and tested the $35 million HiRISE camera.
NASA's Jet Propulsion Laboratory in Pasadena, CA, manages the MRO
mission for NASA's Science Mission Directorate, Washington, DC.
North Polar Layers (Released 03 December 2004)
http://www.msss.com/mars_images/moc/2004/12/03/
Polygon/Cracked Sedimentary Rock (Released 04 December 2004)
http://www.msss.com/mars_images/moc/2004/12/04/
Layers in Shalbatana Vallis (Released 05 December 2004)
http://www.msss.com/mars_images/moc/2004/12/05/
Layers and Streaks (Released 06 December 2004)
http://www.msss.com/mars_images/moc/2004/12/06/
Hypanis Layered Outcrop (Released 07 December 2004)
http://www.msss.com/mars_images/moc/2004/12/07/
Memnonia Sulci Yardangs (Released 08 December 2004)
http://www.msss.com/mars_images/moc/2004/12/08/
All of the Mars Global Surveyor images
http://www.msss.com/mars_images/moc/index.html.
All of the THEMIS images are archived at http://themis.la.asu.edu/latest.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.
HiRISE will produce ultra-sharp photographs over 6 kilometer (3.5 mile)
swaths of the martian landscape with a best imaging at 25 centimeters (10
inches) per pixel, said Alfred S. McEwen of the UA's Lunar and Planetary
Laboratory, principal investigator for HiRISE.
"By combining a fine imaging scale (25 centimeters to 32 centimeters a pixel,
or 10 inches to 12.5 inches a pixel) and high signal-to-noise ratio, it is possible
to resolve features as small as one meter (about 40 inches) wide, a scale
currently well-studied only by landers," McEwen said. "HiRISE will get such
views over any selected region of Mars, providing a bridge between orbital
remote sensing and landed missions." Mission scientists will combine stereo
image pairs to produce detailed maps of the topography and combine images
taken with filters to produce false-color images.
HiRISE will study deposits and landforms created by geologic and climatic
processes, and it will help scientists assess future Mars mission landing sites.
(The next Mars lander will be NASA's first Scout mission, called "Phoenix,"
scheduled for launch in 2007. Peter Smith of UA's Lunar and Planetary Lab
heads the Phoenix mission, the first mission to Mars being led by an academic
institution.)
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
"Ball Aerospace has done a fantastic job building an instrument that meets our
challenging performance requirements," McEwen said. "The HiRISE camera
can collect the equivalent of about a thousand megapixel images in just three
seconds."
12
HiRISE co-investigators are:
Candice Hansen, Jet Propulsion Laboratory, deputy principal investigator
Alan Delamere, Delamere Support Systems Eric Eliason, UA
Virginia Gulick, NASA Ames/SETI Institute
Ken Herkenhoff, USGS Flagstaff
Nathan Bridges, Jet Propulsion Laboratory
Nick Thomas, University of Bern (Switzerland)
Randolph Kirk, USGS Flagstaff
John Grant, Smithsonian Institution
Laszlo Keszthelyi, USGS Flagstaff
Mike Mellon, University of Colorado
Steve Squyres, Cornell University
Cathy Weitz, Planetary Science Institute (Tucson)
The Mars Reconnaissance Orbiter scheduled for launch in August 2005 will
be captured in Mars orbit by a "Mars orbit insertion" maneuver in March
2006. Initially, the spacecraft will fly around Mars in a highly elliptical orbit.
The orbit will become more circular over the next several months by a
technique called "aerobraking." On each of its close swings by Mars in
elliptical orbit, the spacecraft is low enough that it skims the surface of Mars'
atmosphere, creating drag on the spacecraft. The orbiter's path around the
planet becomes more circular on each successive planet flyby. HiRISE will
begin taking photographs when the spacecraft is in a circular orbit, in
November 2006. The primary science mission is for two years, or slightly
more than a martian year. The orbiter can also serve as a telecommunications
relay link for landers launched to Mars in 2007 and 2009. Nominally, the
orbiter mission ends December 31, 2010.
Artist's conception of the Mars Reconnaissance Orbiter over the martian
landscape. Image credit: NASA/JPL.
"With the delivery of the HiRISE hardware, team activities now shift to the
UA and Lockheed Martin," McEwen said. "We'll do a series of flight-like
tests before the spacecraft gets shipped to Kennedy Space Center next spring."
In these operational readiness tests, data from the camera on the spacecraft at
Lockheed Martin will be sent to NASA's Jet Propulsion Laboratory in
Pasadena, CA, then to the HiRISE Operations Center (HiROC) on the UA
campus in Tucson.
"Rather than data coming down from the Deep Space Network, which will
happen once the spacecraft is actually orbiting Mars, we'll command HiRISE
as it sits in a clean room at Lockheed Martin," Eric Eliason said. Eliason
manages activities at HiROC, which is located in the Lunar and Planetary
Lab's Sonett Building.
A dozen people currently staff HiROC. That number will double when the
primary mission begins in 2006. Their tasks include writing command
software, planning observations, uplinking commands, downlinking data,
processing raw data into useful images and monitoring the instrument, Eliason
said.
Contacts:
Lori Stiles
UA News Services
Phone: 520-621-1877
Alfred S. McEwen
Cell phone: 520-270-0701
E-mail: [email protected]
Eric Eliason
Phone: 520-626-0764
E-mail: [email protected]
Related Web sites:
http://hirise.lpl.arizona.edu
http://mars.jpl.nasa.gov/mro/
http://uanews.org/science
Additional articles on this subject are available at:
http://www.spacedaily.com/news/mars-general-04z.html
http://spaceflightnow.com/news/n0412/07mro/
http://www.universetoday.com/am/publish/mro_camera_ready.html
End Marsbugs, Volume 11, Number 46.