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Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
Marsbugs: The Electronic Astrobiology Newsletter
Volume 11, Number 46, 13 December2004
Editor/Publisher: David J. Thomas, Ph.D., Science Division, LyonCollege, Batesville, Arkansas72503-2317, USA.
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, but individual author(s) retain the copyright of specific articles. Opinions expressed in this newsletter are those of the authors, and are not necessarily endorsed by the editor or by LyonCollege. E-mail subscriptions are free, and may be obtained by contacting the editor. Information concerning the scope of this newsletter, subscription formats and availability of back-issues is available at The editor does not condone "spamming" of subscribers. Readers would appreciate it if others would not send unsolicited e-mail using the Marsbugs mailing lists. Persons who have information that may be of interest to subscribers of Marsbugs should send that information to the editor.
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
Articles and News
Page 1PROOF POSITIVE: MARS ONCE HAD WATER, RESEARCHERS CONCLUDE
TexasA&MUniversity release
Page 2NASA SLEEP-WAKE SCHEDULING PROTOCOLS MAY NEED TO BE CHANGED, UNIVERSITY OF PITTSBURGH RESEARCH SHOWS
University of PittsburghMedicalCenter release
Page 2ON TOP OF TITAN'S MOUNTAIN
By Leslie Mullen
Page 3HUNTER OF ALIEN WORLDS SPEAKS AT CORNELLUNIVERSITY
By Larry Klaes
Page 4SPACE COOKING: FEEDING ASTRONAUTS ON MARS-BOUND MISSIONS
By Tariq Malik
Page 4SPITZER AND HUBBLE CAPTURE EVOLVING PLANETARY SYSTEMS
NASA/JPL release 2004-285
Page 5PROMETHEUS PRE-EMPTED? NEW NUCLEAR FISSION MISSIONS EVALUATED
By Leonard David
Page 5MARS LIFE: TROUBLE WITHOUT THE RUBBLE?
By David Noever
Page 6LIFE-SWAPPING SCENARIOS FOR EARTH AND MARS
By Leonard David
Announcements
Page 7LIFTOFF 2005 EXPERIENCE FOR TEACHERS
By Margaret Baguio
Mission Reports
Page 7CASSINI-HUYGENS UPDATES
NASA/ESA releases
Page 10MARS EXPRESS: THE CHANNELS OF REULL VALLIS
ESA release
Page 11MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
Page 11MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
Page 11MARS RECONNAISSANCE ORBITER: ULTRA-SHARP, MARS-BOUND HIRISE CAMERA DELIVERED TODAY
By Lori Stiles
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
1
Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 46, 13 December 2004
PROOF POSITIVE: MARS ONCE HAD WATER, RESEARCHERS CONCLUDE
TexasA&MUniversity release
3 December 2004
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 TexasA&MUniversity'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,' 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.
"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."
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 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:
Read the original news release at
Additional articles on this subject are available at:
NASA SLEEP-WAKE SCHEDULING PROTOCOLS MAY NEED TO BE CHANGED, UNIVERSITY OF PITTSBURGH RESEARCH SHOWS
University of PittsburghMedicalCenter 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 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-hourphase delays without incurring any negative consequences as far as sleep qualityand alertness," said Dr. Monk. "However, based on the findings from thisexperiment, 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 themfor alertness, mood and core body temperature—the best standard for assessingcircadian rhythms. At the same time they recorded their sleep to assess itsduration and quality. The experiment involved a series of nine repeated two-hourdelays in bedtime.
During the study Dr. Monk and his colleagues found that the circadian pacemakerdid adjust itself—but only by about one hour per night rather than the two hoursrequired by NASA's protocol. Because of that, subjects eventually experienced amassive flattening in the amplitude of their circadian temperature rhythmindicating that the biological clock was not doing its job properly. This led tosignificant disruptions in sleep and lowered alertness while awake. More research needs to be done before scientists can advise NASA on how tochange its guidelines.
"There is always some cost to performing tasks when we expect to be asleep, butby the end of the series of experiments, of which this is the first part, we shall beable to advise NASA which approach—gradual delays, gradual advances, all atonce—will lead to the least disruption of an astronaut's sleep and alertness," saidDr. 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 researchsupport.
An additional article on this subject is available at
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.
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.
Scientists would like to know the origin of the atmospheric patches imaged on Titan. Image credit: Hubble Space Telescope/UA Smith.
AM: Do we know what these bright and dark patches are?
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.
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.
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.