Justified & Ancient
- Jan 28, 2002
Sweet, I swear I saw some simulacra faces in those devils. But, I see faces everywhere, and thats another story. Thanks for posting them pics.
The US space agency is celebrating as its robot rovers Spirit and Opportunity reach their second year of science operations on the surface of Mars.
First to land was Spirit, which touched down in the rocky basin of Gusev Crater at 0435 GMT on 4 January 2004.
Opportunity landed on 25 January, rolling into a small crater punched in the dark plains of Meridiani Planum, on the other side of the Red Planet.
The golf cart-sized vehicles were only supposed to survive for three months.
The missions are amongst Nasa's biggest successes of recent years. Both rovers succeeded in their main assignments: finding geological evidence that water once flowed on Mars.
"These rovers are living on borrowed time. We're so past warranty on them," said Steven Squyres of Cornell University, principal investigator for the missions.
Part of the reason for their continuing survival on the Red Planet are the whirlwinds that blow away the dust that builds up on the rovers' solar panels, restoring their ability to generate electricity.
Opportunity made the mission's first profound discovery - evidence that Meridiani Planum was repeatedly soaked by water in ancient times.
Its twin, Spirit, later found its own evidence that water also flowed through rocks at Gusev Crater. Last summer, it completed a daredevil climb to the summit of Husband Hill - as tall as the Statue of Liberty - despite fears that it might not survive the harsh weather.
"When we first took a look around after landing the 'Columbia Hills' seemed impossibly far away," Professor Squyres explained.
"Given its longer life, though, Spirit reached them and became the first explorer to climb a mountain on another planet. 'Husband Hill' is about as tall as the Statue of Liberty, but for a little rover, that was a heck of a climb."
A panoramic image sent back by Opportunity of the crater it settled in after touching down on Mars revealed an outcrop of layered rock. This Martian bedrock was the first of many it would encounter while exploring Meridiani and which would prove crucial to elucidating the history of liquid water on Mars.
Distinct layering in some rocks (called "crossbedding") left ripple-like curves in some rock outcrops at Meridiani. Curious bead-like objects dubbed "blueberries", turned out to be rich in haematite, a mineral that often forms in water.
More recently, a rock was found in which the chemistry indicated the presence of sodium chloride (table salt), which only forms when water has been present.
"The area was soaked, over and over. First, there was the water from which sulfate salt precipitated," said Joy Crisp, Mars rover project scientist.
"Then, for the rocks at the top of craters, there was water that flowed along, transported and broke down pieces of rock, then deposited it layer by layer. Then, there was water that came and soaked the ground in perhaps several episodes."
Both rovers are now showing signs of wear, but no one can predict how long the pair will continue to last on Mars. Mission scientists are still thinking of new destinations to send the robots.
Spirit could soon be headed to rugged terrain south of the Columbia Hills known as "the promised land".
Opportunity is travelling towards a huge, distant depression nicknamed "Victoria Crater" which is 800m (half a mile) in diameter.
"Victoria is a potential 'time tunnel' allowing access to ancient martian material that otherwise would be buried deep beneath the surface and inaccessible," said John Callas, rover deputy project manager.
"The great adventure continues, and both rovers look forward to starting a second martian year of discovery."
ASU Professors of geological sciences L. Paul Knauth and Donald Burt think meteorites, rather than lakes, created the rock formations discovered by NASA's Opportunity rover.
"What we've done is thrown out an alternative that we think is simpler," Knauth said. "A controversy has developed now."
Knauth and Burt's hypothesis does not completely dismiss the idea that water once flowed on Mars. Rather, it implies NASA should search for signs of life in other Martian formations, Knauth said.
NASA scientists initially speculated that sedimentary layers seen in photos taken by the Opportunity and Spirit rovers were formed by evaporating water.
"NASA's Opportunity rover has demonstrated some rocks on Mars probably formed as deposits at the bottom of a body of gently flowing saltwater," a NASA press release announced in March 2004, three months after Opportunity's landing.
But when Knauth and Burt stumbled across these photos on the Internet, they noticed the Martian rocks resembled formations on Earth that were caused by surge impacts, not water.
If the sedimentary layers on Mars were formed by evaporating water, they would look similar to the Grand Canyon, Knauth said.
But the Martian sedimentary layers create what's called a cross-bedding pattern, a feature that occurs when a major impact creates a cloud of debris.
"The layering is a dead ringer for a base surge," Knauth said.
Also, if water had caused the layered patterns, then salts within the rock would have been grouped by solubility, similar to how a bathtub ring is formed.
That wasn't the case in the Martian sedimentary rock, which featured salts of differing solubilities mixed together.
"You don't get that in an evaporating lake," Knauth said.
The Opportunity landing site also featured small BB-like spheres that could have originated from a surge impact.
Burt said these formations occur when a meteorite hits and debris explodes into a cloud.
As both debris and steam condense within that cloud, small uniform spheres that rain down like hail stones are formed.
Knauth and Burt compared NASA's Mars findings and photos to their research on terrestrial surge impacts.
They also contrasted Martian features with those they've studied in Arizona, including the Grand Canyon, Meteor Crater and Tempe's Hayden Butte or "A" Mountain.
They said that while they can't be sure their hypothesis is correct, they believe it is the simplest explanation of the sedimentary layers.
Knauth and Burt suggested NASA search for life in fractures filled with mineral growth.
Those areas, Knauth said, should have trapped any microbes that survived meteorite impacts.
Getting a rover to these fractures, however, might be difficult because the terrain tends to be unsuitable for a gentle landing.
NASA landed both the Spirit and Opportunity rovers in flat areas.
"It's like trying to look at rocks in the middle of Iowa instead of the Grand Canyon," Burt said.
Knauth and Burt published their hypothesis in Nature magazine last month.
http://www.spacedaily.com/reports/Impac ... s_Say.html
Mars Express, the spacecraft launched by the European Space Agency into a near Martian orbit, will have been in business for two years in January 2006. This project - the successor to Russia's Mars-96 - has been a major achievement of European and Russian planetary science.
The craft carries seven scientific instruments to do research similar to the Mars-96 program, and even uses spare OMEGA (Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activite) spectrometers designed for the Russian station to obtain stereoscopic images of the planet's surface. European Union scientists are in charge of all experiments on Mars Express. Russian researchers are taking part officially in six experiments and enjoy equal rights with their European colleagues, to the scientific findings.
The measurements carried out by instruments jointly developed by Russian and West European scientists have produced some important results, with many of them now being prepared for publication.
Mars' atmospheric structure has now been established with a high degree of precision from surface to altitudes of between 100 and 150 kilometers, and its temperature profile up to 50-55 kilometers.
For the first time we now have data on water vapor and ozone present in the atmosphere, and maps showing their distribution.
A new discovery is the night glow of nitrogen monoxide, known to exist on Venus, but never observed on Mars until now. Tiny aerosol particles filling the planet's atmosphere up to altitudes of 70-100 kilometers have been detected.
For the first time water ice has been discovered in the southern polar cap at the end of Martian summers. Maps compiled from OMEGA data, with a resolution of 1 to 3 kilometers, show patches of water ice near the fringes of more extensive areas of frozen carbon dioxide. Its thickness does not exceed several meters, and underneath is a deep-buried layer of water ice, possibly equivalent in amount to the northern polar cap, which is entirely made up of water ice with a small percentage (less than 1%) of dust.
The OMEGA instrument has also completed mineralogical mapping of most of the planet and, for all the variety of minerals present, has failed to detect carbonates (salts of the carbonic acid). They are widespread on Earth and it is their deposits rather than living matter, coal and oil, that concentrate the principal quantity of carbon on this planet. So Mars Express findings do not confirm the presence of CO2 on Mars sufficient to significantly alter the mass of its atmosphere, and, accordingly, change the planet's climate.
One of the important results has been the discovery of methane in the Martian atmosphere, following a long and futile search. Its content was determined at 105 parts per billion. Of course, this is a very small amount, but since the methane keeps disintegrating in the atmosphere, due to photo-dissociation, there has to be a source producing something like 300 tons of methane a year, to keep up the balance in the Martian atmosphere. Such a source could be tectonic activity.
At present Mars is considered tectonically inactive, but the methane in its atmosphere may be due to "point" tectonics: residual volcanism or geothermal activity.
Nevertheless, developed specially to look for such "hot spots," an infra-red radiometer installed on the American Mars Odyssey spacecraft has not yet detected any.
The comets and meteorites falling on Mars can yield only 2-4% of the methane required. So even the most exotic theories cannot be ruled out, including the existence of the cryosphere on the lower border - that is, at a depth of two kilometers, of gasohydrate deposits, and even of methane-generating bacteria, similar to the ones detected in the Earth's deep-lying ecosystems.
Are these highly interesting facts only good to fuel human curiosity, or do they have any practical application?
There is a link between planetary science and Earth sciences - an inter-disciplinary field called comparative planetology. Its essence is that various processes in the atmospheres of Venus and Mars, and on a number of other planets, can be interpreted in terms of terrestrial processes.
In fact, a history of this planet's climate is directly recorded in the geological chronicles of sedimentary rocks, providing a picture of habitation on Earth and its changes up to the moment life appeared on the planet. But even this highly valuable information is often hard to interpret in a simple and straightforward way. Data about the other planets help to decipher the Earth's geological record.
Similarities to other planets help to glimpse not only the past but also the future of the Earth, and to understand how stable our planet's climatic system is. Is it true that an increase in man-generated carbon dioxide in the atmosphere threatens to alter the conditions of habitat? Can slight changes in temperature caused by the increased content of CO2 result in an irreversible build-up of water vapor in the atmosphere and a greenhouse disaster?
Here instrument-based space research on other planets can be helpful, too. Their atmospheres and climatic systems are an excellent bench mark to test all kinds of theories and models of the Earth's future - often advanced on disparate conclusions and with many assumptions. With no biospheric factor to take into account, the climatic systems of other planets are much simpler and easier to describe, and model in quantitative terms, and can provide a sort of natural reference.
http://www.spacedaily.com/reports/Celeb ... eries.html
Published online: 27 January 2006;
Red planet under fire in proposed mission.
Scientists have had a smashing idea that could help them explore beneath Mars's dusty surface. Slamming a hefty chunk of copper into the planet should excavate enough material to reveal water ice or carbon-based chemicals lurking underground, according to a proposed NASA mission.
The idea follows the success of Deep Impact, a mission that fired a copper 'impactor' into comet Tempel 1, while its delivery craft recorded the whole show with an array of sensors (see 'Deep Impact: sifting through the debris').
The new mission takes exactly the same approach to Mars. Called THOR (Tracing Habitability, Organics and Resources), it would be the second of NASA's Mars scout missions, low-cost probes that are designed and built in just a few years. The first scout, Phoenix, is due to launch in August 2007.
THOR has been proposed by Phil Christensen, a planetary scientist at Arizona State University, Tempe, and David Spencer of the Jet Propulsion Laboratory in Pasadena, California.
Christensen estimates that the impactor should be about 100 kilograms or so, and hit the planet at more than 15,000 kilometres per hour. It is hoped this would make a crater roughly 50 metres in diameter, and up to 25 metres deep.
Meanwhile, its mother ship would look for ice, minerals and organic compounds thrown out by the crash.
A cunning plan
Christensen admits that it is a simple enough approach. "I guess there'll be a lot of people out there going, 'Why didn't I think of that'," laughs Christensen. But that simplicity should help to ensure the mission's success, he adds.
Keeping two rovers running around on Mars is a tremendous feat of engineering, but sending something that can burrow or drill is even more challenging, Christensen points out.
Moreover, exploring icy parts of the surface by rover carries the risk that a robot may accidentally seed a site with earthly life. Such a craft could generate enough heat to melt the ice, providing a miniature habitat for microbes.
An explosion of copper is so violent that it neatly avoids that risk, explains Christensen: "It's completely self-sterilizing."
The two investigators have a good track record for similar missions. Christensen already has four scientific instruments on or around Mars, and Spencer was mission manager for Deep Impact. Together they think they have a good shot at winning the go-ahead for their proposal. NASA scout missions are selected from a large pool of ideas in a knockout competition.
"We've made it through the first couple of rounds," says Christensen. This summer he and Spencer will go up against about 15 other proposals, after which three or four will be worked up into detailed mission plans. If THOR gets the nod, they plan to launch in 2011.
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Story from [email protected]:
Space rock re-opens Mars debate
By Paul Rincon
BBC News science reporter
Dendritic material in the Nakhla meteorite, LPSC paper
Dendritic material in the Nakhla meteorite is rich in carbon
A carbon-rich substance found filling tiny cracks within a Martian meteorite could boost the idea that life once existed on the Red Planet.
The material resembles that found in fractures, or "veins", apparently etched by microbes in volcanic glass from the Earth's ocean floor.
The evidence comes from a meteorite held in London's Natural History Museum that was cracked open by curators.
All the processes of life on Earth are based on the element carbon.
Proving carbon in Martian meteorites is indigenous - and not contamination from Earth - is crucial to the question of whether life once arose on the Red Planet.
We don't exactly know what it means yet, but it's all over the thin sections of the Nakhla material
Kathy Thomas-Keprta, Lockheed Martin
Initial measurements support the idea that the "carbonaceous material" is not contamination, the scientists say.
Details will be presented at the Lunar and Planetary Science Conference in Houston, Texas, next month. The research team includes scientists who brought evidence for microbial life in another Martian meteorite, ALH84001, to the world's attention in 1998.
The Martian meteorites are an extremely rare class of rocks. They are all believed to have been blasted off the surface of the Red Planet by huge impacts; the material would have drifted through space for millions of years before falling to Earth.
The latest data comes from examination of a piece of the famous Nakhla meteorite which came down in Egypt, in 1911, breaking up into many fragments.
London's Natural History Museum, which holds several intact chunks of the meteorite, agreed to break one open, providing the researchers with fresh samples.
"It gives people a degree of confidence this had never been exposed to the museum environment," said co-author Colin Pillinger of the UK's Open University.
"I think it's too early to say how [the carbonaceous material] got there... the important thing is that people are always arguing with fallen meteorites that this is something that got in there after it fell to Earth.
"I think we can dismiss that. There's no way a solid piece of carbon got inside a meteorite."
Analysis of the interior revealed channels and pores filled with a complex mixture of carbon compounds. Some of this forms a dark, branching - or dendritic - material when seen under the microscope.
"It's really interesting material. We don't exactly know what it means yet, but it's all over the thin sections of the Nakhla material," said co-author Kathie Thomas Keprta, of Lockheed Martin Corporation in Houston, Texas.
Previous studies of the forms - or isotopes - of carbon in the Nakhla meteorite found a component of which more than 75% is lacking any carbon-14.
Since all terrestrial life forms contain some carbon-14, this component was thought to be either indigenous carbon from Mars or ancient meteoritic carbon.
Professor Pillinger and colleagues are carrying out direct isotopic analysis of the carbonaceous material, but he admits terrestrial contamination is occurring when thin slices of the meteorite are made for analysis.
The same team brought claims about ALH84001 to the world's attention
However, the ratio of carbon to nitrogen in the epoxy used to prepare the thin sections is very different from that of the carbonaceous material in the meteorite's veins.
If it is indigenous to Mars, the authors say the "carbonaceous material" came either from another space rock that smashed into Mars hundreds of thousands of years ago, or a relic of microbial activity.
A resemblance between the material in the meteorite and features of microbial activity in volcanic glass from our planet's ocean floor further support the idea they are biological in origin, says the paper.
If this were the case, the remains of these organisms and their slimy coatings might provide the the carbon-rich material found in Nakhla, the researchers argue.
Peter Buseck, regent's professor of geological sciences at Arizona State University told the BBC News website that he found no strong evidence of a biological origin for the carbon in the meteorite.
He added that it was difficult to determine the origin of carbon in rocks based on microscopy.
The 37th Lunar and Planetary Science Conference runs from 13-17 March in Houston, Texas.
With Google's help, web surfers can now navigate from the plains of Meridiani to the Proctor Crater Dunes on Mars as though they were two local destinations.
Arizona State University's Mars Space Flight Facility and Google teamed up last summer to produce Google Mars (www.google.com/mars/), a mapping tool released Monday, which allows users to view and scroll across the surface of the Red Planet, visiting its many landmarks.
"The goal here is to bring Mars to the general public, to give them access to a tool that lets them explore Mars in the same way that Google Earth lets you explore the Earth," says Robert Burnham, spokesperson for the Mars Space Flight Facility in Tempe, Arizona, US.
More than 17,000 images from NASA's Mars Global Surveyor and Mars Odyssey orbiters fed the planet-spanning mosaic, which can be viewed as a colour-coded relief map showing surface elevation, a collage of optical images or as a product of infrared measurements. The software that allowed the individual images to be pieced together was written by Noel Gorelick from Arizona State University (ASU).
Users can see tagged features such as mountains, canyons, dunes, plains, ridges and craters on the Martian surface. Each tag comes with additional information such as coordinates, size, and date of discovery. And if a particular feature is named after a person or a place, there is information about its namesake.
The infrared map is pieced together from images taken by Mars Odyssey's Thermal Emission Imaging System (THEMIS) and includes details as small as 230 metres across. Cool spots on the surface appear in dark tones while warmer areas appear bright.
"Mars scientists the world over use THEMIS photos," says ASU planetary geologist Phil Christensen, principal investigator for the camera. "It's great that everyone everywhere can now explore this neighbour world using their own computer browser."
The infrared map also highlights four Martian areas that show even greater detail - the volcano Olympus Mons, the "Grand Canyon" of Mars Valles Marineris, and the landing sites of NASA's Spirit and Opportunity rovers.
The Jet Propulsion Laboratory's Digital Image Animation Laboratory used the Valles Marineris data, showing details just 100 metres across, to produce a new simulation, which was also released on Monday. Entitled "Flight Into Mariner Valley", it takes viewers on a virtual flight through the great chasm, revealing its impact craters, rocky spurs and carved out gullies.
The front right wheel of NASA's Spirit rover has stopped working – just as the approaching Martian winter means it is increasingly urgent that it gets to a northerly facing slope, to maximise the sunlight falling on its solar arrays.
"The wheel is not drawing any current at all," says Jacob Matijevic, engineering team chief for the rovers at the Jet Propulsion Laboratory in Pasadena, California, US.
It is not the first time a problem has struck Spirit's front right wheel. The same wheel acted up about five months after the rover landed on Mars on 4 January 2004. As the rover neared the Columbia Hills, the troublesome wheel's motor began drawing about twice as much electrical current as each of the vehicle's other five wheels.
Mission planners then switched to driving the rover backwards to protect the wheel. Spirit also had fewer driving days when in the hills. After this spell, the wheel started working properly again – probably because the wheel's lubricant redistributed itself, helping the current to return to normal.
But now the wheel has completely stopped turning. On Spirit's 779th Martian day – called a sol and lasting 24 hours and 40 minutes – the motor that rotates the wheel broke down. Engineers say the "motor brushes" that provide power to the turning part of the motor may have lost contact.
13 million spins
Both Spirit and its twin, Opportunity, were originally designed to last just 90 sols on Mars. They are currently in their third extended mission and JPL says Spirit's wheels have turned more than 13 million times during the rover's long haul.
"It continues to be an exciting adventure with each day like a whole new mission," says John Callas, the new project manager for the rover mission from JPL. "Even though the rovers are well past their original design life, they still have plenty of capability to conduct outstanding science on Mars."
But for Spirit right now, the focus cannot be on gathering scientific data. Instead the team is focused on getting the rover to a good location to weather the coming Martian winter. Its solar panels are only producing about 350 watt-hours of electricity these days – only enough to power about an hour of driving. That is about 15% lower than it was just a month ago and is less than half the level when the rover first rolled onto the surface of Mars.
So Spirit, having finished studying the layered feature dubbed Home Plate, is now aiming to reach the northerly tilting slope of McCool Hill. There its solar arrays will soak up as much sunlight as they can during their second Martian winter.
Spirit will drive toward its new target backwards, dragging its broken wheel. With power and driving conditions in their compromised state, planners expect to drive the vehicle about 12 metres per day.
http://www.newscientistspace.com/articl ... ckons.html
NASA's Spirit rover has reached safety after weeks of scrambling with low power supplies to reach a place from which to weather the approaching Martian winter. The northern-tilting slope of the spot, dubbed Low Ridge Haven, will help maximise the sunlight reaching the rover's solar panels, ensuring its power stays above the minimum needed.
"We've got a safe rover," say principal investigator Steve Squyres. Spirit is now parked with about 11.5° of northerly tilt, towards the Sun. Squyres told New Scientist: "We're much, much safer than we've been in quite a while. That's huge news for us."
The original plan had been to direct Spirit to the slopes of McCool Hill. But along the way, the rover ran into what the team describes as "an impassable, sandy area" between two outcrops called Oberth and Korolev.
On Thursday 6 April, the rover's controllers instructed Spirit to divert and head toward Low Ridge Haven, less than 20 metres away. At that time, the rover was between 60 and 80 metres from McCool Hill.
Spirit has to be more careful about the terrain it tackles than in the past, thanks to a non-functioning right front wheel. The motor that rotates the wheel stopped working in mid-March, so the rover has been driving backwards, dragging the wheel behind it.
Spirit reached Low Ridge Haven over the weekend and as a result, the rover's power supply has been bumped up by as much as 20%, Squyres says. Science observations are just getting underway at the new site, but he says there are some "wonderful, finely-layered bedrock outcrops" there and it is likely the rover will remain there for the entire winter science campaign.
The science team has had to make some tough decisions about which observations to make and which to cut short as the rover hustled across the plains towards a northerly tilting slope. Squyres says Spirit had to leave the circular target dubbed Home Plate earlier than the science team would have liked. But he now says the outcrop at Low Ridge Haven "might be made of the same stuff".
And with the entire winter to study the feature, Squyres says the science team should not have to make further compromises: "We've had this imperative to drive, drive, drive for months. We've just been screaming around as fast as we can go. That got-to-keep-moving thing is over now. So now we can hunker down and really do science in depth."
http://www.newscientistspace.com/articl ... afety.html
Scientists using data from a European space probe orbiting Mars have produced new topographic maps of the Red Planet.
The "hiker's maps" provide detailed height contours and names of geological features on the Martian surface.
The European Space Agency (Esa), which compiled the maps, said it hoped the maps would become a standard reference for future research on the Red Planet.
The data, from the Mars Express spacecraft, has also been turned into 3-D models of the surface of Mars.
The topographic maps use contour lines to show the heights of the landscape.
The contour lines are superimposed upon high-resolution images of Mars, taken by the High-Resolution Stereo Camera (HRSC) aboard Mars Express.
The maps are much like those of Earth used by hikers and planning authorities.
The samples released by Esa show the Iani Chaos region of Mars because of its major topographical interest.
It is covered in individual blocks and hills that form a chaotic pattern across the landscape.
Mars Express entered orbit around the Red Planet in December 2003.
Water may have once flowed several kilometres beneath the surface of Mars in underground piping, according to new images of pipe-like fractures in bedrock taken by the most powerful camera in orbit around Mars.
Scientists have typically focused their hunt for signs of water on Mars on potential riverbeds, lakebeds and gullies. Now, these fractures could give planetary scientists a new place to look for signs of past water – and potentially life.
"These deeper underground areas may have been an oasis for any sort of biologic activity that may have been occurring," says Chris Okubo, a planetary scientist at the University of Arizona in Tucson, US.
The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter sees long, straight dark stripes on the walls of Candor Chasma, which is part of the giant canyon system Valles Marineris.
Underground aquiferThe stripes, about half a metre wide and as long as several kilometres, are cracks in the ground that may have formed from the weight of overlying rock that has since eroded away. An alternate explanation is that the fractures may have been caused by the faulting process that formed the 4000-kilometre-long Valles Marineris canyon.
Researchers believe the cracks were already there when a liquid – most likely water from an underground aquifer – flowed through them hundreds of millions to 1 billion years ago.
Evidence for the water comes from several observations. The cracks are flanked by light bands, called halos, between 5 and 10 metres wide.
Their light colour could be explained by bleaching. Acidic water flowing along the fractures would have stripped dark iron oxide minerals from the rock, making it lighter in colour.
Water oceans?Minerals in the water may also have been deposited in the rock, cementing the grains together and making them stronger and less vulnerable to erosion. This may explain why the halos are so well preserved while the surrounding rock has eroded over millions of years.
Previous observations have also found signs of water in Candor Chasma. In 2005, the Observatoire pour la Mineralogy, l'Eau, les Glaces et l'Activité (OMEGA) hyperspectral imager onboard Europe's Mars Express spacecraft spotted calcium-rich sulphates in that area.
These sulphates form in the presence of standing water over a long period, so in addition to an underground aquifer, water may have also existed in "oceans" on the surface (see Martian water clues go wider and deeper).
Since the initial images were taken, HiRISE has spotted extensive evidence for these kinds of features in layered rock elsewhere on the planet, primarily around Mars's equator.
Cemented togetherFor instance, it has seen fluid flow features in Victoria Crater just south of the equator (see photo above), where NASA's Opportunity rover is trudging along the rim (see Mars rover snaps panorama of yawning crater). The fractures appear to be surrounded by cemented rock on the eastern crater rim and floor.
One of NASA's goals for Opportunity is to get to that side of the crater. If it is able to get close enough, Opportunity might provide some microscopic observations of the rock to confirm whether the rock has been cemented together by fluid.
Okubo says that future spacecraft, such as NASA's Mars Science Laboratory, which is expected to head to the Red Planet in 2009, could land at some of the other layered deposits to get a closer look.
Since taking these images, HiRISE has actually experienced problems with its detectors, and managers are concerned that the problem could worsen (see Mars's top camera suffers worrying glitch).
http://space.newscientist.com/article/d ... -mars.html
New Maps Of Polar Caps Will Refine Martian Climate Models
Springtime on Mars: The images of Mars' north polar cap (left) were taken by NASA's Hubble Space Telescope (HST), while the maps at right were created from neutron spectroscopy data gathered by the Mars Odyssey spacecraft. The images and maps show the recession of the seasonal polar cap from early to late Spring. The maps reveal the thickness of surface carbon dioxide ice (dry ice), which decreases as the northern hemisphere is exposed to sunlight during the spring and summer. The images and maps extend from the pole to 50 degrees north latitude. (Image Credit: HST Images by JPL/NASA/STScI. Maps by Thomas Prettyman.)
by Staff Writers
Tucson AZ (SPX) Sep 17, 2009
Scientists from the Tucson-based Planetary Science Institute have created the first detailed maps that show the amount of dry ice (solid carbon dioxide) deposited in the polar regions of Mars. The maps reveal how the ice thickness varies with the seasons.
The maps were created from measurements taken by the Mars Odyssey neutron spectrometer, said PSI Senior Scientist Thomas H. Prettyman, who is the principal author of a paper on this work that was recently published in the Journal of Geophysical Research, "Characterization of Mars' Seasonal Caps Using Neutron Spectroscopy."
The spectroscopy data, gathered during two Martian years, allowed Prettyman and his colleagues to accurately determine the thickness of the Martian ice caps over time.
The amount of carbon dioxide ice at the poles varies in response to seasonal changes in sunlight, and about 25 percent of the atmosphere is cycled through the seasonal caps, Prettyman explained.
"We need a detailed understanding of the present atmosphere on Mars in order to answer fundamental questions about the planet's climate history, including whether conditions on Mars could have been suitable for life in the distant past," he explained.
The local thickness of the polar caps depends on several factors, such as the amount of solar energy absorbed by the surface and atmosphere and the flow of warm air from lower latitudes that accompanies carbon dioxide condensation at the poles, Prettyman said.
In the northern polar region, carbon dioxide deposition is skewed toward an area known as "Acidalia," Prettyman observed. Thicker carbon dioxide ice in that region may be caused by frigid winds coming from Chasma Boreale, a large canyon near the Martian north pole.
In the southern hemisphere, carbon dioxide ice accumulates more rapidly in a region known as the south polar residual cap, which is offset from the pole and contains perennial carbon dioxide ice deposits.
Prettyman and his colleagues concluded that the asymmetry in the south polar seasonal cap is caused primarily by variations in surface composition.
"The regions outside the residual cap consist of water ice mixed with rocks and soil that are warmed during summer," he said. "This delays the onset of carbon dioxide ice accumulation in the fall. In addition, heat stored in water-rich regions is gradually released during fall and winter, further limiting ice accumulation."
Prettyman and his colleagues also used neutron spectroscopy to determine how much non-condensable gas (argon and nitrogen) remains in the atmosphere at high latitudes as carbon dioxide condenses.
"We observed strong enrichment of non-condensable gas at the south pole during fall and winter," Prettyman said. "The observed time variation of the concentration of nitrogen and argon provides information about local circulation patterns. This includes the timing and strength of the polar winter vortex, a large-scale, cyclonic flow that inhibits mixing of nitrogen and argon with air from lower latitudes."
Accurate data on the thickness of carbon dioxide ice and its distribution, as well as data on seasonal concentrations of non-condensable gases, will allow scientists to refine Martian general circulation models, Prettyman said. This will give them a deeper understanding of atmospheric dynamics and the planet's climate change over time.
Neutron spectroscopy is key to determining carbon dioxide ice thickness during the long polar nights, Prettyman explained. "Unlike optical techniques, neutron spectroscopy does not require sunlight and can peer into the darkness, revealing details of the seasonal caps that have never been observed before," he said.
Prettyman, PSI Senior Scientist William Feldman, and Timothy Titus of the U.S. Geological Survey in Flagstaff, Ariz., conducted the research with funding provided by the NASA Mars Odyssey Participating Scientist Program. The neutron spectrometer is a subsystem of the gamma ray spectrometer instrument suite on Mars Odyssey.
Plasma Rocket Could Travel to Mars in 39 Days
October 6th, 2009 in Space & Earth / Space Exploration
In the VASIMR rocket, magnetic fields force the charged plasma out the back of the engine, producing thrust in the opposite direction. Image copyright: Ad Astra Rocket Company.
(PhysOrg.com) -- Last Wednesday, the Ad Astra Rocket Company tested what is currently the most powerful plasma rocket in the world. As the Webster, Texas, company announced, the VASIMR VX-200 engine ran at 201 kilowatts in a vacuum chamber, passing the 200-kilowatt mark for the first time. The test also marks the first time that a small-scale prototype of the company's VASIMR (Variable Specific Impulse Magnetoplasma Rocket) rocket engine has been demonstrated at full power.
"It's the most powerful plasma rocket in the world right now," says Franklin Chang-Diaz, former NASA astronaut and CEO of Ad Astra. The company has signed an agreement with NASA to test a 200-kilowatt VASIMR engine on the International Space Station (ISS) in 2013. The engine could provide periodic boosts to the ISS, which gradually drops in altitude due to atmospheric drag. ISS boosts are currently provided by spacecraft with conventional thrusters, which consume about 7.5 tonnes of propellant per year. By cutting this amount down to 0.3 tonnes, Chang-Diaz estimates that VASIMR could save NASA millions of dollars per year.
But Ad Astra has bigger plans for VASIMR, such as high-speed missions to Mars. A 10- to 20-megawatt VASIMR engine could propel human missions to Mars in just 39 days, whereas conventional rockets would take six months or more. The shorter the trip, the less time astronauts would be exposed to space radiation, which is a significant hurdle for Mars missions. VASIMR could also be adapted to handle the high payloads of robotic missions, though at slower speeds than lighter human missions.
Chang-Diaz has been working on the development of the VASIMR concept since 1979, before founding Ad Astra in 2005 to further develop the project. The technology uses radio waves to heat gases such as hydrogen, argon, and neon, creating hot plasma. Magnetic fields force the charged plasma out the back of the engine, producing thrust in the opposite direction. Due to the high velocity that this method achieves, less fuel is required than in conventional engines. In addition, VASIMR has no physical electrodes in contact with the plasma, prolonging the engine's lifetime and enabling a higher power density than in other designs.
More information: www.AdAstraRocket.com
Martian sheen: Life on the rocks
http://www.newscientist.com/article/mg2 ... rocks.html
* 12 February 2010 by Barry E. DiGregorio
WHEN NASA's Viking landers touched down on Mars, they were looking for signs of life. Instead, all their cameras showed was a dry, dusty - and entirely barren - landscape.
Or so it seemed. But what the 1976 Viking mission, and every subsequent one, saw was a scene littered with rocks coated with a dark, highly reflective sheen. That coating looks a lot like a substance known on Earth as "rock varnish", found in arid regions similar to those on Mars. The latest evidence hints that rock varnish is formed by bacteria. Could there be microbes on Mars making such material too?
Rock varnish has long been something of a mystery. It is typically just 1 to 2 micrometres thick, but can take a thousand years or more to grow, making it very hard to discover whether biological or purely chemical processes are responsible. If it is biological, though, the race will be on to discover whether the same thing has happened on Mars - and whether microbes still live there today.
If you go to Death Valley in California, you can find rock varnish covering entire desert pavements. Also known as desert varnish, it forms in many places around the globe, and despite its glacial growth rates, can cover vast areas. The smooth, high sheen, dark brown-to-black coating is mainly made up of clay particles, which bind the iron and manganese oxides that give the coating its mirror-like reflectivity. In the Khumbu region of Nepal, not far from Mount Everest, it has turned the boulders black. Halfway around the world, it enabled ancient peoples to create the Nazca Lines in the Peruvian desert. These giant, elaborate images - some over 200 metres across and created over 1000 years ago - were made by simply removing rows of varnished stones to exposing the lighter stones or soil beneath.
George Merrill coined the phrase desert varnish in 1898, while working for the US Geological Survey (USGS). No one really studied it, though, until 1954, when Charles Hunt showed that the veneer forms on many different rock types - meaning that it wasn't simply a chemical production from a certain kind of rock and prompting the first questions about where it might come from (Science, vol 120, p 183). Hunt went on to find rock varnish in humid regions, tropical rainforests and at high altitudes in the Alps and the Rocky mountains.
Theories on how rock varnish forms weren't long in coming - and, initially at least, biology didn't get a look-in. In 1958 Celeste Engel of the USGS and Robert Sharp from the California Institute of Technology explained it as a chemical weathering phenomenon similar to iron oxide stains - red/orange coatings arising when iron particles from the air collect on the surface of rocks and bind together when made wet by dew (Geological Society of America Bulletin, vol 69, p 487).
It made sense to think that rock varnish had a chemical origin, since many similar-looking coatings were already known to form chemically. Silica glaze, for example, is one of the most common coatings and forms when silicic acid carried in dust and dew condenses onto rock surfaces.
Everything changed, though, when people saw the internal structure of rock varnish. Electron microscopic images taken by Randal Perry and John Adams at the University of Washington in Seattle in 1978 revealed an intricate layer-cake pattern, with black strips of manganese oxides alternating with orange layers of clay and iron (Nature, vol 276, p 489). No other rock coating combines this microlayered mixture of clays and metal oxides.
The implications here were enormous. This microstructure looked strikingly similar to that of fossil stromatolites - layered rock-like structures formed by ancient microbes as they collected sediments from seawater to build themselves a home. Though they still grow today in some isolated spots, stromatolites were one of the first life forms on Earth, dominating the fossil record from 3.5 billion years ago until about 600 million years ago.
That meant rock varnish could have a biological origin, and a flurry of investigations ensued to find out which microbes were responsible. Backing up the idea was the fact that microbes developed the ability to make a manganese oxide coat early in their evolution, to protect themselves from the harsh UV rays of the young sun.
Manganese proved pivotal three years later, for Ronald Dorn at Arizona State University in Tempe and Theodore Oberlander of the University of California, Berkeley. They found what looked like the fossilised remains of a few budding bacteria within the manganese oxide layer. Manganese concentration peaked around them, suggesting these bacteria were involved in producing it.
Dorn and Oberlander then managed to isolate two manganese-depositing microbes, Metallogenium and Pedomicrobium, from the surface of varnish samples collected in California's Mojave desert. When they added these to sterilised chips of rock in test tubes, they were able to grow a thin manganese varnish in about six months. The findings were published under the title "Microbial Origin of Desert Varnish" (Science, vol 213, p 1245).
Anome_ said:I misread the title of that article as "Martin Sheen: Life on the Rocks", which seemed fitting given his history of substance abuse (and his younger son's better publicised problems).