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By Lisa Chu-Theilbar,
Science Communications
SETI Institute
People interested in Mars exploration, like many of the scientists at the Carl Sagan Center (CSC) in Mountain View California, often start by exploring cold, dry, thin aired Mars-like “analogue” sites on earth. Most of these places are isolated and hard to reach. Antarctica, the Arctic, the Peruvian Andes, Kamchatka and other exotic locales offer scientists glimpses into the kinds of environments that may hold clues to understanding Mars and the processes that have shaped it. Of key interest is the extreme or unusual conditions under which life persists. We know that everywhere on earth where we find liquid water, we find life, but what are the limits? How cold, how hot, how high, how deep, can life be and still survive? Temperature, pressure, gravity, pH, salinity, radiation, available nutrients and more all represent parameters that can influence an environment and its ability to sustain life, so areas where these parameters are extreme can be very informative.
One adventurous CSC planetary geologist has found a spot with intriguing potential right here in Northern California. Her name is Dr. Jen Blank and she studies the rocks and streams of Del Puerto Canyon, not far from San Jose, for clues to life on Mars.
A savvy geologist learns much just from looking at a rock. Quickly revealed is much about how the rock was formed, whether at great pressure deep within the earth or by sedimentary processes in an ancient ocean, for example. In the case of Del Puerto Canyon, the area was once ocean crust that has been heaved up on to the continent after experiencing great tension and pressure. Such areas, referred to by geologist as “ophiolites” are relatively rare on earth and are characterized by high concentrations of magnesium and iron. In the rest of the solar system however these “mafic” (ma for magnesium and “fic” for iron) rocks are believed to be typical of rock types that have reacted with water. The rocks in Del Puerto Canyon tend to be twisted, broken and reformed, held together by “cements”, the fine-grained minerals which bind the coarser-grained matrix in some of the area’s most interesting rocks. The tectonic forces that pushed these rocks to the surface have stressed, squeezed and shattered the rocks, leaving them altered chemically, and twisted, broken, and reformed. During these transformations, hot water percolated through the fractures, transporting and depositing fine-grained minerals to form an interconnected lattice of white-colored veins. In addition, cool waters are continually leaking from the rocks. The waters are believed to be a mixture of the rock-derived fluids and rain water that has penetrated down through the cracks. The water drains to the low areas, forming intermittent creeks and streams that disappear during the hottest summer months. The stream bottoms are lined with a primitive pavement of cemented carbonate material formed around pebbles and cobbles. Put all this together and it becomes a very interesting Mars analogue site.
Del Puerto Canyon’s low flowing, seeping springs and streams are particularly interesting to a Mars analogue scientist. First, they are alkaline, rather than the usual neutral or even acidic pH found in the hotsprings and iron rich rivers that are typically studied by Mars scientists. These seeping springs are host to a rich microbial ecosystem of free-floating bacteria, biofilms, and microbial mats. Microbial mats are often studied but are more common in warm, salty water, where they reach thicknesses of more than a meter and form masses called stromatolites, likely candidates for earth’s oldest life forms.
When bacteria form into layers, different chemistries result, ranging from photosynthesizing bacteria on the surface layers to anaerobic sulfur dependent layers buried where no sunlight reaches. The Del Puerto biofilms are less than a millimeter thick and appear in a range of colors from bright yellow and red to dark brown. They appear on rock surfaces above and below the stream’s water level. The microbial mats are thin, only a few millimeters thick, with a distinct structure, leathery to the touch, and those associated with the streams borders appear to be growing in direct contact with the cements. While typical warm salt water stromatolite colonies appear to be fueled by solar radiation, Dr. Blank believes that the leathery Del Puerto canyon mats may be fueled by the mineral energy derived from the slow drain of the springs over the surrounding mineralogy and represent an extreme that pushes our understanding of the limits of life.
Many scientists distrust coincidences and Dr. Blank is no exception. Her chosen area of study has an intriguing geology with unusual mineralogy and chemistry. In conjunction with this is a fairly unique biological ecosystem. Could this be a coincidence or is it more likely cause and effect? Where we find fresh water microbial mats growing in conjunction with mineral cements of a given chemistry, perhaps they influence or even shape one another. Could the cements of Del Puerto Canyon represent a biomarker? Find those distinctive cements in Mars rocks and maybe, just maybe, there was once life nearby.
Friday, March 30, 2007
First Steps To Mars
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by Patrick Barry for Science@NASA
Huntsville AL (SPX) Mar 29, 2007
The landing site is unknown. The rockets are still on the drawing board. Some of the astronauts haven't even been born yet. Never mind all that. NASA's journey to Mars has already begun.
The first steps are being taken onboard the International Space Station (ISS). "Astronauts are stationed on the ISS for six months at a time," says Dr. Clarence Sams, lead scientist for the ISS Medical Project at NASA's Johnson Space Center (JSC).
"Coincidentally, that's about how long it takes to travel to Mars. We can't simulate every aspect of a 50 million mile journey to Mars," he says, "but there are many questions we can answer from low Earth orbit."
For example, what happens to food and medicine exposed to six-plus months of space travel?
Curiously, food kept in orbit seems to lose some of its nutritional impact. Post-flight tests run on astronauts show that "blood and urine markers of nutritional status didn't match expected levels of nutrients in space foods," reports Dr. Scott Smith, head JSC's Nutritional Biochemistry Laboratory.
Furthermore, researchers at JSC's Pharmacotherapeutics Laboratory noticed that some medicines returned from orbit had lost their potency.
This could be a sign of radiation at work: high-speed particles of space radiation occasionally smash into nutrient or medicine molecules, perhaps damaging those molecules and preventing them from functioning properly. So far, though, it's speculation. Neither the cause of the food and medicine breakdown nor how much breakdown is occurring is yet known, say the researchers.
"We may have to come up with a plan for protecting our supplies," continues Sams. "How fast do food and medicines degrade? Are we going to have to put supplies in a radiation-shielded area for the entire trip?"
To help answer these questions, an experiment running on the ISS called Stability of Pharmacotherapeutic and Nutritional Compounds places three identical sets of food and medicine on the station. One will be returned to Earth after 6 months, the second after 12 months, and the third after 18.
That way Scott M. Smith and Lakshmi Putcha, principal investigators for the project at JSC, can figure out the rate at which the foods and medicines lose their potency. This information is important because food and medicines must survive not just the six-month trip to Mars, but the full 3 years of a Mars mission.
Exposure times might even be longer if mission planners decide to send cargo capsules filled with stashes of food and medicine to Mars before the crew leaves Earth.
Other experiments on the ISS examine the bodies of the crew themselves, requiring them to take blood and saliva samples and sonograms while aboard the station.
"There is already quite a bit of data from shuttle flights and such, but you must understand, a lot of the measurements of the past were made pre-flight and post-flight. [We] need to know what's going on in between, during the mission," Sams explains.
For example, it's well known that people lose bone and muscle mass while in weightlessness. But scientists still don't know how that loss progresses while an astronaut is in space. Is there an initial, rapid loss as the body adjusts to being in space, followed by a plateau? Or is it a steady, relentless decline? When planning on being away from Earth's gravity for 3 years or more, these questions become important.
Other questions -- such as how the body reacts to the partial gravity of the Moon or Mars -- will have to wait until NASA sends astronauts back to the Moon in the coming decade. Meanwhile, says Sams, the ISS is an excellent place to start.
by Patrick Barry for Science@NASA
Huntsville AL (SPX) Mar 29, 2007
The landing site is unknown. The rockets are still on the drawing board. Some of the astronauts haven't even been born yet. Never mind all that. NASA's journey to Mars has already begun.
The first steps are being taken onboard the International Space Station (ISS). "Astronauts are stationed on the ISS for six months at a time," says Dr. Clarence Sams, lead scientist for the ISS Medical Project at NASA's Johnson Space Center (JSC).
"Coincidentally, that's about how long it takes to travel to Mars. We can't simulate every aspect of a 50 million mile journey to Mars," he says, "but there are many questions we can answer from low Earth orbit."
For example, what happens to food and medicine exposed to six-plus months of space travel?
Curiously, food kept in orbit seems to lose some of its nutritional impact. Post-flight tests run on astronauts show that "blood and urine markers of nutritional status didn't match expected levels of nutrients in space foods," reports Dr. Scott Smith, head JSC's Nutritional Biochemistry Laboratory.
Furthermore, researchers at JSC's Pharmacotherapeutics Laboratory noticed that some medicines returned from orbit had lost their potency.
This could be a sign of radiation at work: high-speed particles of space radiation occasionally smash into nutrient or medicine molecules, perhaps damaging those molecules and preventing them from functioning properly. So far, though, it's speculation. Neither the cause of the food and medicine breakdown nor how much breakdown is occurring is yet known, say the researchers.
"We may have to come up with a plan for protecting our supplies," continues Sams. "How fast do food and medicines degrade? Are we going to have to put supplies in a radiation-shielded area for the entire trip?"
To help answer these questions, an experiment running on the ISS called Stability of Pharmacotherapeutic and Nutritional Compounds places three identical sets of food and medicine on the station. One will be returned to Earth after 6 months, the second after 12 months, and the third after 18.
That way Scott M. Smith and Lakshmi Putcha, principal investigators for the project at JSC, can figure out the rate at which the foods and medicines lose their potency. This information is important because food and medicines must survive not just the six-month trip to Mars, but the full 3 years of a Mars mission.
Exposure times might even be longer if mission planners decide to send cargo capsules filled with stashes of food and medicine to Mars before the crew leaves Earth.
Other experiments on the ISS examine the bodies of the crew themselves, requiring them to take blood and saliva samples and sonograms while aboard the station.
"There is already quite a bit of data from shuttle flights and such, but you must understand, a lot of the measurements of the past were made pre-flight and post-flight. [We] need to know what's going on in between, during the mission," Sams explains.
For example, it's well known that people lose bone and muscle mass while in weightlessness. But scientists still don't know how that loss progresses while an astronaut is in space. Is there an initial, rapid loss as the body adjusts to being in space, followed by a plateau? Or is it a steady, relentless decline? When planning on being away from Earth's gravity for 3 years or more, these questions become important.
Other questions -- such as how the body reacts to the partial gravity of the Moon or Mars -- will have to wait until NASA sends astronauts back to the Moon in the coming decade. Meanwhile, says Sams, the ISS is an excellent place to start.
Sunday, March 11, 2007
Seeking life on Europa...
As NASA develops its next "flagship" mission to the outer solar system, Jupiter's enigmatic moon Europa should be the target, says Arizona State University professor Ronald Greeley. Although Europa lies five times farther from the Sun than Earth, he notes it may offer a home for life.Greeley, a Regents' Professor, heads the Planetary Geology Group in ASU's School of Earth and Space Exploration. He presented the Europa proposal on Feb. 18 at the annual meeting of the American Association for the Advancement of Science in San Francisco."Europa is unique in our solar system," says Greeley. "It's a rocky object a little smaller than our Moon, and it's covered with a layer of water 100 miles deep." This holds more water than all the oceans on Earth, he explains. Greeley adds that Europa also has the two other basic ingredients of life -- organic chemistry and a source of energy. Scientists have identified four candidate worlds beyond Earth that might contain life, either now or in the past, Greeley says. These four are Mars, Saturn's moons Titan and Enceladus, and Jupiter's moon Europa. Mars is the target of numerous ongoing missions, and NASA's Cassini spacecraft is studying both Titan and Enceladus at present. Cassini's results, however, show that Titan and Enceladus have temperatures hundreds of degrees Fahrenheit below zero and may not hold any liquid water.
NASA's Galileo mission surveyed Europa in the late 1990s. Greeley notes the mission found that Europa's surface ice was mixed with organic minerals that came up from the solid rocky part of the moon or were deposited by meteorite and comet impacts at the surface. Yet Galileo's results raised more questions than answers."We know Europa's surface is frozen," Greeley says. "But we don't know if it's frozen all the way down, or if there's an ocean under an ice shell."The ice thickness is a key question, notes Greeley."Ultimately, we want to get down through that ice shell and into the ocean where any action is," he says. "So it matters whether the ice is 10 yards thick, or 10 miles or more. The data we have today will never answer that question."
NASA's Galileo mission surveyed Europa in the late 1990s. Greeley notes the mission found that Europa's surface ice was mixed with organic minerals that came up from the solid rocky part of the moon or were deposited by meteorite and comet impacts at the surface. Yet Galileo's results raised more questions than answers."We know Europa's surface is frozen," Greeley says. "But we don't know if it's frozen all the way down, or if there's an ocean under an ice shell."The ice thickness is a key question, notes Greeley."Ultimately, we want to get down through that ice shell and into the ocean where any action is," he says. "So it matters whether the ice is 10 yards thick, or 10 miles or more. The data we have today will never answer that question."
Can We Colonize Titan in the Future?
Scientists from all over the world are trying to find another Earth in the endless universe.
Researchers like Robert Zubrin have developed plans to make other planets like Mars inhabitable.
About Titan
Titan is the largest moon of Saturn and the second largest moon in the solar system after Jupiter’s Ganymede. Titan is about 50% larger than our own moon and is also larger than planet Mercury. Titan is also the only moon in the soar system with a dense atmosphere that is even denser than that at Earth. Considering 0.376g Gravity on Mars we can say that in this case Titan doesn’t have much for us as it is having a gravity of 0.14g. Though it is much less than that on Earth yet it is enough to keep humans on the ground.
With so much to offer for the humans still the question remains that can Titan support life…?
Studies have demonstrated that the most important and advantageous target in the solar system for colonization is Titan.
Why Titan?
Titan has an abundant supply of raw materials that are necessary for life. Robert Zubrin has also stated that Titan is the most hospitable extraterrestrial world within our solar system for colonization.
Titan’s atmosphere contains plenty of nitrogen and methane. There is also strong evidence that the liquid methane and liquid water are present under the surface of Titan which are often delivered to the surface by a volcanic activity.
This water can easily be used to generate oxygen. Water and Methane can also be easily converted into rocket fuel which can be used for a power supply. All these gases that are Methane, Nitrogen and ammonia can also be used as a fertilizer for growing food.
Moreover the atmospheric pressure of Titan is the same as five meters underwater. This will reduce the difficulty and complexity of engineering that is required for landing a craft when compared to that in case of almost zero pressure planet like Mars.
This thick atmosphere will also act as a protective shield for solar radiation which can have serious medical problems in humans.
Now let us consider the average surface temperature of Titan. Here is where we start to have some problems. Since Titan is about 1.4 billion km from sun its surface temperature is about -179-degrees Celsius. This means that we should be having effective heat generation and insulation techniques available before we try and land on Titan.
Why is Titan a much better choice than Mars?
Both Titan and Mars are thought to be the places that can be made inhabitable. But still Titan is a much better choice. The reasons for this are:
• Titan has a dense atmosphere that is about 1.5 times thicker than that on Earth. On the other hand Mars is having no atmosphere and will require extensive Teraforming processes before we get an atmosphere on it.
• Titan has abundance of life supporting materials that includes water, methane and Nitrogen. Water can be converted into oxygen and Methane can be used as a fuel for all power needs. On the other hand if we consider Mars, we are not even sure that the planet has some water, forget about all other gases.
• Since Titan has a thick atmosphere so the humans that live there will remain protected from all cosmic radiations. On the other hand the major problem on Mars is that it is not having any such atmosphere to protect life.
• Titan has an induced magnetosphere which can deflect all the harmful solar winds. But we don’t find any of it in Mars.
What are the problem areas?
Despite of the positives of the approach there are also a few problem areas that are to be dealt with, these include:
• Titan is about 1.4 billion Km from the sun. So far that the solar heat cannot reach there. This makes Titan a very cold world where the surface temperature is -179 degrees Celsius. We need to have massive heat generation and insulation systems else all humans will immediately freeze to death.
• Titan has an induced magnetosphere but is not having any of its own which can deflect all the harmful solar winds.
• Though we will remain protected from cosmic and other harmful rays on Titan still humans will be exposed to all these radiations when they are on the way to Titan which will be a pretty long journey.
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