http://www.newscientist.com/article/mg20227094.500-mars-robots-may-have-destroyed-evidence-of-life.html
HAVE Mars landers been destroying signs of life?
Instead of identifying chemicals that could point to life, NASA's robot explorers may have been toasting them by mistake.
In 1976, many people's hopes of finding life on Mars collapsed when the twin Viking landers failed to detect even minute quantities of organic compounds - the complex, carbon-containing molecules that are central to life as we know it. "It contributed, in my opinion, to the fact that there were no additional [US lander] missions to Mars for 20 years," says Jeff Moore of NASA's Ames Research Center in Moffett Field, California.
The result also created a puzzle. Even if Mars has never had life, comets and asteroids that have struck the planet should have scattered at least some organic molecules - though not produced by life - over its surface.
Some have suggested that organics were cleansed from the surface by naturally occurring, highly reactive chemicals such as hydrogen peroxide. Then last year, NASA's Phoenix lander, which also failed to detect organics on Mars, stumbled on something in the Martian soil that may have, in effect, been hiding the organics: a class of chemicals called perchlorates.
At low temperatures, perchlorates are relatively harmless. But when heated to hundreds of degrees Celsius they release a lot of oxygen, which tends to cause any nearby combustible material to burn. For that very reason, perchlorates are used in rocket propulsion.
The Phoenix and Viking landers looked for organic molecules by heating soil samples to similarly high temperatures to evaporate them and analyse them in gas form. When Douglas Ming of NASA's Johnson Space Center in Houston, Texas, and colleagues tried heating organics and perchlorates like this on Earth, the resulting combustion left no trace of organics behind. Ming's team presented their results at the recent Lunar and Planetary Science Conference in Houston.
Iron oxides have also been suspected of interfering with the detection of organics, but perchlorates are probably far more effective, says Chris McKay of Ames. Even if organics make up a few parts per thousand of the soil, Viking or Phoenix could have missed them, he adds, so it is too soon to conclude that these materials are not there. "We haven't looked the right way," he says.
Jeffrey Bada of the University of California, San Diego, agrees that a new approach is needed. He is leading work on a new instrument called Urey for the European Space Agency's ExoMars rover, due to launch in 2016, which will be able to detect organic material at concentrations as low as a few parts per trillion. The good news is that, although Urey heats its samples, it does so in water, so the organics cannot burn up.
Mystery of the missing salt
Organic chemicals are not the only substance that we may have missed on the Red Planet (see above). We should have seen carbonate salts littering the surface.
Weathering breaks down basalt, the dominant rock in the planet's crust, into a clay plus positive ions. These ions should react with carbon dioxide in the Martian atmosphere to form carbonate salts, explains Ralph Milliken at NASA's Jet Propulsion Laboratory in Pasadena, California.
Orbiters have spotted clay on Mars but few carbonates or other salts. We shouldn't assume that they aren't there, however, Milliken says.
Milliken and his colleagues have calculated that weathered Mars basalt should produce equal amounts of clay and salt. Thus in the planet's southern highlands, where thousands of clay deposits have been identified, there should be at least as much salt (Geophysical Research Letters, DOI: 10.1029/2009gl038558). "Chemistry has shown that you can't draw conclusions from observations alone, because you are still missing pieces of the puzzle," says Milliken.
Some argue that the lack of known carbonate salt deposits points to a different atmospheric composition in the past, but Milliken says we should study the rocks directly before making any conclusions
Monday, May 25, 2009
Tuesday, May 19, 2009
A Quaker Friend emailed me a note that there are Quaker Blogs and Other Science Teachers that are Seekers....if you are not a Quaker, excuse my intro.
That Which Boggles (TWB)
http://sillypoorgospel.blogspot.com/2009/04/that-which-boggles.html
I received the email from my friend the science teacher on Darwin’s Birthday.
He was expressing admiration for Quakers. He had read a bit by some British Friend stating that Quakers had no quarrel with Mr. Darwin or the Theory of Evolution. He was impressed, and was telling me so.
I accepted his kudos and for the sake of integrity stated that there were some Friends who might not have much truck with Darwin, but that I was not one of them.
My friend is no kind of religionist. He is intelligent, gentle and kind. He is tolerant of those like me who live their lives in conversation with what I am sure he thinks of as an elaborate imaginary friend called God. But he feels no need of such supernatural supports.
Yet I am not sure that he and I have no common spiritual ground.I think this because I have heard him describe what I would call a mystical experience, what early Friends would call an opening.
He is a science teacher, secondary school. He came to it late after another career. He came to it because he had continuing and powerful experiences in the pursuit of science. I have heard him describe the experience of discovery of that which boggles the mind. He describes this experience with deep passion and obvious joy. He can describe being a good enough student, an attentive enough observer, that he reaches a plane where he bumps into truth so amazing that all the mind can do is boggle – gaze in rapt awe – try to accept what it can only incompletely comprehend. He describes the desire of all scientists to take that comprehension just one step farther than the boggle point. He calls this science. I, of course, have the same experience and call it religion.
But I recognize that his science is one very fine religion.The Worship of That Which Boggles has meeting houses – classrooms and laboratories. It has rituals and methodologies. If you advance far enough you get vestments – lab coats and regalia. It has acolytes. My friend is there for the acolytes. He is the master of novices. He teaches all his students, but he watches for the nascent believers, the ones who get excited when they near the boggle point.
And he is an evangelist. He actively attempts to introduce them to TWB. He knows that not all will be boggled – that only a few will pursue further bogglement - that fewer still will make it their life’s passion. But he scatters his seed widely and harvests where ever life sprouts.
His religion, like mine, believes in the doctrine of continuing revelation. That which we discern, and test, and live into will develop and change and grow as our understanding grows. We both believe in Truth, and we both believe it is blasphemy to claim that you have grasp of the entire truth.I have worshiped at this altar.
For me it was college and the double slit light experiment where light behaves like a brazen floozy, and shows you wave or particle depending on what you ask for. She cannot be both and yet she is. I have been bogged. I occasionally worship with the Bogglers still. Whenever someone will teach me at the Zen beginner’s level that I need. That is why I like to have my friend over for an ecumenical dinner, he is a fine preacher, and I happily sit under his preaching.I believe that his Boggler and mine are one. I do work in a different department.
The division of hearts and souls, tech support, specifically. I am but a lab assistant in the laboratory of sanctification. I help people when their work gets stuck. I know some best practices that produce reliable results. I help them check their numbers. I listen to their reports and give feedback. But once in a while I still get into that Holy of Holys of pure bogglement.
I have stood with souls who are despairing, screamingly suicidal, no hope, no comfort, no reason to live. They stand facing a precipice, contemplating an all or nothing experiment in permanent pain management. I stand shoulder to shoulder with them, but facing the other way - pointing towards life. What always amazes me is how these souls can be simultaneously and completely committed to opposing, contradictory aims. They want to die and they want to live. It cannot be both ways, but it is.
I see wave, they see particle. And then if I am very blessed. In that moment of paradox, they take my hand and take one step away from the edge. Where the strength comes from to do this I do not know. But I know that I am boggled every time. And I know that my simple attention, my observation of their pain, changes something.
That is pastor Schroedinger’s sermon, I believe..
// posted by Peggy Senger Parsons @ Monday, April 20, 2009
That Which Boggles (TWB)
http://sillypoorgospel.blogspot.com/2009/04/that-which-boggles.html
I received the email from my friend the science teacher on Darwin’s Birthday.
He was expressing admiration for Quakers. He had read a bit by some British Friend stating that Quakers had no quarrel with Mr. Darwin or the Theory of Evolution. He was impressed, and was telling me so.
I accepted his kudos and for the sake of integrity stated that there were some Friends who might not have much truck with Darwin, but that I was not one of them.
My friend is no kind of religionist. He is intelligent, gentle and kind. He is tolerant of those like me who live their lives in conversation with what I am sure he thinks of as an elaborate imaginary friend called God. But he feels no need of such supernatural supports.
Yet I am not sure that he and I have no common spiritual ground.I think this because I have heard him describe what I would call a mystical experience, what early Friends would call an opening.
He is a science teacher, secondary school. He came to it late after another career. He came to it because he had continuing and powerful experiences in the pursuit of science. I have heard him describe the experience of discovery of that which boggles the mind. He describes this experience with deep passion and obvious joy. He can describe being a good enough student, an attentive enough observer, that he reaches a plane where he bumps into truth so amazing that all the mind can do is boggle – gaze in rapt awe – try to accept what it can only incompletely comprehend. He describes the desire of all scientists to take that comprehension just one step farther than the boggle point. He calls this science. I, of course, have the same experience and call it religion.
But I recognize that his science is one very fine religion.The Worship of That Which Boggles has meeting houses – classrooms and laboratories. It has rituals and methodologies. If you advance far enough you get vestments – lab coats and regalia. It has acolytes. My friend is there for the acolytes. He is the master of novices. He teaches all his students, but he watches for the nascent believers, the ones who get excited when they near the boggle point.
And he is an evangelist. He actively attempts to introduce them to TWB. He knows that not all will be boggled – that only a few will pursue further bogglement - that fewer still will make it their life’s passion. But he scatters his seed widely and harvests where ever life sprouts.
His religion, like mine, believes in the doctrine of continuing revelation. That which we discern, and test, and live into will develop and change and grow as our understanding grows. We both believe in Truth, and we both believe it is blasphemy to claim that you have grasp of the entire truth.I have worshiped at this altar.
For me it was college and the double slit light experiment where light behaves like a brazen floozy, and shows you wave or particle depending on what you ask for. She cannot be both and yet she is. I have been bogged. I occasionally worship with the Bogglers still. Whenever someone will teach me at the Zen beginner’s level that I need. That is why I like to have my friend over for an ecumenical dinner, he is a fine preacher, and I happily sit under his preaching.I believe that his Boggler and mine are one. I do work in a different department.
The division of hearts and souls, tech support, specifically. I am but a lab assistant in the laboratory of sanctification. I help people when their work gets stuck. I know some best practices that produce reliable results. I help them check their numbers. I listen to their reports and give feedback. But once in a while I still get into that Holy of Holys of pure bogglement.
I have stood with souls who are despairing, screamingly suicidal, no hope, no comfort, no reason to live. They stand facing a precipice, contemplating an all or nothing experiment in permanent pain management. I stand shoulder to shoulder with them, but facing the other way - pointing towards life. What always amazes me is how these souls can be simultaneously and completely committed to opposing, contradictory aims. They want to die and they want to live. It cannot be both ways, but it is.
I see wave, they see particle. And then if I am very blessed. In that moment of paradox, they take my hand and take one step away from the edge. Where the strength comes from to do this I do not know. But I know that I am boggled every time. And I know that my simple attention, my observation of their pain, changes something.
That is pastor Schroedinger’s sermon, I believe..
// posted by Peggy Senger Parsons @ Monday, April 20, 2009
Thursday, May 14, 2009
Surviving Space: Risks to Humans on the Moon and Mars
By Robert Roy Britt
Senior Science Writer
posted: 06:00 am ET20 January 2004
http://www.space.com/scienceastronomy/mars_dangers_040120.html
There is no "biggest danger" in setting up a permanent lunar presence or sending people to Mars, says John Charles, an enthusiastic proponent of both ideas and a NASA analyst of the costs and risks of human space flight: "There are several."
Launch, landing and re-entry are perhaps the riskiest moments of any space venture, history shows. But on long missions, what would otherwise be minor threats could become at best serious limitations or at worst deadly disasters.
Basking in the glow of President Bush's call for sending humans back to the Moon as early as 2015 and then eventually to the red planet, Charles, who works at the Johnson Space Center in Houston, offered up his danger list yesterday:
Lack of a medical facility could turn a mundane injury into a life-threatening situation;
"Psychosocial" pressure will be high in a small group isolated for months or years;
Zero or reduced gravity causes bone and muscle loss;
Dangerous radiation particles are abundant beyond Earth orbit.
"Radiation is a potential show stopper," Charles told SPACE.com, quickly adding that researchers are "getting on top of that" while also learning how to clear the other hurdles.
Total exposure
Any grand leap into the cosmos, as outlined by Bush last week, will start with dangerous baby steps as explorers cautiously venture into the hazardous, radiation-laden space beyond Earth's protective magnetic field. Scientists are still working to characterize the dangers and develop the technologies necessary for safe suits and ships.
This much they know:
Any trip beyond Earth orbit will involve radiation threats not faced by residents of the International Space Station, which sits inside the planet's magnetic field.
A 2-1/2-year trip to Mars, including six months of travel time each way, would expose an astronaut to nearly the lifetime limit of radiation allowed under NASA guidelines.
The Moon, with no atmosphere, is more dangerous than the surface of Mars. Lunar forays will have to be brief unless expensive shielded habitats are built.
Mission planners knew the Apollo astronauts would be at grave risk if a strong solar flare occurred during a mission. The short duration of each trip was a key to creating favorable odds.
"A big solar event during one of those missions could have been catastrophic," said Cary Zeitlin, a radiation expert at the National Space Biomedical Research Institute at Baylor College of Medicine in Houston. "The risk was known. They gambled a bit."
The White House plan calls for a permanent lunar base.
NASA already spends millions of dollars every year on research into space radiation and its biological effects, and more money goes into research on other health risks of long-term spaceflight. The new plan would refocus space station activities on supporting these investigations.
Double dose
Particle radiation in space goes right through the human body and can tear apart strands of DNA, the software of life that resides inside a cell nucleus. Damaged cells can lose the ability perform normally and to repair themselves.
There are two primary forms of hazardous space radiation particles. (These particles are different from electromagnetic radiation, such as X-rays, visible light or the ultraviolet (UV) rays that cause skin cancer.)
High-energy particles emitted by the Sun during intense flares are one type. They move outward at millions of miles an hour and can strike the Earth-Moon system in a day or two. Earth's magnetic field shields the planet from most of these. Some get through, though, especially in intense streams lasting several hours when a storm's magnetic field is aligned in a certain way with that of the planet's.
Earth's atmosphere blocks out most of the rest of these particles.
An astronaut would not want to be caught outside during a solar storm. Even airlines reroute flights when the Sun gets nasty to avoid polar regions, where more of the radiation leaks in.
Someone walking on the Moon, even in a fancy space suit, would be good as naked in the face of the Sun's worst fury.
"If one were exposed to the full brunt of a solar event, that could cause acute effects in the very short term," Zeitlin explained in a telephone interview. "Quite severe illness" could result. NASA says the radiation sickness from a solar flare could kill an unprotected astronaut.
Cosmic rays, the other big space-particle worry, come from undetermined galactic sources and pose a greater long-term risk for cancer, cataracts and other illness, Zeitlin said. Cosmic ray particles are more energetic than their solar cousins.
"These are atomic nuclei stripped of electrons," he explained. "They're able to penetrate many centimeters of solid matter."
Planets and moons offer natural protection against cosmic rays by blocking half the sky.
"When you're in free space the radiation comes at you from all directions," Zeitlin said. "When you're on a planetary surface it's only coming at you from above."
Exposure is therefore about twice as bad while travelling through space compared to being on the lunar or Martian surfaces.
Earth's atmosphere protects us against the cosmic particles as well as the solar. The Martian atmosphere, about 1 percent as dense as Earth's, manages to stop just about all of the solar particles, scientists figure, but it lets most of the cosmic rays through.
Martian irony
Only last year did scientists get the first solid measurements of radiation at Mars. Zeitlin is the principal investigator for MARIE, a radiation detection instrument aboard NASA's Mars Odyssey orbiter.
Zeitlin's team combined Odyssey data with Earth-orbiting satellite measurements of cosmic rays to project the radiation risk to an astronaut in free space and on the surface of Mars. The combined solar and cosmic ray particle exposure is measured in sieverts.
An astronaut in a six-month journey to Mars -- the time required with conventional propulsion -- would be exposed to about 0.3 sieverts, or 0.6 on a round-trip. Eighteen months on the surface (if it takes so long to get there, you might as well stay awhile!) would bring another 0.4 sieverts, for a total exposure of 1 sievert.
Limits set by NASA vary with age and gender but range from 1 to 3 sieverts.
When the Odyssey result was announced, several news reports misrepresented the risk, stating that it might prevent human missions to Mars. Zeitlin allows that it is close to the limits, but he says now, as he did then, that it is a "manageable dose." Further, the limits tend to drop as more is learned about the effects on humans. And, of course, the dose could be lowered with creative shielding technology.
(Interestingly, the best way to protect spacefarers aboard a Mars transport ship might be to surround them with the water they'd need for their journey. The hydrogen in water, scientists have learned, is one of the best absorbers of particle radiation.)
There is more to learn about the risk, however.
For one thing, Zeitlin's estimate, based on the Odyssey data, comes with 20 to 30 percent uncertainty. (In a form of cosmic irony, a solar storm last October disabled the MARIE instrument while leaving Odyssey otherwise in good order. The orbiter is currently serving as a relay for pictures and data coming from the Mars Spirit rover. Only after the rover mission is complete will engineers try to revive the radiation experiment.)
Perhaps more important, long-term space travel might make people more susceptible to radiation harm. It also appears some people are more susceptible than others. More research is needed to understand both these issues, however.
Also, the Odyssey data was collected just after the peak in a known 11-year cycle of solar activity. The levels would be greater during the peak and less at the trough. It might seem, then, that the first human trip to Mars should take place at solar minimum, a 2-3 year stretch every 11 years when sunspots and flares are almost nonexistent.
But there's a catch: "Galactic particle intensity picks up during solar minimum," Zeitlin said. They are higher-energy and more difficult to shield in a space habitat and "impossible to shield completely" on a spaceship.
Nuclear reactors use concrete to contain similar particles.
"You can't lift concrete blocks into space," Zeitlin points out, at least not at the going rate of about $10,000 per pound for launch costs.
Unfriendly Moon
Bush's first planned stop in the cosmos is the Moon. Its danger is, interestingly, not as well charted as that of Mars.
The Apollo astronauts made some measurements of radiation on the Moon, but the results don't provide as complete a picture as what scientists now have of the red planet. But Zeitlin said the Moon would be more dangerous since it has no atmosphere -- probably about half as dangerous as free space (again, someone on the Moon would be protected by the Moon itself on one side).
"The Moon would be worse than Mars and worse than the space station," he said. Short stays, perhaps one to two months, will be the norm early on. "That's a small enough dose of the galactic stuff that you're actually going to be more concerned about the solar particles, especially if you're near solar max," the intensely active part of the 11-year solar cycle.
Lunar visitors won't have the option of just sitting inside some protective shell. The president's vision makes exploration NASA's primary goal. So astronauts will presumably be called on to inspect the lunar countryside. That would present the risk of someone getting caught on a long rover excursion as a solar storm hits.
Warning times for Sun storms can be as little as 18 hours. Far less time is available to make firm predictions of the expected effect of a flare-up.
Zeitlin says a more extensive warning system will need to be established. This is especially true for Mars, which when it's on the far side of the Sun can be hit by solar tempests that don't even register with terrestrial scientists.
And there's more to do.
"We have to get smart about how we design the space suits and do everything we can to limit exposure to solar particles," Zeitlin said. "You can't stop everything with a space suit, but there are better and worse ways to design it."
The Apollo-era suits were not will equipped.
"They would not have done much," Zeitlin said. "We will try to improve on that."
'Ready to go'
NASA employees are ready for the challenge.
"We're ready to go," said John Charles the human spaceflight analyst. "I've been waiting for this for 20 years."
Charles is not among those space buffs dismayed that their ultimate desire to put humans on Mars will first involve a lengthy lunar effort. In the president's vision, the Moon will serve as a testing ground for landing and surviving on Mars.
Charles said the proximity of the Moon and familiarity with it offer a level of comfort.
"We're foolish not to go to the Moon first," he said, "because that's a place where we can practice with some degree of safety." After all, while a Mars trip would logically last two or three years, the Moon is a mere three days away. Either destination, he knows, remains dangerous.
"Anybody who gets hurt is totally dependent on the rest of the crew to take care of him or her," Charles points out. "If you're having a life-threatening trauma, three days can seem like three years."
Under the president's plan, NASA has at least 11 years to ponder the all this.
FAQ: Bush's Space Vision
Measurement of Mars Radiation
Medicine and Space Travel
Space Mailbag
By Robert Roy Britt
Senior Science Writer
posted: 06:00 am ET20 January 2004
http://www.space.com/scienceastronomy/mars_dangers_040120.html
There is no "biggest danger" in setting up a permanent lunar presence or sending people to Mars, says John Charles, an enthusiastic proponent of both ideas and a NASA analyst of the costs and risks of human space flight: "There are several."
Launch, landing and re-entry are perhaps the riskiest moments of any space venture, history shows. But on long missions, what would otherwise be minor threats could become at best serious limitations or at worst deadly disasters.
Basking in the glow of President Bush's call for sending humans back to the Moon as early as 2015 and then eventually to the red planet, Charles, who works at the Johnson Space Center in Houston, offered up his danger list yesterday:
Lack of a medical facility could turn a mundane injury into a life-threatening situation;
"Psychosocial" pressure will be high in a small group isolated for months or years;
Zero or reduced gravity causes bone and muscle loss;
Dangerous radiation particles are abundant beyond Earth orbit.
"Radiation is a potential show stopper," Charles told SPACE.com, quickly adding that researchers are "getting on top of that" while also learning how to clear the other hurdles.
Total exposure
Any grand leap into the cosmos, as outlined by Bush last week, will start with dangerous baby steps as explorers cautiously venture into the hazardous, radiation-laden space beyond Earth's protective magnetic field. Scientists are still working to characterize the dangers and develop the technologies necessary for safe suits and ships.
This much they know:
Any trip beyond Earth orbit will involve radiation threats not faced by residents of the International Space Station, which sits inside the planet's magnetic field.
A 2-1/2-year trip to Mars, including six months of travel time each way, would expose an astronaut to nearly the lifetime limit of radiation allowed under NASA guidelines.
The Moon, with no atmosphere, is more dangerous than the surface of Mars. Lunar forays will have to be brief unless expensive shielded habitats are built.
Mission planners knew the Apollo astronauts would be at grave risk if a strong solar flare occurred during a mission. The short duration of each trip was a key to creating favorable odds.
"A big solar event during one of those missions could have been catastrophic," said Cary Zeitlin, a radiation expert at the National Space Biomedical Research Institute at Baylor College of Medicine in Houston. "The risk was known. They gambled a bit."
The White House plan calls for a permanent lunar base.
NASA already spends millions of dollars every year on research into space radiation and its biological effects, and more money goes into research on other health risks of long-term spaceflight. The new plan would refocus space station activities on supporting these investigations.
Double dose
Particle radiation in space goes right through the human body and can tear apart strands of DNA, the software of life that resides inside a cell nucleus. Damaged cells can lose the ability perform normally and to repair themselves.
There are two primary forms of hazardous space radiation particles. (These particles are different from electromagnetic radiation, such as X-rays, visible light or the ultraviolet (UV) rays that cause skin cancer.)
High-energy particles emitted by the Sun during intense flares are one type. They move outward at millions of miles an hour and can strike the Earth-Moon system in a day or two. Earth's magnetic field shields the planet from most of these. Some get through, though, especially in intense streams lasting several hours when a storm's magnetic field is aligned in a certain way with that of the planet's.
Earth's atmosphere blocks out most of the rest of these particles.
An astronaut would not want to be caught outside during a solar storm. Even airlines reroute flights when the Sun gets nasty to avoid polar regions, where more of the radiation leaks in.
Someone walking on the Moon, even in a fancy space suit, would be good as naked in the face of the Sun's worst fury.
"If one were exposed to the full brunt of a solar event, that could cause acute effects in the very short term," Zeitlin explained in a telephone interview. "Quite severe illness" could result. NASA says the radiation sickness from a solar flare could kill an unprotected astronaut.
Cosmic rays, the other big space-particle worry, come from undetermined galactic sources and pose a greater long-term risk for cancer, cataracts and other illness, Zeitlin said. Cosmic ray particles are more energetic than their solar cousins.
"These are atomic nuclei stripped of electrons," he explained. "They're able to penetrate many centimeters of solid matter."
Planets and moons offer natural protection against cosmic rays by blocking half the sky.
"When you're in free space the radiation comes at you from all directions," Zeitlin said. "When you're on a planetary surface it's only coming at you from above."
Exposure is therefore about twice as bad while travelling through space compared to being on the lunar or Martian surfaces.
Earth's atmosphere protects us against the cosmic particles as well as the solar. The Martian atmosphere, about 1 percent as dense as Earth's, manages to stop just about all of the solar particles, scientists figure, but it lets most of the cosmic rays through.
Martian irony
Only last year did scientists get the first solid measurements of radiation at Mars. Zeitlin is the principal investigator for MARIE, a radiation detection instrument aboard NASA's Mars Odyssey orbiter.
Zeitlin's team combined Odyssey data with Earth-orbiting satellite measurements of cosmic rays to project the radiation risk to an astronaut in free space and on the surface of Mars. The combined solar and cosmic ray particle exposure is measured in sieverts.
An astronaut in a six-month journey to Mars -- the time required with conventional propulsion -- would be exposed to about 0.3 sieverts, or 0.6 on a round-trip. Eighteen months on the surface (if it takes so long to get there, you might as well stay awhile!) would bring another 0.4 sieverts, for a total exposure of 1 sievert.
Limits set by NASA vary with age and gender but range from 1 to 3 sieverts.
When the Odyssey result was announced, several news reports misrepresented the risk, stating that it might prevent human missions to Mars. Zeitlin allows that it is close to the limits, but he says now, as he did then, that it is a "manageable dose." Further, the limits tend to drop as more is learned about the effects on humans. And, of course, the dose could be lowered with creative shielding technology.
(Interestingly, the best way to protect spacefarers aboard a Mars transport ship might be to surround them with the water they'd need for their journey. The hydrogen in water, scientists have learned, is one of the best absorbers of particle radiation.)
There is more to learn about the risk, however.
For one thing, Zeitlin's estimate, based on the Odyssey data, comes with 20 to 30 percent uncertainty. (In a form of cosmic irony, a solar storm last October disabled the MARIE instrument while leaving Odyssey otherwise in good order. The orbiter is currently serving as a relay for pictures and data coming from the Mars Spirit rover. Only after the rover mission is complete will engineers try to revive the radiation experiment.)
Perhaps more important, long-term space travel might make people more susceptible to radiation harm. It also appears some people are more susceptible than others. More research is needed to understand both these issues, however.
Also, the Odyssey data was collected just after the peak in a known 11-year cycle of solar activity. The levels would be greater during the peak and less at the trough. It might seem, then, that the first human trip to Mars should take place at solar minimum, a 2-3 year stretch every 11 years when sunspots and flares are almost nonexistent.
But there's a catch: "Galactic particle intensity picks up during solar minimum," Zeitlin said. They are higher-energy and more difficult to shield in a space habitat and "impossible to shield completely" on a spaceship.
Nuclear reactors use concrete to contain similar particles.
"You can't lift concrete blocks into space," Zeitlin points out, at least not at the going rate of about $10,000 per pound for launch costs.
Unfriendly Moon
Bush's first planned stop in the cosmos is the Moon. Its danger is, interestingly, not as well charted as that of Mars.
The Apollo astronauts made some measurements of radiation on the Moon, but the results don't provide as complete a picture as what scientists now have of the red planet. But Zeitlin said the Moon would be more dangerous since it has no atmosphere -- probably about half as dangerous as free space (again, someone on the Moon would be protected by the Moon itself on one side).
"The Moon would be worse than Mars and worse than the space station," he said. Short stays, perhaps one to two months, will be the norm early on. "That's a small enough dose of the galactic stuff that you're actually going to be more concerned about the solar particles, especially if you're near solar max," the intensely active part of the 11-year solar cycle.
Lunar visitors won't have the option of just sitting inside some protective shell. The president's vision makes exploration NASA's primary goal. So astronauts will presumably be called on to inspect the lunar countryside. That would present the risk of someone getting caught on a long rover excursion as a solar storm hits.
Warning times for Sun storms can be as little as 18 hours. Far less time is available to make firm predictions of the expected effect of a flare-up.
Zeitlin says a more extensive warning system will need to be established. This is especially true for Mars, which when it's on the far side of the Sun can be hit by solar tempests that don't even register with terrestrial scientists.
And there's more to do.
"We have to get smart about how we design the space suits and do everything we can to limit exposure to solar particles," Zeitlin said. "You can't stop everything with a space suit, but there are better and worse ways to design it."
The Apollo-era suits were not will equipped.
"They would not have done much," Zeitlin said. "We will try to improve on that."
'Ready to go'
NASA employees are ready for the challenge.
"We're ready to go," said John Charles the human spaceflight analyst. "I've been waiting for this for 20 years."
Charles is not among those space buffs dismayed that their ultimate desire to put humans on Mars will first involve a lengthy lunar effort. In the president's vision, the Moon will serve as a testing ground for landing and surviving on Mars.
Charles said the proximity of the Moon and familiarity with it offer a level of comfort.
"We're foolish not to go to the Moon first," he said, "because that's a place where we can practice with some degree of safety." After all, while a Mars trip would logically last two or three years, the Moon is a mere three days away. Either destination, he knows, remains dangerous.
"Anybody who gets hurt is totally dependent on the rest of the crew to take care of him or her," Charles points out. "If you're having a life-threatening trauma, three days can seem like three years."
Under the president's plan, NASA has at least 11 years to ponder the all this.
FAQ: Bush's Space Vision
Measurement of Mars Radiation
Medicine and Space Travel
Space Mailbag
Tuesday, May 5, 2009
Inventions Associated with NASA, rightly and wrongly...
Tang came before NASA
NASA, the U.S. space agency, has put people on the moon and robots on Mars, and has sent a probe rocketing towards Pluto and beyond, but contrary to popular belief it did not invent the powdery drink mix Tang. In fact, General Foods began to test-market the orange-flavored concoction in 1957, a year before NASA was born. However, the space agency did help launch Tang on the road to fame when astronaut John Glenn, in 1962, selected the mix for eating experiments in orbit. Tang flew on all Gemini and Apollo missions, a fact that General Foods used to its advertising advantage.
A pen for zero gravity
How to write in space? Regular ballpoint pens, after all, rely on gravity and atmospheric pressure for ink to flow. Inventor Paul Fisher tackled the problem for NASA – without funding from the space agency – with the aptly named Anti-Gravity Pen, which he patented in 1965. The gizmo has a pressurized cartridge that keeps ink flowing under any conditions – zero gravity, underwater, extreme heat and extreme cold. "No matter the conditions you're in, the pen will write," says Timothy Lawson, director of marketing for the Fisher Space Pen Co. NASA embraced the technology in 1968 for the Apollo program, launching the pen to the international fame it continues to enjoy.
NASA helps reduce swimmers' drag
What makes Olympic champion swimmer Michael Phelps so fast? Beyond hours of rigorous training and a diet of champions, he wears an aerodynamic Speedo swimsuit developed with the assistance of NASA wind tunnel technology. NASA and Speedo engineers tested more than 60 types of fabric in the tunnels to figure out which one had the least amount of drag. Drag is the force that slows an object down as it moves through a substance, like a spaceship soaring through the air or a swimmer gliding through the water. The resulting swimsuit, called the LZR Racer, helped Phelps to the top of the podium eight times in the 2008 Beijing Olympics.
Spacesuit's flex finds ski boot fame
The elbow and knee joints of spacesuits have accordionlike corrugations similar to those in a flexible drinking straw. The design prevents internal pressurization- and temperature-control plumbing from kinking as astronauts bend their limbs. In the late 1970s, one of the engineers who helped design the suits applied the concept to ski boots and a cult was born – the Raichle Flexon. The boot's tongue is corrugated, which allows it to flex without distorting the lower shell. Skiers swore by it and when the Swiss manufacturer halted production in 1996, devotees scrounged garage sales and online auction sites for spare parts and replacements. Then, in 2006, to much fanfare in the ski world, Full Tilt brought the model back into production because "the design works so well," says Jason Levinthal, a brand manager for the company.
NASA spin doesn't stick to Teflon
When U.S. astronaut Neil Armstrong took his "giant leap for mankind" on the surface of the moon in 1969, a material called Teflon was in his spacesuit and throughout the spacecraft that helped him and his nation achieve the historic feat. But the famously slippery material, contrary to popular belief, was discovered decades before NASA was formed. The tale of the material's discovery dates back to 1938, when DuPont chemist Roy Plunkett was experimenting with refrigerants. He left one experiment in the fridge overnight, only to find that it turned into a white, waxy solid – polytetrafluoroethylene (PTFE). Trademarked as Teflon, the substance found its way into myriad technologies and products, including the famous nonstick pans.
The bed for astronaut wannabes
As many an off-hour television viewer knows, the Tempur-Pedic mattress uses a material originally developed by NASA and certified by the U.S. Space Foundation, a nonprofit advocacy organization. At the root of Tempur-Pedic's technology is NASA's temper, or memory, foam, which was developed in 1966 as a shock absorber for the space agency's airplane seats. Over the years, the foam has found its way into everything from football helmets to prosthetics. The Tempur-Pedic mattress idea builds on the foam's pressure-relieving properties improved by scientists with the Swiss firm Fagerdala. Horse breeder Bobby Tussel slept on one while at a race in France. Wowed by his night's sleep, he founded Tempur-Pedic in 1992 to sell the mattresses in the U.S.
A zit zapper built with NASA expertise
"Most rocket scientists probably had pimples," Robert Conrad, the founder and chief technology officer of Zeno, says as a way to explain why NASA engineers jumped at the chance to help him develop his zit-zapping gizmo. The device uses a temperature-controlled tip that is applied directly to a pimple to shut down production of acne-causing bacteria. Within a day or two, he says, the zit disappears. Conrad made early prototypes in his garage, but applied to NASA's Space Alliance Technology Outreach Program, or SATOP, for assistance with a more cost-efficient design. Though NASA's solution didn't quite work for his needs, Conrad says it "changed the way I was looking at the problem and helped me come up with a new solution."
Scent is out of this world
Get a whiff of this: A rose flown on space shuttle Discovery in 1998 yielded an out-of-this-world scent that scientists have replicated for use in a perfume. International Flavors and Fragrances sent the rose into space as part of experiments to determine how microgravity affects plants. Researchers found that space changed three major chemical components of the flower, a company representative said. The result was a new fragrance that has a more floral aroma than that of the Earth rose. The scent, called "space rose note," is an ingredient in Shiseido Cosmetics' perfume Zen.
NASA engineer gets world soaked
For anyone who's been blasted with what seems like squirt gun on steroids – the Super Soaker – there's a NASA engineer to thank. Lonnie Johnson helped make propulsion systems for interplanetary spacecraft at the U.S. space agency, but was constantly tinkering at home on side projects that he hoped would change the world for the better. Instead, he changed it for the wetter. He was working on a cooling system to replace the refrigerant Freon when he attached some vinyl tubing to the bathroom sink and blasted his bathtub with a powerful stream of water. The gizmo uses pressurized air to achieve its soaking blast.
Velcro accidentally stuck to NASA
In the weightlessness of space, everything, including astronauts, floats freely unless harnessed down in one fashion or another. Apollo astronauts found a solution in Velcro brand hook-and-loop fastener technology, using it to secure everything from food to notepads to their suits as they ventured around outer space. Though the space agency's embrace of the two-sided fastener likely helped Velcro products rocket to fame, NASA did not invent it. Rather, the invention is credited to Swiss outdoorsman George de Mestral, who became fascinated by the burrs relentlessly clinging to his clothes and dog's fur. He examined them under the microscope and realized they were covered in tiny hooks. Intrigued, he set about developing the technology, which he patented in 1952. The Velcro trademark was registered in the U.S. in 1958.
NASA, the U.S. space agency, has put people on the moon and robots on Mars, and has sent a probe rocketing towards Pluto and beyond, but contrary to popular belief it did not invent the powdery drink mix Tang. In fact, General Foods began to test-market the orange-flavored concoction in 1957, a year before NASA was born. However, the space agency did help launch Tang on the road to fame when astronaut John Glenn, in 1962, selected the mix for eating experiments in orbit. Tang flew on all Gemini and Apollo missions, a fact that General Foods used to its advertising advantage.
A pen for zero gravity
How to write in space? Regular ballpoint pens, after all, rely on gravity and atmospheric pressure for ink to flow. Inventor Paul Fisher tackled the problem for NASA – without funding from the space agency – with the aptly named Anti-Gravity Pen, which he patented in 1965. The gizmo has a pressurized cartridge that keeps ink flowing under any conditions – zero gravity, underwater, extreme heat and extreme cold. "No matter the conditions you're in, the pen will write," says Timothy Lawson, director of marketing for the Fisher Space Pen Co. NASA embraced the technology in 1968 for the Apollo program, launching the pen to the international fame it continues to enjoy.
NASA helps reduce swimmers' drag
What makes Olympic champion swimmer Michael Phelps so fast? Beyond hours of rigorous training and a diet of champions, he wears an aerodynamic Speedo swimsuit developed with the assistance of NASA wind tunnel technology. NASA and Speedo engineers tested more than 60 types of fabric in the tunnels to figure out which one had the least amount of drag. Drag is the force that slows an object down as it moves through a substance, like a spaceship soaring through the air or a swimmer gliding through the water. The resulting swimsuit, called the LZR Racer, helped Phelps to the top of the podium eight times in the 2008 Beijing Olympics.
Spacesuit's flex finds ski boot fame
The elbow and knee joints of spacesuits have accordionlike corrugations similar to those in a flexible drinking straw. The design prevents internal pressurization- and temperature-control plumbing from kinking as astronauts bend their limbs. In the late 1970s, one of the engineers who helped design the suits applied the concept to ski boots and a cult was born – the Raichle Flexon. The boot's tongue is corrugated, which allows it to flex without distorting the lower shell. Skiers swore by it and when the Swiss manufacturer halted production in 1996, devotees scrounged garage sales and online auction sites for spare parts and replacements. Then, in 2006, to much fanfare in the ski world, Full Tilt brought the model back into production because "the design works so well," says Jason Levinthal, a brand manager for the company.
NASA spin doesn't stick to Teflon
When U.S. astronaut Neil Armstrong took his "giant leap for mankind" on the surface of the moon in 1969, a material called Teflon was in his spacesuit and throughout the spacecraft that helped him and his nation achieve the historic feat. But the famously slippery material, contrary to popular belief, was discovered decades before NASA was formed. The tale of the material's discovery dates back to 1938, when DuPont chemist Roy Plunkett was experimenting with refrigerants. He left one experiment in the fridge overnight, only to find that it turned into a white, waxy solid – polytetrafluoroethylene (PTFE). Trademarked as Teflon, the substance found its way into myriad technologies and products, including the famous nonstick pans.
The bed for astronaut wannabes
As many an off-hour television viewer knows, the Tempur-Pedic mattress uses a material originally developed by NASA and certified by the U.S. Space Foundation, a nonprofit advocacy organization. At the root of Tempur-Pedic's technology is NASA's temper, or memory, foam, which was developed in 1966 as a shock absorber for the space agency's airplane seats. Over the years, the foam has found its way into everything from football helmets to prosthetics. The Tempur-Pedic mattress idea builds on the foam's pressure-relieving properties improved by scientists with the Swiss firm Fagerdala. Horse breeder Bobby Tussel slept on one while at a race in France. Wowed by his night's sleep, he founded Tempur-Pedic in 1992 to sell the mattresses in the U.S.
A zit zapper built with NASA expertise
"Most rocket scientists probably had pimples," Robert Conrad, the founder and chief technology officer of Zeno, says as a way to explain why NASA engineers jumped at the chance to help him develop his zit-zapping gizmo. The device uses a temperature-controlled tip that is applied directly to a pimple to shut down production of acne-causing bacteria. Within a day or two, he says, the zit disappears. Conrad made early prototypes in his garage, but applied to NASA's Space Alliance Technology Outreach Program, or SATOP, for assistance with a more cost-efficient design. Though NASA's solution didn't quite work for his needs, Conrad says it "changed the way I was looking at the problem and helped me come up with a new solution."
Scent is out of this world
Get a whiff of this: A rose flown on space shuttle Discovery in 1998 yielded an out-of-this-world scent that scientists have replicated for use in a perfume. International Flavors and Fragrances sent the rose into space as part of experiments to determine how microgravity affects plants. Researchers found that space changed three major chemical components of the flower, a company representative said. The result was a new fragrance that has a more floral aroma than that of the Earth rose. The scent, called "space rose note," is an ingredient in Shiseido Cosmetics' perfume Zen.
NASA engineer gets world soaked
For anyone who's been blasted with what seems like squirt gun on steroids – the Super Soaker – there's a NASA engineer to thank. Lonnie Johnson helped make propulsion systems for interplanetary spacecraft at the U.S. space agency, but was constantly tinkering at home on side projects that he hoped would change the world for the better. Instead, he changed it for the wetter. He was working on a cooling system to replace the refrigerant Freon when he attached some vinyl tubing to the bathroom sink and blasted his bathtub with a powerful stream of water. The gizmo uses pressurized air to achieve its soaking blast.
Velcro accidentally stuck to NASA
In the weightlessness of space, everything, including astronauts, floats freely unless harnessed down in one fashion or another. Apollo astronauts found a solution in Velcro brand hook-and-loop fastener technology, using it to secure everything from food to notepads to their suits as they ventured around outer space. Though the space agency's embrace of the two-sided fastener likely helped Velcro products rocket to fame, NASA did not invent it. Rather, the invention is credited to Swiss outdoorsman George de Mestral, who became fascinated by the burrs relentlessly clinging to his clothes and dog's fur. He examined them under the microscope and realized they were covered in tiny hooks. Intrigued, he set about developing the technology, which he patented in 1952. The Velcro trademark was registered in the U.S. in 1958.
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