Wednesday, December 12, 2012

Life, where, here, there, somewhere unexpected? Testing, testing, testing.


Is it safe to go to space like the Moon and beyond?
- LRK -

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THE APOLLO 17 POCKET MOUSE EXPERIMENT (BIOCORE)[*]

Travel outside the protective atmosphere of Earth can expose a spacecraft and its occupants to potentially dangerous regions of radiation. Missions conducted to date, including those of Apollo, have been fortunate since radiation doses received by astronauts have been low and of no clinical significance. However, as space missions increase in duration and move beyond the moon, the danger from radiation will become more serious.
In order to gain a better understanding of radiation hazards, the Biocore Experiment was flown on Apollo 17. This experiment attempted to assess the degree to which exposure to cosmic ray particle radiation might present a risk to astronauts. In this study, five pocket mice, with plastic dosimeters implanted beneath the scalp, were flown in a sealed canister. The objective was to determine whether microscopically visible lesions, attributable to particle radiation, could be found in brain, eye, and other tissues in these animals.
Particular interest in the effects of particle radiation on tissue arises from the markedly different character of high energy (HZE) particle radiation as compared with that of electromagnetic (E-M) radiation (X-rays., g-rays). The energy deposition (dosage) in E-M irradiation decreases exponentially with penetration depth into the target. In contrast, the energy deposition by a particle can increase as the particle penetrates the target and decelerates, the maximum energy loss per unit path length (LET: linear energy transfer) occurring near the stopping point (Bragg peak) (figure 1). Most of the energy deposition from particle radiation occurs in a very narrow cylinder around the trajectory, within which there is intense ionization of the target’s atoms. While the concept of dosage is not strictly meaningful in assessing the radiobiological effects of HZE particle radiation, perspective on the potential destructive character is obtained by noting that the "dosage" (energy deposition per gram) in the immediate vicinity of the particle trajectory can be on the order of megarads or higher.
For a given incident energy, a charged particle will penetrate a target to a relatively well-defined depth that is a function of the particle’s charge. Collaterally, the LET of a particle at any point along its trajectory is a function of the particle’s charge and distance from the stopping point. In the present experiment, use was made of this last property, that is, measurement of the LET, where the LET of each HZE particle was determined from measurements on the particle’s track in the subscalp detector. Charge and distance to the particle’s stopping point were calculated from the detector data.
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And we sent other life forms to the Moon which required some training.
- LRK -

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This Week in The Space Review - 2012 December 10  

Flight training for Apollo: An interview with astronaut Harrison Schmitt
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This month marks the 40th anniversary of Apollo 17, but before astronaut Harrison Schmitt could fly to the surface of the Moon, he had to learn how to fly. Jason Catanzariti interviews the astronaut on his flight training experience and how it prepared him for his Apollo mission.
http://www.thespacereview.com/article/2199/1
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Another reason to save old computer data.
- LRK -

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SpaceRef Daily Newsletter

Apollo's Lunar Dust Data Being Restored

Forty years after the last Apollo spacecraft launched, the science from those missions continues to shape our view of the moon. In one of the latest developments, readings from the Apollo 14 and 15 dust detectors have been restored by scientists with the National Space Science Data Center (NSSDC) at NASA's Goddard Space Flight Center in Greenbelt, Md.
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Here on Earth search for signs of early life.
- LRK -

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SpaceRef Daily Newsletter

Mining ancient ores for clues to early life

An analysis of sulfide ore deposits from one of the world's richest base-metal mines confirms that oxygen levels were extremely low on Earth 2.7 billion years ago, but also shows that microbes were actively feeding on sulfate in the ocean and influencing seawater chemistry during that geological time period.
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And the McGill link.
- LRK -

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 10 Dec 2012
Mining ancient ores for clues to early life
Scientists probe Canadian sulfide ore to confirm microbial activity in seawater 2.7 billion years ago

An analysis of sulfide ore deposits from one of the world’s richest base-metal mines confirms that oxygen levels were extremely low on Earth 2.7 billion years ago, but also shows that microbes were actively feeding on sulfate in the ocean and influencing seawater chemistry during that geological time period.
The research, reported by a team of Canadian and U.S. scientists in Nature Geoscience, provides new insight into how ancient metal-ore deposits can be used to better understand the chemistry of the ancient oceans – and the early evolution of life.
Sulfate is the second most abundant dissolved ion in the oceans today. It comes from the “rusting” of rocks by atmospheric oxygen, which creates sulfate through chemical reactions with pyrite, the iron sulfide material known as “fool’s gold.”
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Now down at the Antarctic survey site another way to look back in time.
- LRK -

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Scientists search for life under Antarctic ice

British Antarctic Survey drills into ice sheet to find out if life is possible in extreme cold and dark
With the temperature at a balmy midsummer -17c, drilling has started inAntarctica in an attempt to find evidence of life under a sheet of ice two miles (over 3km) thick.
The scientists and engineers from the British Antarctic Survey (BAS) hope to find signs of life in the pitch black, intensely cold, nutrient poor, and pristine waters of Lake Ellsworth, which lies deep below sea level and has been isolated from the rest of the world for at least 100,000 years, but probably much longer.
By the weekend sediment and water samples may tell them if life on Earth is possible in such extreme conditions – and they will be just as interested if they learn it is not, and that they have found the limits of life.
"We are about to explore the unknown and I am very excited that our mission will advance our scientific understanding of Antarctica's hidden world," said Prof Martin Siegert from the University of Bristol. "Right now we are working round the clock in a cold, demanding and extreme location – it's testing our own personal endurance, but it is entirely worth it."
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Now, I not only need to look up, but around, and down under as well.
Thanks for looking with me.
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WHAT THE MIND CAN CONCEIVE, AND BELIEVE, IT WILL ACHIEVE - LRK -

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