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Learning DNA repair from Halobacterium -- a microbe

Posted by gang.li on May 11, 2016 at 5:05 PM Comments comments (0)



In 2004, NASA scientists have known that Halobacterium has a surprising ability to repair its DNA. It do so by having more than 400 genes related to DNA-repair.  The following article explains some fundamentals of Halocacterium in DNA repairing.

http://science.nasa.gov/science-news/science-at-nasa/2004/10sep_radmicrobe/


Some high shool researchers (yes, I mean high school!) in California (Earth to Sky Calculus) has examined how halobacteria behave at high altitude. They fly these microbes onboard helium balloons that can reach altitude as high as 116,524 feet fro sea level. They did this in June 7th, 2014.   From the News at SpaceWeather.com dated on June 13th,  "...During the June 7th flight, onboard sensors registered temperatures as low as -60 C, air pressures of 1% sea level, and cosmic radiation levels 25 times Earth-normal. Those are conditions akin to the planet Mars. Three hours after they were launched, the bacteria landed in the Death Valley National Park: snapshot. This means they experienced a 100 C swing in temperature, a 100-fold change in air pressure, and a 25-fold surge of radiation...."

Subsequent analyses on, e.g., survival rates, and  possible mutations among the halo-survivors can be crucial for future Mars missions.

These activities has led to an article by Wendel, J. published on EOS in 2015, "Can microbes survive multiple trips into the stratosphere?, Eos, 96, doi:10.1029/2015EO027827. Published on 9 April 2015."






Radiation threat to Humans in Space

Posted by gang.li on May 2, 2016 at 4:05 PM Comments comments (0)


For astronauts to have a round trip to Mars, one has to worry about radiation exposures.  Solar Energetic particles and galactic cosmic rays are the most detrimental ones. The former is energetic particles accelerate at solar flares and/or CME-driven shock and the latter from presumably supernovae in our galaxy.  The following gives an overview of radiation hazards to humans in the Space.


Infographic: How Radiation in Space Threatens Human Exploration
Source SPACE.com: All about our solar system, outer space and exploration


How to shield these harmful particles?

Basically, there are two groups of ideas: 1) active protection (using magnetic or electrostatic fields to act as a shield) or 2) passive protection (relying on layered materials).

NASA has offered award money to this problem.

- The results?  See   http://www.space.com/29512-mars-mission-radiation-nasa-challenge.html#sthash.zyLNtCwY.dpuf





Mapping the magnetic mayhem in the heliosheath

Posted by gang.li on May 2, 2016 at 3:30 PM Comments comments (0)

This is an article published in EOS by Colin Schultz.

It discusses an article by Burlaga and Ness on the Journal of Geophysical Research-Space Physics, doi:10.1029/2010JA016309, 2011.

It concerns magnetic structures in the solar wind, expecially in the outerheliosphere, as observed by Ulysses.

Several kinds of current sheets are discussed. These include: proton boundary layers (PBLs), magnetic holes, magnetic humps, sector boudaryies.




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