Thursday, December 12, 2013

Lunar Soil - the fine fraction of the regolith found on the surface of the Moon.

With the present interests in what is going on at our Moon and about to happen with the Chang'e 3 mission, you might wonder if there is any possibility to put humans there again. If you just stay for three days you can bring your own box lunches.  If you really want to think about staying for any extended time you may want to grow some fresh vegetables. 

Easier said than done. Down here on Earth, just throw some soil in a pot, some seeds, add some water, air, and light. Maybe control the temperature range. [brrr, it has been cold this last week and the pepper plant leaves have curled up.]

Hmm, at the lunar environment the composition of soil is different than what I might get here for potting soil. The more we learn about what is available on the Moon, the better we will be able to prepare our indoor hot house.  The less we have to bring up to the Moon the better. 

Both the Chang'e 3 lander and rover will help analyze soil samples and a later mission plans to return some lunar soil to Earth.

Since we will need to dig in to be protected from solar radiation it will be good to know what is under the lunar soil. The Chang'e Jade Rabbit rover has a ground penetrating radar that should be useful. 

- LRK -

Check out the references to the Wikipedia articles that follow. - LRK -
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Chang'e 3 (Chinese: 嫦娥三号; pinyin: Cháng'é Sānhào) is a lunar exploration mission operated by the China National Space Administration, incorporating a robotic lander and a rover. Chang'e 3 was launched on the morning of 2 December 2013 local time (17:30 1 December UTC), which is part of the second phase of the Chinese Lunar Exploration Program.[5][9][10] It will be China's first lunar rover.
The spacecraft is named after Chang'e, the goddess of the Moon in Chinese mythology, and is a follow-up to the Chang'e 1 and Chang'e 2 lunar orbiters. The lunar rover is called Yutu, or Jade Rabbit, a name selected in an online poll that comes from a Chinese myth about a white rabbit that lives on the Moon as a companion of the moon goddess Chang'e.[11] It achieved lunar orbit on 6 December 2013 (Beijing time).[12]
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This article or section documents a current or recent spaceflight. Details may change as the mission progresses.
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A look at what lunar soil is.
- LRK -

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Lunar soil is the fine fraction of the regolith found on the surface of the Moon. Its properties can differ significantly from those of terrestrial soil. The physical properties of lunar soil are primarily the result of mechanical disintegration of basaltic and anorthositic rock, caused by continuous meteoric impact and bombardment by interstellar charged atomic particles over billions of years. The process is largely one of mechanical weathering in which the particles are ground to finer and finer size over time. This situation contrasts fundamentally to terrestrial soil formation, mediated by the presence of molecular oxygen (O2), humidity, atmospheric wind, and a robust array of contributing biological processes. Some have argued that the term "soil" is not correct in reference to the Moon because on the Earth, soil is defined as havingorganic content, whereas the Moon has none. However, standard usage among lunar scientists is to ignore that distinction.
The term lunar soil is often used interchangeably with "lunar regolith" but typically refers to only the finer fraction of regolith, that which is composed of grains one cm in diameter or less.[1] Lunar dust generally connotes even finer materials than lunar soil. There is no official definition of what size fraction constitutes "dust", some place the cutoff at less than 50 micrometres in diameter, others at less than 10.
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Not all of the Moon's surface is pulverized to dust and so we will need to be able to adapt to varying terrain.
- LRK -

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Regolith is a layer of loose, heterogeneous material covering solid rock. It includes dust, soil, broken rock, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestrial planets and moons.
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Moon
Regolith covers almost the entire lunar surface, bedrock protruding only on very steep-sided crater walls and the occasional lava channel. This regolith has formed over the last 4.6 billion years from the impact of large and small meteoroids, from the steady bombardment of micrometeoroids and from solar and galactic charged particles breaking down surface rocks.
The impact of micrometeoroids, sometimes travelling faster than 60,000 mph (96,000 km/h), generates enough heat to melt or partially vaporize dust particles. This melting and refreezing welds particles together into glassy, jagged-edged agglutinates,[2] reminiscent oftektites found on Earth.
The regolith is generally from 4 to 5 metres thick in mare areas and from 10 to 15 metres in the older highland regions.[3] Below this true regolith is a region of blocky and fractured bedrock created by larger impacts, which is often referred to as the "megaregolith".
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The more real lunar soil samples we have the better lunar soil simulant that can be created. These are needed when you start thinking about using lunar materials for on site construction.  I wonder if any of the below is still available.

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Engineering, Construction, and Operations in Space IV
American Society of Civil Engineers, pp. 857-866, 1994

JSC-1: A NEW LUNAR SOIL SIMULANT

David S. McKay, James L. Carter, Walter W. Boles,

Carlton C. Allen, and Judith H. Allton

A new lunar soil simulant, JSC-1, has been developed and characterized under the auspices of the NASA Johnson Space Center. This simulant was produced in large quantities to satisfy the requirements of a variety of scientific and engineering investigations. JSC-1 is derived from volcanic ash of basaltic composition, which has been ground, sized, and placed into storage. The simulant's chemical composition, mineralogy, particle size distribution, specific gravity, angle of internal friction, and cohesion have been characterized and fall within the ranges of lunar mare soil samples. JSC-1 is available for only the cost of shipping.

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Well it looks like some other more recent sources have been made. 

And CAS-1 Lunar Soil Simulant from China..


Thanks for looking up with me.  
- LRK -
 
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WHAT THE MIND CAN CONCEIVE, AND BELIEVE, IT WILL ACHIEVE - LRK -

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