Posted on 05/06/2006 2:39:58 PM PDT by Iam1ru1-2
May 5, 2006: An early, persistent problem noted by Apollo astronauts on the Moon was dust. It got everywhere, including into their lungs. Oddly enough, that may be where future Moon explorers get their next breath of air: The moon's dusty layer of soil is nearly half oxygen.
The trick is extracting it.
Right: Apollo 17 geologist Harrison "Jack" Schmitt scoops up some oxygen-rich moon rocks and soil.
"All you have to do is vaporize the stuff," says Eric Cardiff of NASA's Goddard Space Flight Center. He leads one of several teams developing ways to provide astronauts oxygen they'll need on the Moon and Mars. (See the Vision for Space Exploration.)
Lunar soil is rich in oxides. The most common is silicon dioxide (SiO2), "like beach sand," says Cardiff. Also plentiful are oxides of calcium (CaO), iron (FeO) and magnesium (MgO). Add up all the O's: 43% of the mass of lunar soil is oxygen.
SUBSCRIBE TO Science@NASA
Cardiff is working on a technique that heats lunar soils until they release oxygen. "It's a simple aspect of chemistry," he explains. "Any material crumbles into atoms if made hot enough." The technique is called vacuum pyrolysis--pyro means "fire", lysis means "to separate."
"A number of factors make pyrolysis more attractive than other techniques," Cardiff explains. "It requires no raw materials to be brought from Earth, and you don't have to prospect for a particular mineral." Simply scoop up what's on the ground and apply the heat.
In a proof of principle, Cardiff and his team used a lens to focus sunlight into a tiny vacuum chamber and heated 10 grams of simulated lunar soil to about 2,500 degrees C. Test samples included ilmenite and Minnesota Lunar Simulant, or MLS-1a. Ilmenite is an iron/titanium ore that Earth and the Moon have in common. MLS-1a is made from billion-year-old basalt found on the north shore of Lake Superior and mixed with glass particles that simulate the composition of the lunar soil. Actual lunar soil is too highly prized for such research now.
Above: A lens focuses sunlight onto a vacuum chamber filled with simulated moondust, producing oxygen and "slag." [Larger image]
In their tests, "as much as 20 percent of the simulated soil was converted to free oxygen," Cardiff estimates.
What's leftover is "slag," a low-oxygen, highly metallic, often glassy material. Cardiff is working with colleagues at NASA's Langley Research Center to figure out how to shape slag into useful products like radiation shielding, bricks, spare parts, or even pavement.
The next step: increase efficiency. "In May, we're going to run tests at lower temperatures, with harder vacuums." In a hard vacuum, he explains, oxygen can be extracted with less power. Cardiff's first test was at 1/1,000 Torr. That is 760,000 times thinner than sea level pressure on Earth (760 Torr). At 1 millionth of a Torr -- another thousand times thinner -- "the temperatures required are significantly reduced."
Right: Slag--a low-oxygen byproduct of Cardiff's device. Slag may prove useful as a raw material for bricks, pavement or radiation shielding. [Larger image]
Cardiff is not alone in this quest. A team led by Mark Berggren of Pioneer Astronautics in Lakewood, CO, is working on a system that harvests oxygen by exposing lunar soil to carbon monoxide. In one demonstration they extracted 15 kg of oxygen from 100 kg of lunar simulant--an efficiency comparable to Cardiff's pyrolysis technique: more.
D.L. Grimmett of Pratt & Whitney Rocketdyne in Canoga Park, CA, is working on magma electrolysis. He melts MLS-1 at about 1,400 deg. C, so it is like magma from a volcano, and uses an electric current to free the oxygen: more.
Finally, NASA and the Florida Space Research Institute, through NASA's Centennial Challenge, are sponsoring MoonROx, the Moon Regolith Oxygen competition. A $250,000 prize goes to the team that can extract 5 kg of breathable oxygen from JSC-1 lunar simulant in just 8 hours.
The competition closes June 1, 2008, but the challenge of living on other planets will last for generations.
Got any hot ideas?
Gives a whole new meaning to go suck a rock don't it?
O2 is 24% of the lunar regolith by weight. Cook the regolith and you have OXYGEN up the wazzoo!
Let's get on with it.
L
Of course, the Lunar Surface will present challenges but the Texas towers were gathering oil form 5000 feet in the '50s and now the sew spar technology is drilling for oil in mile deep water!!!
Good Old American Ingenuity!
The moon is 1/3 oxygen. This has been known for a while. What it is short of is hydrogen and carbon. Don't believe there will be domes on the moon, not widespread. There will be hollowed-out caverns. They will dig, and they will have to import some comets.
I wonder if any significant portion of the Martian surface is made up of oxides that could be rendered similarly. It would be wonderful to set up a few thousand solar furnaces (aware as I am of the distance from the sun)and begin turning oxygen loose on Mars.
Yes, Mars also has water and carbon. It looks like a better place to live, but that might be an illusion.
Interesting article. I think these researchers are barking up the right tree, but they need to consider more uses of this slag than just radiation shielding. On earth, slag is used (among other things) in the production of fertilizer. Any sustained human habitation of the moon is going to need grow food.
The article mentions silicon, calcuim, iron, and magnesium oxides, but lunar soil is generally believed to be similar in composition to that of the earth. After nitrogen, potassium and phosphorous, the three next most important plant nutrients are calcuim, magnesium, and sulphur. Plants also need trace amounts of other minerals. The moon is rich in all these elements, except for nitrogen.
This is interesting work, and I wish them well. For a follow on project, they should explore the possibility of separating the elements and purifying the slag into silicon for glass, magnesium and iron for construction, and other elements for fertilizers.
What about nitrogen?
I forgot to mention nitrogen. That will have to be imported also, and that is a problem. Earth is a nitrogen planet, which makes bomb-making and agriculture relatively easy.
I think we're going to need to bring our own sources of carbon and nitrogen. I'm not sure the lunar soil contains significant amounts of those elements.
Water is 89% oxygen by weight. It would be as easy or more easy to extract the oxygen from water as it would be from those rocks. Electrolysis, for example. And you don't have to go to great lengths to melt the water, first, like you do with the rocks.
There is no water proven to be on the moon. Zero.
Tech ping.
Give them the contract.
I guess we could send a few ships full of amonia, at least until our hydroponic technology is good enough to sustain a nitrogen cycle. That would be one stinky spaceship. ;)
The biggest obstacle is the low gravity and consequent low pressure. The Martian atmosphere would have to consist of almost-pure oxygen to be breathable.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.