Aerogel - Nasa's Nano

topic posted Fri, January 20, 2006 - 4:07 AM by  Michael David
Here's an excerpt from the article I posted photos from:

"Aerogel Capabilities

Aerogel is not like conventional foams, but is a special porous material with extreme microporosity on a micron scale. It is composed of individual features only a few nanometers in size. These are linked in a highly porous dendritic-like structure. This exotic substance has many unusual properties, such as low thermal conductivity, refractive index and sound speed - in addition to its exceptional ability to capture fast moving dust. Aerogel is made by high temperature and pressure-critical-point drying of a gel composed of colloidal silica structural units filled with solvents. Aerogel was prepared and flight qualified at the Jet Propulsion Laboratory (JPL). JPL also produced aerogel for the Mars Pathfinder and Stardust missions, which possesses well-controlled properties and purity. This particular JPL-made silica aerogel approaches the density of air. It is strong and easily survives launch and space environments. JPL aerogel capture experiments have flown previously and been recovered on Shuttle flights, Spacelab II and Eureca."

and here's the link to the article:
  • I also posted some pics with more quotes from the article in the photo album.
    • What I'm waiting for is a theoretical substance that I call "vacuget". This could only be fabricated by nanos as it is the same as areogel but with a vacuum in the nano cels. In theory this would float in air and nano cel walls would be strong enough to prevent collapse of the nano cels. Nano fabrication of the cels would be done in a hard vacuum.
      • [quote]In theory this would float in air and nano cel walls would be strong enough to prevent collapse of the nano cels.[/quote]

        Why? Unless you figure it would displace more air than it would weigh so like a ship on the sea still float.... if that would work air travel would take on whole new dimensions....
        • Of course it would float because it weighs much less than the volumn of air it displaces. Imagine a giant flying wing that is filled with vacugel and thus floats at a certain altitude. It is solar powered so it never needs to land. Commuter aircraft bring passengers to and from this craft as it passes over certain countries. In effect, if it is at the right altitude, constant upper atmosphere winds would move it without stress & strain. Planes like this could replace communication satellites and be far cheaper to make and maintain.

          Vacugel could support solar panel/shade cloth covering millions of square kilometers of desert areas, allowing only part of the sunlight to reach the surface (The rest generating electricity.), thus these areas could become lush forests again. They would be held in place by the same nano carbon ribbon that the space elevator is to be made of. The cooler volumn of atmosphere underneath would have its own weather with plenty of water condensed out of the air.

          Vacugel- it can't burn nor escape. And vacuum is much lighter than hydrogen!
          • Remember, Michael's original message: "It is strong and easily survives launch and space environments." If aeorgel is strong enough so it can survive the vacuum of space and has normal atmospheric pressure inside the vells, then vacugel could survive the pressure of the atmosphere. The defense rests!
            • [quote]Remember, Michael's original message: "It is strong and easily survives launch and space environments." If aeorgel is strong enough so it can survive the vacuum of space and has normal atmospheric pressure inside the vells, then vacugel could survive the pressure of the atmosphere. The defense rests![/quote]

              if that reasoning works in the real world then yeah it would be great stuff. Maybe one of the space station's first viable exports. I'm not disputing its value only concerned it may not be as easy as it sounds.
          • [quote]Of course it would float because it weighs much less than the volumn of air it displaces[/quote]

            Depends on how heavy the "foam" needs to be to contain the vacume. Kewl if it would work but if to get cells of the foam strong enough to contain vaccume you have to make it as heavy as a brick it still wont function as you hope.
            • I know, Vlad. I don't know the math on this but if areogel is just slightly heavier than air and the same cells could resist the atmosphere's pressure on a vacuum, then it should float in air. I'm not so much thinking of making this in space but making the cells then having nanos that can remove the air molecules inside. Yeah, I know. We got a bit of research to do before that. I'll bet it's possible though! And if the cell walls of areogel can resist the internal air pressure against the vacuum of space, why not the reverse? I think that these walls are ridgid, not like a balloon. A spherical structure of such a small size, should be fantastically strong. Also, if the vacugel was a single adherent mass, and the outer cells were very thick and strong, the inner ones could be much thinner and weaker. I think! I'm tip-toeing into an area where my knowledge is not very extensive!
              • I think aerogel is like a sponge...when in atmosphere, the spaces between the dendrites (which comprise over 99% of its mass) are filled with air...when in space they would be filled with vacuum...if underwater they fill with water. The idea of it was to create a mass which could slow dust particles travelling at ultra high speeds to a stop without damaging them. The stuff does not and can not capture the vacuum of space and bring it back into the atmosphere...air would replace the vacuum. The tennis racket-like structure that deploys it likely DOES pull it back from the vacuum of space into a sealed environment, but only to protect the samples...the container is what holds the vacuum at that point...not the aerogel.

                The way they make it is a chemical process I believe, not a mechanical one, so I dont know if it could be constructed in such a way as to be solid instead of sponge like. If you want to contain vacuum, it would have to be able to solidify its containment barriers...I dont think it does that.

                Otherwise, you are probably almost right about how light it is...except that since those spaces fill with air, it would be heavier than air when in the atmosphere. Interesting ide you have though.
                • in reading clarify, the SPACES comprise over 99%, not the silica/dendrite structure...that is much less than 1 %.
                  • This is the maximum depth. Additional responses will not be threaded.
                    Your use of the word "dendrites" sent me scooting to the web. I had always thought that this material was made of closed cells, but no. See:


                    So vacugel is further away than I thought. The cells would have to be made by nanos, then nanos would have to remove all gases from the inside of the closed cells. I suspect that it can be made and would be structured like the bubbles in a mass of soap suds foam, but much smaller. Or if a piece of aerogel is taken to space where it loses its air and then is coated with a very thin airproof film so it becomes, in actuality, "vacugel. Would the areogel be able to resist the pressure of the atmosphere at the level where we want to operate?
                    • I think your last suggestion, taking it to space then coating it with a film to contain the vacuum is the most feasible. I dont know what kind of structural strength would be required or if it would be in the realm of current technology, but I would think that since I keep seeing references to aerogels being extremely strong when dried and having other properties (like being able to bond different elements to their structures) that this might be fairly feasible...even without involving the use of complex nano-machinery. It sounds possible to me, just using variations of the current chemical processes. Now if we could just get some commercial labs in space....
              • Maybe fill the cells with HE or H2 something lighter than air? Maybe if they were non flamable the cells could make it hold H2 in such a way to prevent explosion. Or just use HE and not worry about it. H2 is just easier to produce.
                • Just read the other posts, maybe sealing the outer edge with a coating seperating the lighter than air inside from the outside apmosphere. I'm thinking floating seat cussions that could be used as ridged blimps. Imagine shipping through air rather than sea for about the same $$$ expenditure.
                  • This is the maximum depth. Additional responses will not be threaded.
                    Just remember that H is lighter than He, thus has more lift for its volumn. Of course vacuum is far lighter than H but has no resistence to compresion. Also vacuum (in space anyway) is much easier to make and much cheaper that H! The whole idea of vacugel is that it would lift greater loads than H or He under the same conditions. Of course it made no sense until the aerogel concept came along. And carbon nanotube coating? I guess so if it's ridgid enough. And I wonder if the gel could be made of lithium metal? Not all that strong but very much lighter than silica. So we have a lithium gel 'filled' with vacuum, coated with carbon nanotube film, floating in the upper reaches of the atmosphere carrying communication equipment as a replacement for satellites. Shall we patent it?

                    By the way, Vlad, ridgid "blimps" are called zepplins. :)
                    • [quote]By the way, Vlad, ridgid "blimps" are called zepplins. :)[/quote]

                      And if they (zepplins that is) are "Led" properly they make kewl music... but we might not need "vacugel" at all if we could make ridgid vacume filled carbon nano tube "balloons". The hardest problem as I see it would be to get it back into apmosphere. CNT (carbon nanotubes) are 100 times the strength of steel at a sixth of the weight so could concievably contain the vaccume while still being lighter than air. Put those in jet wings in place of fuel tanks and aircraft would need a fraction of their current fuel loads.
                      • Yes, an interesting thought. However, in lighter than air stuff, one tries to get a container as globular as possible because a sphere has the lowest container weight in relation to volume contained.

                        Maybe one could start with a carbon nanotube "balloon" with hydrogen in it, which gas would resist the pressure of the atmosphere. Once it reached a high operational altitude, we pump out the hydrogen leaving a vacuum. At least what hydrogen that didn't have to be vented on the way up. Or we use regular hydrogen helper balloons too. In the stratosphere, where there could be a tenth of surface atmospheric pressure or such, the "balloon" could withstand the pressure and, with a vacuum inside, have much more lifting power. Great minds at work here or what?

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