"The future is in the hands of those who explore ...
and from all the beauty they discover while crossing perpetually receding frontiers,
they develop for nature and for humankind and infinite love."
-Capt. Jacques-Yves Cousteau

Frozen smoke (FROH.zuhn smohk) n.
Scientists have given it many names, solid smoke, blue smoke, and San Francisco fog. Also called Aerogel, in pictures it is almost transparent, hazy at the edges with a light-bluish hue. Hence many researchers have given it the pet name frozen smoke. Composed of 99.8 percent air and a thousand times less dense than glass or comparatively a mere three times as thick as air the properties of frozen smoke put this extremely lightweight, porous substance made from a silica gel as the least dense solid in the world by Guinness World Records. Prepared from a liquid silicone compound, dried in a pressure cooker to maintain its shape the results are described as something similar to ‘a glassy silicon sponge.’

Most versions of frozen smoke date their development to the 1930s, but the Oxford English Dictionary has a few earlier citations from 1923. The earliest published illustrations using the phrase frozen smoke were published around the turn of the millennium:

    Scientists at Lawrence Livermore National Laboratory in California have developed a fluffy substance that contains so little solid matter it is almost invisible, but that can nevertheless support fairly heavy weights.

    The new material, consisting of linked microscopic fibers of silica, has been dubbed ''frozen smoke'' because of its extreme lightness and transparency. The lightest version of the material developed by the laboratory has a density of only 5 milligrams per cubic centimeter, about the density that would result if a teaspoon of water could be dispersed uniformly throughout a volume of more than one gallon.
    —"A Gossamer Cushion," The New York Times, March 6, 1990

In the 1930s by a Stanford University researcher proclaimed it as the lightest solid recognized today, the physics this foam possesses are properties to be marveled about. A chunk the size of a human weighs less than a pound, but can support almost a thousand pounds or the equivalent of a small car.
    Like glass, it is made from silicon dioxide and sand. Unlike glass, it is 99.8% air. The stuff is formally known as aerogel, and unofficially as "frozen smoke". A packet of the glassy, spongy stuff is already aboard a spacecraft called Stardust, designed to catch fragments of a comet called Wild-2 in 2004. Steven Jones of the Jet Propulsion Laboratory in Pasadena has composed an aerogel that weighs three milligrams a cubic centimetre. It has been recognised by Guinness World Records, as the world's lightest solid. "It is probably not possible to make aerogel any lighter than this because then it wouldn't gel," said Jones.
    —Tim Radford, "Science update," The Guardian, May 16, 2002

Ideas that Gel

An aerogel is basically a liquid that has been replaced by air making it a terrific insulator against extreme environments. This is what has captured the most attention recently. As a super thin thermal barrier it could significantly improve the energy efficiency of a house used in furnace insulation, windows or skylights. Employed in the world of high tech it could be applied as super-slim thermal barriers for ultracapacitors in computers to prevent signal crossover -- a common problem in current chips. By encasing mufflers the material it would help deaden the sound of exhaust systems. Today it’s being used as a super-insulator by one trekker across the south pole who is a diabetic using frozen smoke as part of the insulation packaging to keep his insulin supply from freezing and becoming useless in the sub zero temperatures.

Looking for a durable, lightweight, heat-resistant material for airplanes and spacecraft, aerospace engineers began to develop aerogels decades ago. Initially manufactured in labs they were low quality since gravity permits sedimentation causing a layer of dense foam close to the bottom of the container and a slight foam near the top. Over the years many engineers have come up with a variety of ideas to solve this dilemma. One such proposal was to take to the skies. "To make Aerogel clear is the challenge," holds one expert "Once you make it clear, it becomes a whole new product and it opens up a whole new world of applications. .

In April 1996 the first silica aerogels were manufactured in space on a Conquest rocket in hopes of learning enough about the zero-gravity process to mimic it on Earth. One senior engineer, Scott Brown at Alabama’s Institute Engineering Research Center explained that the experiment is somewhat like the process of adding fruit to Jell-O. "When you add banana slices to Jell-O and put it in your refrigerator, the banana settles on the bottom," Brown explains. "But if you add banana to Jell-O in outer space, the banana will disperse more evenly throughout the Jell-O because gravity isn’t dragging it down.” Equipment aboard the Starfire rocket formed a small specimen of aerogel with uniform cell size, wall thickness, and density. Here was evidence suggesting that the irregularities in frozen smoke are diminished when the substance in manufactured in weightless conditions. Truly, aerogel would make just the thing as a window except for one thing: it has to be perfectly transparent. .

Did you know that if flattened out, a cubic inch of aerogel would yield a surface area larger than a football field? Yet what sounds like the stuff of science fiction promises to be incredibly practical. Just a slender panel can safeguard a hand from a blowtorch flame. Even though frozen smoke is only three times the density of air--the material has tremendous insulating capability. The following year NASA scientists found aerogel critical for one of several space missions. Blankets of it acted as phenomenal insulators on behalf of the Mars Pathfinder mission that landed on the Red Planet in the summer of 1997. Using aerogel NASA was able to keep the tiny Sojourner rover warm and running on the surface of Mars to guard against the rover freezing in the chill of a Martian night, when temperatures plunge to -100 degrees.

Encouraged with the results of earlier experimentations, more tests began on the 1998 space shuttle mission Discovery STS-95 where astronauts actually manufactured aerogel in orbit to see if it could be made transparent eager to discover if it could lead to aerogel window manufacturing. Adding to the impetus was the 1997 Kyoto Conference setting international standards for a five to ten percent cut in carbon budgets. Some economists consider this impossible without triggering an economic recession. Under the agreement, carbon percentage allocations have been proposed as tradable items and can be bought by industrialized nations from less industrialized societies, in effect a stock market trading on smog.

    Aerogel may also have a role to play in keeping the atmospheric line clear, the thin air gap that John Glenn described more than 35 years ago. By reducing home heating costs aerogel could reduce global energy needs and minimize the pollutants that inevitably come with energy production. Science Magazine (1998) listed next-generation window technology as a critical point in the US obligations to meet its international global warming commitments
A clear aerogel could offer a way out. One case in point from the December 1997 issue of Today's Homeowner magazine called the NASA aerogel research "Super Stuff" in its cover story entitled "Best New Products for 1998." The article sums up: "The potential market for a clear aerogel is enormous, considering that window heat loss accounts for up to 30 percent of energy lost from a home. A well-designed aerogel window could lower heating and cooling costs by a comparable figure."

Another long-term agenda for frozen smoke is the reduction of industrial waste. Not only would it reduce the energy load, but also its insulating properties can capture waste and polluting gases before they reach the atmosphere. So said one industrial group in earlier 1996 called The Attia Applied Science, Incorporated, "The market for the aerogel absorbents is potentially vast. In principle, wherever alcohol and fossil fuels are used, aerogel absorbents could capture waste gases before they are emitted into the atmosphere."

Four years earlier during the STS-95 mission Senator John Glenn and other astronauts tested whether aerogel made in the weightlessness of space is more transparent than aerogel made here on Earth with less than stellar results. Enter one aspiring engineer Stephen Steiner, who was a spring sophomore at the University of Wisconsin-Madison in 2002. He and three of his classmates took a wild ride in an airplane nicknamed " the vomit comet," in partnership with NASA. They wanted to go weightless to experiment with one type of manufacturing process for aerogel. They had high hopes for a high-tech foam that might transfigure just about everything from refrigerator design to spacecraft. In Zero-G’s they wanted to modify the aerogel so that nanopores, not much bigger than atoms would make a more translucent substance. Researchers at Lawrence Berkeley National Laboratory worked with Steiner’s group to modify the production of aerogel by devising a special oven which succeeded in making a lump of the airy substance."It was very ambitious. I was surprised he was able to do it," says Dr. Arlon Hunt, an aerogel expert at the national laboratory.

After his prize winning research Steiner's next step was to try and get rid of the foggy blue hue. Theorizing that frozen smoke’s big pores caused the dispersing blue and violet light, he conjectured that if they were more homogeneous and even tinier a majority of the light would pass through whole and clear. In 1998 and 1999 these ideas led to the experiments on space shuttle missions suggesting a difference between Earth-made and space-made gels with the hope that what was learned in outer space could be applied to the manufacturing process on earth; but the results were inconclusive.

Undeterred Steiner was sure aerogel structure would be significantly different if manufactured in space, but to test his theories, he had to escape the Earth's gravity."People never consider the role of gravity in chemical reactions," says Steiner, a chemistry major with a penchant for engineering.

In the early spring of 2002, Steiner and his team from Wisconsin's Madison campus arrived at the Johnson Space Center in Houston, Texas to board NASA’s KC-135A.The group wanted to do trials on Steiner’s ideas using simulations during weightless flights on a jumbo jet. As part of the Reduced Gravity Student Flight Program, they flew a succession of sharp parabolic arcs, each person along for the ride were free from the earth’s gravity for about half a minute.

The brief period of weightlessness didn't give Steiner much time since manufacturing the material is a two-step process. Typically the process is begun with the creation of a Jell-O-like substance called an alcogel which is then dehydrated in a high-pressure oven to produce aerogel. Air-pocket size is established during the vital alcogel development, which normally takes a number of hours.

So Steiner worked out a quick gelation process where alcogels were ready in just a few seconds in a semi-automated mini-lab on the KC-135A, but soon discovered that his equipment wasn't up to the task. "Our first attempt was very unsuccessful," he admits. "I didn't understand how sophisticated the engineering had to be. The equipment didn't work."

Steiner had designed his equipment do the chemistry in zero gravity, finally producing two 1.5-inch discs of alcogel, which he dried in his basement over the following summer. The two samples didn’t supply enough for a meticulous scientific analysis, but Steiner is certain he's on the right track. "I've been making aerogels a long time and these alcogels are definitely less blue than they would be if made on Earth," he told one interviewer from National Geographic Magazine. "I think it worked."

To Catch a Falling Star

Everything in the universe, from planets to the particles of our skin, is composed of stardust. Frozen smoke is unquestionably a curious phenomenon of science; did you know it could catch a comet? To date the space age styrofoam has flown on space shuttles, the Mir Space Station and the Mars Pathfinder. The slightly blue material as an effective way to collect tiny particles is the latest generation from earlier recipes coming from a NASA engineer.

Placed on the Stardust probe to catch interstellar and comet dust grains it was launched in 1999, Stardust is scheduled to become the first to return space samples from beyond the moon. The $200 million mission should make contact with comet Wild-2 in 2004 and swing back by Earth to deliver its stellar payload in 2006.

    The collection system will extend from the spacecraft and trap particles as they collide with it. To prevent damaging or altering the particles -- each smaller than a grain of sand and traveling as much as nine times the speed of a bullet fired from a rifle -- the collector uses a unique substance called aerogel. Often called "frozen smoke," aerogel is a transparent blue silica-based solid that is as much as 99.9 percent air. It is as smooth as glass, something like plastic foam without the lumps. A block the size of a person weighs less than a pound but can support the weight of a small car.

    On the trip to Wild 2, (pronounced Vilt 2), the aerogel-equipped collection panel will be deployed to trap interstellar particles traveling in space. During the encounter with the comet, some 242 million miles from Earth, the opposite side of the panel will gather bits of comet dust. Trapped particles will leave a telltale trail through the aerogel that scientists will follow to find the grains and extract them. Upon leaving the comet, the collection panel will retract into its capsule.

    Once the Stardust capsule parachutes into Utah's Great Salt Desert in 2006, the particles it collects will go to Johnson Space Center in Houston and then be parceled out to various research facilities, including the University of Washington. Because comets are about equal parts ice and dust, (Dr. Donald E.) Brownlee believes the particles will be cryogenically preserved interstellar dust left from the birth of the solar system some 4.6 billion years ago. Such grains can be found only in the outer solar system, he believes, because heat has destroyed them nearer the Sun.

    Brownlee's previous work collecting cosmic dust particles led to their being named Brownlee particles. Cosmic dust was brought back to Earth on Gemini missions in the 1960s. Later, high-flying U2 planes and balloons gathered particles from different levels in the atmosphere, and space dust even has been collected from the ocean floor. "A comet mission is the logical extension," Brownlee said.

When the space probe Stardust encounters the comet that originates from border of the solar system; the Oort Cloud, the particles will be traveling up to 6 times the velocity of a rifle bullet. The aerogel on Stardust was developed and manufactured at Jet Propulsion Laboratories to bring home souvenirs from space. Little by little the tennis racket shaped piece of aerogel will gather these fragile and smaller than a grain of sand specks. Because the substance is less dense at the surface where particles impact, the density gradually increases as particle travels deeper and gradually slows to a halt without changing their chemical composition, shape or harming them.

Down to Earth Dreams

NASA-supported research has encouraged a great deal commercial interest in the product for an assortment of industry and consumer applications:
    Under a NASA Small Business Innovation Research (SBIR) contract with the Kennedy Space Center (KSC), Aspen Systems, Inc., Marlborough, Massachusetts, has manufactured a variety of aerogel products, including aerogel superinsulation. ….. Aspen Systems' aerogel-based superinsulation is an innovative, flexible cryogenic insulation with extremely low thermal conductivity. The design of this product takes advantage of the unique properties of specially-made aerogel materials. Aerogels formed at the fiber-fiber contacts of a matrix material force solid heat transfer to occur through the very low thermal conductivity aerogels. Air conduction is greatly reduced due to the very fine pore size of the aerogels.
Since its founding in 1984 Aspen Systems has produced two individual products for NASA one for cryogenic and room-temperature applications, and the other for high-temperature uses. The elastic cryogenic superinsulation was developed for the Kennedy Space Center, while the high-temperature adaptation was designed to Ames Research Center specifications. Since then Aspen Systems has grown into a multi-disciplinary organization with a number of products all set for commercialization. Company know-how ranges from, “energy and environmental systems to specialty materials, photonics, and biotechnology.” Serving an ever widening range of US Federal and state agencies this technologically diversified small business also provides for many industrial and commercial clients. “Commercializing the easy-to-use aerogel superinsulation has already started,” comments Hamed Borhanian, Vice President of Aspen Systems. "We are now in the process of securing investor funds to embark on a full scale commercialization."
    Superinsulation can be manufactured as fully flexible or as relatively rigid, but not brittle, for insulating a wide variety of objects. An external jacket of pipe, foil, or plastic may be employed, as required, to protect superinsulation from environmental or mechanical impact. SBIR (Small Business Innovation Research) awards to Aspen Systems has spawned a unique aerogel fabrication process, in which the physical properties and thermal performance of the aerogels can be tailored for a given application.
The latest batch can endure temperatures as high as 2,600 degrees F (1,400 degrees C) and tips the scales at just .00011 pounds per cubic inch (3 milligrams per cubic centimeter), according to the Guinness Web site.

Literally hundreds of inquiries; ideas and dreams have poured in since Aspen Systems opened its web site advertising its form of aerogels. Imaginations are running wild: from insulation for offshore oil well underwater pipelines to insulation for shipping containers. And how about refractory insulation for automotive firewalls, floorboards, and exhaust systems? Not to mention aerogels as an efficient filtering medium as acoustic damping insulation for buildings, process equipment, and headphones.

Over decades of dreams as progress with aerogels continues, this smoky hued product holds promises of a clearer future and increases the chances of future generations so that one day even the atmospheric haze will not cloud our view of the stars.


"Frozen Smoke" May Be Material of Future:
news.nationalgeographic.com/news/2002/ 05/0508_020508_TVaerogel.html


Guinness World Records:

NASA's 'frozen smoke' named lightest solid:

John Glenn will conduct experiments with 'aerogel' on STS-95:

Keeping insulin warm in Antarctica :
www.post-gazette.com/healthscience/ 20021021antarcticmainsci2p2.asp

Planetary Society:
www.planetary.org/html/news/articlearchive/ headlines/1998/headln-070998.html The Word Spy:

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