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John Glenn will activate an experiment later today that could revolutionize the computer industry and much more
October 30, 1998: Later today John Glenn will flick a switch that could boost the computer industry, lower home heating bills, and reduce global warming. Fifteen minutes later, he's scheduled to go to sleep. Glenn is renowned for his cool demeanor so he probably won't have trouble sleeping so soon after possibly changing the world. It's all in a day's work. Glenn's momentous switch will activate the STS-95 aerogel experiment, a first attempt to manufacture aerogel in low gravity aboard the space shuttle. Aerogel is a remarkable space-age substance that has excited scientists and entrepreneurs alike. In the "Technology to Watch" section of Fortune Magazine, the use of aerogels was cited for more than 800 different product applications ranging from satellites to surfboards. It's the lightest known solid, so much akin to air that it's sometimes called "frozen smoke," yet it's astonishingly strong. A human-sized block of aerogel weighs only one pound but can support the weight of a small automobile. Its insulating properties are remarkable -- A single one-inch window pane of aerogel is equivalent to the insulation provided by 20 to 30 panes of normal glass.
Indeed, aerogel would make a great window except for one detail: it's hard to see through. Aerogel made on Earth is permeated with tiny, irregular pores that make aerogel partially opaque. There is evidence that the irregularities are diminished when aerogel is manufactured in weightless conditions, and that's what Glenn and the other astronauts will try to do tonight.
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See and hear John Glenn discuss aerogel as he prepares for the STS-95 experiment.
Video produced by the American Institute of Physics "Inside Science."
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The aerogel experiment consists of a set of 16 pairs of syringes joined at the nozzles. When John Glenn activates the switch, battery powered motor drives will begin to push and pull the syringe pistons until a barrier breaks. The two solutions are mixed for a preset number of cycles, then the experiment stops automatically. The experiment creates a silicon dioxide gel that is later returned to Earth for supercritical drying as an aerogel. If aerogel could be made transparent it could revolutionize household windows. But that's not all. Aerogel also has an important role to play in space exploration, it could fuel new growth in the computer industry, and it may help reduce carbon dioxide emissions before they reach the atmosphere.
Aerogel in Space
As the world's lightest solid, aerogel can save significant weight on future space vehicles. As one example, NASA considered equipping the Mars rover with solid aerogel tires. Sojourner eventually blasted off with more conventional wheels, but aerogel was used as an insulator to keep the Rover warm on its long journey to Mars and after it arrived on chilly minus100 degree Martian nights.
Aerogel will also be used during the NASA Stardust mission to capture and return dust particles from a comet. The Stardust spacecraft is scheduled to launch in February 1999, and it will rendezvous with comet Wild-2 in January, 2004.
To collect the particles from the comet without damaging them, STARDUST will use an aerogel-based collector, pictured right. When a particle hits the aerogel, it buries itself in the material, creating a carrot-shaped track up to 200 times its own length, as it slows down and comes to a stop - like an airplane setting down on a runway and braking to reduce its speed gradually. Since aerogel is mostly transparent - sometimes called blue smoke - scientists will use these tracks to find the tiny particles. The track is largest at the point of entry, and the particle can be collected intact at the point of the cone. The distinctive shape of the cone will tell scientists the particle's direction of incidence, and allow them to discriminate between cometary and interstellar dust grains.
Aerogel Supercomputers?
It is widely thought that the future of the computing industry relies in large part on new chip materials, such as aerogel, to maintain the growth of computing speed, sometimes called Moore's law. Moore's law, named after the former CEO of Intel, states that the computing power of chip manufacturing doubles every 18 months. Over the next decade, this would translate the current state of the art (300 MHz) desktop PC into a whopping 24 GHz machine! The challenge to maintaining Moore's law down to molecular scale turns out not to hinge on smaller transistors but on better ways to keep the interconnecting wires from shorting across the narrow dividing space between them. That's where aerogel, as the best solid dielectric ever created, may be the secret for next generation growth.
| Computing Speed: Additions per Second |
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1971
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1974
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1979
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1982
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1985
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1989
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1993
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1995
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2006?
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60,000
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290,000
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330,000
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900,000
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5,500,000
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20,000,000
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100,000,000
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250,000,000
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24,000,000,000?
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Aerogel at a Glance
| Property |
Value |
| Density |
0.003-0.35 g/cc |
| Index of refraction |
1-1.05 |
| Thermal tolerance |
to 500 C |
| Coefficient of thermal expansion |
2-4x10-6 |
| Poisson ratio |
0.2 |
| Young's modulus |
106-107N/m2 |
| Tensile strength |
16 kPa |
| Fracture toughness |
0.8 kPa*m0.5 |
| Dielectric constant |
1.1 |
| Sound velocity |
100 m/s |
Aerogel and the Environment
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 prescribed by the late 1997 Kyoto Conference resolutions. The Kyoto Conference set international standards for a 5-10% cut in carbon budgets and this is considered impossible by some without triggering an economic recession. Under the agreement, carbon percentage allotments are proposed as tradable items and can be bought by industrialized countries from less industrialized societies, in effect a stock market trading on smog.
New technology could offer a way out. As an example, the December 1997 issue of Today's Homeowner magazine listed NASA aerogel research ("Super Stuff") in its cover story entitled "Best New Products for 1998." The article concludes: "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...". Reduced industrial waste is another long-term target of aerogel research. Not only is aerogel of scientific interest to reduce the energy load, but also to capture waste and polluting gases before they reach the atmosphere. The industrial group, The Attia Applied Science, Incorporated (TAASI), concluded in 1996: "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."
Indeed the future of aerogel seems wide open, but much of it depends on the STS-95 experiment, scheduled to begin later tonight around 8:30 pm EST. By flipping one small switch John Glenn may be making history, yet again.
Web Links
NASA Stardust Mission Aerogel Page - learn how aerogel will be used to return samples from a comet
Right Stuff for the Super Stuff -- more information about the STS-95 aerogel experiment
NASA Office of Space Sciences -- press releases and other news related to NASA and astrophysics
The house of the future?- Aerogel research could lead to super energy efficient homes
A 24 GHz computer for your desktop.- Aerogel could lead to ultra-fast personal computers.
More Space Science Headlines - NASA research on the web
Life and Microgravity programmatic information from NASA headquarters.
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Author: Dr. David Noever ; Dr. Tony Phillips
Curator: Linda Porter
NASA Official: Gregory S. Wilson
