Right Stuff for the Super Stuff
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October 26, 1998: The coming return of John Glenn to space
highlights the differences between how the world looked to Americans
in 1962 and how it looks to us in 1998.
John Glenn will conduct tests with a space age super-substance
called aerogel on STS-95
In 1962, as the first American to orbit the globe, Glenn reflected on the delicate environmental balance that protects life on the pale blue planet from the harsh and forbidding black matte of stars.
"Each time around, I noticed a strange phenomenon. The stars shone steady as they neared the horizon. Then they dimmed for a bit. But the stars brightened again before actually setting. They appeared to be passing through a layer of haze about six to eight degrees above the earth and two degrees thick."
The haze that Glenn described was the thin line of atmosphere: oxygen to breathe, ozone to shield ultraviolet radiation, and carbon dioxide and methane to trap reflected heat. The gaseous stuff of life. But from orbit, even the Earth's atmosphere acts only as a semi-transparent window to the starlit sky.
For windows and skylights, the "holy grail" - according to Chemical and Engineering News - is a transparent aerogel. Current aerogels, as produced on the ground, however, are not completely transparent, but instead have a slight blue haze to them. However, space-manufactured aerogel has an improved transparency that could make the substance usable in place of window glass.Aerogel is a remarkable substance. It's the lightest known solid, so much akin to air that it's sometimes called "frozen smoke." Its insulating properties are nothing short of remarkable, protecting virtually anything from heat or cold. It was used by NASA to keep the Sojourner rover warm on the surface of Mars where night time temperatures plunge to -100 degrees. A single one-inch window pane of aerogel is equivalent to the insulation provided by 32 windows panes of glass (R-20 to R-32 insulation factors). Truly, aerogel would make a perfect window except for one thing: it's not perfectly transparent. Aerogel made on Earth is permeated with tiny, irregular pores that make aerogel hard to see through. There is evidence that the irregularities are diminished when the substance in manufactured in weightless conditions. Hence the experiment on STS-95. Astronauts will actually manufacture some aerogel in orbit and see what happens. If aerogel could be made transparent it could revolutionize household windows. By some estimates, aerogel costs 3 times the price of glass, but glass manufacturing costs are only about 10% of the purchase price for windows, so aerogel window manufacturing might still carry a large profit margin.
- Aerogel is only 3 times denser than air.
- Its index of refraction is 1 - 1.05.
- It was used to insulate Sojourner during the Mars Pathfinder mission.
- The first silica aerogels were manufactured in space in April 1996 on a Conquest rocket.
- A 1 inch pane of Aerogel has the same insulating power as 32 panes of ordinary glass.
NASA Aerogel Web Site - technical specifications, research notes, and previous aerogel news stories.
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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