The Optically Clear Laminating Adhesive 8141 from 3M, St. Paul, has a scant 0.1% haze level and is free of common defects such as bubbles and dirt because it's manufactured in clean rooms. It also withstands the elements without delaminating or yellowing.

Window maker Eyesaver International Inc., Hanover Mass., uses the film to attach a clear "scratch pane" to the inner surface on Space Station windows. The scratch pane protects the 0.5-in.-thick windows from damage, keeps shards out should a window shatter, and provides a substrate for transparent, conductive, thin-film heaters.

"The 3M product has excellent uniformity, creates zero optical distortion, and coats flat without voids," explains Eyesaver's Steve George. "Station builder Boeing says it's clear enough to photograph through," adds partner Matthew Smillie.

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Eyesaver International workers apply an optical-quality adhesive film from 3M to one of 18 laminated windows for the International Space Station. Seven of the 21 to 29-in.-diameter panes will be installed in the Station's cupola to permit direct views of robotics operations, spacewalks, and experiments. The rest are in the laboratory module. When completed in 2005, the 470-ton Station will contain about 43,000 ft3 of pressurized, habitable space to house a crew of seven.