10 YEARS AGO — 2001
Stirred, not shaken: Solar panels power a 1/8-hp gearmotor to stir up settling ponds in a water treatment process devised by Pump Systems Inc. Stirring the pond pushes oxygen into the water, boosting the rate at which waste decomposes. The result: no smell. Besides making the air fit to breathe, mosquitoes stay away because the water is always moving, and wildlife is returning as the nearby habitat becomes more pleasant.

The stirring motors from Groschopp of Sioux City, Iowa, were tested last winter, left to spin and churn through subzero waters without maintenance or repair. When water-treatment engineers pulled them out this spring, they were still running. The permanent-magnet motors work through a parallel-shaft speed reducer with a 20:1 ratio.

30 YEARS AGO — 1981
Ground tests ending for Satcom III-R: Technicians at RCA Astro-Electronics are shown preparing the RCA Satcom III-R communications satellite for a series of tests in a giant thermal/vacuum chamber. The tests will assure the spacecraft can operate reliably in Earth’s orbit. The satellite will furnish communications for all 50 states, serving the cable-TV industry and providing commercial and government communications.

50 YEARS AGO — 1961
Undersea research— to 6,000 ft — can be carried out in the two-man Seapup VI designed by General Mills Inc., Minneapolis. The 12,600-lb vehicle is less than 19-ft long and 8-ft wide. It is highly maneuverable in vertical, horizontal, and inclined planes. A mechanical arm performs tasks while the Seapup hovers or rests on the ocean floor.

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