Oberg lets me place and glue two of the lower-precision-fit lenses into an assembly that´s clamped to the workbench. Placing them turns out to be easy enough, gluing them even easier. Just squirt a dollop of cement through an 18-gauge needle, then shine a high-intensity ultraviolet spotlight on it for a few seconds—roughly the same way a dentist cures an epoxy filling.
When Micrometeorites Hit
At 5,000 frames per second you can see a place kicker’s foot connecting with a football as the pigskin slowly wraps around his instep. “To see a golf ball,” says Nathan Nebeker, “you’re up to 12,000 frames per second,” because the club is accelerated to terrific speeds by the lever action of the swing. The next order of magnitude, hundreds of thousands of frames per second, allows you to observe fairly high-speed events: Toyota used a rotating-drum Cordin camera capable of speeds of up to 200,000 frames per second
to peer into its see-through engine. The French navy bought a similar camera, along with a special water-sealed periscope designed and built
by Cordin, to observe the effects of explosives striking ships’ hulls.
But when an object strikes a barrier at 16,000 mph, you need sequences shot in the million-fps range to study the violent effects: Hence the Cordin camera at NASA’s Hypervelocity Impact Test Facility in White Sands, New Mexico, where scientists blast space-vehicle components with tiny projectiles to simulate what happens when they are hit by fast-moving space debris (bits of satellite hardware that have come loose, paint chips) and micrometeorites.
About 100 times a year, a two-stage light-gas piston gun at HITF accelerates plastics and metals in various shapes and sizes (up to an inch in diameter) to 16,000 mph, then smashes them into mock-ups of, for example, the outer skin of a spacecraft. Every exposed part is vulnerable, says Dave Baker, HITF project manager, whether it be “a new particle-impact shield, or a cable, or a tether or anything like that.” NASA has many gas-gun facilities around the country but likes an isolated building at White Sands best. “We can shoot hazardous targets here,” says Baker. “Propellant tanks or oxygen tanks, which might explode, or beryllium, which could be toxic.” Every test is filmed with a Cordin rotating-mirror camera. The footage and other data are analyzed by scientists at Johnson Space Center. Baker was mum on whether the recent space shuttle disaster investigation involved HITF work, though it almost assuredly did: Space debris was one of the possible causes linked to the demise of Columbia.