Bad vibrations

Leaks are hard to find because spacecraft are full of life-support systems, computers, controls, gear and research equipment. All those things can hide a leak .Leaks are also hard to find because astronauts can't hear the telltale hiss of escaping air because the hiss is blowing outside the spacecraft and away from searching ears.

So the National Aeronautics and Space Administration (NASA) asked an Iowa State research team led by Dale Chimenti, an Iowa State University professor of aerospace engineering, to develop a sensor that can find leaks by detecting the small vibrations in a spacecraft's skin caused by escaping air. NASA has so far supported the work with $600,000. The Iowa State engineers are working with Invocon of Conroe, Texas, to use their sensor with the company's wireless electronics.

Chimenti's square sensor includes an array of 64 elements that detect vibrations as they radiate along the spacecraft. The different elements pick up vibrations at different times. Those differences can be analysed by a computer to determine the direction of a leak. Add information from multiple sensors, and a leak can be found in about a minute. It can take weeks to find a leak with NASA's current handheld, ultrasonic detection devices.