Micrometeorites and undetectable bits of space junk as small as 0.4 mm pose a serious threat to every current and future manned space mission. These dust-size particles travel as fast as 12 miles per second, packing enough momentum to melt aluminum spacecraft skin -- or turn it into a puff of vapor. To find small holes, astronauts must use handheld ultrasonic devices such as directional microphones -- a time-consuming process. NASA scientists seeking other solutions are focusing on new wireless technologies that can find tiny leaks by tracking vibrations across a spacecraft’s metal skin. "There is turbulence as the air spreads in the vacuum, and that reacts against the plate at the edge of the hole," says Dale Chimenti, a professor at Iowa State University who's developing the inch-long sensors for NASA. The sensors would stud the inside of the shell of a spacecraft, giving mission controllers a faster way to locate leaks before problems arise. Multiple instruments would be needed to safeguard the entire craft and triangulate the signals to pinpoint a location. The technology may not be funded for use in the International Space Station or shuttle fleet, but interest from future space programs is high. Earthbound applications include monitoring pipelines and pressurized oil tankers.