ANN ARBOR – Picometrix, an Ann Arbor-based subsidiary of Advanced Photonix Inc. and a member of the Ann Arbor IT Zone, supplied the imaging systems that NASA used to make sure the foam on the Discovery’s fuel tank could handle the heat from reentry.
Picometrix?s nondestructive evaluation of the foam, which can be up to 12 in. thick, was sprayed on at NASA?s Michoud Assembly Facility in New Orleans, covering a tank 153 ft long and 27 ft in diameter.
Rob Risser, president and general manager of Picometrix and chief financial officer of Advanced Photonix, said that terahertz signals require extreme precision between the pulsed laser source and the semiconductor elements that generate and detect the radiation. Because dragging the laser around the tank is not an option, Picometrix developed a 30-meter-long flexible cable that transported both light and electrical signals.
As for the results, the good news, Madaras said, was that the evaluation methods developed for the foam worked. No critical voids were found, and the foam did not come off at altitudes that would cause damage. This indicated that the void problem thought to be the source of the Columbia space shuttle disaster in February 2003 had been corrected.
Nevertheless, some foam still came off Discovery?s tank during the July 4 liftoff for reasons that are not yet clear. The largest piece of foam that came off Discovery’s tank was barely bigger than a sheet of legal paper and weighed less than an ounce. Like all of the handful of notable foam chunks that peeled away, it came off late enough in the launch to pose no danger to the spaceship.
During the same shuttle’s launch last summer, a 1-pound chunk of foam tore away at a crucial moment. Even though it missed Discovery, it stunned and embarrassed NASA, and forced a one-year grounding of the shuttle fleet, on top of what already had been a 2 1/2-year stand down. The piece of foam that ripped Columbia’s left wing weighed 1 1/2 pounds.
