The crew of the Space Shuttle Discovery may owe a debt of gratitude to a pair of laser-scanning galvanometers.
General Scanning, Billerica, Mass., a member of GSI Group, provides critical laser-scanning and beam-positioning technology to Neptec of Ottawa, Ont. And Neptec's Laser Camera System (LCS) played a vital role in Discovery's recent safe return by supplying detailed 3D images of the ship's heat-shield tiles. The system can detect half-millimeter cracks in the heat-resistant tiles from a distance of up to 4 m.
The LCS system uses a pair of General Scanning's laser-scanning galvanometers, which must survive the severe vibration of the Shuttle's liftoff. Following that, the galvanometers had to drive large mirrors with enough accuracy for image resolution of 350 to 500 m.
"Not only did the scanner meet NASA's vibration specification, it was pretty much indestructible. We shook it as hard as we could and couldn't destroy it," says Iain Christie of Neptec's business development and R&D.
The galvanometers also had to operate in the vacuum of space without outgassing bearing lubricant and contaminating the mirror surfaces. Working together, Neptec and General Scanning found a dry lubricant that solved the problem.