January31, 2007: The U.S. Navy has received its first The ALMDS (Airborne Laser Mine Detection System). Designed to operate from the MH-60S helicopter, ALMDS uses a Laser Imaging Detection and Ranging blue-green laser to detect, and identify naval mines near the surface. Unlike previous detectors, that were "sleds" moving on the surface of the water, towed by a larger helicopter, ALMDS operates from the low flying, and smaller, helicopters. Surface mines are either moored (via a chain to the bottom) or floating (a favorite terrorist tactic), and many float just below the surface. The laser works very quickly, and enables the ALMDS equipped helicopter to quickly check out large areas for surface mines. Terrorists have used naval mines before, of the floating variety. Navies tend to use the more sophisticated, expensive and hard-to-get bottom mines (that lie on the bottom, in shallow water). The first two ALMDS systems cost about $18 million each. The other 43 the navy will buy, will cost somewhat less.