May 15, 2007:
The U.S. Navy wanted a smart bomb
that did not pack as much punch as the smallest one currently available, the
500 pounder. Rather than buy the expensive (over $50,000 each) air force 250
pound SDB (Small Diameter Bomb), the navy simply had some 500 pound bombs
modified to remove about half the explosives. Thus they get the same bomb
explosive performance as the SDB, at half the cost. The SDB, of course, is
designed to penetrate concrete or ground, as well as being much smaller than
the 500 pound bomb. That's all well and good, but all the navy wanted was a
bomb that was safer to use against targets in urban areas, where there are a
lot of civilians about.