Israel has developed a set of sensors, operated from a tethered balloon, that can spot Palestinians trying to launch short range Kassam rockets. The Israeli military admitted that the still secret system was responsible for the recent interruption of a team of Palestinians setting up a Kassam rocket for launch. The army would not say how the balloon mounted sensors operated, but it is probably a pattern matching system that alerts the operators to check out the video image and confirm that it is a rocket launch being prepared. At that point, mortars, artillery, helicopter gunships or nearby troops can be alerted to stop the launch. Over 350 of the Kassam rockets have been fired in the last two years. The crude rockets are constructed in Gaza workshops, and are not very accurate. Only two Israelis have been killed by the rockets, but efforts to stop the use of the rockers have, so far, not been very successful. Only one of the balloon systems, said to cost about two million dollars each, is operational (several hundred feet over an Israeli base just outside of Gaza.) The army wants to buy ten more of the systems, which would enable it to cover all possible launch areas for the rockets. If the pattern recognition software is good enough to spot a rocket launcher being set up, it may be able to tweaked to spot other terrorist activity as well. The Palestinians, however, will adapt to this new eye in the sky, which means, as usual, that no reconnaissance advantage retains a decisive edge for long.