Defense Minister Ehud Barak said on Thursday that the Iron Dome missile defense system "isn't enough to solve all the problems in the South." "It is an illusion to think that the threats have ended, yet it can definitely be said that Iron Dome is an achievement of the Israeli defense ministry." Barak said. The defense minister also responded to the recent wave of missile attacks from the Gaza Strip, stating that Israel will not quietly stand by. Barak's sentiments were echoed by the president of Rafael Advanced Defense Systems Ltd., which is responsible for developing the system's missiles. While successful tests carried out this week prove the Iron Dome missile defense system operates well and will protect Israel from rockets and missiles, "there is no complete protection," president of Rafael Advanced Defense Systems Ltd, Yedidya Ya'ari, told Israel Radio on Thursday morning. Ya'ari stressed that "additional tests are necessary... there is still a lot of work to do." The Rafael president went on to praise the low operating costs of the missile defense system. If the Iron Dome were deployed during the Second Lebanon War, Ya'ari said, the cost of protecting Israel's North would have been lower than the price of an F-15 fighter jet, valued at tens of millions of dollars. Furthermore, the Iron Dome system calculates the estimated point of impact and does not fire the high-cost missile if the incoming rocket is set to strike in open territory. Some critics, however, have maintained that the Iron Dome system's cost is its main flaw, since it uses expensive missiles - estimated to cost tens of thousands of dollars each - to intercept the usually-primitive incoming projectiles fired by terror groups, which are worth hundreds of dollars. The system is slated to become operational and be deployed along the Gaza border in mid-2010. Meanwhile, ten mortar shells fired by Palestinians in the Gaza Strip hit open areas in the western Negev Thursday morning. No one was wounded in the attack and no damage was reported. The recent Iron Dome tests were overseen by the Defense Ministry, the Israel Air Force and Rafael. During the test, the radar succeeded in detecting which rockets were headed towards designated open fields and therefore did not launch an interceptor to destroy them. The missile volleys which the system succeeded in intercepting included a number of rockets that mimicked Kassam and longer range Grad-model Katyusha rockets that are known to be in Hamas's arsenal. News of the successful tests came a day after IDF OC Southern Command Maj.-Gen. Yoav Galantwarned that the quiet in Israel's South may be temporary, stressing that both the army and civilians must be prepared for the next round of fighting with Hamas.