This may be why Saddam Hussein is willing to risk them to test Western resolve as the US administration changes.
The SA-2 first entered Soviet service in 1957, the SA-3 in 1961. Although the former, which can hit aircraft flying at up to 60,000 feet or out to 25 miles and was responsible for downing Gary Powers' U2 spyplane over the Soviet Union in 1960, it is not formidable by modern standards.
The SA-3 can hit aircraft flying up to at least 40,000ft, or out to 20 miles. The air exclusion zone extends for 200 miles from the 32nd parallel down to Iraq's southern border, so they provide only patchy coverage.
SA-2 flies at 1,150 metres per second (2,600 ft/s) - 3.5 times the speed of sound: SA- 3, a two-stage missile, at 660 metres per second (1,500 ft/s). SA-2, carrying a 400lb warhead, is guided automatically by radio commands from the tracking radar: SA-3, with a 200lb warhead, requires commands from a human operator on the ground.
The Iraqis may have modified some SA-2s with an optical guidance system, but analysts do not believe that the surface-to-air missiles south of the 32nd parallel have been modified significantly.