TEL AVIV: The Arrow missile, untested in combat, will be Israel’s last line of defence if Iraq responds to a US attack by launching Scud missiles against the Jewish state.

But whether the world’s first custom-designed and operational anti-ballistic missile will prevail is still an open question among military experts.

“It’s the 64,000 dollar question,” said Uri Bar-Joseph, a strategic studies expert at Israel’s University of Haifa.

The possibility of the Arrow’s failure takes on cataclysmic proportions given concern in Israel that Iraqi leader Saddam Hussein may arm his Scuds with biological and chemical warheads if the United States tries to oust him.

Iraq fired 39 Scuds armed with conventional warheads at Israel in the 1991 Gulf War, causing extensive damage but few casualties.

So far the Arrow is the world’s only anti-ballistic missile to achieve the near impossible feat of intercepting a ballistic missile in the earth’s atmosphere. Experts say it is like hitting a bullet with a bullet.

“It is a very capable interceptor,” Moshe Arens, a former Israeli defence minister who was one of the original backers of the partially US-funded project, said. “It has a high probability of interception.”

The Arrow has performed with flying colours in a battery of tests simulating Scud missile attacks.

“The problem with any system is that until it is put into operation, real operation, wartime operation, you don’t know how well it will work,” Bar-Joseph said.

There are already two Arrow missile batteries deployed in secret locations in Israel intended to shield the entire country from missile attack. A third is due to be deployed soon.

Some experts have raised the possibility that Saddam may not be able to fire a shot at Israel at all as US or Israeli commandos and planes would try to locate and destroy Scud launchers first.

SECONDS TO SPARE: Success or failure in the Arrow’s pending duel against the Scud will be measured in seconds and millimetres as it soars into the earth’s atmosphere to intercept the incoming missile some 80 kms above the ground.

From the moment its Israeli-developed Green Pine radar system detects an incoming missile, the firing system has three minutes to launch an Arrow, locate the incoming Scud and shoot it down before the missile hits Israeli territory.

The secret of the Arrow’s effectiveness is that instead of directly hitting the attacking missile, the Arrow blows up near the incoming missile and destroys it.

Israelis have bitter experience with missile batteries bearing billion dollar price tags which are touted as their best defence against ballistic missile attack.

In 1991, they had high hopes that the US Patriot missile would protect them from Iraqi Scuds.

But experts said the Patriot failed miserably to intercept and destroy Scuds, partly because when the Iraqi missiles re-entered the atmosphere they did not maintain their trajectory.

While most experts agree that the Arrow is in an entirely different league from the Patriot, they all acknowledge that its true capabilities will be known only after it has tasted combat.

Its success rate is estimated at 95 per cent. But it is the five per cent failure rate that sends chills down the spines of Israelis fearing Iraqi Scuds with payloads of anthrax spores, smallpox viruses or deadly VX and Sarine gases.—Reuters