From Gaza, an array of makeshift rockets packs a counterpunch

Occupied Jerusalem: The rockets are smuggled via ship and tunnel from Iran, Libya, Sudan and Syria and, increasingly, manufactured from water pipes and household items in what a senior Israeli intelligence officer called Gaza’s “high-tech” sector - about 70 makeshift factories staffed by 250 men and overseen by a few dozen engineers and chemists.

And while these rockets rarely hit high-value targets and have not killed a single person - the vast majority are stopped by Israel’s Iron Dome system or explode in open fields - the sheer number fired by fighters into Israel since July 8 has shaken Israeli society, offering a sobering counterpunch to its superior firepower. The rockets have reached far into the north, threatening the commercial centre in Tel Aviv and beyond.

“They judge their achievement not just by the number of casualties but also by the harassment and the disruption to life they cause,” Uzi Rubin, a retired Israeli general and pre-eminent weapons expert, said of the fighters. “A lucky hit can cause a lot of damage and casualties, and that could happen at any time.”

The Israeli military estimates that Hamas, the Islamist movement that dominates Gaza; Islamic Jihad; and other fighters had a combined arsenal of 10,000 imported and homemade rockets at the start of the latest conflagration, about double their cache at the end of the last battle, in 2012. Military officials said their intense bombing had destroyed a third to half of those weapons, which they said are mainly stored underground and fired from parking lots, apartment windows and schoolyards, or through trap doors that are quickly re-covered with soil or stones.

The rockets are code-named for Palestinian heroes and for their range: The R-160 honours Abdel Aziz Rantissi, a founder of Hamas, with a 160km reach from the Gaza Strip to the Israeli port city of Haifa. The J-80, able to hit Tel Aviv, memorialises Ahmad Al Jabari, a commander assassinated at the start of the last big battle.

Osama Hamdan, a Lebanon-based Hamas leader, said on Israel Radio last week that the eradication effort is ultimately futile and that each spent or destroyed rocket can be easily replaced “within hours.”

The first crude Qassam rockets, fired in 2001, barely cleared Gaza’s border. On the first day of the current fighting, a Syrian-made M-302 hit near Hadera, 70 miles north.

Israel meticulously analyses every rocket piece that falls in its territory, has intercepted dozens of weapons shipments and expends extensive intelligence resources scoping out the operation on the ground.

“Rocket production is one of the prosperous sectors of the Gaza Strip - there is a very organised array of research and development and production,” said a senior intelligence officer. “Technologically, we are speaking about very simple rockets. They are not accurate at all. They make them by using very simple raw materials, mostly.”

Materials like 6-, 9-, 10- and 12-inch water pipes. Filled with propellant mixed from fertilizer, oxidizer, ammonia perchlorate, aluminum powder and other ingredients. Capped by warheads shaped by ironworkers. Under the tutelage, in some cases, of moonlighting chemistry or physics professors. Instructions are also available on the Internet.

“You need to be an engineer, but it’s not too difficult to learn it,” said another military official. “After you have the basic design, after you have the specific plan, you can do it. You don’t need a huge factory to do it, you can do it in a garage.”