Iran’s Natanz Tough Nut to Crack

Israeli Defense Minister Ehud Barak is in town this week to discuss with White House and Pentagon officials what to do about Iran’s nuclear program. Accompanying Barak is Israeli Transport Minister Shaul Mofaz; he’s the former IDF chief who set off a firestorm recently when he said an Israeli military strike against Iran is “unavoidable.” Current IDF Chief of Staff Gabi Ashkenazi was here last week and met with his Pentagon counterpart, Admiral Michael Mullen. Ashkenazi reportedly said he favors a diplomatic solution, but also issued the standard declaration that “all options must be prepared” for stopping Iran’s nuclear program.

There has been considerable debate about whether Israel could even carry out an effective air strike against Iran’s nuclear program. Analysts say there are too many factories, labs and reactor sites dispersed too widely across the country. According to a 2006 paper published by two MIT doctoral candidates (one of the most thorough pieces of analysis available), it would be impossible for Israel to knock out the entire Iranian nuclear program but the target set could be narrowed to the most critical facilities. They identify the critical nodes as: the Esfahan uranium conversion facility, the gas centrifuges at the Natanz enrichment facility and the heavy water plant and future plutonium production reactors at Arak.

The MIT analysts identify Natanz as the most difficult target because much of the facility is buried deep and covered with layers of concrete. Israeli bombs would have to penetrate the earth covering, bore through the concrete layers and then dump enough bombs into the hole to generate blast pressures that could damage or destroy the equipment inside. They figure the strike package would have to drop a combination of roughly 24 BLU-109 2,000 lb. and BLU-113 5,000 lb. bunker busters on Natanz. The facilities at Esfahan are not buried and those at Arak are not hardened, so those targets sets would be relatively simple to destroy with no more than 24 2,000 pound GPS guided bombs.

What does Israel have as far as deep strike weapons? The MIT folks count at least 25 F-15I (the Israeli version of the F-15E Strike Eagle) and 20–50 F-16I, both airframes configured specifically for deep strike missions. Israel also has a large number of F-16s that could be fitted as strike aircraft, Wild Weasel jamming aircraft and over 40 F-15A and C versions to escort the bombers. Developments in precision targeting, specifically GPS guided bombs, means all Israeli aircraft carry bombs considerably more accurate than those used in the Osirak raid. They envision a 50 plane strike package evenly split between F-15I and F-16I aircraft.

Then the question becomes how well can Iran defend its airspace. Iranian aircraft are a mix of the old and the very old. Iran’s most modern fighter is the Mig-29, of which they have maybe 40. They also have a large number of 1970s era F-4, F-14, F-5 and some newer Chinese built F-7M and F-6. Iranian fighters would be operating over friendly territory, advantageous when they need to refuel or rearm. They could also draw on ground control radar to guide them into favorable attack positions against IDF aircraft roaming Iranian air space. If the Iranian aircraft could get into firing position against Israeli bombers, which is admittedly a big if, they have sufficiently modern air-to-air missiles that they could probably down a few.

It’s not Iran’s fighter jets that could pose the real challenge, as the Iranian air force is more of an “antique show,” says David Ochmanek, an analyst with RAND who directs an ongoing study for the U.S. Air Force that examines future threats from Iran. The real threat to an attacker, he says, are Iranian surface-to-air missiles. There are reports that the Iranians field some of the newer Russian-built double digit SAMs, such as the SA-10, though not the newer and more potent SA-20 (the newer Russian designation is S-300 and S-400). The S-300 is considered by some accounts to be comparable to the U.S.-built Patriot air defense missile.

Ochmanek says the double digit SAMs are far more capable than the earlier SA-2, SA-3 and SA-6. The newer systems have high powered radars that are difficult to jam and more powerful, faster missiles. Barry Watts, an analyst at the Center for Strategic and Budgetary Assessments, a Washington thinktank, and a Vietnam-era fighter pilot, says if pilots could spot the smoke trails of the earlier generation of SAMs they could outmaneuver them because of the G-force limitations of those older missiles. With the latest generation SAMs outmaneuvering doesn’t work. “Those missiles went from ten G missiles, to about thirty or forty G’s,” which means the missile’s turn rates are vastly improved, he said. Coupled with the new powerful radars, “if the missile is locked up on you and it’s guiding, the only thing you can do is pull the ejection handles and get out of the airplane.”

Iran has also reportedly bought the fairly sophisticated Tor-M1 SA-15 Gauntlet, a short-range mobile SAM system. The Tor M-1’s greatest strength is its mobility, which, because of Iran’s sizeable and mountainous terrain, could make for a very difficult target because it can pop-up almost anywhere. Iran lacks the resources to protect all of its air space, so it relies on “point defense,” deploying its anti-aircraft guns and missiles around strategically important sites, Ochmanek says.

The MIT folks figured that to carry out an effective strike, twelve F-15Is would have to arrive over Natanz, six F-16I over Esfahan and five F-16I over Arak. Their analysis said that a 50 plane strike package would provide the Israelis significant attrition cushion. The paper’s authors note that to cause the operation to fail, Iranian air defenses would have to down close to 40% of the attacking Israeli jets, an attrition rate that would exceed even the disastrous U.S. raid on Ploesti in Word War II. The MIT analysts conclude that largely because of advances in precision weaponry, “Israeli leaders have access to the technical capability to carry out the attack,” and that it would be no more risky than that of the 1981 raid on Osirak.

If a couple of students from MIT came up with that conclusion, the Israeli intelligence and military communities probably have a fairly high degree of confidence in the success of air strikes. The Israelis likely believe they can set back any progress the Iranians have made in nuclear enrichment by at least five years. What that would buy Israel and the rest of the world in terms of changing Tehran’s policies
is anybody’s guess.