By Gav Don for the Saker Blog

Israel has dropped repeated hints at a major strike on Iranian nuclear facilities in the near future

Two weeks ago Israel’s prime minister Naftali Bennett announced the start of a new campaign against Iran at the annual conference of Israel’s Institute for National Security Studies. Here Mr Bennett said “the campaign to weaken Iran has begun”. He described the campaign as multi-dimensional, including moves in the nuclear arena, the economy, cyber warfare, and overt and covert action, but gave no details on specific actions or plans.

Israel has carried out attacks on Iran’s centrifuge plant at Natanz twice in the past two years, with a third incident widely reported a couple of months ago. Further offensive action against Iran is in practice dependent on the agreement and cooperation of the United States. At a meeting of Secretary of State Blinken and Foreign Minister Yair Lapid in October 2021 Mr Blinken stated baldly that if negotiations to restart the JCPOA failed then the US would turn to “other options”. Israel’s defence Minister Gantz visited Washington in December 2021, where he is reported to have tabled the proposed timetable for an Israeli strike.

On April 6th Israeli news sources showed Israeli Chief of Staff Lt General Aviv Kochavi addressing a group of NATO air commanders assembled in Israel. Among his remarks he referred to “…preparations for an operation in Iran that is currently undergoing expedited preparatory work.”

A week before General Kochavi’s speech the US ambassador to Israel, Tom Nides, said on Israeli TV that the US does not expect Tel Aviv to “sit quietly and not do anything” if a new JCPOA deal is struck with Iran. He added ““We’ve been very clear about this. If we have a deal, the Israelis’ hands are not tied. If we don’t have a deal, the Israelis’ hands are certainly not tied,”. He added that whether or not an agreement is reached, “Israel can do and take whatever actions they need to take to”.

An air strike on Iran would probably aim to damage Iran’s Uranium enrichment centrifuges using bunker-busting bombs delivered by either F15 or F16 strike aircraft. Israel is already equipped with the BLU 109 bomb but the penetration capacity of that weapon is measurable in small numbers of metres of combined overburden and reinforced concrete. Tehran has spent the past year visibly building deep bunkers underneath a mountain adjacent to the Natanz surface plant, which are almost certainly too deep for the BLU 109 to damage.

Open source intelligence analysts estimate that the new plant is protected by about 150 metres of overburden. The new chambers are not only deep, but their exact location is also not discernible from surface works. The actual overburden may be much deeper than 150 metres. To succeed in damaging the working chambers of the underground complex even a much larger bomb than the BLU109 will have to be targeted exactly.

The US Air Force has developed a much larger bunker-busting bomb, the 2.5 tonne GBU 72, whose first (successful) test-drop from an F15 took place in July 2021. Israel has a handful of F15s, but no GBU 72s. The GBU 72’s penetration capabilities are not in the public domain but one source suggests that its design specification is to penetrate 50 metres of overburden and 5 metres of concrete. Even that enhanced penetration and blast power may be too little to damage the centrifuge chambers.

Apart from the challenges of targeting, an air strike on Iran’s nuclear facilities demands a 4,000 km/six-hour mission which would probably have to use Saudi air space. The mission would require refuels, either from Israel’s air tankers, or by landing in Saudi Arabia or UAE en route. A month ago Israel carried out a major long-range strike exercise over the eastern Mediterranean, practising air to air refuelling over distance and long endurance missions, and last week concluded a joint exercise with aircraft from the Greek, US, French and Italian air forces, Iniochos 2022, which included an Air Power Contribution to Land Ops component (a long name for ground attack).

Israel has scheduled major joint military exercises for this coming May. Exercises can be used to cover preparations for actual war. An attack would require much more than just the delivery of bunker-busting bombs. Iranian air defences would have to be detected and suppressed in advance, and assets would have to be placed in readiness to recover aircrew whose aircraft were either shot down or lost to accident or mechanical failure en route. An attack on Natanz would be likely to commit most of the Israeli air force and would require active cooperation and support from Sunni Gulf states in the provision of bases for search and rescue, emergency diversion and ground bases for electronic warfare assets.

The large GBU 72 may have marginal prospects for success. Israel may be seeking access to the even larger Massive Ordnance Penetrator. The MOP is a 14 tonne bunker-busting bomb which is reported to be capable of penetrating 60 metres of overburden, where it detonates a 2.5 tonne high explosive warhead with a large kill-radius. Use of the MOP would require use of USAF strategic bombers (the B2 Spirit, in practice) to deliver it.

Another piece of the evidential puzzle in the public domain is the fact (reported by Haaretz in December 2021) that Israel Defence Forces have been allocated $2.9bn to prepare for an attack on Iran. Israel’s air force is equipped with approximately 40 F15 aircraft capable of carrying large ordnance. It’s difficult to see how the bombs themselves can soak up much of that budget, begging the question of what else Israel might be planning to use. It is also, of course, possible that the strike being trailed in public is just an attempt to pressure Iran to come to terms at the JCPOA talks in Vienna.

Three days ago IAEA inspectors reported that Iran has moved machinery used to manufacture parts for enrichment centrifuges into the Natanz plant from Karaj, and that these are currently under IAEA seal. After what appears to be extensive construction work the Natanz site may well have been extended either to a distance from its surface infrastructure or to a greater depth.

Israel captured one Natanz construction plan in 2018, but it seems likely that Tehran will have changed the tunnel design. Public sources show three entrances. These may be duplicate entrances to a single complex or entrances to two or three complexes. Even the size of Natanz’s tunnels and equipment halls is not in the public domain. The early stages of low-enrichment require more centrifuges than later stages (Iran is reported to have reached stocks of 60% U235, and needs 95% U235 to build a functional weapon).

Israel would either need intelligence from inside Natanz to target the halls themselves, or a very large number of bombs and therefore aircraft. Entrance portals are easier to see, and the plan may be to seal the tunnels rather than destroy them. However construction plans for bunkers usually include emergency exits/entrances which are generally concealed from view in innocuous surface structures at some distance from the actual bunker. The Natanz tunnel complex is 2.2 kms southwest of the original (surface) Natanz complex, where its emergency access could be hidden.

Iran is not a state that suffers attacks passively, though it still has an unusual record of being a state that has not directly attacked another state since the Anglo Persian War in 1856. However Iran has actively promoted proxy wars against Sunni states and their clients, and one of its largest proxies – Hezbollah and Palestinian Islamic Johad – would almost certainly be used to retaliate against Israel for an attack on Natanz. Hezbollah is reported to have a stock of several thousand short-range rockets hidden away on Israel’s northern border.

Historically the use of ballistic unguided rockets and other projectiles has inflicted a highly adverse cost ratio on Israel. A “Qassam” unguided rocket with a 10 kg warhead costs around a thousand dollars to manufacture, while the Iron Dome missile which shoots it down costs a hundred times as much. Israel has been working on this problem and last year announced the successful development of a new 100 kw “directed energy” weapon system (using a laser) capable of destroying small rockets and missiles at a cost of a few dollars in electrical power. The new system (whose name is likely to be Iron Beam) is reported to be functional and is expected to be fully operational by the end of this year but it is possible, indeed likely, that some part of that $2.9bn has been allocated to speeding up the roll-out of Iron Beam units.

It takes just several seconds of laser contact to ignite an incoming rocket, allowing a single Iron Beam to handle many more live targets than Iron Dome. Iron Beam will not be perfect – laser energy is absorbed by rain, dust and cloud – but the new system will blunt a retaliatory missile attack by Hezbollah, and reduce the number of “leakers” – missiles which make it through to be shot down by Iron Dome.

Israel is also presently in the process of carrying out extensive pre-emptive action against PIJ in the West Bank – perhaps a sign of preparations to reduce Iranian blowback.

Another Iranian option for retaliation could be escalation of attacks on Israel-owned shipping. A quiet naval war has already been running between Iran and Israel for at least one year, and possibly two. Israel’s own IDF annual summary admitted to “around 100” maritime operations in 2021, of which “dozens” [so, most] were special operations. Attacks on Iranian shipping appear to have ceased in July 2021, perhaps because Shia militias now effectively control one of the two main road routes from Iran to Damascus, but explained by Israeli sources as a response to the attack on the tanker Mercer Street in the Gulf of Oman by a suicide drone.

Rear Admiral Shaul Chorev, head of the Haifa Research Center for Maritime Policy and Strategy at the University of Haifa, was quoted earlier this year saying “In my view, those who had the last word here were the Iranians. They challenge our freedom of navigation in the Gulf of Aden, and it appears as if we stopped our activities to target Syria-bound tankers. Russia also entered the picture, saying it would guard Iranian oil tankers. The result was that strategically, a new maritime front was opened, distant from Israel and out of the operational capabilities of the Israeli Navy”.

Syria is not the only state whose oil supply is vulnerable to attack at sea. Israel imports all of its 200 kb per day oil consumption by ship. While Israel will probably be able to protect its oil imports at sea, it would find it much harder to protect the much larger fleet of Israeli-owned merchant shipping, particularly when that shipping is sailing in or past Iranian waters in Hormuz. We may see the IRGC step up attacks on Hormuz traffic via drone strikes, short range missile attacks or even boarding and capture. An extreme reaction might be Iran’s use of its large and capable flotilla of Ghadir submarines to sink non-oil Israeli-owned shipping in Hormuz with torpedo attacks.

In response to that Israel is likely to call the US Navy in aid, leading to possible armed conflict between the US and Iran for the first time. Iran might seek to bring retaliation home to Israel by attacking Israel’s gas production platforms and pipelines in the East Mediterranean. The targets are tough – well protected and at great strategic distance from Iran , but just on the doorstep of Syria. A creative and determined mind could probably find a way, and a successful attack would inflict substantial economic and psychological damage on Israel.

None of the evidence of preparations and intent that we can see is definitive. The level of publicity being given to the preparations may just be Israel setting up a visible latent threat as a spur to a new JCPOA, or as a distraction from other less visible moves. May might bring a clear answer, or it might not. We may not have long to wait to see. Both Israel and Iran might do well to heed the old adage – “when you seek revenge, first dig two graves”.

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