A conventional wisdom has developed that only the United States has the capacity to destroy Iran’s nuclear enrichment facility at Fordow, and that the US most certainly does have that capability.
But what if that second assumption is false? Could it be that Iran’s Fordow enrichment site is actually not vulnerable to destruction from the air?
Unfortunately, the answer is that it could be so. Not that it IS so, but the common assumption that only depth and layers of rock and concrete are the obstacles an airstrike would face is likely incorrect.
No, I am not talking about impregnable air defenses or anything so easily dealt with. The layered defenses that everybody assumes are the only other obstacles really are not significant problems for the United States. By the time any B-2 bombers reached Fordow the US and Israel will likely have total air supremacy, and any remnant air defenses would be unlikely to present much of a threat.
It is the nature of Fordow itself that is the problem. The farther down the rabbit hole I dig, the more obvious it becomes that removing Fordow from the board for a long time will be very, very difficult.
The first problem has to do with the possibility that Fordow’s production facility may not be protected by rock and concrete of uniform density, but may instead be designed with a strategically designed lattice of concrete and rock of varying density and reinforcement that serve to divert the Massive Ordnance Penetrator from a straight trajectory. If so, the bomb’s trajectory could be directed away from its underground target. It might dig down to the right level, but not necessarily in the right place.
It’s also not quite clear what, exactly, the GBU-57’s penetration capability is. The common figure discussed is 200 feet of penetration through rock or concrete, but some people claim that the 200-foot claim is based on travel through soil, which presents considerably less an obstacle than reinforced concrete.
More recently, they published that the MOP had received an upgrade that allowed it to hit targets up to 200′ (60 m) underground.
That was reportedly based on a USAF news story and seems to be the number being used by most of the media.https://t.co/tL2UOccIm0
— Geoff Brumfiel (@gbrumfiel) June 17, 2025
What do I mean by that? I mean that the type of ground your impacting greatly influences how deeply your weapon can penetrate.
The equations for this have been well known for decade, and you can actually look them up. THANKS OSTI!
Source: https://t.co/vGkY6nLHty pic.twitter.com/9iIGdd2bsl
— Geoff Brumfiel (@gbrumfiel) June 17, 2025
BTW, if you substitute “medium strength rock” with “silty clay” you get a depth of 80 m, which is a lot closer to the advertised penetration depth.
But of course, Fordow isn’t buried under “silty clay”. pic.twitter.com/kigfmcZOMb
— Geoff Brumfiel (@gbrumfiel) June 17, 2025
I can’t comment on that because I don’t know. It does seem likely that the advertised 200 foot depth is…optimistic.
But even assuming the 200 foot assumption is correct, nobody is claiming that one MOP can reach the actual facility underground because it is almost certainly much deeper than that, so any strike would involve multiples of the bomb striking in exactly the same place nearly simultaneously. That is because the debris from the first strike will fill up the hole just dug, so the closer in time the second strikes to the first the better penetration one would get.
Then there is the question of design and depth of the facility. Blueprints of the Fordow facility have been leaked–assuming those are real–so we have a good idea of what it looked like several years ago. If we assume that it remains the same now as then, we have a good idea of where to strike to cause maximum damage.
However, there is dispute about the precise depth of the facility, and that matters a lot. While there is certainly a point where a near miss would be nearly as good as a direct hit to take out some fraction of the facility, Fordow certainly has blast doors between sealed sections. The goal is to limit the damage to one section should it be penetrated.
Then there is the issue of how many strikes it would take to ensure that the maximum damage is done. I assume that success in the mission would not be classified as complete destruction, although that would be ideal, but rendering Fordow unusable in the near term. The consensus seems to be that no matter how successful this series of strikes being carried out by Israel and the United States might be, Iran will be able to restart its nuclear program within a year or so. It already has a large amount of enriched uranium, and the technology is well understood.
But in order to do that kind of damage, it wouldn’t take one B-2 with two bombs to get the job done, but more like a dozen or more bunker busters. The site is so deep, there are so many unknown variables, and the cost of failure is so high that the US would be committing massive resources to ensure that the job gets done.
As many as half of our stockpile of MOPs would likely be committed to doing the job. This, in itself, is likely not an obstacle to their use as it would be with other weapons–we wouldn’t use up half our Patriots or JDAMs for a mission like this–because the MOP was designed for just this kind of mission. It is highly specialized, and replacing our stockpile in a reasonable period of time would be relatively cheap and quick. We are unlikely to need to use them again any time soon, so anxiety about magazine depth wouldn’t be much of an obstacle.
Still, it would take a LOT of sorties of our most valuable strategic aircraft into a country with lots of warning they are coming. The mission is not without risk, success is not certain, and the political cost of failure would be comparatively high. The GBU 57 is a powerful deterrent as a threat in being; it would lose some deterrent value if it failed to accomplish the one mission for which it is designed.
This may be why Trump has been hesitating to actually deploy it. He hopes Iran will surrender its nuclear program without having to test the MOP in combat against such a difficult target. We know it works in testing. We don’t know if it will do the job we want it to do right here, right now.
