Steve Clean Subterranean Warfare – An Pressing DoW Want With out An Proprietor
This article beforehand appeared in Cipher Brief.
The DoW urgently wants to arrange its scattered subterranean warfare property right into a single unified group. Ideally, a Direct Reporting Portfolio Manager (DRPM) for Subterranean Warfare, reporting to the Deputy Secretary of War. (The Department already makes use of this mannequin for unmanned methods, important weapons and Golden Dome.) This group would have three portfolios: Subterranean Resilience, Subterranean Sensing and Subterranean Defeat. The workplace would combine validated necessities, experimentation, testing, acquisition, and fielding.
Subterranean Resilience
During the 2026 Iran clash, Iranian ballistic missiles and low-cost drones hit U.S. installations throughout eight Middle Eastern international locations. Hundreds of buildings and buildings had been broken or destroyed. The Navy’s Fifth Fleet headquarters in Bahrain was among the installations hit hard. Iranian weapons broken one E-3 airborne early-warning aircraft and five KC-135 tankers on the bottom in Saudi Arabia. (The official inspector-general report documents the damage.) Despite thousands of successful interceptions, the assaults uncovered the vulnerability of concentrated, above-ground property.
The rapid redeployment of the B-1s from RAF Fairford within the UK after warnings of an Iran-linked menace (reported as a possible drone attack) made the purpose: unsheltered concentrated high-value plane are susceptible even means exterior the theater.
The assumptions the U.S. has made about air superiority, missile protection, plane dispersal, constructing hardening, and the survivability of concentrated ahead bases had been all flawed. While we had been ready for ballistic missiles and hostile plane, drone swarms mixed with ballistic missiles saturated and acquired by our defenses.
Washington’s response has been to take a position billions of {dollars} in counter-drone and missile protection methods. Yet public finances paperwork reveal no comparable effort to place susceptible plane, gas, command-and-control nodes, and munitions out of hurt’s means – sheltered, underground (or in area). (Agile Combat Employment, dispersal, hardening, deception, shelters, and fast runway restore had been by no means designed for a mixed drone and missile onslaught.)
The Pentagon has acknowledged for many years that underground amenities are among the many only methods an adversary can blunt U.S. standard superiority. It described that problem explicitly in 1999. Gaza and Ukraine ought to have made it abundantly clear.
China, Russia, North Korea, and Iran use underground amenities, dispersal, hardening, and deception to make their very own high-value property more durable to search out, assess, and disable. We must underground property that can not be rapidly changed: command posts, comms nodes, ammunition, gas distribution factors, restore amenities, key energy methods, upkeep spares, and high-value plane or drones.
The division wants an integrator that coordinates resilience throughout the Military Departments, Joint Staff, combatant instructions, protection companies, and intelligence group and offers Subterranean Resilience.
However, resilience is just one a part of subterranean warfare.
Subterranean Sensing and Defeat
The U.S. must know the place adversaries’ underground amenities are situated, and the interior structure of these amenities. Today, these bespoke beautiful methods for tunnel detection, robotic mapping of accessible tunnels, Hard and Deeply Buried Targets (HDBT) characterization, and goal defeat are siloed in organizations scattered throughout the DoW and different components of the nationwide safety institution. Most of those methods nonetheless require boots on the bottom. Once a goal is discovered, Combatant Commands want an built-in system that may characterize and destroy these targets, with out first gaining bodily entry. Today, for the deepest amenities which means bombing from the air. Iran is the living proof.
Background. Iran’s path to a nuclear weapon is by enriching uranium. Natural uranium consists of 0.71% uranium-235 (U235) and it’s solely the U235 that’s used to construct a bomb.Iran makes use of centrifuges to separate U235 and improve its focus (enriching it.) One centrifuge received’t do a lot, however connecting hundreds of centrifuges collectively into cascades and working them for months can produce kilos of U235 .
2008 President of Iran Mahmoud Ahmadinejad touring Natanz enrichment facility
Iran’s underground nuclear enrichment website at Natanz had effectively over 10,000 centrifuges put in throughout dozens of cascades, and their Fordow nuclear enrichment website was constructed for 16 cascades, roughly 3,000 machines. Before the June 2025 strikes, Iran’s three declared enrichment facilities contained greater than 20,000 centrifuges in 125 full-sized cascades.
The tough estimate wanted for one Iranian nuclear weapon is ~100 lbs of U-235 at 60% enrichment or 55 lbs of U-235 at 90% enrichment (fashionable designs use much less.) The distinction is vital, the lighter the weapon the better it’s to suit on a missile.
At its peak (Feb 2025 to June 2025) Iran’s cascades had been delivering ~86 lbs of uranium enriched to 60% which is about 50 lbs of U-235 per month, which is just under one potential weapon every month. (Most weapons use U235 enriched to 90+% as a result of that allows a smaller, extra dependable design. Getting to that stage in Iran may take days or perhaps weeks working the cascades, however constructing it right into a weapon would nonetheless be wanted.)
Deeply Buried Targets Versus Bunker Busters. One of the said targets of the U.S. strikes on Iran was to take away their capability to construct nuclear weapons. This required the U.S. to destroy their deeply buried underground nuclear enrichment websites. The largest standard bomb within the U.S. navy’s arsenal is the 30,000-pound GBU-57 Massive Ordnance Penetrator, carried by the B-2 Bomber. A 2019 description stated it may attain targets so far as 200 ft underground (its precise effectiveness relies on geology, concrete, facility design, entry factors, and the usage of a number of weapons). The Iranians knew this and constructed their nuclear enrichment websites underground. The Fordow website is ~260 to 300 ft underneath limestone and dolomite. The Natanz website is 25 to 160 ft underground, protected by a 25-foot concrete protect. (But public estimates are everywhere.)
Iran declared Isfahan as an enrichment complex to the IAEA the day earlier than the June 2025 strikes; inspectors by no means acquired inside it, subsequently its depth and geology are unknown, however hypothesis is that the enrichment complicated is 260 to 330 ft underground. Another suspected enrichment facility is in Pickaxe Mountain, the place the precise depths, geology, are unknown however estimates put the power 250 – 330 ft under the summit. Both Isfahan and Pickaxe had been Iran’s shift towards “deep mountain basing” to flee the attain of standard navy strikes.
In June 2025 in Operation Midnight Hammer U.S. B-2 bombers dropped 14 GBU-57 bombs on top of Fordow and Natanz. At Isfahan (Esfahan) greater than two-dozen submarine-launched Tomahawks hit tunnel entrances and floor targets. In March 2026, strikes at Natanz hit its entrance.
According to the Institute for Science and International Security, the 22,000 centrifuges at Natanz, the Natanz pilot plant, and Fordow are almost certainly wrecked. What could have survived is the enriched uranium, the spare components, and the individuals, and that’s the downside. The International Atomic Energy Agency estimated (in June 2025) that Iran had about 970 kilos of uranium enriched to 60%; it has since misplaced observe of the place it’s. Iran’s recognized uranium conversion capability at Isfahan was damaged, which it wanted to show the stockpile of enriched uranium right into a weapon, and there’s no public proof that enrichment has resumed at Natanz, Fordow or Isfahan. We by no means hit Pickaxe Mountain or the Isfahan enrichment facility with the GBU-57. The strikes have set Iran again, however nobody is aware of for a way lengthy.
While the GBU-57 MOP can’t cleanly punch by stable rock, the talk has shifted from an absolute bodily destruction calculation to a purposeful denial calculation—that means the navy’s objective can be to seal Iran’s nuclear property in a mountain tomb quite than blowing them up straight.
Did We Succeed? Our said objective was to forestall Iran from quickly rebuilding the aptitude to construct nuclear weapons, however there’s no certainty that we did that. Repeated airstrikes could have broken the buried enrichment vegetation, however we will’t show it or account for the buried enriched uranium inside. The truth is that it’s extraordinarily troublesome to see how a lot harm the bombs did to Hard and Deeply Buried Targets (HDBTs) from the air, and with out inspectors on the bottom, figuring out for certain is guesswork. Putting boots on the bottom would carry monumental prices and dangers. Negotiating the removing and inspection of weapons grade uranium would rely upon Iranian cooperation and a approach to confirm we acquired all of it. All dangerous selections.
There is one other rising choice: autonomous drilling gear.
Subterranean Sensing and Defeat. It’s not onerous to think about that with sufficient boots on the bottom the U.S. may safe a touchdown zone, fly in drilling gear and have crews drill a whole lot of ft vertically or hundreds horizontally to both place sensors and/or explosives. The U.S. has had organizations constructing specialised gear and coaching for breaching tunnels in Combatant Commands and scattered throughout the DoW for years (DTRA, DARPA, Army ERDC and CAVES and CZ5 applications, SOCOM, Sandia and the Army’s half-billion-dollar underground-training push (2018) and ATP 3-21.51 Subterranean Operations.) One may even think about that there are groups already trained and equipment ready to go. And one can equally think about the Iranians are ready for them.
What’s new is autonomous drills that would present post-strike bomb harm assessments and/or destroy Hard and Deeply Buried Targets (HDBTs) with out seizing the location. They is likely to be inserted covertly; extra probably they’d want air cowl whereas they work.
The mixture of AI, robotics and autonomy strikes this from science fiction to the doable.
Anduril, The Boring Company, Exodigo, Phoenix Boring, Earthgrid and Traysar are doable candidates to ship these methods. There are probably others as effectively.
(Disclosure: after my first blog about undergrounding critical assets, I invested and have a monetary curiosity in corporations on this area.)
Surface survivability and subterranean sensing and defeat are not one Service’s downside, and so they received’t be solved by a single system or an incremental repair. Something essentially disruptive has modified within the nature of uneven warfare and there’s no going again. While we’re actively chasing instant options (Golden Dome, JIATF-401, et al), we have to rethink the character of power safety, and navy and civilian transport systems safety.
The U.S. wants a coherent safety and survivability technique throughout the DoW and all sectors of our marketplace. This dialog must be not solely about how we do it, however how we arrange it, how we finances and pay for it, and the way we quickly deploy it.
Lessons Learned
- The DoW wants to arrange its scattered subterranean property right into a single group: a Direct Reporting Portfolio Manager (DRPM) for Subterranean Warfare, reporting to the Deputy Secretary of War
- It ought to have three portfolios – Resilience, Sensing and Defeat
- Providing validated necessities, experimentation, testing, acquisition, and fielding to Combatant Commands.
- Protection and survivability options aren’t as attractive as shopping for plane or weapons methods however they stands out as the key to successful a struggle.
- Subterranean Sensing and Defeat want to maneuver from bespoke special-operations capabilities into customary doctrine.
Filed underneath: National Security |
