GBSD: The Case for Modernization So Obvious Even Two Think Tankers Get It.

Admiral Charles Richard, Commander of the United States Strategic Command, pushed back on the small but vocal disarmament advocacy clerisy who are trying to pressure the incoming Biden administration to eliminate the Ground-Based Strategic Deterrent (GBSD) program.  While on a Zoom call with the Defense Writers Group, Adm Richard remarked, “I don’t understand frankly how someone in a think tank who actually doesn’t have their hands on the missile, looking at the parts, the cables, all the pieces inside” is qualified to make such recommendations.

The authors humbly disagree with the Admiral on this point.  You don’t need to put your hands on the physically atrophying cables or subject yourself to the unsafe and decaying launch control facilities to fully appreciate the necessity for modernizing the most responsive leg of the nuclear triad.  Even those of us in think tank world should be able to appreciate the pragmatism embodied in the GBSD program to protect the homeland and our allies in a cost-effective, threat-informed, and stabilizing manner.

GBSD is meant to replace the Minuteman III intercontinental ballistic missile system (ICBM) system, which first entered service in 1970 and has been extended well beyond its original service life. The current Minuteman III system has been service life extended several times since its deployment and, according to GAO reports, is experiencing challenges “related to aging facilities, aging infrastructure, and parts obsolescence.”  Because of the extent of the asset and facility attrition in this 50-year-old weapon system, Air Force officials have warned that the Minuteman III will be “unable to meet full mission requirements should deployment be required” much longer. The reality is that choosing not to pursue GBSD, given the cost and difficulty of attempting yet another service life extension of Minuteman III, is choosing to give up the triad’s land-based missile leg.

Opponents of GBSD consistently make a series of poorly reasoned arguments for eliminating the triad’s land-based leg, and, as the saying goes, these points are so wrong, even the opposite wouldn’t be true.    

The triad’s land-based leg is the least expensive leg of the triad to operate and maintain over its lifetime.  It does not require large crews or expensive fuel and maintenance costs, like nuclear-powered submarines or heavy bombers.  GBSD does not require overseas basing or overflight rights, nor does it require large and expensive fleets of aerial refueling tankers, as does the bomber force.  It does not assume that an adversary will forever be unable to locate our submarines at sea, which, given the state of technology advancement –including artificial intelligence and “big data” – is not a safe assumption into the future.

ICBMs remain consistent, visible and responsible mainstays of our nuclear deterrent.  The only challenge that ICBMs now face is the failure to modernize them as planned, but this would result from policymakers’ will, not any change in the global threat or design or mechanical failure.

In particular, ICBMs and GBSD are stabilizing to the international order that the Biden Administration will inherit and seek to improve.  Our allies, specifically those in NATO and the Indo-Pacific, depend upon the safe, secure, and credible nuclear deterrent that the U.S. extends to them as foundational to their security.

The incoming Biden Administration, which seeks to improve the nation’s standing among its allies, would do well to support a strong modernized nuclear deterrent – including full support of GBSD – that is so vital to U.S. allies (many of which have foresworn their own nuclear weapons because we promised them the security made possible by extending our deterrent).

Lastly, we give much credit to previous Democratic administrations that started out with the admirable goal of eliminating nuclear weapons and ultimately realized such a vision, given current and likely future security realities, is folly.

The role, risks, funding, and programmatic questions associated with nuclear weapons capabilities is a legitimate and necessary public discourse that anybody in civil society should be welcome to contribute to, whether from a think tank, within the government, or in defense industry. But the reality is that our strategic competitors are also watching these debates and often interfere in them. Even those guided by the best of intentions must understand that their complicity in the erosion of a credible nuclear deterrent will only invite continued development and deployment of nuclear weapons by our adversaries that can end our way of life and that of our allies.

These two think tankers believe GBSD remains an integral part of our nuclear deterrent.  There is a term for a decision by the United States to choose to fail to modernize its ICBM force, while Russia and China are actively modernizing theirs: unilateral disarmament.

Tim Morrison was a Deputy Assistant to the President for national security for President Trump and is now a Senior Fellow at the Hudson Institute.  Sarah Mineiro was the staff lead of the Strategic Forces Subcommittee on the House Armed Services Committee for the House Republicans and is now an Adjunct Senior Fellow with the Center for New American Security.


Hwasong-15 (KN-22) and Hwasong-16 (KN-27)

Hwasong-15 Transporter erector vehicle

Hwasong 16 at the 75th WPK anniversary parade 2020.

The Hwasong-15 (KN-22) was launched for the first time on November 29, 2017, when this liquid-fueled ICBM flew on a lofted trajectory to an altitude of 4,500 km. If flown on a standard trajectory, it could have a feasible reach of 13,000 km, which, according to David Wright of the Union of Concerned Scientists, “is significantly longer than North Korea’s previous long-range tests.” According to North Korea’s Korean Central News Agency (KCNA), this flight test was of “an intercontinental ballistic rocket tipped with super-large heavy warhead” which could reach “the whole mainland of the U. S.”

The new ICBM, presumably a Hwasong-16, appears to be approximately 25-26 m long and 2.5-2.9 m in diameter—about 4-4.5 m longer and about 0.5 m larger in diameter than the North’s Hwasong-15 ICBM flight tested once in November 2017. Indeed, the new missile has been correctly characterized as the world’s largest mobile ICBM—in part because countries with ICBMs generally seek to make their road-mobile ICBMs smaller so they can be more mobile and concealable.

That said, we estimate the new missile’s launch weight at roughly 100,000-150,000 kg, compared to some 80,000 kg for the Chinese DF-41 solid-propellant, road-mobile ICBM and about 104,000 kg for the former Soviet SS-24 rail-mobile solid ICBM.

The first stage of the new ICBM appears large enough in diameter to accommodate four of the Soviet RD-250-sized rocket engines believed to power the Hwasong-15 (which uses two in its first stage). The number and type of engine used in its presumed second stage are unclear, making the new missile’s throw-weight capability uncertain. Based on the assumption of four RD-250-type engines in the first stage, however, we estimate the new missile could, in principle, deliver 2,000-3,500 kg of payload to any point in the continental United States—much greater than the Hwasong-15’s assessed 1,000 kg payload capability to the same range.

But why would the North Korean’s need or want such a big missile? Especially since the Hwasong-15 would appear to have sufficient range/payload capability and room for improvement to meet North Korea’s operational targeting needs, and is much easier to move and conceal. There are two main possibilities, which are not mutually exclusive.

First, there may be a political rationale for producing or parading the new system. An unexpected “super heavy” ICBM would be a classically Khrushchevian statement of North Korea’s technical prowess, the robustness of its ability to threaten the US, and the permanence of its nuclear weapons status. It is worth noting that there has been no open-source evidence that the new ICBM’s apparent first-stage propulsion system has been ground-tested, and one analyst has noted that “no North Korean ICBM design that was *first seen at a parade* has seen flight-testing to date.”

Second, there may be operational reasons to make such a large missile. The North may want to be able (or to be seen as able) to deliver a much larger payload to anywhere in the US.

In terms of larger payloads, the North may be working toward developing multiple independently-targetable reentry vehicles (MIRVs). Perhaps the North’s current nuclear RVs are larger and heavier than we expect, and so the Hwasong-15 cannot carry enough such RVs along with the size of post-boost vehicle (PBV) the North currently can provide to dispense them. Or perhaps the Hwasong-15 can be MIRVed but the North wants to be able to deliver more MIRVs per booster.

It should be noted that North Korea has not demonstrated a militarily useful MIRV capability, which is technically demanding. For example, it has yet to flight test a PBV, much less the deployment of MIRVs from a PBV. Given the technical demands of MIRVs, it might instead first deploy non-independently targetable Multiple Reentry Vehicles (MRVs) like the US, USSR, and UK did. Even in this case, the North might want more payload capability to deploy more or larger MRVs.

Another reason for having a bigger payload capacity is the desire to carry more and/or more RV-like (heavier) decoys to spoof US missile defenses than is possible with the Hwasong-15. Alternatively, the North may have decided that it wanted to possess or portray the capability to deliver a “super heavy” single large thermonuclear RV against US cities for political or deterrent effect. While this also is Khrushchevian in nature, one should recall that the Soviet SS-18, Chinese CSS-4 and US Titan-II ICBMs were deployed with massive single RVs having up to nine megatons of yield.

Another size-related question raised by the new ICBM is: why make it road-mobile? Here, too, there could be a political component; after all, it is the world’s biggest mobile ICBM. But to the extent the North truly intends to deploy this system, it would almost certainly judge that road-mobile basing would be more survivable than silo- or other fixed-basing, even though the sheer size and weight of the new ICBM would render it less mobile than the Hwasong-15 and more constrained in the portions of the road network it could use, (limited to smooth, paved roadways), and probably needing to fuel the missile after it was erected at a launch site (adding to vulnerability and reducing response time).

Missiles of North Korea

North Korea’s questionable ICBM “Hwasong-16” (HS-16)




Aztec warriors wielding macanas (macahuitl), which are oak swords or clubs fitted with rows of obsidian blades. Aztec warriors used these weapons to slash, inflicting long bleeding wounds, or sever, as when they decapitated a mare Cortés’s party brought.

Cortés did battle with thousands of Aztec warriors during his campaign of exploration in Central America. They were a fearsome people from warrior societies based around two predators – the eagle and the jaguar. Many dressed in the image of these animals to terrify enemies. Warriors could only join these societies if they had captured enemy soldiers or become renowned as great warriors through the rank and file of the Aztec military. Their weapon of choice was the macuahuitl sword, a club-like weapon with obsidian blades sticking out of the ends, which the warriors would use to beat their victims to death.

By far the single most important weapon used by Aztec soldiers was the macuahuitl, a kind of saw-sword carved of wood and affixed with an edge of obsidian razor blades and bitumen adhesive. Most examples were about three and a half feet (1.06m) long but others were of such size that they had to be wielded with both hands. It appears infrequently if at all in Mesoamerica during earlier times when war was more of an elite activity, so we presume that its widespread use among the Aztecs emerged in response to the need to arm and train large armies of commoners as quickly and efficiently as possible. During the Conquest, one Spaniard described seeing “an Indian fighting against a mounted man, and the Indian gave the horse of his antagonist, such a blow in the breast that he opened it to the entrails, and it fell dead on the spot. And the same day I saw another Indian give another horse a blow to the neck that stretched it out dead at his feet.” From such accounts we learn that the macuahuitl had little other purpose than to severely maim if not actually dismember the enemy. The Aztecs also employed a closely related weapon called a tepoztopilli as a halberd. These were carved from wood and featured a long, wide, wedge-shaped head fitted with a row of obsidian blades much like the macuahuitl. They varied in length from three to seven feet (1.06-2.13m) in length. Cuauhtli would have been assigned to wield such a weapon during his first battlefield experiences. It allowed him to stand at the rear of the line and shove or jab the weapon, harassing the enemy from a safe distance while the more experienced warriors fought in hand-to-hand combat at the front of the line.

Israeli Manufactured Drones

A Harop in its transportable launcher. Thanks to its folding wings, the weapon can be launched from a truck- or ship-mounted canister or configured for air-launch. Confirmed customers include India and Azerbaijan.

Launch of a Harop and (inset) the terminal dive onto its target. Flying at speeds of up to 225kts, the drone also boasts a radar cross-section of less than 0.5m².

IAI’s Rotem is a vertical take-off and landing loitering munition that employs the tried-and-tested quadcopter configuration. In a series of trials in southern Israel in 2018, the company evaluated the attack drone against targets including simulated terrorist cells, explosive devices and unarmoured vehicles.

The Orbiter 1K is Aeronautics’ first loitering munition and utilises the structure of the Orbiter 2 man-portable UAV. The Orbiter 1K is launched from a catapult and can fly for up to three hours.

IAI’s Green Dragon. Early last year, photos appeared showing a Green Dragon launcher on board one of the IDF’s Hetz-class fast attack missile craft, marking the first confirmed naval application of the weapon.

The Israel Defense Forces (IDF) have performed a series of aerial attacks in recent months, mainly on targets in Syria, to foil Iranian efforts to equip its proxy, the Hezbollah terror organisation based in Lebanon. Tehran has sought to provide the group with increasingly accurate surface-to-surface missiles and rockets that have been used in attacks on Israel.

Some reports from Syria indicate that manned fighter aircraft were not detected over the targets. Israel generally remains silent about the particular weapon systems used in these highly accurate attacks, but the IDF has a wide variety of options in its armoury. One of these is loitering weapon systems.

Until fairly recently, loitering weapons were considered a `luxury’ item for IDF fighting units, but they are now almost a baseline requirement for many of the country’s offensive operations. Such systems are currently in considerable demand and Israel’s defence industries are working hard to supply them.

Undoubtedly, Israel’s loitering weapons made a major leap forward some five years ago. Until that time, the country’s only operational system in this class was the Harop, developed by Israel Aerospace Industries (IAI) on the basis of the 1980s-era Harpy. Like its predecessor, the Harop was designed specifically to destroy high-value targets, including air defence radars.

The Harop consists of a munitions unit, a transportable launcher and a mission control shelter, the last of these providing a real-time control function for the weapon using `man-in-the-loop’ guidance.

The Harop can be launched from various transportable platforms, including sea- and ground-based canisters, or it can be air-launched before navigating towards the potential target area. It can be launched at any angle, including horizontal or vertical trajectories, and the sealed container ensures protection from harsh battlefield conditions.

The Harop is armed with a 35lb (16kg) warhead and is equipped with an advanced POP-250 day/night optronic payload produced by IAI’s Tamam Division. It has an operational range of 6,230 miles (10,026km) and an endurance of six hours.

Mini Harpy

Big and heavy, the Harop was built to attack hardened targets, but the trend towards loitering weapons has also resulted in a diversified range of sizes and payloads for different applications. Last year, IAI unveiled the Mini Harpy, based on Harop technology.

In an interview with AIR International, Boaz Levi, general manager and executive vice-president of IAI Systems’ Missiles & Space Group, explained that the Mini Harpy is designed to neutralise radiation-emitting threats such as radars and other air defence systems: “The system was designed to provide operators with control up to the last moment, including cessation of attack at any stage. Electrically powered, it is extremely quiet, carries a shaped charge of approximately 17 pounds [8kg], operates over a range of 62 miles [100km] for a duration of two hours and has a total weight of 100 pounds [45kg].”

He added that the Mini Harpy is fitted with a dual sensor working in the electro-optical (EO) and electromagnetic realms.

Tactical Systems

While IAI’s main loitering weapon systems are the massive Harop and the downsized Mini Harpy, the company has also developed devices for smaller units on the move. One is the Green Dragon, a tube/ canister-launched attack drone designed for use at the battalion and brigade levels.

The Green Dragon weighs only 33lb (15kg) and carries a small EO seeker and a warhead weighing just 5.5lb (2.5kg). Despite its small size, it is considered useful against most tactical targets, loitering for 1.5 hours at distances of 24 miles (39km) from the control point. The launch tubes can be carried in a backpack or as a stack in groups of 12 to 18 on board a vehicle.

The Green Dragon uses a hardened tablet computer to control the entire mission, with a single unit capable of conducting both surveillance and attack. The operator can designate and engage the target as it appears on the tablet screen, or else halt the operation at any time before impact, using a built-in `abort and circle’ capability designed to prevent collateral damage or mistaken targeting.

VTOL Rotem

Back in 2016, IAI unveiled a new lightweight loitering munition. The system is named Rotem and weighs around 10lb (4.5kg). This vertical take-o­ and landing (VTOL) device is powered by electric motors driving four rotors and it carries an interchangeable day/ night payload. The Rotem is armed with two hand grenade-size explosive units. The company says the system is intended for troops involved in urban warfare and that it can be controlled to “get through a window”. The Rotem has an endurance of 30-45 minutes and a soldier can carry three or four such systems and operate them using a tablet-size control unit similar to that used for the Green Dragon. A single infantryman can fly the Rotem using simple `point and click’ commands on the controller. The system is also equipped with an acoustic sensor to avoid collision with obstacles in the area of operation.

Other Manufacturers

Once it became clear that there was a significant market for loitering weapons, other Israeli companies joined the e­ ort. Four years ago, Raytheon teamed up with UVision to win an order to supply the Israeli-developed Hero-30 loitering munition to the United States Special Operations Command under the US Army’s Lethal Miniature Aerial Missile System (LMAMS) programme, for which a contract is expected in the coming months. The programme aims to purchase 25,000 examples of a new loitering weapon over a 15-year period. If the Hero-30 is selected, Raytheon will serve as primary contractor.

The derivative of the Hero-30 developed for the US Army will be lighter and carry a smaller warhead. The current version weighs 6.5lb (2.9kg) and is armed with a 1lb (0.45kg) warhead and is carried in a canister that also serves as a pneumatic launcher. After launch, the electric motor is switched on and the drone locks on to the pre-designated target, transmitting video to the operator via a handheld unit. The Hero-30 is equipped with a day/night sensor and has a 30-minute endurance, loitering at altitudes between 980ft and 2,000ft (300 and 609m). The data link developed for the system provides control up to a maximum range of 6 or 24 miles (10 or 40km), depending on the antenna used.

UVision says it has identified an increased demand for small loitering munitions in recent years, mainly due to operational lessons from tackling international terrorist groups. A company source said: “The capability of small units to attack sources of fire independently has become crucial in combat in urban areas.”

In response to this trend, Israeli industries are working to develop more such systems. Some are already at an advanced stage, while others remain studies. However, there seems little doubt that the variety of loitering weapons will increase dramatically in the near future.

Last year, UVision unveiled its latest design, the Hero-400EC. This is larger than the Hero-30 and has a distinctive cruciform aerodynamic shape. According to the company, this ensures accuracy and reduces collateral damage. Its electric motor enables it to loiter silently above a target, ready to instantly respond to `pop-up’ threats.

The company adds that the Hero-400EC was developed to meet a growing operational requirement for a loitering weapon that can remain in the air for extended periods, provide a substantial warhead effective against a wide variety of targets and deliver missile-level pinpoint strike capabilities.

The Hero-400EC uses `man-in-the loop’ technology and advanced electro-optical/ infrared (EO/IR) payloads that can locate, track and strike static or moving targets accurately and without warning. The system features a low noise and thermal signature, plus a modular multi-tube launcher that can be adapted to a wide range of platforms, thereby offering air, land, and sea capabilities. The new drone’s abort capability also allows automatic re-entry into the loitering mode, re-engagement with the enemy or a return to the recovery area using a parachute. It has a maximum take-off weight of 88lb (40kg) and a warhead weight of 22lb (10kg), with an endurance of up to 2 hours.

UVision has also developed the Hero-120, which can be fitted with a range of powerful multi-purpose warheads. This model is intended for pinpoint strikes in populated urban areas or remote locations with minimal collateral damage. An endurance of more than an hour and a loitering range of up to 24 miles (39km) enable independent operation by frontline forces, including precision strikes against time sensitive targets. Featuring low acoustic, visual and thermal signatures and fully gimballed and stabilised day/night tracking, the Hero-120 can also provide critical situational awareness and real-time intelligence via its advanced data link. Recoverable using a parachute, the system is also cost-effective.


The Israeli unmanned systems manufacturer Aeronautics has joined the development effort with its new Orbiter 1K loitering weapon. The new system is based on the structure and design of the firm’s Orbiter 2 and marks the first time Aeronautics has developed a loitering device.

The Orbiter 1K is launched from a catapult and can fly for 2-3 hours, carrying a multi-sensor camera with day and night channels. The system is compact and easily operated from a personal ground-control system.

Aeronautics says that, given a specific waypoint, the Orbiter 1K can detect and destroy a moving or a stationary target. The system can also operate within a predetermined area, independently scanning the area before detecting and destroying the target. If the target isn’t detected or if plans change, the system’s recovery capability allows it to return to its base camp and land safely using a parachute and airbag.

According to Dany Eshchar, deputy CEO at Aeronautics, the first armed Orbiter 1Ks will be supplied to undisclosed foreign customers in coming months, only confirming the company has received orders for “hundreds” of systems.

Military commanders in Israel and elsewhere clearly want more loitering weapons – and fast.

Snorkel?! Part I

Histories of the Battle of the Atlantic universally fail to appreciate the impact that the introduction of the snorkel had on the evolutionary shift in U-boat operations at the end of the war.

German U-boat histories of the Second World War are dominated by the period 1940–43 and written by, or about, veterans that never saw a single operational patrol in a snorkel-equipped U-boat. Out of the top twenty-five U-boat aces of the war, only one – Heinrich Lehmann-Willenbrock – commanded an operational snorkel-equipped U-boat. However, he did not take part in the inshore campaign during this cruise. Well-known U-boat commanders including Kretschmer, Lüth, Topp, Merten, Prien, Schepke, Witt and Lemp never experienced a patrol on a snorkel-equipped U-boat nor had any understanding of its potential.

Lothar-Günther Buchheim, author of the popular anti-war book Das Boot, never sailed on a snorkel-equipped U-boat. Yet he disparaged the device in his follow-on 1976 book Der U-Boot Krieg, even though he admitted ‘it was a life saver’. The U-boat force was given an ‘orthopedic contraption’, Buchheim stated colourfully, by leadership that called it an ‘epochmaking invention’. While Dönitz gave the snorkel device due credit in his post-war memoir, he also had no practical experience with the snorkel and spent only about twenty pages covering the period of the U-boat war from 1944–45. He longed only for the day his ‘wolves’ could return to the heyday of convoy warfare.

The problem in German U-boat veteran historiography is that no one grasped how the snorkel fundamentally altered the nature of submarine warfare. The potential resumption of anti-convoy operations remained paramount in the minds of Dönitz and his U-boat men because it recalled the heyday of success and brought meaning to the force’s sacrifices. However, there was never going to be a resumption of such operations because the challenge of submerged communications was never overcome during the war. Not even the introduction of the Type XXI ‘wonder weapon’ was going to change that fact. There was never a post-war survey by German naval historians of the impact of the snorkel within the U-boat fleet, leaving the broader understanding of the Battle of the Atlantic overwhelmingly distorted towards the earlier period of convoy battles.

Most British and American authors remain content to view the Battle of the Atlantic through the narrow optic of convoy warfare, and within that limited view argue that the U-boat as a weapon system was defeated in May 1943. Many opine that continued resistance by the U-boat force after May 1943 was folly, despite any wartime technical developments.

As an example, Ed Offley’s 2011 work, Turning the Tide: How a Small Band of Allied Sailors Defeated the U-Boats and Won the Battle of the Atlantic, argues the well-worn thesis that the U-boat was defeated in May 1943 and forced to withdraw from the Atlantic. His view of the U-boat’s continued deployment during the following two years was that they served little purpose beyond ‘cannon fodder’. While he briefly discusses Dönitz’s actions to restore the U-boat force, he cites only the future development of the high-speed Electro-boats and Walter turbines, never once mentioning the snorkel. Offley, like many authors, is content to interpret the remaining years of the Battle of the Atlantic through the balance sheet of tonnage sunk versus U-boats destroyed.4 It is a victor’s perspective that offers little historical value.

Arguably, one of the most audacious attempts at solidifying the victor’s perspective of the Battle of the Atlantic came from former Second World War US Submarine veteran Clay Blair, who took a direct attack in his assessment of both the U-boat and its technology. He was determined to counter what he believed was a growing U-boat ‘mythos’ in the late 1980s and early ’90s, fuelled in popular literature by scores of U-boat veteran memoirs and movies such as Das Boot that found eager audiences in Great Britain and the United States. Blair published his two-volume history Hitler’s U-Boat War starting with Volume 1 in 1996 and continuing with Volume 2 in 1998. His scope was the U-boat itself and not just the convoy battles of the mid-Atlantic. In the foreword of his first volume he set a contrary tone regarding wartime technological advances in the U-boat force by dismissing any evolutionary value of the Type XXI offhandedly, despite the known benefits of its hull form and internal mechanics widely copied after the war by all major navies. He specifically dissected its snorkel apparatus into ‘imperfect’, ‘hazardous’ and ‘nightmarish’. In his second volume he addressed the introduction of the snorkel across the U-boat diesel force in counterfactual terms. He stated that the snorkel was ‘technically primitive’; only employed for one to four hours a day; a snorkelling U-boat was completely ‘deaf’ and could not use its radio receivers or hydrophones; a U-boat that snorkelled could not use its periscope; snorkels were prone to emit exhaust smoke; snorkels leaked carbon monoxide into the pressure hull; a snorkelling U-boat had no way to get rid of its waste; and arguably the most erroneous statement that ‘almost without exception, U-boat crews distrusted snorts and hated to use them’. All of Blair’s statements are gross exaggerations or counterfactual when compared against period primary documents. In Blair’s desire to diminish the evolutionary contribution to modern submarine development made by German wartime engineers, he asserted that the US Navy advanced into the nuclear-powered submarine age with such sophistication as to leave behind all ‘hopelessly archaic’ German technical innovations, like the snorkel. His amateurish historical assertions are contradicted by official US Navy technical assessments.

In the earliest published work on the last year of the Battle of the Atlantic, British naval historian V E Tarrant, writing in his 1994 book The Last Year of the Kriegsmarine, May 1944–May 1945, stated that the snorkel ‘was never welcomed by the majority of the U-boat crews’. His work on this critical, transformative period of the Battle of the Atlantic only focused on the building programmes related to the new Electro-boats and ignored the evolution of tactics and operations brought on by the snorkel. While American authors might be excused from understanding the snorkel’s impact, as snorkel-equipped U-boats only made an appearance off the US East Coast in the waning months of the war, the British, and to a lesser extent the Canadians, dealt with them for an entire year during the inshore campaign.

The point of view that the diesel U-boat was defeated in May 1943 as a weapon system and that the snorkel, unwelcome by U-boat crews, had little or no impact during the war is not corroborated by wartime or post-war primary documents. The diesel U-boat as a weapon system was not defeated in May 1943, only the surface-based Wolfpack tactics it employed against mid-Atlantic convoys. The U-boat survived, and even thrived with the introduction of the snorkel, as the Western Allies struggled to overcome the resurgent menace it had once thought defeated. While it is true that defeating the Wolfpack alleviated the single greatest threat to Great Britain’s survival and thus the Allied war effort, the introduction of the snorkel and shallow-water tactics diminished Ultra’s impact and continued to strain Allied resources. The idea of snorkel-equipped Type XXIs returning to the mid-Atlantic to reignite convoy warfare certainly was a threat that the Allies remained concerned about until the end of the war, but the reality was that BdU planned to send them individually to the coasts of North America and the United Kingdom to operate continually submerged close to Allied ports and within narrow channels and waterways. Surface-based Wolfpack tactics were gone forever.

Canadian maritime historian and former Wilfrid Laurier University professor Roger Sarty is one of the very few historians of the period who viewed the last twelve months of the Battle of the Atlantic through the filter of the snorkel’s impact. He wrote in his 1997 article ‘The Limits of Ultra: The Schnorchel U-boat Offensive Against North America, November 1944–January 1945’ that the:

Schnorchel caused profound difficulties for the Allied anti-submarine forces because of the change in U-boat tactics that the new equipment made possible. Submarines that neither signalled nor surfaced were safe from the radar-equipped aircraft that had long been the basis of the successful, economical defence of coastal waters … It soon became clear that protection of shipping against a single schnorchel boat well-situated in coastal waters required fully as many warships and even more aircraft than an active defence of a large convoy at mid-ocean against dozen of submarines.

Sarty was closer to historical reality than most authors writing of this period.

Wartime View

No Allied power endured the struggle against the German U-boat in the mid-Atlantic and along their coast more than Great Britain. In November 1944 Royal Navy Captain Clarence Howard-Johnson, who served as the Royal Navy’s Director of the Anti-U-boat Division, declared during the resurgent U-boat’s inshore campaign that:

The snorkel has had such far-reaching results that the whole character of the U-boat war has been altered in the enemy’s favour. Frequently he has managed to penetrate to and remain on our convoy routes in focal areas with impunity in spite of intensive air and surface patrols. With more experience in training and with the confidence engendered by his present immunity from air, and often from surface attack, he is likely, in the future, to do us more real harm than he has up to the present.

This was a sentiment echoed by Royal Navy Admiral Submarines Sir George Creasy, who directed British submarines to adopt the snorkel during the war on a limited trial basis in order to understand this innovation and how to counter the emerging threat. He soon recognised that there was no longer a future for the surface-bound submersible as the age of the true submarine was within technological sight.

The performance of the snorkel in the latter half of 1944 was so successful that the Ministry of Propaganda decided to capitalise on the technical innovation. The following radio broadcast aired on 22 March 1945 in conjunction with the release of Die Deutsche Wochenschau, which showed newsreel footage of the new snorkel-equipped U-boats. The snorkel was considered a ‘secret’ development for nearly a year and was now unveiled to the German public for the first time. It is a surprisingly accurate account of the Battle of the Atlantic:

The German public has learned about the new technical development of U-boat warfare for the first time from the report concerning the air mast of the U-boat, which appeared in the High Command communiqué. The facts now published were apparent already in the news of the past few weeks. When a number of U-boat commanders were decorated with the Knight’s Cross of the Iron Cross it was emphasised that they had won it in particularly difficult areas and on their first operational trip. Furthermore, on recommendation of Grand Admiral Dönitz, the Führer awarded the Knight’s Cross with Swords to Prof. Hellmuth Walter for his special merits in the technical development of the German U-boats. Lastly, the monthly declarations of Roosevelt and Churchill on the U-boat campaign as well as the speeches of Canadian and North American ministers of which we have given reports in our service, showed the enemy’s considerable anxiety about this steady increase of German U-boat successes …

It has been emphasised in the German reports that the latest successes were achieved not by an entirely new type of U-boat, but by boats of the type which have proved efficient during the period of 1941–1943, and which were fitted with the air mast to enable them to proceed continuously submerged …

Now also the U-boat crews, in spite of being severely strained physically by long months of submerged travelling, are effectively using their new technical equipment, above all in the most dangerous areas close to the enemy ports. In the shallow waters a U-boat, once discovered by the enemy, finds himself in a most difficult situation. But the men of the U-boats take upon themselves these dangers and losses because of the better chances of successes as at this stage every sinking of an enemy ship is particularly important. It is by no means intended to speak now prematurely of a ‘new large-scale U-boat offensive’. The reports on the air mast show, however, that important technical inventions have been made, with which we again overtake the enemy’s U-boat defence.

Compare the above propaganda broadcast to the actual Top Secret intelligence assessment by OP-20-G released just one month later on 20 April 1945 that stated plainly: ‘The last 46 days has seen a marked increase of U-boat pressure against allied shipping, despite the desperate situation in the Homeland and in the Baltic …’ This intelligence assessment issued just weeks before the end of the war in Europe is a clear testament to the fact that the U-boat was not a defeated weapon system. It had survived the ‘Black May’ of 1943 and remained a tactical, if not strategic, concern for the Allies.

Enigma ciphers were ordered changed as concern grew in BdU of their possible compromise. While some Enigma ciphers required days to break, significantly diminishing their value, others still had to be broken. Kurier – the new flash transmission system that could not be read by Allied cryptologists – was being increasingly employed.

Operational U-boat deployments increased to the highest level in more than a year. Allied ship sinkings were up and there was continued concern about the potential deployment of the Type XXIs. The largest concentration of U-boats in nearly three years arrived off the North American coast despite the knowledge of their movement through Ultra and the deployment of the single greatest anti-submarine screen employed by the US Navy in its history. What hampered the U-boat’s success continued to be the ability, though reduced, of Allied cryptologists to ascertain U-boat deployments and re-route convoys.

The final situation update of the U-boat force was written by OP-20-G’s Navy Reserve Lieutenant W V Quine on 2 May, just days before the end of the war. He noted that there were 192 U-boats in the Atlantic and Arctic, with 118 at sea and seventy-four in port. This was an increase of seven over the previous week. He assessed that:

As yet there is no sign of any serious break-up in the German naval organisation in the Baltic. The situation is still quite confused because of the continual transferring of [U-boats] out of the enemy’s reach in the rush to get [U-boats] finished for frontline operations. Orders, however, seem to be carried out effectively and the loss of [U-boats] appears to be relatively small.

Quine’s final assessment contained one of the last Ultra intercepts of the war that noted the singular importance of the snorkel. On 24 April a wireless message was intercepted that read ‘complete repairs, including installation of snorkel, in Rostock on 6 Type XXIII and in Wismar on 3 Type XXIII was assured’. With the Soviet Army surrounding Berlin, the US Army on the Elbe River and the British advancing on the main U-boat production facilities in north-west Germany, the U-boat force remained potent and organised. The installation of the snorkel remained one of the highest priorities for BdU, even in the last days of the war.

What a snorkel-equipped U-boat demonstrated during the war, too often lost on period historians, was that a submarine that didn’t surface and didn’t transmit by radio was almost impossible to track, find and destroy. It was a situation that foreshadowed the future of ‘Total Undersea Warfare’ in the atomic and nuclear age.


Technologies – The Schnorchel

Star Wars and Tank Wars

On the evening of March 23, 1983, a long black limousine pulled up to the south gate of Ronald Reagan’s White House. In the back sat Edward Teller, now seventy-five years old. Teller was not exactly sure why he was here. He had just flown in from California, where he lived, because the aide who called him three days earlier said President Reagan thought it was important that he be at the White House on this night.

Walking with a limp and a cane, Teller made his way through the White House foyer, up the stairs, and into the Blue Room. There he was greeted by Admiral John Poindexter, the Military Assistant to the President for National Security Affairs. Poindexter suggested Teller have a seat. Thirty-six chairs had been set up in neat rows. Teller sat down and waited. In another seat was the Jason scientist and Nobel laureate Charles H. Townes, the principal inventor of the laser.

At 8:00 p.m., in a nationally televised address, President Reagan announced to the world his decision to launch a major new research and development program to intercept Soviet ICBMs in various stages of flight. The program, the Strategic Defense Initiative (SDI), would require numerous advanced technology systems, the majority of which were still in the development stage. DARPA would be the lead agency in charge until SDI had its own organization.

President Reagan said that the reason for this radical new initiative was simple. When he first became president, he was shocked to learn that in the event of a Soviet nuclear strike, his only option as commander in chief was to launch an all-out nuclear attack against the Soviets in response. Reagan said he was not willing to live in the shadow of nuclear Armageddon—mutual assured destruction. The United States needed the capability to strike down incoming Soviet missiles before they arrived. This bold new SDI program would allow for that.

For decades, defense scientists like the Jason scientists had been grappling with this conundrum of ballistic missile defense and had concluded that there was no way to defend against an onslaught of incoming ICBMs. Now, Reagan believed that technology had advanced to the point where this could be done sometime in the not-so-distant future.

The Strategic Defense Initiative involved huge mirrors in space, space-based surveillance and tracking systems, space-based battle stations, and more. But the element that got the most attention right away was the x-ray laser, which scientists at the Lawrence Livermore National Laboratory had been working on since the 1970s. Very few people outside the Livermore group understood the science behind an x-ray laser, and even fewer knew that x-ray lasers were powered by nuclear explosions.

Several days after Reagan’s speech, Secretary of Defense Caspar Weinberger was leaving the Pentagon to brief Congress on SDI. Walking alongside him was Undersecretary Richard D. DeLauer, a ballistic missile expert. Secretary Weinberger was having trouble grasping the science behind SDI and DeLauer was trying to explain it to him.

“But is it a bomb?” Secretary Weinberger asked.

DeLauer was candid. As the former executive vice president of the missile company TRW, Inc., and with a Ph.D. in aeronautical engineering, DeLauer understood the science behind the x-ray laser. “You’re going to have to detonate a nuclear bomb in space,” he told the secretary of defense. “That’s how you’re going to get the x-ray.”

This put Secretary Weinberger in an untenable position. President Reagan had assured the public that his new program would not involve nuclear weapons in space. “It’s not a bomb, is it?” Weinberger asked a second time.

DeLauer chose his words carefully. He said that the x-ray laser didn’t have to be called a bomb. It could be described as involving a “nuclear event.”

In a 1985 interview for the Los Angeles Times, DeLauer relayed this story verbatim. He said that the secretary of defense “didn’t understand the technology,” adding, “Most people don’t.”

The laser was invented in the late 1950s by Charles Townes, who in 1964 was awarded the Nobel Prize in physics. In the most basic sense a laser is a device that emits light. But unlike with other light sources, such as a lightbulb, which emits light that dissipates, in a laser the photons all move in the same direction in lockstep, exactly parallel to one another, with no deviation. To many, the laser is something straight out of science fiction. In a 2014 interview for this book, Charles Townes, then age ninety-eight, confirmed that he had been inspired to create the laser after reading Alexei Tolstoi’s 1926 science-fiction novel The Garin Death Ray. “This idea of a flashing death ray also has a mystique that catches human attention,” said Townes, “and so we have Jove’s bolts of lightning and the death rays of science fiction.” A half century after Tolstoi wrote about the Garin death ray, George Lucas modernized the concept with Luke Skywalker’s light saber in the science-fiction film Star Wars.

One of the first sets of experiments involving lasers, mirrors, and space took place in 1969 and has been largely lost to the history books. The experiment began on July 21 of that year, said Townes, when, for the first time in history, two men walked on the moon. While on the lunar surface, “astronauts Neil Armstrong and Edwin [Buzz] Aldrin set up an array of small reflectors on the moon and faced them toward the Earth.” Back here on earth—which is 240,000 miles from the moon—two teams of astrophysicists, one team working at the University of California’s Lick Observatory, on Mount Hamilton, and the other at the University of Texas’s McDonald Observatory, on Mount Locke, took careful notes regarding where, exactly, the astronauts were when they set down the mirrors. “About ten days later, the Lick team pointed the telescope at that precise location and sent a small pulse of power into the tiny piece of hardware they had added to the telescope,” said Townes. Inside the telescope, a beam of “extraordinarily pure red light” emerged from a crystal of synthetic ruby, pierced the sky, and entered the near vacuum of space. A laser beam.

Traveling at the speed of light, 186,000 miles per second, the laser beam took less than two seconds to hit the mirrors left behind on the moon by Armstrong and Aldrin, and then the same amount of time to travel back to earth, where the Lick team “detected the faint reflection of its beam,” explained Townes. The experiment delivered volumes of scientific data, but one set was truly phenomenal. “The interval between launch of the pulse of light and its return permitted calculation of the distance to the moon within an inch, a measurement of unprecedented precision,” said Townes. The laser beam was able to measure what stargazers and astronomers have wondered since time immemorial: Exactly how far away from earth is the moon?

While the astrophysicists were using laser technology for peaceful purposes, the Defense Department was already looking at using lasers as directed-energy weapons (DEW). In 1968 ARPA had established a classified laser program called Eighth Card, which remains classified today, as do many other laser programs, the names of which are also classified. Directed-energy weapons have many advantages, none so great as speed. Traveling at the speed of light means a DEW could hit a target on the moon in less than two seconds.

After hearing Reagan’s historic announcement from a front-row seat in the White House Blue Room, Edward Teller and Charles Townes had decidedly different reactions. Teller embraced the idea and would become a leading scientist on the Strategic Defense Initiative and the follow-up program, called Brilliant Pebbles. Charles Townes did not believe Reagan’s SDI concept could work.

“For a president who doesn’t know the technology one can see why [it] might be appealing,” said Townes. “It doesn’t really seem very attractive to me, or doable. But you can see how from a matter of principle it sounded good to Reagan. It’s like an imaginary story of what might be done.”

The day after the speech, Senator Edward Kennedy criticized the president’s initiative, calling it a “reckless ‘Star Wars’ scheme.” The name stuck. From then on, the president’s program became known around the world as “Star Wars.” Science fiction and science had crossed paths once again. For the general population, real-world lasers, death rays, and directed-energy weapons were scientifically impossible to grasp. Science fiction was not so hard.

Congress worried that SDI was not technically feasible and that it was politically irresponsible. That even if the technology were successful, it could trigger a dangerous new arms race with the Soviets. But after debating the issue, Congress gave the Reagan White House the go-ahead for the Strategic Defense Initiative, and over the next ten years, nearly $20 billion was spent. It is often said that the Clinton administration canceled the SDI program, when in fact it canceled only certain elements of the Strategic Defense Initiative. SDI never really went away. In 2012 the Fiscal Times reported that more than $100 billion had been spent on SDI technologies in the three decades since Reagan first proposed the idea, $80 billion of which had been spent in the past decade.

SIMNET: A Turnkey Cloud-Based Simulator for UAS Suppliers

Space remains a domain where domination has long been sought but where all-out war has never been fought. For scientists and engineers working on DARPA’s SIMNET program, the focus would remain on land. There had been steady progress with the SIMNET program in the year since director Larry Lynn gave it the go-ahead, including the fact that the Army was now involved. Which is how, in the spring of 1984, Jack Thorpe, now a major, found himself maneuvering a sixty-ton M1 Abrams tank up over a muddy hill deep in the pine-forested back lot of the legendary armor school at Fort Knox, Kentucky.

“When we started SIMNET, the threat was on Soviet armor warfare,” says Thorpe, “meaning tanks.” This meant that simulating tank warfare was SIMNET’s first priority. The desired goal was to create a virtual reality that felt real. So Thorpe and the DARPA team were at Fort Knox, driving through the mud, attempting to “capture the sense of tankness,” says Thorpe. DARPA had big plans for SIMNET, with a goal of building four SIMNET centers to house a total of 360 simulators, roughly 90 per site. At the time, Thorpe and the DARPA team were working on the first two simulators, which would be models of M1 Abrams tanks.

Because there would be no motion in these simulators, the emphasis was placed on sound. Science Applications International Corporation (SAIC) of La Jolla was in charge of working with field units at instrumented training ranges and collecting data. The defense contractor Perceptronics Corporation of California was hired to design the fiberglass and plywood simulators and wire them for sound. “For someone on the outside, the sound of the hundred-and-five-millimeter tank gun firing at a target downrange is incredibly loud, but for a person inside the tank the experience is totally different,” says Thorpe. Because of the overpressure, there is almost no noise. “It’s incredibly quiet.” What there is inside is movement, which, Thorpe says, “is a totally different kind of sound.” The audio specialists with Perceptronics replicated the sound inside the tank by simulating the loose parts that vibrate when the gun fires. “Coins in the glove box,” recalls Thorpe, “loose bolts, anything that’s not tied down.” Back in the laboratory, to convey that rattling sound, audio engineers filled a metal pie plate with nuts and bolts, then glued the pie plate to the top of a subwoofer which they hid behind the fiberglass in the tank simulator. Then Bolt, Beranek and Newman of Boston, which had been a principal contractor on ARPANET, developed the networking and graphics technology for the simulators.

The 1986 annual armor conference at Fort Knox was a milestone in SIMNET history, the first test run of two DARPA SIMNET simulators. General Frederic “Rick” Brown and another general would test the systems, and there was a lot resting on what they thought of a simulated war game. Thorpe recalls the first two simulators as being “about eighty percent [complete], made of fiberglass and plywood, with one hand control to control the turret.” The two SIMNET tank simulators had been set up roughly twenty feet apart. The generals took their seats and the DARPA team piled inside.

“Neither general had any experience in the virtual world,” says Thorpe. “Here’s General Brown looking at a screen in front of him with an icon of the other tank. I say, ‘There in that tank, that is the [opposing] general.’ He doesn’t get it. So I say, ‘Turn the turret and point it toward the other tank.’ The turret turns. General Brown got a little giddy. He gets it, I think,” Thorpe recalls. “I tell him to load a sabot [round]. ‘Sir,’ I say, ‘if you trigger here, you can shoot the general.’”

General Brown fired the virtual weapon. On the screen, General Brown watched the other general’s tank blow up. “Everything went dark,” Thorpe recalls, in the virtual world, “the general and his crew were ‘dead.’” From the other tank, in the other fiberglass and plywood box, Thorpe heard the other general call out, “‘Reinitialize!’” Inside his simulator, the second general’s tank came back to life. He swung his turret around, put General Brown in his sights, and fired at him.

In that “reinitialize” moment, Thorpe says, he became convinced that both generals were sold on SIMNET. “The behavior in a virtual world is the same behavior as the behavior in the real world,” Thorpe says.

After its initial trials, and with the endorsements from two U.S. Army generals, the SIMNET project had considerable momentum, and the DARPA teams went into production mode. In nine months, DARPA had constructed a building at Fort Knox the size of a small Costco. Inside there were roughly seventy tank simulators, each made of fiberglass, and each with the approximate dimensions of an M1 Abrams tank or a Bradley fighting vehicle. “The building was designed like a hockey rink,” Thorpe says. Power and networking cables dropped from the ceiling. “Entire tank battalions would enter the SIMNET center and begin training together, as if they were in a real tank battle.” Real-world problems had been built into the system. “If you left your virtual electricity on overnight, in the morning your battery would be dead,” Thorpe recalls. “If you didn’t pay attention to landmarks and disciplined map reading, you got lost in the virtual battle terrain. It was force on force. One group against another.” Competition drove the training to a whole new level. “The desire to win forced people to invent new concepts about how to beat their opponents.”

A second SIMNET center was built at Fort Benning, Georgia, then another at Fort Rucker, in Alabama, for attack helicopter training. In 1988 a fourth SIMNET center went up at the U.S. Army garrison in Grafenwoehr, Germany, also for armor vehicles. In DARPA’s SIMNET, the U.S. Army saw a whole new way to prepare for war. Then an unexpected new center was requested by the Department of Defense.

“The high rankers at the Pentagon wanted a simulation center of their own,” recalls Neale Cosby, who oversaw the engineering on this center. The facility chosen as the host was DARPA’s longtime partner the Institute for Defense Analyses, just down the street from DARPA in Alexandria. The IDA offices were located in a collegiate-looking yellow-brick and glass building located at 1801 North Beauregard Street. In 1988, Cosby recalls, much of the ground floor, including the cafeteria, was taken over by DARPA so an IDA simulation center could be built there for Pentagon brass. Cosby recalls the production. “We covered all the windows with camouflage, laid down a virtual tarmac made of foam, set up fiberglass helicopters, tanks, and aircraft cockpits, then networked everything and wired it for sound.” Finally, a mysterious feature was added, one that no other SIMNET center had. For reasons of discretion, Cosby and Thorpe called the feature a “flying carpet.”

“It was a way for [participants] to put themselves into the virtual world not as a pilot or a tank driver or a gunner, but anywhere” in flight, says Cosby. “It was as if you were invisible.” At the time, the details of the invisible component were classified because the flying carpet feature was a way for Pentagon officials with high clearances to experience what it would be like to fly through a virtual battle in a stealth fighter jet. These were the results of DARPA’s “high-stealth aircraft” program, which began in 1974.

Over a ten-year period, DARPA and the Army spent $300 million developing simulation technology. In the summer of 1990 the SIMNET system was transferred over to the U.S. Army. Its first large-scale use was to simulate a war game exercise undertaken by U.S. Central Command (CENTCOM), in Tampa, Florida. For years CENTCOM had sponsored a biennial war game exercise called Operation Internal Look, based on a real-world contingency plan. The Internal Look war games trained CENTCOM’s combatant commander and his staff in command, control, and communications techniques. The exercises involved a pre-scripted war game scenario in which U.S. forces would quickly deploy to a location to confront a hypothetical Soviet invasion of a specific territory. In the past, the war games had taken place in Cold War settings like the Zagros Mountains in Iran and the Fulda Gap in Germany.

In the summer of 1990 the Cold War climate had changed. The Berlin Wall had come down eight months before, and CENTCOM commander in chief General Norman Schwarzkopf decided that for Internal Look 90, U.S. forces would engage in a SIMNET-based war game against a different foe, other than the Soviet Union. A scripted narrative was drawn up involving Iraqi president Saddam Hussein and his military, the fourth largest in the world. In this narrative, Iraq, coming off its eight-year war with Iran, would attack the rich oil fields of Saudi Arabia. In response, U.S. armed forces would enter the conflict to help American ally Saudi Arabia. Because new SIMNET technology was involved, realistic data on Saudi Arabia, Iraq, and neighboring Kuwait were incorporated into the war game scenario, including geography, architecture, and urban populations, this for the first time in history. In playing the war game, CENTCOM battle staff drove tanks, flew aircraft, and moved men across computer-generated Middle Eastern cities and vast desert terrain with the astonishing accuracy and precision of SIMNET simulation.

“We played Internal Look in late July 1990, setting up a mock headquarters complete with computers and communications gear at Eglin Air Force Base,” General Schwarzkopf wrote in his memoir. And then to everyone’s surprise, on the last day of the simulated war game exercises, on August 4, 1990, Iraq invaded its small, oil-rich neighbor Kuwait—for real. It was a bizarre turn of events. Science and science fiction had crossed paths once again.

Months later, after the Gulf War began and ended, General Schwarzkopf commented on how strangely similar the real war and the simulated war game had been.

“As the exercise [i.e., the Gulf War] got under way,” General Schwarzkopf said, “the movements of Iraq’s real-world ground and air forces eerily paralleled the imaginary scenario of the game.”

Nebelwerfer rocket launcher.

A diagram of the new Nebelwerfer 150mm ammunition

These rockets were fired from a six-tube launcher mounted on a towed carriage adapted from the 3.7 cm PaK 36 carriage. This system had a maximum range of 6,900 metres (7,500 yd). I am uncertain whether these weapons were used in the Western Desert, but photographs record them in Tunisia, Sicily and Italy, Normandy and the NWE campaign, and of course on the Russian front. Nearly five and a half million 15 cm rockets and six thousand launchers were manufactured over the course of the war.

The 15-cm (5.9-in) German artillery rockets were the mainstay of the large number of German army Nebelwerfer (literally smoke-throwing) units, initially formed to produce smoke screens for various tactical uses but later diverted to use artillery rockets as well. The 15-cm (5.9-in) rockets were extensively tested by the Germans at Kummersdorf West during the late 1930s, and by 1941 the first were ready for issue to the troops.

The 15-cm (5.9-in) rockets were of two main types: the 15-cm Wurfgranate 41 Spreng (high explosive) and 15- cm Wurfgranate 41 w Kh Nebel (smoke). In appearance both were similar and had an unusual layout, in that the rocket venturi that produced the spin stabilization were located some two-thirds of the way along the rocket body with the main payload behind them. This ensured that when the main explosive payload detonated the remains of the rocket motor added to the overall destructive effects. In flight the rocket had a distinctive droning sound that gave rise to the Allied nickname ‘Moaning Minnie’. Special versions were issued for arctic and tropical use.

The first launcher issued for use with these rockets was a single-rail device known as the ‘Do-Gerät’ (after the leader of the German rocket teams, General Dornberger). It was apparently intended for use by airborne units, but in the event was little used. Instead the main launcher for the 15-cm (5.9-in) rockets was the 15-cm Nebelwerfer 41. This fired six rockets from tubular launchers carried on a converted 3.7-cm Pak 35/36 anti-tank gun carriage. The tubes were arranged in a rough circle and were fired electrically one at a time in a fixed sequence. The maximum range of these rockets was variable, but usually about 6900m (7,545 yards), and they were normally fired en masse by batteries of 12 or more launchers. When so used the effects of such a bombardment could be devastating as the rockets could cover a considerable area of target terrain and the blast of their payloads was powerful.

On the move the Nebelwerfer 41s were usually towed by light halftracks that also carried extra ammunition and other equipment, but in 1942 a half-tracked launcher was issued. This was the 15-cm Panzerwerfer 42 which continued to use the 15-cm (5.9-in) rocket with the launcher tubes arranged in two horizontal rows of five on the top of an SdKfz 4/1 Maultier armoured halftrack, These vehicles were used to supply supporting fire for armoured operations. Up to 10 rockets could be carried ready for use in the launcher and a further 10 weapons inside the armoured body. Later in the war similar launchers were used on armoured schwere Wehrmachtschlepper (SWS) halftracks that were also used to tow more Nebelwerfer 4 Is, The SWS could carry up to 26 rockets inside its armoured hull.

The 15-cm (5.9-in) rockets were also used with the launchers intended for the 30-cm (11.8-in) rockets, with special rails for the smaller rockets fitted into the existing 30-cm (11.8-in) launcher rails.
PRO document WO 291/2317, “German use of the multi-barrelled rocket projector”, dated 07 Jan 1944, has a couple of things to say on this question.

It gives safety zones from several sources. A German circular dated March 1942 gives safety zones for own troops for 15cm rockets as 500m in range and 300m in line from each edge of the target area, and says that concentration of own troops should be avoided for 3000 metres short of the target. Other reports give safety zones of 500 yards and 600 metres.

It also gives the results of three firing trials with captured rockets:

15cm Nebelwefer trial in North Africa
Rounds QE Mean range (m) m.d. dispersion in range (m)
10 6° 3′ 2710 252
5 30° 7018 130
5 45° 7723 115

15cm HE trial in North Africa
Rounds QE Range (yds) m.d. range (yds) m.d. line (yds)
10 6° 3’ 2954 247 77
4 30° 7675 142 37
5 30° 8446 127 34
Trial in England, 15cm HE and smoke
Type Rounds QE Range (yds) m.d. range m.d. line time of flight (secs)
HE 22 15° 4565 107 42 17.73
Smoke 15 15° 3509 117 33 13.60
PRO document WO 232/49, “Role of rockets as artillery weapons”, says that with Land Mattress the dispersion in range approaches that of guns, but in line is still six times as much. It also says that the safety zone for Land Mattress is 500 yards.

At 8000+ yards, a single 6 rocket Nebelwerfer can place them onto a football field? Considering the heavy payload and the range, that’s pretty good chucking. If I’m reading the figures correctly, and if a football field is about 100m long, then it means that it would put half of them within a football field’s length of the MPI — in other words, the 50% zone would be two football fields long.

Whether the MPI is accurately adjusted onto the target is another question, and as the point of MRLs is surprise fire I would expect the registration process to be less accurate for NbWs than tube artillery because of the practice of using silent or offset registration to preserve surprise.

AGM-28 Hound Dog

The AGM-28 was an air-launched cruise missile with a range approaching 800 miles. Known as Hound Dog, it was only carried by certain versions of the B-52 Stratofortress bomber. It was termed a “stand off” weapon in that it could be launched at targets keeping the bomber well away from any local defenses. The turbojet engines of the paired AGM-28s mounted beneath the inboard wings of a B-52 could be used to supplement its takeoff power, once airborne the bomber could refuel the missiles’ fuel tanks. No Hound Dogs were ever fired in anger, and they were withdrawn from use in 1978.

B-52F-70-BW 57-0163, 320th Bombardment Wing, Strategic Air Command, North American AGM-28A Hound Dog stand-off missile carrier

The first of the nuclear-tipped missiles carried by the B-52E, F, G and H models, Hound Dog was operational with SAC from September 1961 to 1976. One could be carried on a pylon suspended beneath each wing of a B-52G between the fuselage and the inboard engine nacelles. Two basic models of Hound Dog – GAM-77 (later AGM-28A) and GAM-77A (later AGM-28B) were produced. The missile was not capable of pin-point accuracy but it was designed as a standoff or ‘roll-back’ weapon to ‘soften’ enemy defences or target complexes up to 700 miles away during attacks by the bombers, much like the later AGM-69 SRAM. AGM-28B differed from the AGM-28A mainly in having a more accurate inertial guidance system and repositioning of the KS-120 astrotracker device from the missile pylon to the missile body. The B-52 could use Hound Dog’s Pratt & Whitney J52-P-3 turbojet engines for extra power on heavyweight take-offs and the missile’s tanks could be topped up by the B-52 in flight. Hound Dog had an inertial guidance system, which was updated by the B-52’s onboard system just prior to launch. The first Hound Dog-equipped B-52G unit was the 4135th Strategic Wing, at Eglin AFB, Florida, which first deployed in December 1959. On 17 January 1962 B-52Gs of the 4038th Strategic Wing at Dow AFB, Maine, became the first operational unit to go on alert status with the new missile. A total of 703 units were built and at its peak in 1963 the Hound Dog force numbered 593, but the missile was rapidly rendered obsolete and withdrawal from service was begun in 1967. At the end of June 1975 it was finally taken off alert duty and the last AGM-28 was scrapped in June 1978.

On 12 April 1960 a B-52G crew in the 4135th Strategic Wing at Eglin AFB, Florida, successfully launched a GAM-77 (AGM-28) Hound Dog air-launched attack missile as the climax of its 20½-hour captive flight to the North Pole and back. The 4135th Strategic Wing had been the first Hound Dog-equipped B-52G unit and first deployed in December 1959. The crew completed extensive tests of both the B-52G and the Hound Dog’s guidance system in temperatures as low as -7.5 degrees. On 14 December a B-52G of the 5th Bomb Wing at Travis AFB, California, completed an official record-breaking flight of 10,078.84 miles without refuelling in nineteen hours forty-four minutes. The aircraft, commanded by Lieutenant Colonel T. R. Grisson, flew a closed-circuit course from Edwards AFB, California, to El Paso, Texas, Andrews AFB, Maryland, Ernest Harmon AFB, Newfoundland, Eielson AFB, Alaska, Philip, South Dakota, and back to Edwards.

The first B-52H flew on 20 July 1960. Due to extensive rework and advanced technologies each B-52H model cost $9.2 million apiece. (The first ‘B’ models cost $14.4 million each and the B-52E eventually cost $5.9 million per aircraft.) One of the reasons for the B-52H order was a requirement to carry four GAM-87A Skybolt missiles on twin missile-launcher pylons. Though the pylons were developed the B-52s never carried Skybolts operationally, as the missile was cancelled in 1962. The B-52 force reverted to AGM-28 Hound Dogs for a further fourteen years and the new B-52H models were retrofitted for Hound Dogs in 1963.


Intermediate-range, air-launched, ramjet-powered, single warhead cruise missile.


Studies of the development of the GAM-77 Hound Dog began in 1956 when the USAF issued a General Operations Requirement for an air-to-surface missile for the B-52 bomber aircraft. The design requirements called for a 4 MT nuclear warhead (later reduced to 1 MT) to be carried a maximum range of 560 km, at M2.0 at over 17,000 m (55,000 ft) altitude. The contract for the development and production of Hound Dog was awarded to North American Aviation in 1957. The W-28, a 1 MT warhead, which had been developed for the Mk 28 bomb, was selected for Hound Dog. In 1958 growing concern about both the perceived unfavourable shift in the strategic balance and the increasing vulnerability of penetrating bombers prompted the USAF to accelerate development of the GAM-77, now designated AGM-28. In 1959 compatibility of the W-28 warhead to the Hound Dog missile was established and the first prototype missile was successfully tested. The first production AGM-28A Hound Dog was delivered to the Strategic Air Command (SAC) in December 1959 and SAC launched its first AGM-28A in February 1960. Because of certain deficiencies in the initial production missiles, development continued and an improved version GAM-77A designated AGM-28B was introduced into service in 1961.

The B-52 could carry two of the missiles, one on each of its two underwing inboard pylons, although the two missiles degraded the B-52 flight performance. However, the SAC crews found that they could shorten the B-52s take off run by using the Hound Dog engines in addition to the bombers eight engines, and bomber fuel could then be transferred to the missiles before they were launched.


AGM-28 Hound Dog was a streamlined, long slender missile with a canard and delta wing configuration. Under the rear half of the fuselage was a large ramjet engine on a short pylon. The missile was 12.95 m long, had a body diameter of 0.72 m, a wing span of 3.70 m and a launch weight of 4,350 kg. Guidance was by a self-contained inertial system produced by North American’s Autonetics Division that operated the canard and wing control surfaces. The propulsion unit was the Pratt & Whitney J52 ramjet engine, which developed a thrust of 3,400 kg. The engine had a centre-body air intake and a variable propulsive nozzle to modulate the thrust and turbine temperature under different flight conditions. The missile payload was 790 kg and consisted of a W-28 nuclear warhead that had a yield of 1 MT.

When launched in its high-level profile, Hound Dog had a cruising speed of M 2.0 and range of 1,180 km. The maximum range at low level was 630 km with a speed of M 0.83 at 300 m altitude. The accuracy of the missile, 1,850 m CEP at full range, was probably adequate considering the yield of the warhead.

Operational status

The AGM-28A Hound Dog entered service with the USAF on B-52 bombers in 1960. This was followed by AGM-28B in 1961. The numbers of Hound Dog missiles in the B-52 fleet grew rapidly from 54 in 1960, rising to 593 in 1963 of which over 400 were AGM-28Bs, and by this time 29 SAC wings were operational with the AGM-28. Hound Dog production ended in 1963 and the number of missiles declined to 308 in 1976. The USAF phased out the Hound Dog in 1976, replacing it with the smaller AGM-69 SRAM. The last Hound Dog was retired for scrapping on June 15, 1978, from the 42nd Bomb Wing at Loring Air Force Base, Maine


Length: 42 ft 6 in (1295.4 cm)

Diameter: 2 ft 4 in (71.12 cm)

Height: 9 ft 4 in (284.48 cm)

Maximum Span: 12 ft 2 in (370.84 cm)

Function: Air-to-Surface

Weight: 10,147 lbs (4,607 kg)

Warhead: W28 Nuclear Warhead, 1 MT

Guidance: Inertial

First Use Date: 1959

Producer: North American

Users: US Air Force

Other Designations: WS 131B, GAM-77

Status: Was operational, withdrawn from use 1978

Airborne cruise missile AGM-28A/B (GAM-77/GAM-77A) Hound Dog