The US Nuclear Arsenal: W67, Poseidon, and the Soviet Response
YAZU W67: An ambition that failed to take off
W67 — a three-stage thermonuclear device using the "fission + fusion - fusion + fission - fission" scheme. Its development began in June 1966 at Los Alamos National Laboratory, but was discontinued about a year and a half later, in January 1968. The 2-megaton warhead was intended to be the most advanced in terms of specific yield, surpassing not only the W56 but any other nuclear device in the American arsenal, and indeed anywhere in the world. It was housed in a Mark 17 warhead, and the primary goal was to extract maximum energy output. Only one partial test of the primary module was conducted before the program was canceled. Expert Chuck Hansen identifies this test with experience Crosstie Zara.
The task proved overly ambitious and ran into a series of technical problems. According to the plan, the unit and its charge were supposed to weigh 900 pounds (410 kg), but by November 1966, the project had already hit the lower limit of 938 pounds (425 kg). The reason for this was the more serious protection against nuclear hazards than originally planned. weapons enemy. The charge itself weighed 675 pounds (306 kg).
The W67 was briefly resurrected in 1970 as part of the program CAFE (C-3 Alternative Front End) for the Poseidon. This was a backup plan: if the MIRV warheads failed testing, the MIRV program would be canceled, and the Poseidon would have to revert to a single-warhead design. Two warhead options were considered. Mark 1 Prime from a rocket Polaris A-1The nuclear power plant without the block housing and the automation unit reached the design weight of 680 pounds (310 kg).
As a result, the project of a universal monoblock for the latest ICBMs Minuteman III and SLBMs Poseidon closed, and all efforts were focused on promising MIRV (MIRV) combat equipment: the W68/Mk.3 warhead for the Poseidon and the W62/Mk.12 for the Minuteman-3.
Underwater test launch of the American UGM-27A Polaris A-1 ballistic missile
How the "bus" was shared: Mailman, Blue Angels, and Carousel
In November 1964, it was planned to develop, jointly with the Air Force, a single warhead based on the existing W62/Mk.12 for MIRVs and for SLBMs Polaris B-3, and for the Minuteman III ICBM. Early on, the plan was to equip the naval missile with six warheads. The deployment method from the Polaris A-3 proved unsuitable, so three options were put on the table.
- Mailman — based on Air Force developments for the Minuteman. It envisioned a "bus": a platform with a guidance system and engine, from which warheads would be sequentially released at predetermined points along the trajectory.
- Blue angels — with a control system similar to the Polaris. Each unit received its own guidance and propulsion system.
- Carousel — the rocket would spin up at the end of its boost phase, and the blocks would fly apart due to centrifugal force. This option didn't provide individual guidance and was quickly abandoned.
The first two options provided individual guidance for each unit. The most interesting was considered Mailman: unlike Blue angels it did not require modification of the W62/Mk.12 unit and allowed the installation of another unit. And although the OSD (Office of the Secretary of Defense, the central office of the US Department of Defense) insisted on the W62/Mk.12 with a capacity of 170 kt, SPO (Special Projects OfficeThe Naval Special Programs Command (NSPC) began developing an alternative. This was the W68/Mk.3, which carried a smaller payload: it was weaker, but allowed more pods to fit on the missile. Thus, the original six-pod design gave way to a more dense configuration.
In November 1964, Robert McNamara sent a memorandum to the President recommending that funds be allocated to begin work on Polaris B-3 $35 million in the 1966 budget. The technical specifications were expected to be approved during the 1965 fiscal year. They wanted a missile with improved accuracy and throw-weight, capable of destroying a single hardened target or several unhardened ones spaced up to 75 nautical miles with a single missile. On January 18, 1965, President Johnson announced the start of development of a new generation of SLBMs. The administration was criticized for the lack of new strategic systems, and for political reasons, the missile was given a resonant name. UGM-73 Poseidon C-3.
Fatal Mistake: Why They Abandoned the All-in-One PC
As development progressed, the option of a single-warhead megaton-class Mk.17, which would have offered a high probability of hitting heavily defended targets, surfaced. But by the end of 1965, the W68/Mk.3 was chosen. It was significantly inferior in yield to the W62/Mk.12, but more warheads could fit on a missile. Initial calculations showed that, for a given CEP (circular error probable—a measure of impact accuracy), multiple warheads covering a target from different angles would statistically deliver a more reliable hit than a single powerful warhead with the same CEP. This is where the W67/Mk.17 single-warhead was abandoned.
Later SPO calculations refuted this logic, but it was too late: the concept was implemented, the money was spent. The SPO's concerns that the Air Force was developing the blocks for its ICBMs without regard for fleet, will prove to be suboptimal for marine applications.
By January 1966, the missile's basic specifications had been approved. The primary objective was to penetrate Soviet missile defenses, while the destruction of hardened targets was relegated to secondary importance. The range was maintained at the Polaris A-3 level, 4,600 km. The Mk.3 was chosen as the payload. At the insistence of the OSD, a request to increase the accuracy (CEP) by 50% was added, but not made mandatory.
W78 warheads installed inside Mark 12A re-entry vehicles
The Poseidon SLBM is on display at the USS Bowfin Submarine Museum.
YAZU W68: A Little Miracle of Miniaturization
W68 Created in the late 1960s at Lawrence Livermore National Laboratory, the device weighed only 150 pounds (68 kg) with an official design yield of 40 kilotons of TNT. The design was revolutionary for its time and influenced many subsequent systems thanks to its breakthrough in warhead miniaturization.
The W68 was designed with four fuse options:
- low altitude radio fuse with backup contact fuse;
- high altitude radio fuse with timer backup;
- High altitude timer with backup contact;
- conventional contact fuse.
The loaded W68/Mk.3 unit weighed 91,4 kg.
The MIRV consisted of a combat, instrument, and propulsion compartment. The instrument compartment housed a three-axis gyrostabilized platform and an electronic computer, which guided the missile during its boost phase and deployed the RVs to individual targets. The guidance system provided a CEP of approximately half a nautical mile, or 926 meters. Accuracy was subsequently improved through a series of upgrades: in 1974, the radio navigation system's receivers were updated. Loran-CBy the early 1980s, the navigation system had been modernized. Transit, which more accurately determined the coordinates of the missile carriers, as well as the INS and computer, based on a new electronic base and gyroscopes with electrostatic suspension. All this increased the CEP to 600 yards (≈550 m).
The warhead compartment could accommodate up to 14 W68/Mk.3 warheads, each with a 40-kt payload, and a maximum throw-weight of 4,800 pounds (≈2,177 kg). It was the switch to the lightweight W68/Mk.3 instead of the more powerful but heavier W62/Mk.12 that allowed the number of warheads to be increased from the original six to ten to fourteen. The warhead's propellant system included a continuous-burning solid-fuel gas generator and eight pairs of nozzles that changed the direction of the gas flow; this controlled the warhead's orientation and thrust vector. The range and area of the warhead's deployment zone depended on the number of warheads: the lighter the payload, the higher the final velocity and range.
- 14 blocks: The speed at the end of the OUT was 5,650 m/s, the range was 2,500 nautical miles (4,600 km); the blocks were only scattered over the target, without individual guidance.
- 10 blocks (basic version): throw weight - 4,000 pounds (1,814 kg), velocity of the final warhead - 6,250 m/s, range - 3,200 miles (5,900 km), dispersal zone - 150 miles (278 km).
- 6 blocks: Throw-weight is 3,000 pounds (1,361 kg), velocity of the final warhead is 6,700 m/s, range is 3,780 nautical miles (7,000 km), dispersal zone is 300 miles (556 km) in range and up to 100 miles in azimuth.
Now the main idea. If the Americans had adopted the W67/Mk.17 monoblock for UGM-73 Poseidon C-3According to the author's estimates, they could have developed an SLBM with an intercontinental range of approximately 9,500 km by the early 1970s. The logic is simple: the lighter the payload, the higher the terminal velocity and range. If six warheads weighing approximately 1,360 kg gave a range of 7,000 km, then a single lightweight single warhead weighing 410–425 kg would accelerate the missile to 7,200 m/s at the end of the UT, increasing the range to intercontinental. The USSR only developed a missile with similar characteristics in 1976. R-29D with a range of 9,100 km on the then newest Project 667B SSBNs.
Instead, it wasn’t until the late 1970s that a truly long-range SLBM was developed, UGM-96A "Trident I (C-4)", but a full-fledged intercontinental UGM-133A "Trident II (D5)" appeared only in 1989. If the Americans had made the right decision in 1970, and the interim, essentially temporary, UGM-96A "Trident I (C-4)" might not have been needed at all.
How were things going in the USSR?
In 1955–1956, Research Institute 1011 (now VNIITF, Snezhinsk, Chelyabinsk-70) received a government assignment: to create new, powerful thermonuclear warheads for submarine-launched ballistic and cruise missiles. These weren't just regular warheads, but fundamentally new ones, significantly different in design from the RDS-37 prototype. The first such warhead was intended for the R-13 naval missile, which was assigned to SKB-385, headed by Academician Viktor Petrovich Makeev.
The designers had to translate the physicists' theoretical design into drawings and fit the charge into the rocket. But the requirements seemed impossible: the proposed charge didn't provide the warhead with stability in flight. A solution was found. K. I. Shchelkin and his deputy V. F. GrechishnikovThey proposed placing a lighter primary module first in flight and reducing the overall weight of the warhead by integrating its body with the outer casing of the charge. The solution became common ground for SKB-385 and NII-1011, uniting the two organizations, now RFNC-VNIITF named after. Academician E.I. Zababakhin и State Research Center named after Academician V. P. Makeev, for many years, right up to the present day.
On February 27, 1958, the RA-48 thermonuclear charge, designed specifically for the R-13, was tested with excellent results. Its TNT equivalent was 1450 kilotons. In 1960, the charge, mounted on the R-13 missile of the D-2 missile system, entered production and entered service, and in the fall of 1961, a combat launch over Novaya Zemlya confirmed its yield. The technique of combining the warhead body and the charge casing solved the problem brilliantly, but it is not universally applicable: it rigidly connects the charge and the casing, which is not always suitable.
Development also took another path. Almost simultaneously with NII-1011, the KB-11 theorists proposed their own physical scheme (VNIIEF, Sarov, Arzamas-16) - Corresponding Member of the USSR Academy of Sciences Yuri Nikolaevich Babaev and academician Yuri Alekseevich TrutnevIt was primarily developed by KB-11 designers; this is the AA-49 warhead. Its main advantage was that it was designed independently of the warhead shape, was self-contained, and could be used with any launch vehicle. Its development began with a test on February 23, 1958, which yielded almost 900 kilotons. The AA-49 was installed in the warhead of the R-21 missile of the D-4 complex, where it became the standard warhead; the throw weight of the 4G55 warhead was 1179 kg. Its yield was 1.5 times lower than that of the RA-48, but it also weighed 400 kg less.
And then the race for range began: our first-generation SLBMs, the R-13 (650 km) and R-21 (≈1400 km), lagged far behind the American ones. Polaris A-1 (2200 km) and A-2 (2800 km).
Second-generation charges: catch up and don't give in
The new AA-49 design easily fit into the development of naval missiles and allowed for the full-scale deployment of second-generation medium- and intercontinental-range missiles. Here are just a few of the key objectives that were successfully addressed:
- an increase in the number of missiles on the boat from three to 16 – parity with the American SSBN George Washington;
- increased accuracy due to more advanced domestic equipment;
- Reducing the weight and dimensions of warheads by approximately half without losing charge efficiency.
In 1967, the D-5 system, with a fully-fledged R-27 SLBM (with a range of up to 2500 km), entered service on Project 667A SSBNs. In 1973, the D-9 system was adopted, with a two-stage R-29, the world's first intercontinental SLBM with astronomical guidance, significantly improving accuracy.
Soviet submarine-launched ballistic missile R-27U (GRAU index 4K10)
And in 1966, VNIITF created the revolutionary RA-82, and its fate exactly repeated history The equally revolutionary American W47: like the W47, the PA-82, despite its remarkable compactness, suffered from insufficient yield and low reliability. The warhead was compact, and it was immediately ordered for four launch vehicles: two Makeyevka SLBMs (R-27 and R-29) and two ICBMs—the Chelomeyev liquid-fueled UR-100 and the Korolev solid-fueled RT-2. The 4G10 naval warhead weighed 650 kg in its casing, while the ICBM warhead weighed slightly more—730 kg. The estimated yield was 1 Mt.
But reliability failed. During tests on October 27, 1966, on Novaya Zemlya, both explosions produced 30% shortfall The calculated yield, and this is based on Soviet data. American estimates of the same two explosions differ significantly from ours: Norwegian seismographs reported 422 and 415 kilotons. These figures, however, should be treated with caution: some of the data in the open American press comes from intelligence community estimates and may diverge from reality.
Example. In the reference book Nuclear Notebook: US and Soviet/Russian intercontinental ballistic missiles, 1959–2008 an expert Christensen (Bulletin of the Atomic Scientists, 2008) for the Soviet SS-11 Sego M2/3 (UR-100K UTTH, 15A20U), one of our first ICBMs with a dispersive MIRV (MRV - multiple re-entry vehicle(Multiple warheads without independent targeting), the yield of a single warhead is listed as 220 kt. A year earlier, in the same annual article, the yield for the same warhead was listed as 350 kt. This, incidentally, refers to the 15F204 warhead with the RA-65 "physical package."
CIA analysts are skilled at counting silo-based and mobile launchers based on satellite imagery. But when it comes to what's hidden under silo covers and in launch tubes, estimates become more uncertain, and the picture becomes significantly distorted.
D-5 Modernization: Lose Weight, Increase Range
On June 10, 1971, the Council of Ministers issued a decree on modernizing the D-5 system to increase the range of the R-27. Two options were considered:
- a multi-missile reentry vehicle (MRV) with three non-individually targetable pods, while maintaining maximum range;
- lightweight monoblock warhead - for increased range and accuracy.
The system was named D-5U, and the missile was named R-27U. Replacing the nuclear warhead in the same 4G10 warhead casing reduced the throw-weight of the single warhead from 650 to 405 kg and increased its range by 40%, from 2500 to 3000 km.
The Road to MIRV: The RA-83 and a Tough Start
Since 1967, the All-Russian Research Institute of Instrument Engineering had been working on small-sized thermonuclear charges, without yet being tied to a specific munition. In September 1967, a group of theorists (E. I. Zababakhin, L. P. Feoktistov, B. M. Murashkin, N. V. Ptitsina) released a report on preparations for the test of an 85-kg charge. This small-yield RA-83 charge was tested on October 21, 1967, on Novaya Zemlya; the TNT equivalent was approximately 100 kilotons.
The warhead could have been developed for a multiple warhead. By government decree, the Machine-Building Design Bureau and the All-Russian Research Institute of Instrument Making were tasked with developing a MIRV for the R-27U with three compact 170-kg MIRVs. Since this was a dispersive MIRV (MRV), the warhead dispensed with a dispersive module and its own propulsion system, and the throw weight was just over half a ton.
By May 1974, several warheads of two types had been tested. The results were disappointing: the warhead was 30 kg heavier than its foreign equivalent, the W58/Mk.2. Polaris A-3 and twice as weak. It was necessary to select the casing materials and develop new automated systems. The All-Russian Scientific Research Institute of Instrument Making joined the Communications Research Institute of the Ministry of Medium Machine Building, and together they created an extremely lightweight automated system, no more than 10% of the warhead's weight. By 1975, the yield had almost doubled. The new systems were planned to be equipped with MIRVs with seven to ten warheads; in 1975, the All-Russian Scientific Research Institute of Experimental Physics (VNIIEF) joined the work.
Soviet submarine-launched ballistic missile (SLBM) R-29
A-88: The Workhorse of the Soviet Arsenal
In 1973, VNIIEF produced its finest creation, a series of medium-class 500-550 kt warheads designated A-88. This was arguably the most widely produced thermonuclear warhead in the Soviet Armed Forces of the 1970s. It was installed on almost everything: from tactical, operational-tactical, and anti-ship cruise missiles to strategic ICBMs and SLBMs. Between 1974 and 1985, according to various estimates, between 8000 and 10,000 warheads were produced.
In the Strategic Missile Forces in the second half of the 1970s and the first half of the 1980s, all 4th generation missiles with MIRVs carried A-88 in the 15F174 warhead body: 10 blocks on the R-36M UTTKh (SS-18 Mod 4), 6 each on UR-100N UTTH (SS-19 Mod 2) and 4 each on MR UR-100 (SS-17). The A-88 was also used for single-block missiles, like the old 3rd generation RT-2P (SS-13 Mod 2), as well as the latest RT-2PM "Topol" of the 5th generation (from the mid-1980s)SS-25). In total, the Strategic Missile Forces received approximately 7000 A-88 devices. In the late 1980s, all of them were modernized: the nuclear payload was upgraded with a new third stage and the designation A-134, the yield was increased to 750 kt, and the service life of the warheads and charges was extended.
From 1973 to 1977, the Soviet Navy actively replaced the unreliable and heavy RA-82 missiles with the light A-88 on the R-27 and R-29 missiles. On the R-29, the replacement had the same effect as on the R-27: the range increased from 7800 to 9100 km. The missile was named R-29D (the equipped weight of the unit is 370 kg).
To be continued
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