Thread by @MikeBlack114

Today we're going to talk about one of the lesser known but had significant potential "could have beens" from the early Cold War: the GAM-87 Skybolt

By the late 1950s the US strategic nuclear forces were in transition: bombers delivering gravity weapons still were the cornerstone of our posture, but forward deployed M/IRBMs were tasked to deliver strategic weapons, and the first US ICBM (Atlas) went operational in 1959

While the AF had a on/off relationship with ICBM development (a topic for a different discussion), it perceived two potentially mortal threats to its bomber force: increasingly capable Soviet air defenses (Gary Powers would be shot down in 1960) and the Navy's Polaris SLBMs

The former threatened the ability of the bombers to deliver their weapons, while the latter threatened the existence of an AF nuclear mission altogether

To address the first the AF accelerated development of stand-off weapons intended to suppress Soviet air defenses

(As an aside using kiloton yield nuclear weapons for SEAD is......a very early Cold War thing to do)

The AF had been interested in stand-off weapons since WWII; a variety of development projects led to the GAM-63 Rascal, a relatively short ranged missile intended for use from the B-47

The Rascal had many issues and was never operationally deployed; instead the AF accelerated development of the GAM-77 (later AGM-28) Hound Dog cruise missile, intended to be delivered by the new B-52 bomber coming online at that time

While the Hound Dog would help make B-52s more survivable, it did nothing to address what the AF saw as the true problem: the Problem of Polaris

To address this threat, the AF began the WS-199 development program

WS-199 was an "anything goes" effort to address Polaris, but began gravitating towards one weapon: an air-launched ballistic missile

An ALBM would combine the best of all systems: the flexibility of bombers, speed of ICBMs, and survivability (through airborne alert) of SLBMs

To flesh out what was within the realm of the technically possible, the AF undertook two developmental programs under the auspices of WS-199

Bold Orion demonstrated that a two stage ALBM could be successfully released off a bomber (it also demo'd a nascent ASAT capability)

High Virgo expanded that to include the ability to release an ALBM at supersonic speeds, using a B-58 as a demo vehicle

Based off of these demos, the AF pressed with beginning development of an operational ALBM, the GAM-87

While the AF perceived an urgent need for this weapon, the rest of DoD was somewhere between ambivalent and hostile to the idea

The JCS even went so far as to "question the need for extending the service life of the manned bomber"

(Laughs in 60 year old B-52)

This disconnect in high level guidance/support would plague the Skybolt throughout development

The AF took the lack of a hard no in '59 as good enough and got Douglas on contract as the prime, with Aerojet developing the solid rocket motor and Nortronics the guidance system

However, the first crisis was not far away: in the fall of '59 lack of funds from DoD forced the AF to tell Douglas to suspend all work for a month until DoD released the money (that sounds familiar)

Development continued after the release of funds. While the WS-199 demos had proven the concept was sound, it is inportant to note the technical challenges faced by the program:

First, the solid rocket motor. SRMs do not like the following things: shock, vibration, temp cycling, and prolonged cold soak

Guess what is all present on a weapon employed off of a bomber?

Aerojet developed a heater blanket and improved propellant to meet these challenges

Next, the guidance. This was the 1950s, there was no GPS. While pinpoint precision was not required w/nukes, the potential for use as a strategic weapon in addition to the suppression mission meant it needed to be capable of going after hardened tagets

In addition, air launch introduces complexities not found in ground or sea launch. In order for any navigation system to work, it must know where it is starting from. This is challenging when the launch platform is moving at 500 knots

Previous efforts like Hound Dog were cruise missiles. The much longer cruise time provides greater opportunity to correct errors. An ALBM would be under powered flight for a very short amount of time, after which its ability to adjust trajectory would be limited to impossible

Nortronics developed a state of the art system that used stellar alignment and a fix from the launch aircraft to cage the intertial navigation system prior to launch

Upon further improvements after testing it was capable of a ~3K CEP

The last major challenge of note is the logistics handling and support equipment. This was a big weapon...10K+ lbs and almost 40' long

Douglas had to work w/Boeing to design a new pylon/launcher and also had to develop new handling/loading equipment

(As an aside you'll note a difference in appearance between the two RVs...the left is an early sphere-cone-cylinder-flare design. After testing it was determined that a the simplified sphere-cone design on the right was optimal)

The weapon was originally set to carry a W47 warhead from Polaris, but due to concerns about safety/reliability, as well to standardize w/the Minuteman I, the decision was made to shift to the W59

CC @Casillic

This was also not going to be a US-only weapon. Due to a desire to have an air-launched capability for basing reasons as well as issues with their Blue Streak project, the UK jumped on board. Intended launch platform was the Vulcan

By the early '60s the program was facing many challenges. An additional funding problem had caused a 6-9 month slip and cost $50M. Early cost estimates had proven significantly lower than actual. Most significantly, DoD still did not fully support the development

In addition, DoD continued to attempt to "help." This help came in the form of driving 70 program reviews of different types in the space of 18 months

The AF had learned from early mistakes and had effectively flattened the management structure by establishing a pseudo-independent program office outside normal channels led by a one-star with a direct line to senior leaders (similarities to today's Section 804 authorities)

The DoD under McNamara went the opposite direction, demanding an onerous amount of reports and exercising oversight well past the point of micromanagement

By the time the system was ready for flight test in the Spring of 1962, its future was murky at best. Polaris was operationally deployed and boasted a similar CEP while land based ICBMs continued to improve in responsiveness and accuracy with the deployment of Minuteman

The first 5 flight tests all ended in some type of malfunction, yet were still successful in achieving all first stage test points and well over half of all second stage test points

Despite the increasingly technical maturity, development of MMII sounded the death knell for Skybolt. Polaris could accomplish the strategic deterrent mission with more survivability and cheaper, while the increasing cost also meant MMII could perform suppression cheaper

(I leave unaddressed the actual feasibility of using an ICBM in a SEAD role)

The final wrinkle was the involvement of the UK. Cancellation would leave them high and dry; after much angst and frantic discussion the decision was made to sell them Polaris, a SLBM partnership that continues to this day

In December 1962, the day before the final (and successful) flight test, the program was formally cancelled

See here for related thread on the "why"

https://twitter.com/MikeBlack114/status/1094737429314105344?s=19

https://twitter.com/MikeBlack114/status/1094743121378922496?s=19