Monday, November 3, 2024

Guided Munitions Inventory Management, Producibility, and their Effects on Strategy (Part 1 of 2)

I’d like to follow up on Bryan’s post from this part March about how the Navy’s intention to end Tomahawk Land Attack Missile (TLAM) procurement in FY15—several years earlier than previously planned, and nearly a decade before the TLAM’s successor reaches Initial Operational Capability—is inescapably fraught with risk. As Bryan correctly observed, should the U.S. be drawn into one or more conflicts during this gap period, it would be impossible to replace TLAMs expended in combat. Nor could the U.S. grow the TLAM inventory during peacetime if strategically necessary; other combat arms would have to assume a greater share of the land-attack load. The resultant risks would be evident to allied and potential adversary leaders alike, perhaps with concomitant effects on American conventional deterrence credibility.
Bryan’s most important points, however, regarded guided munitions-age warfare in general:

“It is not 1939.  We do not have endless untapped industrial capacity that will build 50,000 airplanes and 6000 ships and boats.  We have limited production lines in incredibly high-tech factories that rely on a precious supply of skilled workers who are not reproducible overnight.  Any war with another major power will expend PGM’s at a rate our industrial base will strain to replace.”

His observations were also recently echoed in an outstanding
National Interest article by Chris Dougherty, as well as in subsequent commentary by CDR Salamander. My own commentary flows from Bryan’s, Chris’s, and the CDR’s arguments.
The challenges of conventional munitions production in war are hardly new. As Chris noted in his article, Britain’s lack of munitions production infrastructure and its limited access to certain materials necessary to produce the cordite propellants for artillery shells had major battlefield effects—and thus dramatic strategic as well as domestic political effects—during the First World War’s initial twelve months. Nevertheless, munitions production prior to the mid-20th Century was manpower-intensive and not knowledge-intensive. In other words, workers in munitions factories did not require a great deal of technical knowledge about what they were producing. All that they generally needed to know was how to operate their tools, and teaching this could be done quickly in many cases. If a country possessed a sufficient supply of raw materials, then increasing the number of workers and (readily manufacturable) tools would under most circumstances result in increased munitions production within a given period of time.
This relationship no longer exists. Production of finely-manufactured components such as field-programmable gate arrays, microelectromechanical systems, and monolithic microwave integrated circuits used in modern conventional guided munitions is very time-consuming and often requires workers with months (and sometimes several years) of specialized technical education. The tools required to produce such components require a great deal of time and worker knowledge to manufacture as well. The same holds true for any high-performance alloys or composites used to manufacture the weapon’s body. Furthermore, the resultant weapon’s complexity will generally demand time-consuming factory acceptance testing to ensure it is fully functional and thus ready for field deployment. Production timelines are therefore quite lengthy. TLAM represents this well: it takes two years to produce a round once ordered, and some of its key components have 20-month lead times (many of which are likely subcontracted out to small niche manufacturers). Bryan was quite right, then, when he noted that guided munition production could never be as rapidly expanded as was the case with ‘dumb’ munitions up through the Second World War. One could even argue that today’s situation has more in common with the pre-industrial era, in which a prime limiting factor on armaments production leaned was the availability of tradesmen who had gained their skills through years of apprenticeship.
It also stands to reason that as a guided weapon’s capability increases, so does its unit procurement cost. A weapon’s range is a very good proxy for its unit cost, and as the price tag increases relative inventory size decreases. Barry Watts’s excellent 2011 monograph, “The Evolution of Precision Strike,” hammers this home. Watts contrasted the Department of Defense’s (DOD) FY12 Programs of Record (PoR) for two precision-guided air-launched munitions: the roughly 500 nautical mile-range Joint Air-to-Surface Standoff Missile-Extended Range (JASSM-ER) and the roughly 15 nautical mile-range Joint Direct Attack Munition (JDAM). According to his source, DOD’s publically-available December 2011 Selected Acquisition Report (SAR) to Congress, FY12 program plans called for inventories of 2,531 JASSM-ERs at roughly $1.5 million a copy and 232,875 JDAMs at roughly $27,000 a copy.[i] Watts noted that this translated into a nearly 50x JASSM-ER average unit cost premium over JDAM, with obvious implications for the inventory sizes of both. For comparative purposes, per the December 2013 SAR the TLAM Block IV PoR appears to carry an average unit cost of roughly $1.38 million.
Now let’s look at the demand-side of guided munitions economics. As Chris Dougherty observed, ever since the First Gulf War the defining popular assumption about modern conventional combat has been that guided munitions employment results in short but intense conflicts. The rationale for this is straightforward: if only a few guided munitions must be fired in a single salvo to gain a high probability that at least one will successfully neutralize or destroy a given target, and if platform production is even more time-intensive than was the case during the Second World War, then once one of the belligerents loses enough campaign-critical platforms or endured enough damage to its military infrastructure (bases, command and control architecture, logistical support, etc.) the conflict should wrap up fairly quickly.
Such a view is overly simplistic. Bryan, Chris, and the CDR were quite correct in noting that guided munitions expenditure rates are likely to be quite high in a major conventional conflict—perhaps significantly higher than prewar planners’ assumptions. This is not mere conjecture; it is a historically recurring fact. In conflicts ranging from the 1982 Falklands War to NATO’s 2011 strike operations against Libya, forces’ operational tempos became pressured and their ability to attain campaign objectives faced steeper risks when they expended certain advanced ordnance types faster than they had anticipated.
Sometimes these consumption rates were driven up on the margins by malfunctioning munitions. It stands to reason that the more complex a system is, the higher the latent risk that an undiscovered design shortcoming or subtle manufacturing flaw (sometimes unique to very specific operating environments or tactical circumstances) will reveal itself at a very inconvenient moment. Robust testing and evaluation throughout a weapon program’s entire lifecycle can reduce but never completely eliminate this risk. While highly effective mitigations can be employed to operationally and tactical hedge against malfunctions during combat, the overall inventory still declines with each munition fired.
Guided munitions expenditures were also affected by targeting ‘quality.’ Despite their use of advanced intelligence, surveillance, and reconnaissance systems, modern belligerents have unilaterally wasted weapons against naturally-occurring phenomena (example: ambiguous or misinterpreted sensor contacts); civilian vehicles, vessels, and aircraft mistaken for military platforms; and invalid sites (example: structures that the attacker incorrectly believes to contain adversary forces or resources). Similarly, on several occasions wily belligerents have been able to entice their opponents into wasting advanced munitions against decoy forces or lowly-valued infrastructure. The fog and friction of combat makes it impossible to completely eliminate munitions wastage due to forced or unforced errors; the only question is how well one’s targeting methods and firing discipline holds down the frequency of mistakes. Soviet submarines’ anti-surface warfare tactics provide an excellent example of this in practice, as their commanders were indoctrinated to fire torpedoes from extraordinarily close ranges to targeted ships in order to avoid wastage of these difficult-to-replace weapons.[ii]
A belligerent’s guided munitions consumption rates would be additionally affected by its opponent’s technological, tactical, and doctrinal countermeasures. If the only thing active and passive defenses did was drive up the salvo size an attacker needed to use in order to achieve a desired ‘kill probability,’ the attacker could compensate by manufacturing more munitions as possible. However, this assumes the attacker was able to base its peacetime munitions procurement decisions upon a thorough and accurate understanding of its opponent’s holistic defensive effectiveness. This may not be attainable with high confidence outside of wartime experience, with the result being that more weapons may need to be expended per defended target to achieve a ‘hit.’
A final wrinkle occurs if a war becomes protracted. Even if a belligerent exhausts its opponent’s ability to wage peer-level warfare, the latter may be unwilling to immediately concede strategic defeat. As Japan demonstrated with its kamikaze operations of 1944-45, it is quite likely that a weakened but still resolute opponent would embrace unconventional operating concepts in hopes of driving the stronger side’s costs of war continuation up to politically intolerable levels. Ending the opponent’s ability to fight on in this way might require many more guided munitions than what was necessary to neutralize his mainline forces. As Clausewitz reminds us, a nation’s will to fight is driven by its leaders’ political objectives and its people’s passions. Unless both of these factors are either brought to heel (if such a thing is possible in a given conflict) or otherwise satisfied through some sort of political settlement, a conflict can continue on in ways and forms that prevent the stronger side from merely pocketing its gains and walking away.
The aforementioned considerations highlight the very real possibility that a country might find out the hard way that its prewar stockpile of one or more advanced munitions types was inadequate for achieving its strategic objectives. As I’ve noted previously:

“A firing decision can therefore represent a hefty opportunity cost to the attacker, as the weapons inventory must be managed against requirements needed for the duration of the campaign and as coercive “bargaining chips” for the political-diplomatic endgame. It follows that the more complex a weapon or the more limited the resources the attacker can allocate to its production, the longer its users must wait for replacements. In a prolonged conflict, the effect is magnified if the defender can restore damaged units’ most operationally important capabilities faster than the attacker can replenish weapons. All of this means that it may not matter whether cost differentials allow the attacker to procure several times as many offensive weapons as the defender has ships, aircraft, or land-based sites. It also may not matter that the number of offensive weapons available significantly exceeds the number of targets in track. As with all decisions involving a scarcity, the central metric would seem to be the prospective attacker’s self-estimated campaign-level opportunity cost of striking at a given point in time.” (Pg. 95)

The nature of this opportunity cost varies: the employment of relatively expensive standoff-range weapons draws down arsenals that are difficult to replenish during war, while the employment of relatively inexpensive and therefore numerous short-range weapons exposes firing platforms (and skilled personnel) that may be even more difficult to replace. It is also important to note that this logic applies just as much for defensive guided munitions such as surface to air missiles and ballistic missile defense interceptors as it does for offensive guided munitions.  

Tomorrow, a concluding look at how munitions inventory sizes and producibility will not only affect a strategic concept's viability, but also may shape the characteristics of a given war.


[i] Of interest, the December 2013 SAR indicates a planned inventory of 2,877 JASSM-ERs and 272,648 JDAMs at roughly the same unit costs reported in December 2011.
[ii] Norman Friedman. Network-centric Warfare: How Navies Learned to Fight Smarter through Three World Wars. (Annapolis, Md.: Naval Institute Press, 2009), 341.

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