In October 2022 a US destroyer and supply ship pulled alongside each other in San Diego harbour to attempt something the Pentagon had never tried before -- reloading missiles on a US warship at sea rather than tied up alongside a pier.
A year later in September 2023, the Pentagon had achieved another first when it reloaded an SM-2 surface-to-air missile aboard another US destroyer in an Australian port as part of the US-Australian "Talisman Sabre" military drills.
Both exercises were intended to open the door to considerably expanding the ways in which US warships could be rearmed more quickly and conveniently.
Such a capability, military planners have long argued, would be critical in the event of a major war such as that which could be sparked by a Chinese invasion of Taiwan. Fast forward nine months, however, and the fact that modern Western missile defences can swiftly exhaust the stockpiles available at their disposal has been brutally laid bare by events in the Red Sea and Ukraine.
How rapidly the US now moves forward on those plans will be a strong indicator of how worried the US really is over a potential major war in Asia or beyond. Some analysts, meanwhile, worry that between them Russia, China and Iran might hope Western stockpiles could be exhausted before a major great power conflict even begins.
Since January, US and European warships have fired dozens of anti-aircraft missiles at incoming drones and rockets launched by the Iran-backed Houthi movement in Yemen. Once they have exhausted their on-board stocks, however, they must withdraw from the immediate region to a major naval facility.
For the US that most likely means Bahrain in the Gulf, Diego Garcia in the Indian Ocean or Soudha Bay in Crete, Gibraltar for the British or their own home ports for most other Europeans.
That is challenging enough given the current Red Sea situation, which currently sees missile or drone attacks most days. In a larger conflict in Asia, ships that could not be resupplied with anti-aircraft missiles might be unable to defend themselves long enough to make it to a port where they could restock. The handful of US missile reloading facilities in Asia -- in Japan and Guam -- could easily be targeted with Chinese missiles, while sailing to Hawaii or California would take ships out of the line of battle for two or three weeks respectively.
In January, US Secretary of the Navy Carlos Del Toro told the Surface Navy Association annual symposium in Arlington Virginia that speeding up what the Pentagon calls the Transportable Re-Arming Mechanism for US naval warships was now a top priority, with offshore tests planned for summer 2024.
Reloading them is a challenging process as the missiles must be lifted vertically, meaning that the procedure is likely only ever likely to be possible in relatively calm conditions.
Various Pentagon and think tank papers have been highlighting the need for such a capability since 2017 at least, particularly in a major war. Only in the last two years, however, has a real sense of urgency emerged, forced by Pentagon worries that China might make a move against Taiwan as soon as 2027, as well as the remarkable consumption rate of missiles in Ukraine and the Red Sea.
US officials have declined to give details of what they call the "burn rate" of the number of missiles so far fired in the Red Sea confrontation, but CBS News reported in February that at least 100 missiles -- both the anti-aircraft SM-2 and larger SM-6 which can also engage surface targets -- had been fired by US warships since October.
The SM-2 costs around US$2 million (73.4 million baht) per missile while the SM-6 costs $4 million.
While the most modern US Arleigh Burke class destroyers -- the mainstay of the US surface fleet -- can carry upwards of 90 missiles in their vertical launch tubes, these include a variety of types, including Tomahawk land attack missiles and a range of other weapons to engage submarine, surface, air and missile targets. The stockpiles of almost all of those weapons, some analysts warn, are well below what might be needed for a major conflict.
According to manufacturer Raytheon, it has so far delivered only around 500 of the multi-use SM-6 missiles to the US military. While production will increase over the next five years, the current Pentagon budget will only add 125 new SM-6s this year and only 1,055 over the next half-decade.
Estimating the number of SM-2s is harder, particularly as multiple versions have been bought since the first variant entered service in the 1970s, but what is clear is that current Pentagon procurement plans are nowhere near where they were in the late Cold War, when the Reagan Administration ordered well over 1,000 in a single year.
In an apparent effort to further boost the US naval defensive missile stock, in January the Pentagon announced it was working with manufacturer Lockheed Martin to integrate the latest variant of the Patriot air defence missile used by the US Army with the US Navy's Aegis system.
Those missiles, however, are also in heavy demand elsewhere, including to defend Taiwan and protect Ukraine against an intensifying Russian barrage of missiles and drones. This week, as missiles rained down on Ukraine's third-largest city Kharkiv, Ukrainian President Volodomyr Zelenskyy said the Patriot was now amongst the most critical systems Ukraine needed to survive.
"If they keep hitting [Ukraine] every day the way they have for the last month, we might run out of missiles and the partners know it," he said. According to Ukraine's President Volodymyr Zelenskyy, at least 25 more of the US systems with 6 to 8 launchers each were needed to properly defend exposed areas of the country.
Exactly how many Patriot systems Ukraine already has is not entirely clear – but so far it has only publicly received two, one from the US and one from Germany. At least two of its individual launchers appear to have so far been destroyed according to video imagery released by Russia.
The number of Patriot rockets fired by Ukraine so far has also, unsurprisingly, not been publicly released. The sole manufacturer of the missiles, however, Lockheed Martin, has provided more details on how many rockets it can make a year.
According to the company, by the end of last year it was building 500 of the latest PAC-3 MSE rockets for Patriot every year in its Camden, Arkansas production plant, with funding from the US Army in place to extend this to 550. Anticipating further demand, the firm is unilaterally planning to be able to make 650 a year by 2027, building a new facility to do so.
Even that rate of production, however, might struggle to defend Ukraine against the current level of Russian attack.
When it comes to artillery shells -- where Western spies have also been strained to their limits by the combat requirements of Ukraine -- the US and European nations are now engaged in an increasingly frantic effort to both source and build sufficient stocks to allow Ukraine to hold the front this year while also restocking their own arsenals which have been increasingly emptied to support Kyiv.
Doing the same for air defence missiles will likely be considerably more expensive and time-consuming. Failing to do so, however, might prove even costlier if it persuades those in charge in Moscow and Beijing that they might be able to win in any future war. REUTERS
Peter Apps is a Reuters columnist writing on defence and security issues.