In part 4 of this series, I looked at how deploying from offshore airbases would allow the F-35A to operate relatively far away from Australia in areas that are strategically important to us.

However, this is not a straightforward exercise. Even putting aside the issue of finding an amenable host country, the F-35A needs substantial infrastructure to operate. It’s not just the 8,000-foot runway, but fuel, munitions, maintenance facilities, apron space and so on. There aren’t a lot of candidates for bases that could quickly be put into service, particularly in the South Pacific.

This leads to another problem: it would be obvious to adversaries where our air force was operating from, which would dramatically simplify their early warning challenge. It would also simplify their targeting problem, and modern long-range missiles are sufficiently precise to target runways and even aircraft on the ground.

Addressing these challenges is part of the evolving concept of distributed long-range fires, which seeks to complicate an adversary’s targeting problem by moving away from a small number of fixed bases and increasing the options for striking the adversary. One element of this is deployable land-based missiles (more on those in future posts).

It has also been argued that the short take-off and vertical landing (STOVL) variant of the joint strike fighter, the F-35B, could contribute to this operating concept. Since the F-35B can take off from much shorter runways, it potentially opens up a greater number of airfields. Long, straight stretches of highway could possibly also serve as runways.

The US Marine Corps has been experimenting with operating its F-35B from ‘pop-up’ bases in the Pacific. Essentially, it would use the mobility provided by its amphibious forces to seize islands, establish improvised airfields, operate them for a short period, and then relocate before the adversary can respond.

The F-35B has a smaller range and carries fewer munitions than the conventional F-35A, but if this approach offers a way to get the F-35 and its fifth-generation suite of sensors into the fight, it should at least be considered. However, there are significant obstacles to implementing it, particularly for a force the size of Australia’s.

The key problem is that the F-35B still needs all the other inputs I’ve mentioned, in particular fuel. Depending on the kind and number of sorties flown, the requirement for fuel quickly becomes hundreds of tonnes per day. Flying that fuel into a pop-up base would require a huge logistics train. A US study that analysed this issue concluded that flying in the fuel for even one base would involve most of the Marine Corps’ 60 C-130s (the Australian Defence Force has 12). The larger C-17As could deliver more fuel but would quickly render an improvised airstrip unusable.

Alternatively, the fuel could be put into bladders and flown directly from amphibious ships to the improvised base. But that would require large numbers of heavy-lift helicopters—many more than the ADF’s 10 CH-47F Chinooks (assuming there was space for them on the ships). It would be very difficult to sustain high-tempo operations.

Another approach would be to relocate frequently between improvised airbases on a larger land mass. The same study argued that around 60 vehicles would be needed to move the operation, and there’s still the problem of sustaining fuel supplies that may still need to be flown in. Whichever way you look at it, there’s a big logistics tail.

So the bill for all the enablers necessary to support distributed STOVL operations could be much more than the cost of the F-35Bs themselves, which already have a higher unit cost than the F-35A.

Since ships are designed to carry bulk fuel and stores, it would be much simpler to operate the F-35Bs directly from a ship which can be resupplied with fuel and stores from other ships. ASPI and others have looked at this issue (here and here, for example). The benefit is that it gets the F-35 into a fight that it potentially couldn’t reach otherwise, so it can contribute its sensors and weapons to both enhance and protect other ADF systems around it.

Even with its reduced weapons carriage, the F-35B would provide a potent strike or close air support option in a range of scenarios. And a moving airbase certainly complicates the adversary’s targeting picture.

The disadvantages have also been enumerated. If the ADF didn’t want to reduce its current amphibious lift capability, a third or even fourth landing helicopter dock or a similar large, flat-topped vessel would be required (noting that the first two cost over $3 billion), preferably optimised to support air combat operations. It’s unlikely that a vessel of that size could maintain a sortie rate that could sustain a continuous combat air patrol, if that was the effect sought.

To get the F-35Bs up in time to provide air defence, their host ship would likely also need an airborne early warning capability (though perhaps this could be provided by an innovative drone). And much of the navy would need to be devoted to protecting the ships, reducing its ability to perform other tasks. Even then, their survival would not be assured in highly contested environments. Nevertheless, an amphibious taskforce with the F-35B would be more survivable than one without it.

It’s certainly possible to make a case for the utility of the capability. The benefits seem to outweigh the disadvantages for the US, Japan and (potentially) South Korea, which are putting F-35Bs on ships of a similar size to our LHDs—and operating in highly contested environments. But the question must always be, is it a more cost-effective way to deliver the effects sought than other options?

The assumption underlying this series is that in an age of strategic uncertainty, Australia’s defence organisation should enhance its options to project military power. We’ve seen that any option relying on the F-35 would require a huge investment in enabling capabilities to break through the aircraft’s inherent 1,000-kilometre range limitation.

All of those options must be subjected to the cost-effectiveness test, particularly when there are other possible solutions that don’t rely on the F-35. In coming pieces, I’ll examine some of those alternatives.

This article first appeared at ASPI's The Strategist.

Image: Reuters.