Australia should be paying close attention to the imminent appearance of the Xian H-20 stealth bomber built by the Aviation Industry Corporation of China. The aircraft will greatly improve China’s ability to hit distant targets, such as those in Australia.

Part of the solution for dealing with the H-20 is to a large degree Australian: skywave over-the-horizon radar technology.

The People’s Liberation Army Air Force has shown teasing renderings of the bomber in a recruitment video, highlighted by Joseph Trevithick of The War Zone. Trevithick judges that the video is official, and I agree.

Having written in late 2018 that China would probably reveal the H-20 in the flesh in 2019 (it didn’t), and in late 2019 that the event should be ‘close’ (it wasn’t), I hesitate to be so bold again. But I will be anyway, because the teasing by the PLAAF with images is a good hint that the aircraft’s unveiling is near. There’s at least a fair chance that we’ll see the bomber rolled out in 2021 in preparation for its first flight, and I would lay money on it appearing by the end of 2022.

Judging from the six years between the first appearance of AVIC’s Chengdu J-20 and that fighter’s entry into service in 2016, a PLAAF bomber squadron should have its first H-20s by the late 2020s. If so, the type should be operational in useful numbers in the early 2030s.

What will we see when it appears? Almost certainly an all-wing or blended-wing-body aircraft, maybe without stealth-degrading vertical surfaces. It should remind us much of the US Northrop Grumman B-2 bomber, though Trevithick sensibly points out that the H-20’s planform could be simpler (and better) than the B-2’s. The PLAAF’s rendering of an H-20 under wraps shows no sign of the winglets that appeared in another apparently official hint at the configuration in 2018; that depiction may have been intended to confuse us (but, then again, so could the latest). The image in the video does, however, show curious pairs of bumps near the tips of each side of the upper wing surface. Whatever they are, they will degrade stealth—if the H-20 really has them.

In 2016, PLAAF commander General Ma Xiaotian described the forthcoming type as a long-range bomber, which must mean it will fly a good deal further than the AVIC Xian H-6, officially said to have medium range. The H-6 is a derivative of the Soviet Tupolev Tu-16. In its H-6K version, it has a strike radius without refuelling of more than 2,000 kilometres, depending on payload, and a gross weight of 95 tonnes. Since the US Air Force says the 153-tonne B-2 has an intercontinental range (conventionally, 5,500 kilometres for a ballistic missile, which could be taken as the minimum likely radius for the B-2), it would not be surprising to see a strike radius of at least 4,000 kilometres for the H-20.

That reach can be extended with cruise missiles—but H-20s will rely less on such weapons, because the bombers will be able to pass closer to opponents’ radars without detection.

It can’t be repeated too often: preparation for and conduct of war is economic, an allocation of finite resources. Militaries always (or should always) seek the maximum offensive and defensive effect for the least expenditure. Much of the importance of the H-20 is that it will greatly improve China’s bang-per-buck ratio for defended targets.

Cruise missiles are hard and costly to shoot down; Australia is virtually defenceless against them. Barely discussed is that an unimaginable range of Australian military and civilian facilities and infrastructure can be knocked out by cruise missiles. For example, we endlessly debate the cost of submarine programs, but where, exactly, does the Royal Australian Navy expect to refuel and restock these vessels after each war patrol? Which facilities are expected not to be smoking ruins?

The most optimistic thing that Australia can say about Chinese cruise missiles is that weapons of that category are themselves costly; Tomahawk missiles cost around US$1 million (A$1.3 million) each, even after four decades of production. So China’s stock of cruise missiles is necessarily limited. If Australia were fighting alongside the US, China might not have many rounds to spare to send south. Most high-priority targets for cruise-missile attack would be on Guam and in Japan and Taiwan.

For Australia, these mildly comforting thoughts evaporate if a stealthy enemy can approach targets close enough to lob cheap and abundant free-fall or gliding bombs at them—and that is indeed one of the advantages of a stealth aircraft. Even if a stand-off distance of a few hundred kilometres is needed (say, because the defender has deployed a combat air patrol backed by an air-surveillance aircraft) the economics of the attack are improved by use of cheapish cruise missiles with only moderate range.

So far, so depressing. But H-20s may be tracked despite their stealth. One means may be from space, particularly from a huge constellation of small tracking satellites envisaged under the US’s National Defense Space Architecture. Further, a here-and-now capability is in the Royal Australian Air Force’s Jindalee over-the-horizon radar network, based on technology in which Australia, unusually, is probably the world leader.

Counterstealth radars use longer wavelengths (lower frequencies) than are ideal for precision, because the radar cross-section (reflectivity) of a stealth aircraft generally rises rapidly with wavelength. So such radars use not the X band typical of a fire-control radar (with wavelengths of 3.75–7.5 centimetres) but the L (15–30 centimetres) or even VHF (1–10 metres) band. VHF approaches the ideal: a wavelength equal to the dimensions of the target, a condition at which stealth designers run short of answers.

Well, the three Jindalee radars reach that ideal. To achieve the ionospheric bounce that allows them to see beyond the horizon, they operate in the HF band, with wavelengths of 10–100 metres. It’s safe to say that they can easily track B-2s (wingspan 52 metres, length 21 metres) and that they would pick up H-20s with no more difficulty.

The precision of Jindalee is an extraordinarily important but secret issue. We can at least say that, if these high-frequency radars cannot directly cue fighters or surface-to-air systems, they can cue other sensors; these, being closer to the target, might achieve a precision track and complete the kill chain.

So the Jindalee system, already crucial for observing Australia’s continental approaches, will become even more important in the age of the H-20. And knocking out Jindalee becomes correspondingly important to Chinese planners.

Sad to say, the surveillance system looks vulnerable. The arrays, emplaced in remote sites in the outback, appear to be modular and may be hard to shut down by knocking out segments, but they send their data to a hub that controls them at RAAF Edinburgh near Adelaide. That’s a single point of failure if ever there was one. Yes, cruise missiles are expensive, but there’s good value for money in firing a few from a submarine in the Great Australian Bight after dialling in the coordinates of that facility.

Australia must attend to this vulnerability.