The defence strategic review ^[1] has identified a glaring gap in Australian Defence Force capability—the almost complete absence of any form of long-range layered integrated air and missile defence (IAMD).

The long-held assumption that Australia is protected by its geography, with its splendid isolation from regions of instability and a sea–air gap to our north as an impassable strategic moat, means we’ve been slow to protect ourselves from a growing missile threat at longer ranges.

The review notes that China’s military build-up is now the largest and most ambitious of any country since the end of World War II.

While the review doesn’t specifically identify the threat posed by China’s strike capabilities, it’s clear that Australia’s north is wide open to long-range, medium-range and intermediate-range ballistic missiles, hypersonic weapons and advanced land-attack cruise missiles, all of which can now be employed by China’s navy, air force and rocket force.

The review says Defence must deliver a layered integrated air and missile defence capability urgently, and that it ‘must comprise a suite of appropriate command and control systems, sensors, air defence aircraft and surface (land and maritime) based missile defences’.

The review warns against the pursuit of a ‘perfect’ solution that won’t be available quickly enough or at an affordable cost, but urges military-off-the-shelf solutions. It says Defence must ‘reprioritise the delivery of a layered IAMD capability, allocating sufficient resources to the Chief of Air Force to deliver initial capability in a timely way and subsequently further develop the mature capability’.

IAMD is about networks and systems of systems rather than individual platforms. More specifically, it’s about kill chains comprising sensors and shooters and the command-and-control links between them and decision-makers. The goal is to defeat incoming missiles, be they ballistic or air-breathing cruise missiles or low-level aircraft and autonomous vehicles.

The complexity of IAMD and the highly technical nature of the challenge posed by ever more sophisticated attacking systems, with hypersonic weapons now on the horizon, will drive up project costs and generate delays if the goal is a comprehensive solution to provide what some call an ‘astrodome defence’. In considering IAMD, it’s important to distinguish between national missile defence ^[2], of the type deployed in the United States to defend against a very limited nuclear attack, and defending key targets against a directed attack by conventional missiles.

The objective for IAMD in Australia must be to defend geographical environments on and around key military facilities—particularly in the north—from direct missile attack, including by hypersonic weapons ^[3] and advanced autonomous aerial vehicles. It should not be to protect the entire nation, or to provide a leak-proof astrodome defence that is technically unachievable within a short time and would be prohibitively costly.

Effective ground-based air and missile defence systems that Defence should consider are available. Project Air 6502 ^[4] is intended to deal with medium-range threats, and Air 6503 ^[5] with high-speed advanced-missile threats.

The Australian Army is already deploying the Kongsberg–Raytheon NASAMS ^[6] (National Advanced Surface-to-Air Missile System) to deal with shorter-range threats. It is one of the most advanced short- to medium-range ground-based air-defence systems available and is designed to counter threats such as drones, fixed- and rotary-wing aircraft, and cruise missiles. Four NASAMSs have been used in Ukraine with great success against cruise missiles and armed drones. Seven more are to be provided. NASAMS is a highly networked system that can engage up to 72 targets concurrently. The system’s networked nature allows it to defend a wide region.

NASAMS’ maturity and availability make it the logical path for further development if Defence wants longer-range IAMD capabilities quickly. Its open and distributed architecture would enable additional longer-range interceptor missiles to be integrated into the system. The AMRAAM-ER missile with a range of 70 kilometres has been integrated into NASAMS, and Raytheon’s SkyCeptor missile has a range of 200 kilometres.

IAMD must also meet the challenge posed by longer-range medium- and intermediate-range ballistic missiles, such as China’s DF-26 IRBM ^[7]. Lockheed Martin’s THAAD ^[8] (Terminal High-Altitude Area Defence) system would enable the ADF to intercept ballistic missiles in the terminal phase (as they re-enter the atmosphere) out to 200 kilometres. Raytheon and Lockheed Martin are the lead companies selected to support Defence’s guided weapons and explosive ordnance ^[9] enterprise, enabling the option to manufacture missiles in Australia. Combining an inner layer based on enhanced NASAMS and an outer layer based on THAAD could effectively defend the north against ballistic missiles.

A key technical challenge in intercepting very high-speed missiles at long range is early detection. That’s even more difficult with manoeuvering hypersonic glide vehicles, which could be delivered by China’s DF-17 medium-range missile and DF-27 intermediate-range hypersonic glide vehicle. Relying on sensors to detect a missile launch by such a vehicle reduces the chance of early warning, especially if the craft can fly low and use terrain masking to minimise detection.

For Australia to have longer-range IAMD effective against emerging threats such as the DF-26 and DF-17, the system should have networked sensors based on satellites in orbit. Space must play a role, with small satellites dedicated to missile detection, early warning and tracking in low-earth orbit to extend early detection and expand reaction times.

Australia already gains access ^[10] to missile threat information via the US space-based infrared system, and will also have access to its successor, the next-generation OPIR ^[11] (overhead persistent infrared) satellite. But IAMD opens up a new opportunity for Australia’s commercial space sector to develop sovereign missile early warning capabilities to complement and augment the US system under the Combined Space Operations initiative. IAMD shouldn’t just be a ground-based capability—space needs to be part of any ADF system to counter longer-range high-speed threats.

Collaboration on space-based missile early warning, detection and tracking, including for manoeuvering hypersonic threats, would fall neatly into the AUKUS Pillar 2 priority area of hypersonics and counter-hypersonics. Traditional ballistic missiles such as the DF-26 and DF-21D are hypersonic. China is developing hypersonic glide vehicles and in 2021 tested a ‘fractional orbital bombardment system’ ^[12]. Investment in IAMD must embrace new threats and must be able to engage high-speed, long-range capabilities.

The challenges are to meet these threats without requiring a silver bullet and to deliver a capability quickly and at a reasonable cost. Establishing IAMD won’t be easy.