With the prospect of increasing human activity on and around the Moon in coming decades, there is growing defence interest in monitoring activity and operating in new regions of the space domain. Australia needs a policy discussion to evaluate how it can play a broader role beyond the orbit of geostationary satellites, a volume of space known as xGEO.

In particular, Australia should assess the benefits of being an active contributor in building a space economy and in ensuring space security and sustainability beyond the near-Earth region. It would do this with allies.

The discussion should be part of AUKUS Pillar 2, in preparation for the 2026 National Defence Strategy (NDS) and Integrated Investment Program (IIP). It should also inform broader civil and defence space cooperation with the United States and other partners.

The region of space as far as geostationary orbit (GEO), 36,500km above the equator, has been closely monitored for decades. But now space domain awareness (SDA) is increasingly looking at xGEO, which goes to the Moon and a little beyond to include all the Earth-Moon LaGrange points—places where gravitation from the two bodies is balanced and where spacecraft can loiter. (See the accompanying infographic.)

The US Space Force established ^[1] the 19th Space Defense Squadron two years ago to undertake SDA within xGEO space.

Within xGEO, Australia already plays a role in supporting the US Artemis project to return a human presence to the Moon. Our contribution is the Australian Space Agency’s Moon to Mars Initiative ^[2], looking to grow an Australian role in the space economy and support lunar and Martian exploration.

But more can be done, particularly through expanding a national SDA architecture to support not only activities near Earth but in xGEO, too.

The 2024 National Defence Strategy (NDS) and its accompanying Integrated Investment Program (IIP) maintain ^[3] recognition of the importance of SDA, which was highlighted in the 2020 Defence Strategic Update and Force Structure Plan. Specifically, the 2024 NDS and IIP support Australia’s role in supporting SDA under Operation Dyurra ^[4] as part of the US-led Operation Olympic Defender. Specific capability that supports the SDA mission includes the establishment of a Deep Space Advanced Radar Capability (DARC) (a project that dates back to the 2016 Defence White Paper), which is to be hosted alongside a US-provided Optical Space Surveillance telescope and C-Band space-surveillance radar at North West Cape on the westernmost point of the continent.

These capabilities will allow Australia to share intelligence on space activities with its partners and others under the 2013 Combined Space Operations (CSpO ^[5]) initiative, examining objects both visually and using radar out to GEO. Furthermore, a range of commercial space surveillance capabilities, both surface and space-based, complement these Defence-run sensors. Australia has an important role in supporting the SDA efforts of allies, thanks to its southern location, dark skies and mild climate.

However, we should be looking further in anticipation of the next NDS and IIP and prospectively greater interest in space in AUKUS Pillar 2.

A natural complement to ground based sensors for SDA now being established would be for Defence to fully embrace a space-based capability as the next phase of SDA. This would allow more comprehensive SDA between low Earth orbit and GEO and, if positioned correctly in GEO or beyond, could support US requirements for SDA across xGEO. It would be an obvious progression from DARC in Western Australia to develop space surveillance satellites owned and operated by the government or Australian companies. The satellites could also be built by Australian commercial space companies that already provide space-based SDA, such as Sydney-based HEO ^[6], and launched by Australian launch vehicles from Australian launch sites. Once positioned, these Australian satellites would be a key part of an expanded SDA capability serving the CSpO.

This should then be complemented by a larger role for Australia in supporting space logistics and mobility to enable more flexible and cost-effective xGEO access. These can be undertaken in direct support of civilian space activities under Artemis through leadership of the Australian Space Agency, but also to support future ^[7] US Space Force space mobility operations ^[8] in this region. Australia’s Defence Space Command would take on the role. Both could fully benefit from supporting and using Australia’s commercial space sector in providing the means to undertake this role.

A military role in xGEO is highly contentious. A recent debate ^[9] between Namrata Goswami and Bleddyn Bowen highlighted opposing views, with Bowen dismissing the Moon’s economic value, and its relevance to traditional military use of force on Earth. He labelled advocates of a xGEO capability for the US Space Force as ‘cislunar militarists’ and suggested that supporting such a capability was premature until a greater understanding of the nature of lunar resources was acquired.

In contrast, Goswami pointed to increasing astro-strategic competition and the importance of ensuring access to space resources to build a space economy beyond GEO. She also notes the potential for counterspace capability based beyond GEO to launch a surprise attack on geosynchronous satellites. It’s notable that absence of xGEO SDA would worsen that risk.

The prospect of warfare in xGEO is probably not likely in the short to medium term. However, space forces must take a long-term view that recognises a future human presence on the Moon is not simply for planting more flags and leaving more footprints but for exploitation of space resources. Competition over those resources is quite possible, and Bowen’s dismissal of such a prospect is unconvincing.

But there is a clear need for ascertaining the economic and astro-strategic value of the Moon to make informed choices on policy. Yet that value, if realised, can only be exploited if lunar resource wealth can be turned into prosperity or critical national capability, ideally in space or where possible on Earth. Resource exploitation on the Moon must be practical for the Moon to be relevant. That, in turn, demands an ability to ensure a sustained human presence on and around the Moon—that is, in xGEO—and to prevent an opponent from denying access to those resources or to the Moon itself.

With this future in mind, there is a real opportunity for Australia to adopt a more forward-looking approach to its Moon to Mars Initiative to take the next step to embrace xGEO SDA. It should also seek to explore ways to provide space logistics and mobility throughout xGEO for both civil and military applications alongside key allies and partners. If the Moon is a basis for a space-based economy, it is vital that Australia alongside its allies have access, and we must lift our gaze beyond GEO to a more ambitious approach to space.