The US Missile Defense Agency (MDA) is inviting a public consultation on a decade-long proposal to test missile defences at Guam, with the intention launching two test flights per year for the next ten years. 

As part of an Environmental Assessment/Overseas Environment l Assessment (EA/OEA) made available by the MDA on 1 June 2024, the current missile defences at Guam are described as capable of defending against regional ballistic missile threats. 

However, it points to an increase in the technological level of such threats as a motivating factor for the further development of Guam’s missile defences, and for the proposed test flights. 

The proposed flight tests and tracking exercises are intended to test the validity of a ‘system of systems’ or ‘backbone’ for missile defences at Guam, focusing on the Terminal High Altitude Area Defense (THAAD), Aegis Weapon System (AWS), Phased Array Tracking Radar to Intercept  of Target (Patriot) Advanced Capability-Three (PAC-3) Missile Segment Enhanced (MSE) system, and the Indirect Fire Protection Capability (IFPC) system.

In recent history, the US deployed THAAD systems to Guam in response to threats from the nuclear advances of North Korea in April 2013, but the most recent proposals to increase Guam’s missile defence came under the Biden administration in 2022, which cited the defence of Guam against missile threats from China as a motivating factor for a $892m investment.

The tests will also increase the Department of Defense’s (DoD) understanding of supporting sensors to counter a range of threats including short-, mid-, and longe range ballistic missiles, cruise missiles, and hypersonic missiles. The tests are intended to advance Command and Control (C2), battle management and communications at Guam, and in theatres globally. 

The US territory of Guam is a key location for US influence in the Pacific theatre, enabling US forces to respond to crises in the Indo-Pacific, and deter adversaries. 

An assessment of China’s land based missile systems published in 2023 in the Journal of Policy and Strategy found that China had approximately 100 Intercontinental Ballistic Missiles (ICBM), including both nuclear and conventional versions of the DF-26 missile, capable that are reaching capable of reaching Guam.

The public consolation under the National Historic Preservations Act for the missile defence trials at Guam is open electronic submissions of evidence for the period until 2 July, 2024.