Chinese surface-to-air missiles firing during an exercise. Photo: Global Times

On Sunday, China conducted an anti-ballistic missile (ABM) test within its borders. China’s Defense Ministry briefly described it as a successful land-based midcourse missile interception test, emphasizing that it was defensive in nature and not aimed at any other country.

However, the Chinese state-owned Global Times took a more hawkish tone, saying that the test demonstrates the reliability of China’s missile shield against US nuclear-tipped intercontinental ballistic missiles (ICBM) and intermediate-range ballistic missiles (IRBM) in the Pacific.

This test may show China’s increasing efforts to protect its land-based nuclear arsenal. “The development of our nuclear force is very limited. That means we must ensure the survivability of our nuclear force,” said Shao Yongling, a military expert who was previously with the People’s Liberation Army missile force.

China fields a variety of Russian and domestically-made missile defense systems. While China’s Defense Ministry did not identify the system used in the test, it is likely to be the Mid-Course Interceptor, which is still under development and projected to achieve initial operating capability before the late 2020s. It is claimed to have good initial capability against IRBMs and is potentially upgradeable to intercept ICBMs and submarine-launched ballistic missiles.

A ballistic missile has three flight stages: boost, midcourse and terminal phases. A boost-phase interception is ideal, as the incoming missile has no chance to deploy countermeasures early in the flight. It prevents the missile from reaching hypersonic speeds (more than Mach 5), which would make interception impossible.

The drawback of a boost-phase intercept is a very short opportunity for a successful interception. Ground-based sensors must detect and relay launch information as quickly as possible, and interceptor missiles should be close to the target or extremely fast.

In contrast, a midcourse-phase interception offers the most extended time window for a successful intercept. At this stage, the missile is no longer powered and follows a predictable ballistic arc as it re-enters the atmosphere. Missile defense systems can fire multiple interceptor missiles from a few sites to protect a large area.

True, at this point the incoming missile could deploy countermeasures – although defensive systems also have more time to identify real warheads from decoys.

A terminal-phase interception requires defensive systems to be very close to the target, as this phase is usually less than one minute long. Terminal-phase defenses protect strategic targets such as troop formations, bases, and staging areas.

It is plausible that China is building a system analogous to the US Ground-Based Midcourse Defense (GMD) system, the only US missile defense designed to protect the US homeland against a long-range ICBM attack.

Since 1999, there have been 17 GMD tests, each involving a target ballistic missile, with nine successful intercepts. Thus, the US-based think tank Center for Strategic and International Studies (CSIS) gives the system a lackluster 53% success rate.

In contrast, according to the Global Times, China has confirmed successful midcourse intercept tests in 2010, 2013, 2018, and 2021. However, we do not know how many failed Chinese attempts took place so it’s impossible to assign a success rate.

China’s efforts to expand its land-based nuclear arsenal may also be the impetus for its spate of midcourse intercept tests to defend its launch facilities. Last year, the Washington Times reported that China had constructed 119 ICBM silos in a desert near Yumen, marking a significant expansion of its modest nuclear arsenal from around 250-350 warheads.

The US moves to upgrade its strategic nuclear arsenal may have also influenced China to expedite the development of its missile shield. In addition, the US 2018 Nuclear Posture Review mandated the rapid modernization of US nuclear forces, given China and Russia’s modernization of their nuclear arsenals.

In April this year, the US designated the LGM-35A Sentinel as the new ground-based leg of its nuclear triad, replacing the long-serving Minuteman missiles, which have been in service for 50 years.

In addition to upgrading its land-based nuclear arsenal, the US has begun constructing the Columbia-class nuclear ballistic submarine, the largest and most advanced submarine built by the US. The US plans to have a dozen Columbia-class subs, with the first boat entering service by 2027. Each sub will carry 16 of the submarine-launched ballistic missiles that in total account for 70% of the US nuclear triad.