Amid escalating tensions between China and the Western bloc in the South China Sea, following the United States' move to undertake freedom of navigation exercises in the contested waterway and deploy massive military force alongside its European military partners, Beijing's People's Liberation Army (PLA) has constructed a number of artificial islands and strategically located reefs which it has gradually fortified into formidable military installations. These bases have been key to China's strategy of balancing the growing American and Western military presence in the region, and while they initially boasted negligible defences they today pose a serious challenge to Beijing's potential adversaries' ability to project power in at sea. Amid increasing numbers of d increasing numbers of overflights by U.S. bombers, Chinese outposts were in late 2017 equipped with the first HQ-9 surface to air missile batteries and airfields and hangers to house elite J-11B air superiority fighters. The deployment of advanced combat aircraft to the outposts has led a number of analysts to compare them to immobile defensive aircraft carriers - an apt description considering their role and capabilities.
The HQ-9 surface to air missile system is closely related to the Russian S-300 PMU series of surface to air missile systems, and was developed by China shortly after acquiring Soviet S-300 systems from a cash strapped Russia in the aftermath of the Cold War. The weapons system fires two stage missiles armed with large 180kg warheads, and travel at speeds of up to Mach 4.2. These missiles make use of thrust vector control, and are guided by a combination of inertial guidance, mid course uplink and active radar terminal guidance systems. The HQ-9 has an engagement radius of up to 300km, and poses a major threat to hostile aircraft at all altitudes. The missile system has been widely relied on by the PLA for long range anti aircraft roles, alongside the more advanced S-400 acquired from Russia, and has been deployed with coverage of the Korean Peninsula amid growing tensions and the threat of U.S. attack in early 2017 as well as onboard Chinese warships such as the Type 055 destroyer.
Recent reports have indicated that Beijing has as of May 2018 deployed more advanced variants of the HQ-9 to the South China Sea, the HQ-9B, which is according to Chinese sources more sophisticated than the S-300 PMU-2 and surpassed in an anti aircraft role only by Russia's S-400. The weapons system employs much newer microelectronics, providing far superior computing technology as a result. This significantly enhances the weapon's signal and data processing and guidance support, while the weapons system also incorporates advanced semi active radar homing & infrared homing capabilities. The weapons system's advanced guidance systems, computing power, speed, range and high payload makes it extremely lethal against enemy aircraft, and is likely to deny hostile aircraft access to much of the South China Sea's airspace at a number of strategic locations in light of its recent deployment. Stationing the HQ-9B to maritime outposts will make an excellent complement to PLA Air Force fighter squadrons, long range anti ship missiles such as the YJ-12 and advanced electronic warfare systems also recently deployed to these outposts. The weapons system is set to pose a serious threat to the Western bloc's military operations in the South China Sea.