The Russian S-400 TRIUMF (NATO designation SA-21) surface to air missile (SAM) entered the global media spotlight late in 2015 when Moscow deployed the system after Turkey’s shoot-down of a Russian Su-24 FENCER airplane near the Syria border on Thanksgiving Day. The Russian deployment compelled Turkey to pause its air operations and reportedly impacted the execution of U.S. and coalition air operations in the region, demonstrating the considerable reach and influence of this advanced air defense system.
This episode demonstrated the S-400’s potential as a weapon with strategic effects, a role that China, the first export recipient of the system, may seek to exploit in future crises. In April 2015, Russia announced the sale of four to six S-400 battalions to China. It remains unclear where China will deploy the assets. However, deployment of the system could influence the regional security order and dramatically impact the ability of the United States and its allies to respond to crises related to Taiwan, the Koreas, and the East and South China Seas.
What is the S-400?
The S-400 is the most dangerous operationally deployed modern long-range SAM in the world. Its maximum effective range is up to 400km (215 nautical miles). The system reportedly can track 100 airborne targets and engage six of them simultaneously. The S-400 reportedly has the capability to counter low-observable aircraft and precision-guided munitions, and is also reportedly extremely mobile.
The SAM is an excellent example of an anti-access/area-denial (A2/AD) system. The idea of A2/AD is to prevent an opposing force from entering an area and limit an opposing force’s freedom of action in an operational area. As Robert Haddick recently emphasized at War on the Rocks, A2/AD systems pose a unique problem to U.S. power projection and the ability of the U.S. military to maintain its technological edge over adversaries.
Yet Russia’s deployment of the S-400 reveals that such systems can have even broader strategic effects. Though not the first SAM to threaten aircraft at hundreds of miles in range — SA-5, deployed since 1966, has a range of 150 nautical miles — the S-400’s capabilities render it far more dangerous than a traditional defense-oriented SAM system. It can engage a wide range of targets, including stealth aircraft and cruise missiles. Its range against aircraft operating at medium or high altitudes is so great that it can threaten aircraft in neighboring countries within their own air space. This capability alone raises the risk of operating such expensive aircraft anywhere near a deployed S-400 system.
A single S-400 missile that costs a few million dollars could bring down an asset worth hundreds of millions of dollars, such as the RQ-4 unmanned intelligence aircraft, F-22 or F-35 fighters, or worse, a B-2 bomber worth over $2 billion per plane. And it could do so from farther away than any adversary SAM has yet been capable of. The S-400 thus offers a favorable cost ratio that could influence decision-making at strategic levels.
Potential Applications for China
Fielded in sufficient numbers and in combination with other advanced air defense systems, the S-400 can strengthen and extend China’s already robust network of A2/AD capabilities. These include the S-300PMU and HQ-9 (range 200km) SAM systems and the DF-21D (range 1,500km) anti-ship ballistic missiles (ASBM). The exponential system-of-systems effect of these weapons continues to pose a serious threat to the credibility of U.S. security assurances to allies and partners that have disputes with China.
The S-400 system could enable Chinese forces to deter or influence the behavior of aircraft and the application of airpower in peacetime. Russia’s deployment in Syria has already illustrated this possibility. While Russia has shown no intention of using the S-400 to engage U.S. or coalition aircraft (except perhaps those belonging to Turkey), air operations planners in the theater have likely developed new procedures to guide manned and unmanned aircraft flying within range of the S-400. If Russia chose to do so, it could have effectively neutralized the effectiveness of U.S., French, or NATO aviation based in the Mediterranean. A subsequent coalition turn to standoff munitions would significantly increase the per-shot cost, possibly dissuading more vulnerable allies from participating in the U.S.-led high-end conflict.
The strategic influence of the S-400 becomes even clearer when the system is viewed through the lens of potential military crises or contingencies along China’s periphery. Although open-source information about the deployment of this system in China remains unclear, there are several plausible candidate locations. U.S. and allied leaders should not be surprised if China deploys the S-400 to support operations against Taiwan, near the Senkaku Islands in the East China Sea, along the North Korean border for peninsula contingency operations, and in the South China Sea to support operations to defend sovereignty claims.
Deployed along the Taiwan Strait, the S-400 operating envelope against non-stealthy aircraft at medium or high altitudes would cover the entire territory of Taiwan and reinforce the coverage provided by the S-300PMU and HQ-9 SAMs. In the event of conflict, any aviation forces that took to the air from Taiwan would thus immediately risk being shot down. For the most part, participating U.S. air forces and U.S. naval aviation would similarly need to operate well east of Taiwan to avoid the SAM threat. Intelligence, surveillance and reconnaissance (ISR) airplanes operating at such distances would have little ability to accurately monitor developments west of Taiwan, thus constraining their utility as a means of providing third-party intelligence to Taiwan or to demonstrate U.S. resolve early in a crisis through a show of force. Without detailed, accurate and timely tactical intelligence from ISR platforms to guide their attack, allied fighter and strike aircraft (assuming that they survived within the SAM envelope) would become highly vulnerable in any effort to fight air and surface threats. U.S. and Taiwan planners must therefore plan to yield air superiority to the Chinese, accept high levels of risk to U.S. aviation assets, or contemplate what could be highly escalatory mainland strikes against the mobile SAM systems to neutralize the threat.
Deployments of the S-400 by China along the Korean border and on the Shandong peninsula would allow coverage over most of North Korea. In the event of a war between the two Koreas, China could deploy the system to coerce Pyongyang or deter U.S. and South Korean forces from carrying out air operations that Beijing regarded as destabilizing. China could also use the S-400 in conjunction with S-300PMU and HQ-9 SAM systems to put at risk air operations from U.S. carrier assets operating in the Yellow Sea, thus forcing the ships to operate east of Korea. By carefully positioning S-400 systems, China could also try to exert influence by compelling the United States and South Korea to coordinate air activity with Chinese military authorities under the pretense of air activity de-confliction. This might enable Beijing to throttle the tempo of U.S. and allied operations.
The Senkaku Islands lie just beyond the range of an S-400 system deployed on China’s coast. Nevertheless, the deployment of the system in a crisis involving the Senkakus could again help China exert influence over the situation. The S-400 could provide air cover for maritime platforms that sortied from China’s coast towards the Senkakus. If paired with joint ship-borne SAM systems such as the HHQ-9 and a combat air patrol (CAP) provided by land-based fighter aircraft, the combined effect could help extend SAM-enabled air cover over the Senkaku Islands, a capability Japan would find difficult to match. Japanese and U.S. planners must thus plan carefully to contest a Chinese CAP and strike the Chinese SAM-equipped combatants while operating outside the range of the land-based S-400 or accept a possible loss of air superiority over the islands in a crisis or conflict.
The stationing of strategic nuclear submarines and potentially an aircraft carrier at Hainan Island provides China with significant reason to station the S-400 system and other missiles systems on that island, where the combined effect could exert influence over the northern part of the South China Sea. China has also built up artificial islands that could support the deployment of this system in the middle of the Spratly Islands, allowing them to control the airspace over the entire range of islands. In a crisis, China could use the SAM system to control the presence of foreign reconnaissance aircraft, degrading the ability of the United States and other countries to gain an accurate picture of tactical developments. In a militarized crisis with rival disputants, controlling the airspace over the entire Spratly Islands would grant a tremendous operational advantage over rival claimants. In the event China decided to impose an Air Defense Identification Zone (ADIZ) in the South China Sea, an S-400 deployment in the Spratlys as well as on Hainan Island and/or the Paracel Islands would lend serious credibility to Chinese enforcement efforts. Still, doctrine, weather, and the isolated position of the islands may bound the utility of the S-400 on South China Sea islands. Because the S-400 relies on its mobility to ensure survivability, placement on an artificial island on the Spratly Islands would render the systems highly vulnerable to attack. The corrosive effects of high humidity and salt water would also make maintenance of the unmarinized S-400 system especially difficult, particularly at so remote a location.
For China, the S-400 supplements and reinforces other important A2/AD capabilities such as the S-300PMU and HQ-9 SAM, the DF-21D anti-ship ballistic missile (ASBM), electronic warfare sets, and air-launched cruise missiles. The combined effect of these mutually reinforcing weapons systems will boost Beijing’s confidence that it can challenge the viability of U.S. military interventions in contingencies along China’s borders.
Without major investments in stealth and counter-SAM technologies, or major changes to training and strategic guidance in the face of such systems, the United States faces considerable challenges to countering this threat. The United States relies on a combination of stealth, electronic attack, decoys, and radar-homing missiles to counter air defense systems. The arrival of the S-400 will not likely change that approach, but it will impose greater challenges to its execution. If the United States chooses to operate outside the envelope of the weapons system, air missions will not likely be worth conducting because so few airborne capabilities can operate effectively at so distant a range. Suppression through missile attack on the S-400 offers one possibility, but the mobility of the systems makes for an elusive target. Moreover, the escalatory implications of strikes on Chinese territory to destroy the equipment make this a risky option at best.
U.S. and allied planners and policymakers will need to think through more viable and less escalatory ways to address the threat of the S-400 and related advanced SAM systems in a contingency involving China and a U.S. ally or partner. Alternatively, they may simply need to accept a higher level of risk. New operational concepts may be required to deal with the threat, such as a greater reliance on fifth-generation — and in the future, sixth-generation — stealth aircraft, or advanced tactics that limit the exposure of aircraft to the SAM threat.
Planners may need to either accept the possibility of higher losses to high-end military platforms or consider re-investing in low-cost expendable platforms such as UAVs. For the longer term, U.S. decision-makers should plan on developing countermeasures to the S-400. This may require investments in electronic jamming and other electronic measures to confuse or deny the ability of the S-400 radar to track aircraft. In all cases, the S-400 will provide China a powerful weapons system certain to exacerbate an already formidable A2/AD challenge for U.S. military forces in peacetime, in crisis, and in conflict.
Timothy Heath is a senior international defense research analyst at the nonprofit, nonpartisan RAND Corporation.
Photo credit: Vitaly V. Kuzmin