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Missile interception from Yemen to the South China Sea

The guided-missile destroyer USS Mason in the Suez Canal on Oct. 20, 2016, days after missiles were aimed at it from rebel-held areas of Yemen. (U.S. Navy handout)

Missile interception from Yemen to the South China Sea

One year ago, the American warship USS Mason defended itself from attacking cruise missiles while patrolling the Red Sea. It was a minor affair with few shots fired and no one hurt. But it was noteworthy for its global security implications.

On Oct. 9, 2016, Mason’s radar detected two anti-ship cruise missiles launching 48 kilometres away from rebel-held areas of Yemen. They flew low over the water at about 1,100 kilometres an hour, and would reach the ship in just over two minutes.

Missile defence layers

Mason is a guided missile destroyer designed for air and missile defence. Sailors control its weapons from the combat information centre, a windowless room lit with Aegis computer system screens. Those weapons create several layers of defences.

The ship first launched two long-range Standard interceptor missiles. It followed those with one medium-range Evolved Sea Sparrow interceptor. The interceptors would try to shoot down the incoming cruise missiles. The ship also launched a Nulka decoy to fool the cruise missiles’ radar.

One cruise missile hit the water 19 kilometres away from the ship. It may have been hit by an interceptor. The other crashed on its own 14 kilometres out. The USS Mason consequently did not need to use its last line of defence, a short-range Phalanx gun, seen here:

A few days later, on Oct. 12, another cruise missile attacked Mason. It apparently was shot down 13 kilometres away, about 45 seconds before it would have struck. The ship fended off more cruise missiles on Oct. 15.

Other countries’ warships employ similar defences, though with fewer layers. For example, Australia’s Hobart-class destroyers have Aegis systems, Standard interceptors and Phalanx guns. Canada’s smaller Halifax-class frigates carry Sparrows and Phalanx.

Record books and textbooks

Another missile “anniversary” occurs this month. Anti-ship cruise missiles claimed their first success 50 years ago. On Oct. 21, 1967, Egypt sank the Israeli destroyer INS Eilat.

Since that time, the USS Mason is only the second warship believed to have downed a hostile cruise missile using an interceptor. That earns it a mention in naval history. Britain’s HMS Gloucester was the first. It destroyed an Iraqi cruise missile with a Sea Dart interceptor on Feb. 25, 1991.

Mason’s hostile cruise missile interception was also the first for the Aegis combat computer system. The U.S. introduced it several decades ago to counter missile-laden Soviet warships. It must have been gratifying for sailors and developers to see years of preparation pay off. The real Aegis-versus-missile fights seemingly unfolded in textbook fashion.

The Aegis-equipped destroyer USS Hopper launches a Standard missile in the Pacific Ocean in July 2009. (U.S. Navy)

The U.S. Navy is now updating those textbooks. It studied Mason’s rare encounters for lessons in interception training and procedures. It then shared that knowledge across its surface fleet.

The rarity of real battles motivates my missile combat research. My mathematical models are simplistic substitutes for real experience. But hopefully they provide clues about relationships between offence and defence, effective salvo sizes and the value of attacking first.

Dangerous contrasts

Other lessons, or warnings, also follow from the USS Mason attacks. For example, heavily armed Mason’s success contrasts with the fate of the unarmed transport ship Swift. An earlier cruise missile from Yemen set that transport on fire. As a U.S. admiral noted, ships now need “a fabulous set of radar and missiles” to survive near hostile coasts.

Mason’s high-tech defence also contrasts with warships’ continued vulnerability to low-tech threats. Examples include mines (for example, USS Princeton in 1991) and suicide boats (USS Cole, 2000). Collisions with other ships (USS Fitzgerald, 2017) or harbour bottoms (USS Antietam, 2017) are also risks. Against those threats, technological superiority provides little help.

A third contrast exists between the costs of attack and defence. The threatening cruise missiles were likely 10 times cheaper than the interceptors Mason used up in defence. They were also 1,000 times cheaper than the ship they might have sunk.

Strategic implications

Nonetheless, the USS Mason’s success is reassuring for naval strategists. Fleets around the world rely on missile defences like those. They enable aircraft carriers, transports and other ships to perform their missions in hostile waters.

One caution: The Yemen rebels fired older cruise missiles, just a few at a time. Some newer ones fly twice as fast, giving defenders less than a minute to respond. Better-armed opponents could have trucks, ships, submarines and/or aircraft firing missiles by the dozen.

Many countries can thereby make their local waters very hazardous. Think Iran and the Persian Gulf, China and the South China Sea or Russia and the Baltic Sea.

Non-naval strategists might also be reassured. Warships with upgraded versions of the same computers, radars and interceptors provide limited ballistic missile defence to countries along the Mediterranean Sea or the Sea of Japan.

Similar land-based equipment in operation in Romania and under construction in Poland protects Europe against Middle East ballistic missiles. Japan likewise is building two land sites to defend against North Korea.

All told, there is a lot riding on the USS Mason’s experience.