As North Korea leader Kim Jong-un celebrated his country’s first “successful” firing of a submarine-launched ballistic missile Thursday, South Korea was left wondering how soon and severely the missiles will threaten security on the peninsula.

Most estimates were based more on speculation than solid proof, but one thing looked certain: The hermit kingdom’s SLBM prowess is far more advanced and developing at a quicker pace than previously anticipated by the South’s military.

“Considering the pace of development in other countries with SLBM, we expect it will take the North about 3-4 years (until deployment),” Defense Ministry spokesman Moon Sang-kyun had said in April, when Pyongyang’s SLBM launch blew up after a brief 30 kilometer-flight.

While the ministry said that it cannot rule out possibility of the actual deployment taking place sooner, the general assessment of the launch within the military was that it was a politically-motivated “show.”

Some even said that Pyongyang revealed how fragile its SLBM program is, saying the North “showed off what it should not have.”

But the military’s optimism was confounded Wednesday, as the North’s missile flew 500 kilometers, well beyond the Koreas’ territories and into Japan’s air defense identification zone. It is believed that if it had been fired using a conventional method, the missile would have flown well over 2,000 kilometers, putting the entire peninsula within its range.

Confusion has resounded within the military, with some going so far as to say that it “would not be surprising” if the North deployed it later this year.

Although it is common practice for a weapon to undergo multiple tests before being deployed in the field, North Korea has a history of stationing weapons that have undergone little or no testing for actual use. 

Its intermediate-range ballistic missile Musudan has been stationed in the front lines since 2007, but its first test launch was carried out only this year. 

As in the case of the SLBM, the military had questioned the Musudan’s capacity to properly fly, prior to its first successful launch in June. 

The South Korean military’s intelligence has been behind the eight ball before. 

On the heels of a North Korean Rodong ballistic missile launch earlier in the month, the Joint Chiefs of Staff said that it was a solitary missile launch.

But the US Strategic Command contradicted the report by saying two missiles were fired, one of which exploded in midair. The JCS later claimed that it knew of the second missile, but had elected not to share the information based on a judgement call.

Some suspect that the questionable optimism about the SLBM derives from a lack of proper means of defense to the weapon.

As of now, the most effective means to defend against the weapon is a pre-emptive strike on the submarine when signs of a launch is detected. The second option is to take down the submarine on the move by using Navy assets, including the Aegis-equipment destroyers.

The contingency plan in case all of the above fails is to detect and intercept the missiles. The Patriot missiles currently operated by the US Forces Korea are incapable of catching up with the SLBM fired Wednesday, which has an estimated maximum velocity of around Mach 10. 

While projectiles from the Terminal High Altitude Area Defense system could theoretically intercept the missiles, its forward-based radars would have trouble detecting missiles fired from behind.

“Most ballistic missile defense radars are designed to have a 120-degree field of view, and have trouble detecting submarines infiltrating from behind. ... When North Korea procures an SLBM, it is virtually impossible to defend against it,” said Park Hwee-rhak, the dean of graduate school of politics and leadership at Kookmin University. 

The military claims that its planned deployment of the Korea Air and Missile Defense system will enable it to intercept the missiles, but the KAMD is slated for completion in the mid-2020s. 

Even the THAAD missile defense system has yet to have been deployed on the peninsula. Allies plan on stationing it next year.

With the timeline of the SLBM appearing to have drastically sped up, there are concerns that the ill-advised optimism of the South Korean military may leave the country all but defenseless. 

By Yoon Min-sik (minsikyoon@heraldcorp.com)