Early warning system previously suggested a North Korean missile could hit the US, triggering a temporary scuffle

It was “ugly”, a US lawmaker briefed on the launch. Defense officials immediately “did not have a good feel for its capabilities”, this person said.

Preliminary telemetry readings – which can be inaccurate and are often discarded when more data are available – suggested the missile could pose a threat as far as Alaska or the Aleutian Islands off the California coast, people familiar with the matter said. Two sources told CNN. ,

Within minutes, the US Northern Command and Northern American Aerospace Defense Command (NORAD) rejected those initial readings and assessed that the missile posed no direct threat to the United States mainland. The test weapon – which sources say was a less maneuverable version of a hypersonic glide vehicle designed to evade missile defense – sprayed harmlessly into the sea between China and Japan thousands of miles from threatening the US.

But in those few moments of uncertainty, the situation escalated so quickly that the Federal Aviation Administration, which is part of regular inter-agency discussions on when such missiles are launched, grounded some planes For about 15 minutes on the West Coast at about 2:30 p.m. PST Monday.

According to air traffic control recordings, the grounding forced air traffic controllers to ground some aircraft while others were briefly in the air, but when the pilots were asked to explain the reason for the grounding, the controllers suffered damage. Some controllers mistakenly referred to it as a national ground stop, something that hasn’t been seen since 9/11.

The question, now, sparks that initial burst of urgency — and perhaps, why the FAA reacted the way it did.

“What we’re seeing here is a normal process of coordination and communication, some of which were decisions made early that probably didn’t need to be made,” Defense Department spokesman John Kirby told reporters Thursday afternoon.

NORAD stressed that it was the FAA’s call to issue a ground stop and that it had not issued any warnings or warnings as a result of the North Korean missile launch.

“As a precaution, the FAA temporarily halted departures at some airports along the West Coast,” the FAA said in a statement on Tuesday. “The FAA takes regular precautionary measures. We are reviewing the process around this ground stop as we do after all such incidents.”

The FAA did not respond to CNN’s multiple requests for comment on Thursday.

A US official said the ground stops were not communicated through the FAA’s Air Traffic Control System command center located in Warrenton, Virginia, and instead went directly to regional centers on the West Coast.

Tuesday’s launch was the second such launch by North Korea within a week. But the first, last Thursday, was far less sophisticated, South Korean officials have said.

US officials are still making their own assessment of the most recent test, but analysts who closely track North Korea’s weapons development programs on Tuesday identified the missile used as a “maneuverable re-entry vehicle”. As is – is still a hypersonic glide vehicle that can change course after re-entering the atmosphere but has limited range and maneuverability compared to more advanced systems.

“It’s basically falling apart,” said Jeffrey Lewis, a weapons expert and professor at the Middlebury Institute of International Studies. “It’s falling with style.”

Lewis said it is not unusual for detection systems such as radar or infra-red satellites to struggle to determine a missile’s trajectory in the first moments after launch.

“If it’s a regular old ballistic missile, they can usually calculate it well, but you have to wait for the engine to stop firing,” he said. “So that’s why you sometimes see mistakes, because you’re trying to calculate it before the engine is off, and if you’re at a weird angle, you can see it’s going up, but Not in which direction.”

In any case, there is no doubt that the launch violated UN Security Council resolutions that prohibit North Korea from any ballistic missile activity. And arms control experts have consistently warned that Pyongyang’s weapons development program remains a long-term threat to the United States and its allies.

US officials familiar with North Korea’s weapons development programs say Pyongyang’s efforts to develop a hypersonic missile come as no surprise — North Korea has publicly telegraphed its intention — even though the missile launched on Tuesday Some of the unique abilities displayed by him were astonishing. Those sources declined to specify which abilities were unknown.

In January last year, North Korea publicly stated that it had “ended research into developing various combat missions, including hypersonic gliding flight warheads for new types of ballistic rockets, and was preparing for their test manufacturing”. “

Still, after years of high-profile diplomatic exchanges between former President Donald Trump and North Korean leader Kim Jong Un, the Biden administration has so far taken a relatively low-key approach to North Korea, even that it has continued to condemn the trial by Pyongyang.

CNN’s Natasha Bertrand and Pete Muntian contributed to this report.