Here’s how long it could take North Korean nuclear missiles to reach US cities


icbm intercontinental ballistic missile north korea hwasong 14 RTX3A3DK
A July 2017 test launch of
North Korea’s Hwasong-14 missile system.

KCNA via Reuters


  • North Korea’s recent weapons tests suggest it could
    launch a weapon to the US.
  • The range of a North Korean nuclear missile may extend
    as far as New York City.
  • The flight time to NYC, for example, might be about 40
    minutes and 30 seconds.
  • However, very little is publicly known about the
    capabilities of North Korea’s ICBM technologies.

North Korea has the world on edge.

In July, the isolated nation test-launched intercontinental
ballistic missiles, or
ICBMs
, that can reportedly deliver nuclear warheads to
targets thousands of miles away. And as journalists revealed in
August, US intelligence officials think North Korea has also
figured out how to
miniaturize
its warheads to fit atop ICBMs.

While many weapons experts
question
the exact capabilities of North Korea’s latest
hardware, few deny it represents worrisome progress toward the
nation becoming a credible nuclear threat. Experts are also
concerned the maturing ICBM program could proliferate nuclear
weapons
around the world
, raise the likelihood of
nuclear accidents
, and bring the world closer to
the brink
of what could be a
global calamity
.

“Based on current information, [the July 28] missile test by
North Korea could easily reach the US West Coast, and a number of
major US cities,” David Wright, a
physicist and the co-director of the Union of Concerned
Scientists’ global security program, wrote in a recent blog
post
.

To estimate how long it’d take for North Korean missiles to reach
key US targets, Business Insider called up Wright for help.

The interactive feature below shows approximate flight times from
the North Pyongan province (where the ICBMs were test-launched)
to several key US targets. Those locations include Washington DC,
New York City, Los Angeles, Honolulu, Chicago, Anchorage, and
Guam — where there’s a major US military presence.

Wright said the above flight times and distances are not ironclad
and come with numerous caveats.

For one, they’re calculated based on what is publicly known about
North Korea’s Hwasong-14 ICBM system and its July 28 test launch.
Wright estimated the missile to have a maximum range of about
6,500 miles, which would bring it just shy of Washington, DC.

“The range of a ballistic missile is tied to its speed. It’s just
like throwing a ball; the faster you throw it at a given angle,
the farther it will travel,” Wright said, adding that the
burn-out velocity — or speed an ICBM reaches when it shuts off
its engines in space — isn’t known, among other variables.

Given the correct angle of launch and some modifications, he
thinks North Korean ICBMs might be capable of reaching between 3
and 4.2 miles per second at burn-out.

“I’ve tried to put in numbers that I think are related to North
Korean missiles,” said Wright, who is considered an arms control,
missile technology, and space weapons expert. “I get those from
years of playing around with this stuff.”

Another unknown is payload weight.

The Hwasong-14 missile test reportedly flew some 2,300 miles into
the sky, for a total flight time of about 47 minutes. It also
lofted a reentry vehicle — a device that protects one or more
warheads from burning up when plowing through Earth’s atmosphere
— but it’s uncertain if the dummy vehicle accounted for the
weight of an actual warhead. (The lighter a payload, the faster,
higher, and farther a missile can go.) There’s also evidence that
the
reentry vehicle failed and broke into pieces
on its way back
down.


North Korean leader Kim Jong Un inspects the intercontinental ballistic missile Hwasong-14 in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang July 5, 2017. KCNA/via REUTERS
North
Korean leader Kim Jong Un inspects the intercontinental ballistic
missile Hwasong-14 in this undated photo released by
KCNA.

Thomson
Reuters


Just as important, Wright said his numbers and flight paths don’t
account for Earth’s movement.

“When you launch, the Earth doesn’t stay still. It rotates
underneath the missile,” Wright said. “Trying to do this on a
rotating Earth gets really complicated.”

This not only requires over- or under-shooting a missile, but
also makes the physics of targeting far more complex.

“The range of a ballistic missile is tied to its speed, and if
you’re firing east, you get a little bit of a speed boost from
the Earth’s rotation,” Wright said. He added that it depends on
whether you’re firing at a target to your north or south, since
Earth moves faster at its equator than northern or southern
latitudes.

Finally, the numbers also assume a North Korean ICBM could thwart
missile defense systems, such as the US military’s latest
kill
vehicle
” technology, and actually reach its intended target.

“If you’re launching your missile, you need to figure out how
fast it’s going, shut off engines at the right speed, and keep it
pointed in the right direction,” Wright said. “That’s hard to do
really accurately.”


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