What’s an ICBM, anyway?

North Korea’s big missile test, as shown on  state TV.
North Korea’s big missile test, as shown on state TV.
Image: AP/KRT
We may earn a commission from links on this page.

The intercontinental ballistic missile (ICBM) is back in the news in a big way now that North Korea claims to have developed this advanced weapons technology following a test flight on July 4. If true, this would give the Kim regime the ability to launch a nuclear weapon at Alaska, and perhaps the continental United States itself, within just half an hour.

Whats an ICBM, anyway?

It’s a rocket; usually, two rockets stacked on top of each other designed to deploy in stages. It’s capable of carrying a weapon more than 5,500 miles.

Why do they matter?

Obviously, because they could bring nuclear weapons to your house. But only seven countries in the world—the US, the Soviet Union/Russia, China, France, Israel, India and now North Korea—have ever developed this technology. There are three reasons for that: It’s hard to make a vehicle to carry multi-ton weapon to the other side of the planet. A country only needs them if they have nuclear weapons technology—and a strategic reason to use them. Packing an ICBM with conventional explosives turns out to be a pretty inefficient way to wage war.

What’s the point of an ICBM strategy?

ICBMs came of age during the Cold War, when the US and the Soviet Union engaged in a nuclear arms race. The proliferation of these terrifying weapons, combined with the ideological conflict between the two superpowers, created a whole new approach to thinking about conflict. Being able to launch missiles into space, either from the ground or from submarines, bolstered each country’s ability to promise “mutually assured destruction” in the event of a pre-emptive nuclear attack, thus deterring such a strike. (This is a simplification of a quite complicated approach to these conflicts that bolstered the development of game theory, for which the economist Thomas Schelling won a Nobel prize.)

While the Cold War is over, countries still approach nuclear deterrence with ICBMs with similar goals. There is still an element of global politics, such as the US and its allies France and the United Kingdom, which uses American-made ICBMs, competing with Russia and China to assert power. In 2011, the US and Russia concluded a treaty intended to limit their ICBM arsenals. But there are also regional power players, such as Israel, India and North Korea, which seek to use the threat of nuclear deterrence to stave off conflict with local adversaries.

Why are they so hard to build?

Gravity. Building any kind of space vehicle is hard because the force needed to hurl sizable objects out of the atmosphere is enormous, and channeling it requires sophisticated engineering capabilities. Nuclear warheads are particularly heavy, and because they have to fly so far, the problem is magnified compared to shorter-range missile systems. David Wright, who monitors arms control at the Union of Concerned Scientists, notes that this means making much larger—and more expensive—rockets: “a 3-stage missile capable of carrying a 1-ton payload 10,000 km would still have a mass of 80-90 tons.” That’s a big rocket!

Are the North Koreans bad at building them?

Not as bad as you might think, given the coverage of their test failures. Jeffrey Lewis, director of the East Asia non-proliferation program at the Middlebury Institute of International Studies, notes that the first US ballistic missile, Redstone, failed nine of its first 10 tests. While the North Koreans have had a mixed record developing its own missiles, compared to those it uses that are based on Chinese or Russian technology, their work is still respectable. Some of the delays are arguably political. In 2000, US spies forecast that the country could have an ICBM by 2015, but the North Koreans held off on tests for several years to win diplomatic advantages.

“We imagine [the North Koreans] to be incompetent buffoons, but…statistically speaking they are clocking in at a pretty decent number: Well over 50% of the launches work,” Lewis told Quartz last month.

Have the North Koreans actually built one?

Lewis is fairly convinced by the July 4 test, writing that “given the extremely high altitude it reached during its 39 minutes of flight, the Hwasong-14 is clearly an intercontinental-range ballistic missile that can reach parts of the United States. And it represents a reality that is here today: North Korea is determined to hold the United States at risk with nuclear weapons.”

Other experts wonder if there are still hurdles that remain. One big challenge of ICBMs is making sure the weapons payload survives the heat and force of re-entering the atmosphere so it can explode at its target. South Korea’s defense minister, Han Min-koo, said that the recent test doesn’t provide enough evidence that North Korea has mastered this technology for him to say that his northern neighbor possesses an operational ICBM.

What does it mean for geopolitics?

North Korea already had the capability to threaten US allies Japan and South Korea with nuclear weapons, and despite the cavalier approach of some American policymakers to this reality, the biggest obstacle to a war on the Korean peninsula remains what a bloody mess it would be for the civilian population. But if North Korea can plausibly threaten the United States with nuclear weapons, it will be harder for the US to back South Korea with military force. North Korea’s totalitarian strong man Kim Jong-Un has seen how US-led regime change has impacted leaders without nuclear weapons like Saddam Hussein and Muammar Gaddafi, and he wants to do his best to ensure he doesn’t follow in their footsteps.

At the moment, the US appears to have little leverage with North Korea. Any effort to compel Pyongyang to halt its weapons-development program would need deeper cooperation from China than the Trump administration has proven able to extract. Trump, who bluntly promised that North Korea would never have ICBMs, now has no good options left and may have to actually make one of those great deals he’s always going on about.