There are many existential threats facing the human race. The menace of environmental catastrophe looms, as does the outbreak of new plagues, new wars, food shortages, even the theoretical possibility of an extinction-level asteroid impact. One such threat that has been downplayed since the end of the Cold War is the possibility of another nuclear attack, or string of attacks.
This is a threat, however, that we should take seriously. The Bulletin of Atomic Scientists made headlines in January when they moved the Doomsday Clock thirty seconds closer to midnight. As it stands, the world appears to be potentially on the brink of nuclear war. The Clock indicates the level of danger the planet is currently in, and is currently at its most dire point since 1953.
As nuclear technology has improved, nuclear deterrence tech has improved along with it. But just how advanced is that tech? Is it enough to actually keep us safe from a nuclear strike?
In this article, we will take a look at the history of nuclear deterrence, and how those countermeasures stack up against the realities of modern nuclear strike capabilities. With the stakes so enormously high, it is important to know what tools we may have, or not have, at our disposal.
The world's first nuclear bomb, American, was detonated in a test explosion on July 16, 1945. Since then, there have been two nuclear attacks on civilian populations - Hiroshima and Nagasaki, during World War II.
The Hiroshima bombing in 1945 immediately killed about 75,000 people and, by 1950, the death toll had climbed to 200,000. The Nagasaki bomb, dropped three days after Hiroshima, killed 40,000 in the initial blast and had killed about 140,000 by 1950. These areas are still coping with after-effects. To this day, there are still a disproportionate number of stillbirths and deformities in infants due to lingering nuclear radiation.
The end of World War II and the start of the Cold War saw the world gripped in a state of protracted panic over the threat of nuclear holocaust. American schoolchildren were shown PSA reels instructing them to "duck and cover" in the event of a nuclear attack, as shown above. The only defense at the time was an attitude that came to be codified in the policy of Mutually Assured Destruction, or MAD.
Originally called "massive retaliation" by John Foster Dulles, the policy originally threatened war against the USSR if they invaded Europe, even if they used nuclear weapons. MAD is still seen as a deterrent against nuclear war, as retaliatory attacks would be too costly for either side to launch any nukes of their own.
Nuclear bombs were carried in aircraft until the advent of the Intercontinental Ballistic Missile, or ICBM, in 1957. The first ICBM was the Soviet R-7. Both the USSR and the United States had been working on ICBM prototypes based on the design of the Nazi A9/10 missile. The ICBM is, today, the primary means by which a nuclear warhead would be launched.
If a nuclear warhead were delivered by airplane or cruise missile, deterrence would be significantly more feasible. However, the ICBM travels at extremely high speeds until it breaks orbit, making them very difficult to target and destroy. An ICBM is not susceptible to typical anti-air weapons that could be used against enemy aircraft.
Ballistic missiles are classified by how far they can travel and what type of fuel their rockets use. Shorter range ballistic missiles are called "theater ballistic missiles," while longer range missiles, including ICBMs, are called "strategic ballistic missiles." ICBMs are propelled by rocket fuel, either solid or liquid, and then deliver their payload in freefall. Once a warhead is dropped, it travels at speeds up to 20,000 mph, or Mach 25. That's five miles per second. These realities make them extremely hard to combat.
It is because of the ICBM's size that it's such a technical challenge to intercept them with missiles. In order to stop them, we first have to detect them in time to get countermeasures into position and deploy them. This window is a matter of minutes. The sophistication of our detection technology has improved significantly in recent decades, but reactions have to happen at lightning speed.
Stopping a nuclear attack is one of the most complicated technical problems in the world. The picture would be muddled enough if the ICBM were simply delivering one nuclear warhead. Things get significantly more complicated, however, when you consider the fact that a single ICBM will carry multiple warheads, and will implement defensive countermeasures of its own to prevent the warheads from being destroyed.
Unfortunately, there are quite a few gaps left in our defensive capabilities when it comes to a fully-fledged nuclear attack. Reality is not irredeemably bleak, though. There are a handful of methods science has developed to help prevent a nuclear warhead from connecting with its target. But are they effective enough to rely on exclusively? Unfortunately, no. They will probably be effective, in a limited way. Diplomacy is still the best defense.
The ICBM poses a daunting challenge to our defensive capabilities. They are not, however, invincible. A look into the ICBM's operational stages will give us a clue into how they might be thwarted.
An ICBM's trajectory phase can be broken down into roughly three stages. First, during the "boost phase," the warhead is propelled upwards into orbit, at around 90 to 125 miles, by a large rocket that burns solid or liquid rocket fuel. This phase lasts about four minutes.
The boost phase is followed by the mid-course phase, in which the booster rockets stop firing and the ICBM continues traveling through space. This is the longest phase, and presents the best window of opportunity for the warheads to be destroyed, lasting about twenty minutes.
This is followed by the terminal phase, in which the warhead or warheads fall at extremely high speeds to hit their targets. This only lasts about a minute at most, and countermeasures here are extremely difficult to pull off. ICBMs do not have many vulnerabilities, but defensive measures developed to stop them are designed with one of these three stages in mind. For better or for worse, these countermeasures have never been tested in a real-life nuclear attack scenario.
In order to respond to a nuclear launch in a timely manner, the launch first has to be detected. Ideally, detected immediately. The difference between stopping a nuclear warhead and not stopping a nuclear warhead could be a matter of seconds. The rocket that delivers the warheads into orbit is significantly slower just after launch than when it has momentum, making it a much easier target.
Before the advent of modern satellites, which we use for detection these days, the world's militaries relied upon radar posts that were set up close to suspected nuclear launch areas. These radar posts were able to detect when an object had risen to a conspicuous altitude, at high speed. It was not difficult to infer from this data what objects were missiles and which were not. This was, at the time, the only form of detection available to us.
Nowadays, militaries rely on much more sophisticated networks of satellites that monitor the ground with infrared sensors. When the satellites pick up heat blooms from rocket launches, they notify the people who are in a position to do something about it. Of course, nuclear launches may hypothetically go totally undetected, which poses a very grave threat.
An ICBM's launch phase, during which the rocket first lifts off the ground, is when it's at its most vulnerable for attack. It is, however, very difficult to actually mount an adequate countermeasure in the time it takes the rocket to accelerate out of Earth's atmosphere.
In order to intercept a missile, an faster missile must be fired at a trajectory to intercept it. You also have to have lightning-fast response times, and be able to launch your countermeasure from a place that's close enough to the ICBM to actually be able to hit it before it's out of range. Despite the fact that the initial part of the launch is when the ICBM is moving most slowly, it is exceptionally difficult to actually do anything about it.
Things get even more complicated when you consider that ICBMs can be launched from any number of places, that are hard to predict. They can be launched from submarines or hidden bases, which may be totally out of range of any anti-ballistic missile that could strike it while the striking is good. There are many obstacles to detecting the launch quickly enough, and responding to it in a timely enough manner to prevent the rocket from reaching space.
Anti-ballistic missiles (ABMs) are surface-to-air missiles that were specifically designed to intercept and destroy ballistic missiles, such as the ICBMs that would be used to deliver nuclear payloads. In addition to nuclear warheads, ballistic missiles can also carry chemical and biological weapons, or conventional, non-nuclear warheads.
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Of all the ABM systems in the world, only three are robust enough to intercept an ICBM. One of them, the A-135 anti-ballistic missile system, was built to defend Moscow. It came online in 1995, replete with Gorgon and Gazelle missiles that are tipped with nuclear warheads. Another, the Israeli Arrow 3 system, first became operational in 2017. It was designed for "exo-atmosphere" attack on ballistic missiles during their second phase, when they are in space.
The American ABM system, the Ground-Based Midcourse Defense System, formerly known as National Missile Defense, started active testing in 1996. Unlike the other two systems, the ABM system launches non-explosive kinetic projectiles. It is, by the government's own admission, not robust enough to defend against an all-out nuclear war with a megapower like Russia. However, it is believed that the ABM may provide adequate protection against attack from smaller states.
Another method that could potentially be used to shoot ICBMs out of the sky before they can make orbit is attacking them with airborne lasers, like the one attached to the nose of this Boeing 747-400F. The United States has designed this laser, the Boeing YAL-1 Airborne Laser Testbed weapons system, which uses a chemical oxygen iodine laser, or COIL, to destroy ballistic missiles.
The YAL-1 has successfully destroyed two missiles during testing exercises conducted in 2010. However, the program was canceled in December of 2011. The airborne laser has not flown since 2012, when it flew to the airplane graveyard at Davis-Monthan Air Force Base in Tuscon, Arizona. It has since been scrapped completely.
The idea was unworkable because of how close at hand the aircraft would have to be to the ICBM at the time of its launch. Because the laser diffuses in power over distance, it would have to be relatively close up to the missile in the first place. A tricky proposition, as most ICBMs would be launched well behind enemy lines. The laser-equipped aircraft would have to, at least, be patrolling close to a hostile border, which could increase tensions.
Hopefully, in the event of a nuke being launched, it can be destroyed before it makes it through the planet's atmosphere. If this is not achieved, the warhead will have to be destroyed during the second leg of the ICBM's journey, its "mid-course" phase. This phase provides the longest window of time for a defense to be mounted and implemented.
While the ICBM is apparently vulnerable as it flies under its own momentum in Earth's orbit, complications abound. For one, an ICBM does not just carry one warhead. An international treaty allows for an ICBM to carry up to ten warheads on a single rocket. In addition to these ten warheads, they are also equipped with mylar balloon decoy warheads that are dropped along with the real ones.
The decoys, the same shape and color as the nuclear warheads, cannot be differentiated by detection systems. The decoys, once inflated, will fall with the warheads and debris from the missile, making targeting and destroying the nukes more difficult. Any defense mounted against a mid-course ICBM would have to pick and choose which warheads to target for destruction. There's not a very big margin for error in that decision, either.
Many attempts have been made to design a defense system that can adequately rise to the challenge of intercepting nuclear warheads during this mid-course phase. The most well-known was the Strategic Defense Initiative, a pet project of Ronald Reagan's that was more commonly known as the 'Star Wars' program. Star Wars is, today, considered a failure and a joke.
Star Wars was intended to be a space-based system that would use satellite mounted and ground-based weapons to destroy multiple targets before they could hit their targets planetside. It was, however, merely a dream. The technology during the eighties was not up to the challenge of fulfilling the Reagan administration's vision.
Star Wars saw many developmental iterations, using weapons as various as lasers, missiles and particle beams. These weapons were to be guided by computer and command and control systems and radar networks. Various approaches and different iterations of these elements were tested throughout the eighties, though they never coalesced into something workable. While Star Wars as a cohesive whole never saw the light of day or dark of space, multiple ideas generated in the R&D led to technologies that are still being worked on today.
There is one method that shows great promise, and may be our best defense against ICBMs in their mid-course phase. It's called a Kinetic Impact, or "Kill," vehicle.
It is a small device, weighing roughly ten pounds, that is launched in space to collide with and detonate nuclear warheads. They are not rigged with explosives of their own, relying instead on force of impact to explode the nukes. Once they've been launched, they are guided by thrusters to ensure they connect with their targets. Pictured here is the Multiple Kill Vehicle (MKV), a device that launched Kinetic Impact warheads to intercept multiple targets. The MKV underwent successful testing in 2008, and appeared to be a viable option for nuclear countermeasures.
Secretary of Defense Robert Gates announced in 2009 that the Pentagon was restructuring its budget. The MKV program didn't make the cut. The idea has not been scrapped, though. A program similar to the MKV was set underway in 2015 by Raytheon, Boeing and Lockheed Martin. They are currently developing a Multi-Object Kill Vehicle that will hopefully improve upon the original design. The technical requirements of such a vehicle being implemented successfully are daunting. It is not known when a prototype will be ready.
Once a nuclear ICBM launch is detected, and if there are not countermeasures in place to destroy the missile before it enters space, an MKV could be deployed against the warheads as they fall towards Earth. The defender would launch a missile carrying the MKV, or MKVs - up to twelve of them. The MKVs, once within range of the enemy ICBM, would be deployed in a cloud.
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The MKVs, guided by their thrusters, would accelerate into all the potential targets that could be warheads, including decoys. Sounds good in theory. Reality is, of course, not so easy.
The missile detection systems involved would have to use high-res, x-band radar and advanced image recognition software to correctly ID the targets amidst a field of missile debris. They would then communicate with the MKV to upload final coordinates to its tracking system. This would all happen while the MKVs and their targets would be closing on each other at about 0.5 miles per second. This exercise, which sounds like something out of Star Trek, would have to be conducted with complete accuracy the first time it was ever implemented in a real-life nuclear attack. A tall order, with dire consequences.
All of the preceding detail applies to the thought experiment of a single ICBM being launched, intercepted and (hopefully) destroyed. This, however, is entirely a thought experiment.
In the real world, an attacker would probably not launch only one ICBM. In the event of a full-scale nuclear attack by one of the nuclear powers, there would be dozens of ICBMs launched. They would probably be launched from different launch locations, approaching their targets from multiple angles. They would also probably arrive in waves, providing scant time to regroup between attacks.
In such an event, it is extremely unlikely that any defense system currently in place could successfully destroy all incoming warheads. Even assuming that those defense systems are mostly successful, that still leaves a very deadly margin of error. An attacker would only need to get a fraction of their nuclear payload to their targets for the attack to be "successful." While the attacker only needs to get a minority of their warheads through the defender's countermeasures, the defender cannot afford to make even a single mistake.
The grimly named "terminal phase" describes a warhead's path from orbit in a freefall trajectory towards its target on the ground.
If deterrence is unsuccessful during the boost and mid-course phases, only the terminal phase remains as a window of time to prevent impact. As we get closer to the wire, deterrence options get slimmer. Defense is still possible, however.
Deterrence is theoretically possible in the terminal phase with early defense warnings and ABMs tipped with nuclear warheads, that could be launched to detonate near the falling warheads. The explosions could destroy the warheads, or render their guidance and arming systems inoperable with the electromagnetic pulse that issues from a nuclear explosion.
Even in a best case scenario, this method still involves detonating nuclear weapons in the atmosphere above populated areas. The best case scenario looks less likely these days, as warheads are now made with radiation-hardened electronics. There's also the ever-present problem of whether or not ABMs are armed and ready to launch close enough to the targets to make a difference. If a more undeveloped area were to be targeted, the chances of a good defense being mounted diminish significantly. There is also, of course, the reality that an ABM arsenal used in this way would have to be large enough to target potentially dozens of warheads.
The picture should be pretty clear by now: nuclear deterrence technology has not caught up to nuclear weapons delivery technology adequately enough to be relied upon.
The defense methods described all require a very high degree of precision and sophistication to be pulled off in time. None of them have been tested in a real-life nuclear attack, either. For now, the best defense against nuclear war appears to be the longstanding policy of Mutually Assured Destruction.
MAD worked during the Cold War, but the political landscape is radically different than it was during that time, when the world's sensitivity to nuclear fear was highest. Hopefully, this tension will hold, and not break. Many people throughout history have been critical of MAD. Reagan once described it as "a suicide pact." The notion of nuclear deterrence through might has come under increasingly intense scrutiny over the decades, with critics claiming that there is actually no evidence that an enormous nuclear arsenal has any real deterrence value.
The United States also leads the world in "counter-proliferation," an ongoing campaign to pressure nascent nuclear powers into ceasing their development programs and relinquishing nuclear materials (or having them destroyed). Speculation about what nuclear deterrence will look like in the future breaks down along philosophical and technological lines. There are new developments in both.
In 2017, U.S. Chief of Naval Operations Admiral Jonathan Greenert claimed that America's ballistic missile defense technology would hit "the asymptote of our limits" in ten years. Meanwhile, other nuclear powers are rapidly improving their offensive ballistic missile technology. There are, however, new countermeasures potentially in the offing.
Directed energy weapons are, once again, being developed. The new lasers will likely be mounted to Unmanned Aerial Vehicles (drones) that will fly at high altitudes for long periods of time, monitoring for ICBMs in their boost phase. Railguns are also being considered as a countermeasure against "hypersonic attacks," including the newly developed hypersonic glide vehicle (pictured) - a glider that can be equipped with nukes and travel in the Earth's atmosphere at speeds up to mach 10.
Most interestingly, "left-of-launch" measures are being developed to halt a missile attack before it can begin. Most promising among these are cyber weapons that could disable enemy missiles and render them incapable of entering their boost phase. Some people even speculate that such a cyber weapon may have prevented North Korea from testing a missile on March 22 of 2017. None of these present a comprehensive solution, but they may help the United States preserve its dominance over, or at least technological parity with, its potential rivals.
The specter of nuclear war has caused major political rifts, both domestically and abroad, since the dawn of the nuclear age. There is still a strong political current in the United States that is unsympathetic with the government's drive to continuously expand and renew our nuclear arsenal. Detractors of this philosophy say that the threat of a technologically superior arsenal is the only defense we really have against another nuclear bomb being used.
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As nuclear technology becomes more studied, and the rest of the world catches up with America and its Western European allies, nuclear politics will become increasingly murkier. It will likely grow harder and harder to maintain any kind of reliable control over the world's nuclear storehouses. Many people believe that America should lead the way in gradually drawing down nuclear tensions by disarming some or all of its stockpile.
If there is a diplomatic and political option to stave off a nuke being dropped, it must be taken seriously, and pursued. Hopefully we are never in a position to have to use any of the last-ditch technological means at our disposal to patch things up. It may, by then, be too late. Hiroshima and Nagasaki should remain history's only implementation of nuclear weapons.