Could USA Defend it's Homeland Against a Nuclear Missile Attack
In east Europe, the war over Ukraine has heated up to unprecedented levels. Despite being cautioned against it, Russian president Vladimir Putin has authorized the use of chemical weapons against the stubborn Ukrainian resistance. Thousands have died since the attacks began. The president of the United States of America had warned Putin there would be “appropriate response” if he dared to use weapons of mass destruction. Stockpiles of American VX gas had been moved to Europe in anticipation of just such an event, and now cruise missiles laden with the deadly gas rain down amongst Russian troops.
VX is banned by the UN's Chemical Weapons Convention of 1993, but the US has retained its Cold War era stockpiles as a deterrent. Now thousands of Russian soldiers die as the deadly nerve agent paralyzes their bodies and they slowly asphyxiate to death. Russia is quick to respond with the use of low yield, tactical nuclear weapons inside NATO bases in Poland. President Putin claims these bases are legitimate targets, as it's through here that NATO and partner nations such as Japan and Australia have been resupplying the Ukrainian army. Thousands more die in the attacks, and NATO responds in kind.
Just hours later, NATO nuclear weapons are striking bases along the Russian border, destroying troops, armored vehicles, aircraft, and thousands of tons of critical supplies badly needed by Russian forces inside Ukraine. For twelve hours there is no reply and the world breathes a sigh of relief. Perhaps this small exchange of tactical nuclear weapons is enough. Maybe a full-blown nuclear confrontation can be avoided. Those hopes are dashed however as twelve hours and eleven minutes after the first nuclear strikes inside Russia, Russia's nuclear forces unleash a small- but deadly salvo- against NATO's strongest member, the United States. The United States has approximately half an hour to react, but can the US really defend the homeland from a nuclear attack? The first line of defense against nuclear weapons comes with detection, and for this task the United States has been operating Defense Support Program satellites for decades.
These special satellites use very sensitive infrared sensors to detect the tell-tale infrared plume of a rocket launch, and they do it from a geosynchronous orbit many thousands of miles above the earth! Their unique orbit allows them to always face the same side of the Earth at all times, much like the moon, so they can remain vigilant twenty four seven and have zero lapse in surveillance. Traditional satellites that orbit the earth will only be able to observe one part of the earth for a limited time, and even constellations of satellites can produce coverage gaps over time. As added defense, the high altitude of DSP satellites makes them difficult to destroy or interfere with from earth, making them more resilient during a conflict.
Defense Support Program satellites are aging however, and currently being replaced with the new generation Space Based Infrared System, which builds on the core concepts of DSP and adds more robust capabilities such as better resolution to detect the launch of even smaller, shorter range missiles, and increased resiliency against attempts to spoof, jam, or destroy them. SBIRS High GEO 1 was launched on May 7th, 2011, and two other classified satellites believed to be a part of the program were also launched in 2006 and 2008. Further satellites have since then been launched, giving the United States a robust early warning capability.
SBIRS Low was planned to be a constellation of 24 lower orbit satellites meant to also track ballistic missiles, but with the ability to distinguish between warheads and decoys- a critical need if an incoming nuclear attack is to be stopped. The system would have had two major sensors: a scanning infrared sensor which would acquire ballistic missiles during the boost stage of flight, and a tracking infrared sensor which would follow the missiles and also track warheads, debris, and decoys. SBIRS Low was eventually absorbed into the Space Tracking and Surveillance System program, which aimed to test technologies for the tracking of missiles to aid in targeting. STSS proved to be very successful, tracking not just traditional ballistic missiles and their payloads, but even intermediate-range ballistic missiles which have a shorter flight time and are thus harder to track and target. In tests, the STSS program successfully destroyed intermediate-range ballistic missiles by guiding interceptors to their targets.
The program further proved its capabilities on 8th July 2011 when it was tested against a short-range air-launched target, simulating a shorter-range air-launched cruise or similar missile. Since these missiles are already hoisted high up into the atmosphere, they are much smaller and dimmer as they require less powerful rockets burning for a shorter amount of time to get them to their target. In September 2021 the two satellites taking part in STSS testing were decommissioned and moved to higher orbits to prevent accidental collisions in the future with other objects in the same orbit. Since then the US has been very secretive about any low-altitude missile tracking and targeting systems, but it's likely they are looking for more survivable options given the proliferation of anti-satellite weapons in the militaries of China and Russia.
Once an incoming missile is tracked, targeting data can be fed to interceptor systems- and of those the US has a few with varying rates of success. During the Cold War, President Ronald Reagan imagined a comprehensive anti-ballistic missile defense system that would make the United States safe from nuclear attack. Since then attempts to implement successful missile defense have proven... difficult. The main problem is that ballistic missiles are moving at thousands of miles an hour, giving any defenses very little time to react, and even less time to launch a second set of countermeasures if the first fail. The second problem is the sheer altitude of an incoming ballistic missile. These missiles leave the atmosphere and cruise through space for the mid-course portion of their flight, meaning that any defense against ballistic missiles requires the ability to reach up and into space.
This requires a missile of significant size if taking the traditional ballistic approach. Another option is laser weapons, but they are mostlyineffective due to atmospheric scattering, and would instead need to be installed on satellites. Thanks to dispersal of the beam though, these satellites would have to be in fairly low orbits, which means you would need a lot of them to maintain a constant screen of protection over the US homeland. The next issue is actually hitting the missile itself.
Our best option for missile defense is kinetic- meaning that the best method we have for destroying a nuclear ballistic missile is by using another missile. However, this requires two missiles moving at thousands of miles per hour to physically ram into each other- a ballistic missile is moving so fast that traditional anti-air kill methods such as fragmentation warheads that only require a missile to get close to its target to shred it with shrapnel, simply aren't effective. Plus, ballistic missiles are large and once they are in their mid-course phase simply shredding some critical systems isn't going to stop it from releasing it’s nuclear payload down on your head. It's been described as hitting a bullet with another bullet, and requires math so precise it would make Einstein cry himself to sleep at night. Even the slightest miscalculation, or a particularly strong gust of wind as the interceptor rises into the sky, could be enough to spell a miss, and thus the US has developed some very powerful computers to guide interceptors to their targets. To be safe though, an intercept attempt will typically involve multiple interceptors.
But there's yet another hurdle in knocking out incoming enemy ballistic missiles- decoys and countermeasures. A modern missile is capable of carrying multiple warheads, but only some of these will be real. The rest will be dummy warheads meant to lure enemy interceptors. This means that it's best to intercept a missile before it has a chance to release its payload- but this is highly unlikely and requires missile defenses very close to the launch site.
It's the entire reason that Russia has been so cautious about US missile defenses in Europe, and China has joined in after the deployment of US missile defenses to South Korea. With multiple decoys, an interceptor has to strike the correct target or else you've just wasted a very expensive missile of your own and accomplished nothing. But ballistic missiles will also carry chaff to confuse radar tracking the incoming warheads. Basically a cloud of highly radar reflective material, it's un-stealth technology meant to be as visible as possible and thus confuse radar, making targeting impossible. The best, or worst part is that it's really cheap too, basically costing only a few thousands of dollars while defeating radars and computer systems costing tens of millions of dollars. So how in the world does the US defend against nuclear attack? The main defense against nuclear attack on the homeland seeks to destroy the enemy missile during the midcourse phase, this is when the missile has entered space and is cruising along, making small adjustments, and preparing to enter the atmosphere.
This will be the largest portion of a missile's flight path depending on how far away the target is. To knock enemy missiles out of space, the US has developed the Ground-Based Midcourse Defense system. These large missiles are designed to fly into space and smack head-on into an enemy missile, using a dummy, kinetic kill warhead to smash the enemy missile into dust. The system consists of approximately 60 interceptors deployed in two bases, one in Fort Greely, Alaska and one in Vandenberg Space Force Base, California. A third site was proposed to be based in Poland, but Russia got extremely upset over it and it was eventually canceled.
This geographic dispersal allows GMD missiles to knock out threats coming from Europe,which would be traveling over the north pole, and threats from Asia or the Pacific. If you're wondering how the system defends against missile launches from enemy submarines close to shore, it doesn't, and you better hope that on that day the US navy is on the ball and hunting down hostile subs. The GMD system is made up of six main sub-systems.
The first is the exoatmospheric kill vehicle. This consists of a solid metal 140 lb (64 kg) interceptor fitted with various maneuvering thrusters. These thrusters wouldn't help the kill vehicle accelerate, but are instead to help the interceptor make course adjustments and hit its target with pin-point accuracy.
The Exoatmospheric Kill Vehicle was meant to be replaced with a Redesigned Kill Vehicle in 2025, but the contract was canceled due to serious design problems detected by the Department of Defense. A replacement will have to wait until the Next Generation Interceptor program begins to mature. Next is the boost vehicle, the massive rocket that carries the interceptor up and into space. This comes with its own missile silo and silo interface vault, all located underground.
The Battle management command, control, and communications system, or BMC3, helps guide the missile to its target by feeding it targeting data and ensuring uninterrupted communications with the interceptor and boost vehicle. Ground-based radars, space-based early warning radars, and forward-based X band radars all make up the final sub-systems of the GMD program. These veritable fleet of radars are all designed to provide high resolution data during various phases of an incoming missile's flight, and their capabilities are classified at the highest levels. It's thought that these highly sensitive radar systems are so capable that they can detect aliens farting inside their UFOs- and they need to be if they're going to have any chance of hitting an incoming ballistic missile with another missile. GMD's effectiveness has been a subject of much contention, especially since it's cost the US billions of dollars. To date, the system has a success rate of about 55%, and critics are quick to point out that none of these tests have been carried out against dummy targets using a full suite of countermeasures.
In reality, one could expect a success rate much, much lower than 55%. Luckily, the US has additional layers of protection against nuclear missiles. In response to Russia's anger over the proposed deployment of a missile shield in Poland, the US shifted focus to the development of the Aegis Ballistic Missile Defense System. This system is split into two components, the ABMD is designed to destroy short to intermediate range ballistic missiles while they are still in the atmosphere, either on ascent if close enough to a launch site, or more likely on descent.
AEGIS BMD, also known as Sea-Based Midcourse, is designed to intercept ballistic missiles during their flight through space, and is thus capable of targeting missiles of any range. The origin of this program is in the mid-1980s with President Reagan's Strategic Defense Initiative, the much vaunted attempt at creating a shield against any missile threat. Initially SDI called for space-based railguns, but forty years on and railgun technology is far from mature with the US navy canceling its own railgun cannon project.
A new system known as Lightweight Exo-Atmospheric Projectile, or LEAP was developed and testing began in conjunction with the sophisticated AEGIS system. LEAP would eventually lead to several successful tests against ballistic missile targets and become Aegis Ballistic Missile Defense, using the Standard Missile-3 to pulverize a ballistic missile. The first Block 1 system was delivered in October 2004 and an Aegis 3.0 update delivered
in 2005. The world's best air defense system had just gotten the capability to knock ballistic missiles out of the sky. AEGIS BMD would prove so successful that Aegis Ashore was developed as a land-based component, with a NATO Aegis Ashore ballistic missile defense system site being built in Romania, and in Poland.
On May 21st, 2014 Aegis Ashore successfully detected, tracked, and destroyed a ballistic missile target. Aegis ballistic missile defense, whether ashore or at sea, uses the Rim-161 Standard Missile 3 for mid-course interceptions, and the RIM 156 Standard Extended Range Block IV for termminal-phase interceptions. An interceptor is launched from a vertical launch cell and guided to its target by its home ship or AEGIS Ashore facility, it then collides with an enemy missile with over 130 megajoules of kinetic energy, requiring no explosive charge. Interceptions inside of the atmosphere, or during the terminal phase of an attack, carry blast fragmentation warheads since the reentry vehicle of a missile is much smaller than the larger ballistic missile body that needs to be destroyed during the mid-course in order to neutralize the threat. The benefit of AEGIS ballistic missile defense when mounted on ships is that ships are mobile, and thus can be quickly repositioned to defend likely target areas- or to be closer to likely launch sites. As it's better to target a ballistic missile as early as possible to avoid it deploying countermeasures, the ability to reposition your ballistic missile defenses is greatly valued by the US Navy.
As is the ability to help cover facilities or locations that may be left vulnerable either because no other defenses exist, or because mid-course defenses have failed. A terminal-phase interceptor fired from an AEGIS equipped ship may be the last-ditch effort that saves your city from nuclear annihilation. The US, Japan, Romania, and Poland all have Aegis Ashore facilities, and the US Navy has 5 Ticonderoga-class cruisers and 28 Arleigh Burke class destroyers equipped with ballistic missile defense capabilities. These ships are split up with 17 assigned to the Pacific Fleet and 16 to the Atlantic fleet.
Future shipbuilding plans however calls for 80 to 97 total ships to be equipped with ballistic missile defense capabilities within the next thirty years. This is driven not just from fears of nuclear attack, but by the necessity of protecting the US Navy from China's ever-evolving anti-ship ballistic missiles. China's missiles represent a serious threat to America, and could push the US Navy out of the South pacific for good if not countered. The US has also helped Japan equip four of its ships with ballistic missile defense capabilities, and this number is also expected to rise in response to the development of North Korean nuclear weapons and the Chinese threat.
The next layer of protection for the United States is the Terminal High-Altitude Area Defense system. THAAD, as it's also known, was first proposed in 1987 as a mobile ballistic missile defense system. At the time, the problem with ballistic missile defenses was that they were vulnerable to conventional attack as their locations were well known.
Adding mobility not only increased survivability, but also allowed the US Army to move them to locations where no other ballistic missile defense capabilities existed. At first, THAAD failed miserably, scoring only two successful intercepts out of eight tests. However, as the technology matured the success rate increased to nearly 100%- though again the system has been criticized for not tackling realistic threats making full use of dummies and countermeasures. This hasn't stopped the system from being exported to US bases around the world, and even for use with partner nations such as Turkey, the United Arab Emirates- where it intercepted a Houthi ballistic missile in 2022-, South Korea, Romania, and Israel. THAAD works much the same way as any other terminal-phase defense system.
Its powerful AN/TPY-2 X-band radar tracks the target as it flies through space, and once it's plotted where and when the target will re-enter the atmosphere, launches an interceptor. The interceptor is then guided to the target by the radar where it uses a kinetic warhead to smash the incoming missile to pieces. THAAD is believed to be so effective that China has complained about its deployment to South Korea, despite US assurances that its goal is to protect the nation from North Korean nuclear weapons.
Next, the US has one final line of defense for ballistic missile intercepts- the US Army Patriot missile defense battery. Originally, the Patriot system was meant to take on airborne threats, but as the threat grew to include cruise missiles and ballistic missiles, the system was evolved to allow it to destroy these faster, nimbler targets. As a replacement to the Nike Hercules system, the Patriot is now the US Army's only line of defense against airborne targets. The Patriot's main appeal is its ease of set-up, requiring less than an hour to prepare for operation. All of its components, including fire control, and the launchers are all truck or trailer mounted, giving them great mobility. The Patriot uses AN/MPQ-53 and AN/MPQ-65 passively electronically scanned array radars, which are faster and more efficient than older mechanically scanning arrays like the type you've probably seen deployed on Russian vehicles inside Ukraine.
The AN/MPQ-65 radar features a second traveling wave tube which amplifies the radar's signal and gives it more power to track and detect hostile threats. Unlike similar SAM units, the Patriot uses only a single unit to search, identify, track, and engage targets, while other systems use multiple radars to do the same job. The Patriot's radar beam is very narrow in comparison with traditional radar dishes. This however allows it to focus more energy in a smaller space, which in turn allows it to better detect and track small, very agile and high-speed targets such as missiles. The radar also has increased effectiveness against stealth aircraft, and the focused beam is very resistant to attempts to jam it or interfere with its operation.
If the system detects it is being jammed, it quickly changes frequencies to avoid the jamming signal, repeating as necessary to provide good data to intercepting missiles. Patriot missiles work much the same way as any other terminal-phase defense system, by launching a missile on an intercept course with an incoming target. This is a short-range defense only though, and can only protect small geographic locations and only during the terminal phase of a ballistic missile's flight.
In essence, Patriot batteries are the last line of defense when all other options have failed. The current state of US ballistic missile defenses leaves some serious doubts as to whether protecting from a nuclear attack is realistically feasible. To date, successful intercepts have been carried out under very controlled conditions, and there's a lot of reason to doubt that any of these systems would be able to defeat a modern ballistic missile equipped with a full host of countermeasures. Even if capable of doing so, each intercept would require multiple salvos of interceptors for redundancy, which means that even with the full complement of US ballistic missile defenses operating at peak efficiency, only small pockets of the US homeland could be offered some measure of protection in the case of all-out nuclear war. Compared with the ballistic missile defense capabilities of other nations though, this might be all that's needed for the United States to survive as a nation, and to do so in a far better state than any of its potential adversaries.
To be truthful though, that's not saying much as the global consequences of a full nuclear exchange will likely trigger human extinction anyways. This brings up the question if ballistic missile defense is even worth it, especially considering the extreme cost. To try to improve ballistic missile defense in the future, the US is already looking at new technologies. During the 2000s the US experimented with an airborne laser concept. Essentially just a Boeing 747 equipped with a massive laser at its nose, the Airborne Laser solved many of the problems of ballistic missile defense- namely the difficulty in guiding a kill vehicle to its target when both it and the target are flying at hypersonic speeds and over great distances. The Airborne Laser could instead target a missile during its most vulnerable phase- the boost phase- and destroy it at the speed of light.
In multiple tests, the Airborne Laser successfully destroyed ballistic missiles and other airborne targets. However, ultimately the project was scrapped in 2010 due to numerous problems. First, the laser was only effective at very short ranges due to atmospheric scattering, so as Secretary of Defense Robert Gates stated, if the laser was to be used to intercept missiles from Iran, it would have to be orbiting inside of Iran's national borders to do so.
Secondly, in order to successfully defend against ballistic missile threats from a single hostile country, a fleet of 10 to 20 of the aircraft would be required at a cost of 1.5 billion each, and costing $100 million a year to operate. The Airborne Laser was officially dead- but the data gained from testing has been invaluable in developing other directed energy weapons. In fact, the concept of an airborne laser has now been once again resurrected, only this time with the laser mounted on very high latitude unmanned drones.
These drones would fly at altitudes far in excess of large jet aircraft such as the original test platform, and at such heights would maintain laser beam integrity over longer ranges. An unmanned drone flying at 65,000 feet would be able to engage targets as far way as hundreds of kilometers, and a fleet of smaller unmanned drones would be cheaper to procure and operate. They could also fly for very long periods of time through airborne refueling. As technology improves, we may once again see the return of the canceled Airborne Laser program, albeit in a much different form than predicted by its original builders. It's even possible that lasers could be installed on low earth satellites, and this would in fact be the most efficient method of ballistic missile defense. However, doing so would prompt other nations to begin arming their own satellites and create a space weapons race.
Inevitably, in order to protect from space-based interception, nuclear weapons would logically be moved into space themselves where they could be dropped straight down onto targets below, making most forms of interception impossible or mostly useless. But as it stands today, while the US could probably successfully defend from an attack by a rogue state such as North Korea, there is little hope of surviving even a moderate exchange of nuclear weapons even after hundreds of billions spent in ballistic missile defense. Now go check out What If There Was Nuclear War Between The US and Russia to find out just how bad you're (insert bleep SFX here), or click this other video instead!