Nukes in Space: Should You Be Losing Sleep Over Them?
By Tory Bruno
The short answer is: It depends…
If we are talking about a nuclear power source, then no. There are nuclear power sources in space on scientific probes right now and have been for decades. These are in the flavor of Radioisotope Thermoelectric Generators (RTGs), also known as “nuclear batteries.” RTGs are relatively harmless and extremely safe. They can’t detonate, melt down, or even really hurt you unless you literally break into the fuel and eat it. A real RTG is, in fact, way less hazardous than even Mark Watney thought it was.
If we are talking about a fission reactor, then please stand behind the radiation shield, but, again, not inherently “destabilizing.” These will be essential for permanent off-earth human habitation as well as certain in-space propulsion applications. You should expect that nuclear reactors in space will become commonplace in the decades to come.
If, on the other hand, we are talking about nuclear warheads, then yes, that would be worth a few sleepless nights. These would be bad. Very, very bad…
A nuclear warhead deployed from space to the surface of the earth would be inherently destabilizing to the current system of deterring nuclear war. This is why the 1967 Outer Space Treaty, which generically bans any weapons in space, also specifically calls out a prohibition of Weapons of Mass Destruction (WMDs) in orbit.
Likewise, a warhead deployed in space with the intention of being detonated in space would also be inherently destabilizing to deterring conventional conflict on earth, especially between Great Powers.
Let’s start with nukes dropped from space as the worst, most dangerous, and hopefully least likely prospect.
Nukes Launched from Orbit
Basing nuclear weapons in space that target terrestrial targets from orbit, would undermine the entire strategic deterrent regime. Any significant deployment of such a capability would quickly become a 21st Century Cuban Missile Crisis.
The concept of strategic (nuclear) deterrence is based upon creating a certainty in the mind of our adversaries that a nuclear attack upon the U.S., or our allies, would be responded to with an overwhelming and devastating retaliation. This retaliation must be believed to create a cost to the adversary that would far, far outweigh any perceived benefit from their attack. It must be massive in scale, more than could ever be absorbed, and, most importantly, inevitable.
This principle is why U.S. President John F. Kennedy went high order back in October of 1962 when Nikita Khrushchev began putting nukes in Cuba. At only 90 miles from Florida, a ballistic missile could deliver a nuclear warhead into Washington, D.C. in around 15 minutes. Given the crude missile warning technology of the day, as well as the lack of any realistic missile defense capability, this would mean that the senior leadership of the United States could be instantly killed, without warning, at any moment, leaving no National Command Authority to order a retaliation. So much for nuclear deterrence…
A warhead launched from orbit simply updates this scenario to today. Low Earth Orbit (LEO) would become the new Cuba.
The detection of a warhead attacking from orbit is problematic. Our primary nuclear attack warning systems are now deployed in space, but this is not the scenario they were intended for. The Space Based Infrared System (SBIRS) is the marquee constellation in this mission area. SBIRS is designed to detect, classify, and track ballistic missiles. Not relatively cold, dim, tiny warheads already in space. Even if a deploying warhead is observed by a ground-based RADAR, SBIRS, or a new space based situational awareness satellite, it would take time to understand that it wasn’t a deorbiting spacecraft or bit of space junk. It would take more time to track it long enough to predict its intended target. And finally, even more time to queue a missile defense asset to acquire and make an intercept, even if one were in the right place to do so.
Given that a warhead launched from LEO could strike any target on earth in a few minutes, this scenario drives us all the way back to 1962…
Today’s deterrent regime involves both sides understanding each other’s capabilities, weapons, and basing modes. A limited attack could be blunted. A large-scale attack would be easily detected and quickly retaliated against with forces that are launched before the attack arrives.
In other words, there is no incentive for either Vladimir Putin or Xi Jinping to launch a first strike against U.S. nuclear forces or our National Command Authority (the President). It just wouldn’t do any good. We would see it coming and make the retaliation inevitable.
If, on the other hand, Xi or Putin could instantly kill U.S. leadership without warning, using a “magic nuclear bullet from space,” might they believe that the ensuing delay and confusion could allow an opportunity for a massive terrestrial nuclear attack that would sufficiently degrade our retaliatory response enough for their side to survive?
Would Putin sacrifice only a couple of Russian cities to be rid of the U.S. and NATO forever, in one fell swoop?
Would Xi willingly sacrifice a hundred million or so of China’s billion and a half people to obtain the same result?
I would not want to learn the answer to those questions…
Fortunately, I think this very destabilizing scenario is unlikely because it is so extremely escalatory and risky, forcing us to put our nuclear forces on a hair trigger.
A nuke intended to detonate in space, however, is another matter.
Nukes Detonated in Orbit
A nuclear warhead intended to detonate in space is far less escalatory because it would not be an obvious opening shot in a full-scale nuclear attack. However, it could be very destabilizing as a prelude to a conventional terrestrial conflict with the U.S.
The United States has the most technologically sophisticated military, the most powerful navy, and the most successful, battle-hardened armed forces in the world. With our ability to project force over vast distances and our global network of allies, the U.S., and her friends, have an ability to stunt terrorism, discourage aggression, and deter major conflict that has not previously been seen in human history.
The power of the world’s free nations, led by America, to keep the peace is essential in a time of peer adversaries who are committed to territorial expansion, hegemonic dominance, and the spread of their own authoritarian disregard for basic human dignity.
There is, however, a potential vulnerability in our otherwise invulnerable power, and it’s one of our greatest strengths.
Not very long ago, space became responsible for substantially increasing the effectiveness of our armed forces. We enjoyed total dominance in the ultimate high ground, an uncontested, unthreatened environment from which to see all, communicate everywhere, and never be surprised. This use of space transformed our military into virtual Olympians of the globe. So much so, that we have doubled down over the years, integrating space into all our operations, systems, and capabilities.
However, space is no longer just a force multiplier. It has become more. Space is now essential to our basic military effectiveness. We really can’t fight without it.
This is precisely why Russia, and especially China, have invested heavily in antisatellite capabilities. They are doing this to degrade our military effectiveness by attacking and denying the use of those space assets that our forces are so completely dependent upon. Russia has also taken specific steps to be able to operate without space at all. It is undeniable that both Russia and China are far less dependent upon space than we are. If these adversaries could deny the U.S. our use of space, even if it were to cost them their own, then they might believe they would be leveling the playing field here on earth.
The U.S. has not sat idle to this threat. We have not only set up an entirely new branch of the armed forces to focus solely on space, the U.S. Space Force, we have also invested heavily in technologies and architectures to make our heretofore fragile and unprotected assets much more resilient. That is to say, we are designing and fielding systems that can absorb an attack and keep on fighting.
The quintessential example and clear focus of this strategy is Proliferated LEO (PLEOs). These are large, distributed networks of satellites in Low Earth Orbit that perform communications and several other essential missions. They number in the hundreds or even thousands of individual satellites and are inherently global in coverage. Because they are large, distributed networks, their mission capability degrades gracefully as individual assets are knocked out. This strategy is intended to avoid offering Russia and China the tempting target of a handful of fragile and exquisite satellites that could be easily attacked, creating a Pearl Harbor event in space.
It is also important to understand that true, durable resiliancy always requires dissimilar redundancy. While proliferated LEO networks offer a level of redundancy, they have their own vulnerabilities including their easy accessibility from earth. But in combination with higher orbit, less network dependent assets, real resiliency is achieved, along with an enormous complication of the adversary’s mission, forcing them to simultaneously attack in multiple domains across vast distances.
But like all Great Power competition, such an environment stimulates a back and forth. A strategy followed by a counter strategy, and so forth.
It can be said with confidence that our adversaries are thinking hard about how to cope with the new PLEO element of our resilient architecture.
One approach could be to conceal a nuclear warhead within an otherwise innocuous LEO satellite. Detonating that warhead in situ would create a large Electromagnetic Pulse (EMP) in orbit. Operation Starfish, which detonated a nuclear warhead in space over the mid Pacific at an altitude of 400km, inadvertently did electrical infrastructure damage 1,000 miles away in Hawaii and caused the failure of at least half a dozen unsuspecting spacecraft in orbit at the time.
Even today, civilian infrastructure is not designed for this scenario and spacecraft in LEO are generally neither nuclear, nor deep space radiation hardened because the earth’s magnetosphere offers considerable protection from effects originating from beyond earth.
Consequently, even a limited number of nuclear weapons detonated in LEO might be expected to do severe damage to satellites there. Hundreds or thousands of PLEO satellites would be instantly disabled. Others would die over time. Unable to maneuver to avoid collisions within their densely populated orbital shells, dead satellites would eventually collide, creating large, propagating debris fields that cascade through the constellation. The mega constellations of satellites intended to achieve resiliency through their large numbers would become graveyards of orbital debris, rendering those orbits unusable for future constellations.
Having thus defeated the U.S.’s strategy of space resiliency by using proliferation technology against itself, the adversary might then perceive a leveling of the playing field. This could embolden them to commence a conventional conflict on earth, no longer fearing the unrivaled power of the U.S. and Allied militaries. We have already seen Putin open an invasion with a cyber attack on civilian space assets. Nukes in space would be a simple scaling up to take on the U.S. and NATO.
We must also consider that while the US would consider a hostile nuclear detonation in space to be a watershed event of huge import, unthinkable in its ramifications, and therefore, self deterring, Russia and China might not. We must contemplate that these countries might see such an attack in a very different light than the use of a nuclear weapon on earth. One involves the immediate and large scale loss of life, a true weapon of mass destruction that is certain to trigger a nuclear retaliation, while the other would kill no one (directly) and merely destroy infrastructure. Under this viewpoint, the threshold for use might be much lower than we would assume when looking through our lens rather than theirs.
Therefore, a nuclear warhead placed in LEO can only be viewed as a potential prelude to a Great Power conventional conflict. This makes such a capability very destabilizing because it could create confidence in the mind of an adversary that they could take on the U.S. in a regional or theater level war and prevail.
So, What Does it All Mean?
Put simply, the presence of nuclear warheads in space would be both provocative and destabilizing. Nuclear weapons detonated in space could defeat U.S. space resiliency. This would be a relatively inexpensive way to level the playing field and embolden action against the U.S. or an ally. Thus, destabilizing the conventional deterrence status quo.
Awareness of a significant operational deployment of nuclear warheads in critical orbits would likely stimulate a heightened conventional forces preparedness and intense economic and diplomatic pressure to remove them.
The presence of nuclear warheads in orbit that can attack ground targets from LEO would be extremely escalatory and destabilizing to the fundamental strategic deterrent regime. Such an action could pressure U.S. nuclear forces to go on continuous high alert and encourage a hair trigger posture. Never a good thing when the gun fires nuclear bullets…
A similar diplomatic and economic response would follow their discovery. However, the President would also be forced to consider preemptively destroying these weapons in orbit at the slightest sign of increased tensions. An act that is also inherently escalatory.
So, yes. Nuclear warheads in space would be worth some hard thinking and more than a few sleepless nights…
Tory Bruno is the CEO of United Launch Alliance, a leading space launch provider. He is an experienced Rocket Scientist with a deep background in space, nuclear deterrence, and missile defense. Tory has served on the Defense Innovation Board, is a member of the National Space Council’s Users Advisory Group, and is a member of the National Academies of Sciences, Engineering, and Medicine.
