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Military planners need to consider threats not just from conventional anti-satellite weapons but also alternatives once dismissed as “unthinkable.” (credit: DRDO)

Enhancing space deterrence thought for nuclear threshold threats (part 1)

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Most governments when asked to choose between war and peace are likely to choose peace because it looks safer. These same governments if asked to choose between getting the first or second strike will very likely choose the first strike…once they feel war is inevitable, or even very probable.
- Herman Kahn, On Thermonuclear War (1960)

Space fighting is not far off. National security has already exceeded territory and territorial waters and airspace and territorial space should also be added. The modes of defense will no longer be to fight on our own territory and fight for marine rights and interests. We must also engage in space defense as well as air defense.
- Teng Jinqun, People’s Liberation Army Analyst (2001)

Since the Cold War, the idea that nuclear weapons would have any impact upon space power theory, space deterrence, or space defense postures was considered unlikely. After all, the nuclear weapon’s influence upon foreign policy and strategy had taken a back seat to non-proliferation regimes and sanctuary theory, therefore making any need for deterrence of space attacks, especially at higher nuclear thresholds, unnecessary. However, recent scholarship has pointed to the fact that the world is now in the midst of a second nuclear age, one in which great power competition has returned, but with non-peer adversaries also acquiring capabilities for nuclear use and space access.[1] What does this environment mean for space deterrence given the proliferation of ASAT weaponry, missiles, and EMP weapons? This article provides background on these new dynamics of the strategic situation and reviews an alternate strategic analysis framework for credible space deterrence that is tailorable to a particular crisis’s context.

The second nuclear age and changes in deterrence theory

In the past few decades, nuclear weapons non-proliferation efforts have proven ineffective. As a result, the spread of nuclear weapons has emerged from “natural causes” of state interest.[2] This means that, despite attempts at norms and globalization efforts meant to limit the spread of such weapons, “normal dynamics of fear and insecurity that have long characterized international affairs” have led to nuclear weapons returning for a second act.[3]

Not all adversaries can be viewed as rational, reasonable, and predictive, and therefore a unified deterrence theory is ineffective in the modern world.

Thomas Schelling stated that “there is a tendency in our planning to confuse the unfamiliar with the improbable. The contingency we have not considered looks strange; what looks strange is thought improbable; what is improbable need not be considered seriously.”[4] Now with the shift to a strategic environment in which nuclear weapons technologies and the means to deliver them effectively are actively pursued by rogue states like North Korea, the possibility of limited nuclear use may be on the rise.[5] As Herman Kahn states in his book, Thinking about the Unthinkable in the 1980s, “Some of the ideas [regarding nuclear use by states] are not on anyone’s minds, but probably should be.”[6] Put another way, “nuclear weapons exist. They are spreading. As a result, the United States may face a situation where other countries may use them.”[7] Due to the “second mover advantage” that North Korea gains through learning from Russia and China, what does that mean for deterrence and escalation thought?

Deterrence theorists have modified their theories somewhat because of the different strategic contexts of the second nuclear age. The “third wave” theorists such as Keith B. Payne or Therese Delpech argue that not all adversaries can be viewed as rational, reasonable, and predictive, and therefore a unified deterrence theory is ineffective in the modern world.[8] In addition, the personal beliefs, intentions, and worldviews that exist in the multiplayer, multicultural environment of today’s international system imply that more understanding of a state’s strategic culture and decision-making calculus is required to effectively posture for credible deterrence.[9] In addition to strategic culture, two scholars argue that not just any posture, but one capable of escalation dominance adds credibility to deterrence frameworks in this new nuclear age.[10]

Kerry Kartchner and Michael Gerson argue that strategies of escalation dominance claim to be more relevant to today’s strategic environment than in the past.[11] This is because escalation dominance “does not depend on shared commitment to a particular set of understandings or rules” and therefore might be more helpful in dealing with revisionist powers and states of concern that are either not invested in the international order’s rules and norms of behavior or are trying to rewrite them through action.[12] Escalation dominance, if done correctly, relies “purely upon superior brute force and war-winning strategies, coupled with the credible threat to employ those forces and strategies if necessary.”[13]

This credibility of threat is key. If a government or actor lacks the forces necessary to escalate or engage in a war-winning strategy, then escalation dominance will be lacking. An example of escalation dominance being successfully employed against the US is the Russian use of nuclear posturing to deter NATO and US intervention in the invasion of Ukraine in 2014. Russia postured its nuclear forces per its doctrine of escalate-to-deescalate and the open threat to use those nuclear forces if any conventional force entered Russian territory.[14] Escalation dominance was viewed as a credible possibility by NATO, and Russia seized Crimea and added it to the territory of the Russian state.[15]

With this context in mind, and with the possibility of having to include higher threshold events or crises within the National Strategy for Space of the US, one possible option based on third-wave thinking on deterrence and escalation dominance is the tiered, tailored approach to space deterrence.[16]

A review of the framework for credible space deterrence

The framework suggested in Reversing the Tao began with a look at the strategic level viewpoint necessary to understand the threat and operational environment within which all scenarios would play regarding DoD postures for deterrence in space. National leaders therefore are required to acknowledge four items of importance to frame the situation.

First, American strategists should recognize that deterrence requires getting into an adversary’s decision-making process through observation and analysis of its strategic culture, doctrine, and behavior.[17]

Policymakers and strategists must view space systems as a critical infrastructure of the United States and not just a support structure for force enhancement and terrestrial operations.

Second, strategists and policymakers must acknowledge that space is an offensive, dominant medium.[18] As a result, in order to provide effective deterrence in a standard space power environment, much less at the higher nuclear thresholds of the second nuclear age, the US must actively protect its space systems through a credible offensive- counterforce capability to reverse the first-strike instability, at least up to the kinetic weapons threshold.[19] A kinetic ASAT’s use could not only be a threat or use of force for active deterrence in the conventional sense but could also be part of an adversary’s nuclear strategy.[20]

Next, theorists of the third wave suggest that any future national security space posture should acknowledge that damage limitation measures such as active defense of US critical space and terrestrial infrastructures are vital to ensure credible deterrence in scenarios of vertical escalation.[21] Deployment of active defenses supports the view expressed by second nuclear age scholars such as Keith B. Payne, who argue that to exercise force projection in regional contexts of the second nuclear age as means to deterrence requires management of risk to the US homeland and deployed forces. To ensure an adequate management of risk requires damage limitation measures such as “offensive capabilities for counterforce strikes; active defenses such as air and ballistic missile defenses; and passive defenses such as physical protection” and hardening against space-borne EMP.[22]

Finally, policymakers and strategists must view space systems as a critical infrastructure of the United States and not just a support structure for force enhancement and terrestrial operations.[23] The view of space systems as critical infrastructure has been a view in national strategy and doctrine for years, but it has never been fully funded or executed broadly by senior leadership as a critical infrastructure normatively.[24]

Following the strategic framing necessary to tailor deterrence to potential adversaries, the posture suggested in the framework in Reversing the Tao includes a tiered structure: Tier 1 space deterrence scenarios deal with the merger of the nuclear and space power threats that could impact the homeland; Tier 2 space deterrence deals with most counterspace threats across the counterspace spectrum and up the vertical escalation ladder; Tier 3 deterrence deals with strictly reversible counterspace threats and means to escalate.[25] Having the physical means to achieve escalation dominance is vital to this framework for space deterrence. To help clarify the thresholds of escalation in a space power context, even those that combine with nuclear use, the author devised the following escalation ladder (See Figure 1).[26]

Non-Interference/Peaceful Use of Space

  1. Freedom of Action in Space (civil, commercial, military use of space for benefit of nation and world)
  2. Intelligence/SSA Collections (Passive/Active)

Reversible, Yet Purposeful Interference Threshold (Deny/Degrade)

  1. Passive Jamming
  2. Active Jamming/Cyber Attacks
  3. Laser Tracking/Dazzling
  4. Unauthorized, Rendezvous and Proximity Operations Near U.S. or allied spacecraft
  5. Posturing/Mobilization of Destructive Space Attack Forces

Irreversible, Purposeful Interference Threshold (Damage)

  1. High Energy Chemical Laser
  2. High Power Microwave Weapons Use

Kinetic, Debris Generation Threshold (Destroy)

  1. Kinetic Energy (KE) Anti-Satellite (ASAT) missiles (Terrestrial Based- LEO)
  2. Kinetic Energy (KE) Anti-Satellite (ASAT) weapons (Co-Orbital)
  3. Kinetic Energy (KE) Anti-Satellite (ASAT) missiles (Terrestrial Based- GEO)

Nuclear Use Threshold (Destroy)

  1. Terrestrial Fractional Orbital Bombardment Systems (FOBS)
  2. Orbital Electro-Magnetic Pulse (EMP)
  3. Orbital Nuclear Strike against spacecraft (all orbital regimes affected)

Figure 1. Space Power Escalation Ladder. (Reproduced from Christopher Stone, Reversing the Tao: A Framework for Credible Space Deterrence, CreateSpace Publishing, 2016).

To explain the escalation ladder tool, the first threshold describes the ideal peacetime condition of non-interference and the international peaceful use of space. The first threshold also describes conditions supported by customary norms such as freedom of action in space for civil space exploration, commercial space development, and military uses of space for the national and multinational interest. In addition, it also includes military operations such as intelligence and space situational awareness operations to ensure the status quo is maintained by all spacefaring nations and the monitoring of arms control treaties.

The next threshold addresses the first level of purposeful attack along the reversible side of the counterspace spectrum. Examples can include passive or active jamming of radiofrequency communications, tracking or illumination by lasers upon surveillance satellites, unauthorized rendezvous and proximity operations near US or allied spacecraft, or even posturing and mobilization of destructive, space attack forces on Earth. This threshold has been the current norm of behavior in space for the last decade or so.

Once the kinetic threshold has been crossed, destruction of US space assets is the adversary’s clear objective within its destructive space warfare concept.

The next threshold of the space power escalation ladder is the first set of damaging counterspace attacks. This threshold consists of two rungs of chemical laser use or high-power microwave weapons systems. High-energy chemical lasers, in the current context, refer to terrestrial-based laser systems, although high-energy space-based lasers have been proposed and discussed for decades.[27] Deterrence theorists of the Cold War, such as Keith B. Payne, have argued that deploying laser systems into orbit, especially for defensive purposes, could aid nuclear deterrence stability.[28] High-power microwaves are another form of directed energy weapons that can “produce effects that range from denying the use of electrical equipment to disrupting, damaging, or destroying that equipment” onboard spacecraft.[29] While these can deny and degrade spacecraft systems, these types of weapons systems, terrestrial-based or orbit-based, serve to bridge the destructive threshold of space power attack.

Once the kinetic threshold has been crossed, destruction of US space assets is the adversary’s clear objective within its destructive space warfare concept.[30]30 These rungs of escalation within this framework for space deterrence decision making includes kinetic energy anti-satellite (KE ASAT) missiles (terrestrial-based) with ranges of low Earth orbit (LEO) all the way up to geostationary orbit (GEO). In addition, co-orbital ASATs deployed in space are included within this threshold. Co-orbital ASATs are kinetic weapons that can be based in orbit and used to strike other satellite targets, interceptors, or other attacking satellites.[31] While current counterspace postures within this threshold are limited to terrestrial- based KE ASAT missiles and a few test co-orbital ASATs, future deployment modes could be multilayered and multiuse for both space-on-space and space-to-ground attacks. Writings from near-peer potential adversaries such as China indicate that this type of multilayer attack architecture is part of its future space strategy.[32]

As one continues to the top of escalation tool, the maximum damage that could be done is by crossing the threshold to nuclear use. These less familiar weapons systems could be used to affect critical space infrastructure in orbit, destroy terrestrial targets such as power grids and command and control centers, or both. This type of scenario constitutes a Tier 1 Deterrence event. One example of this is an electromagnetic pulse (EMP) employed via Fractional Orbital Bombardment Systems (FOBS) or satellites.

An EMP is defined as the interaction of high energy nuclear radiation with the atoms of the atmosphere causing damaging surges of electric power.[33] When a nuclear explosion occurs at high altitude or in space, “the EMP signal it produces will cover the wide geographic region within the line of sight of the detonation.”[34] This EMP capability can produce “widespread and long-lasting disruption and damage to the critical infrastructures that underpin the fabric of U.S. society.”[35]

An EMP attack has three phases. The E1 phase occurs when “gamma radiation during the first 10 nanoseconds from the nuclear detonation rips electrons out of the atoms in the atmosphere.”[36] This process induces very high voltages in electrical conducers, most of which are not designed to protect against such levels of surge. E2 is generated when the scattered gamma rays and emissions, produced by neutron collisions from the explosion for one nanosecond, pulse similar to a lightning bolt. Because of this similarity, this is one area that can be easier to protect against.[37] Finally, E3 is a slow pulse lasting hundreds of seconds and is a result of the impact of the EMP on the Earth’s magnetic field. E3 is similar to the geomagnetic storms that occur in nature and can negatively impact such things as power lines and spacecraft systems in orbit.

In testimony before a 2004 committee on EMP, Gary Smith of Johns Hopkins University stated that the effect of such an attack “can be continental in scope.”[38] Continent-wide damage is possible because a detonation at an altitude of 500 kilometers means the entire continental United States, as well as parts of Canada and Mexico, and vital parts of our critical space infrastructure would be impacted by such a strike.[39]

Lowell Wood also of Johns Hopkins University, previously described the potential impact of EMP before a hearing of the House Armed Services Committee in 1997:

We essentially…move [the United States] back in time by about one century and you live like our grandfathers and great-grandfathers did in the 1890s until you rebuild. You do without telephones. You do without television, and you do without electric power…and if it happens that there is not enough fuel to heat with in the winter time and there is not enough food to go around because agriculture has become so inefficient and so on, the population simply shrinks to meet the carrying capacity of the system.[40]

This assessment led the EMP Commission to assert that a high-altitude or space-borne EMP strike upon the homeland could lead to many deaths over a short period of time. Commission member Ambassador Henry Cooper testified, “We do not have experience with losing the infrastructure in a country with 300 million people, most of whom don’t live in a way that provides for their own food and other needs.”[41] As a result of this lack of data and given our technology-dependent society and the populations presently considered, it appears 10 percent, or 30 million people, “would probably be the range where we could survive as a basically rural economy.”[42]

The threat of an EMP strike, from high altitudes or in orbital space, taking the United States back over a century to a rural society may seem far-fetched, but this is not just considered likely by security focused groups and think tanks, but also by studies conducted within the arms control community. This agreement by seemingly disparate agendas provides additional weight to the concerns regarding this threat.

In the early twenty-first century, most national economies are heavily dependent upon infrastructures, both terrestrial and space-based, that rely on electricity and electronics.[43] These infrastructures are interdependent and overlapping, creating a situation where even a localized impact in one or more urban areas could have tremendous negative consequences. An EMP explosion in or near an urban area or on a continental scale “has the capability to produce widespread and long-lasting disruption and damage to critical infrastructures, creating the possibility of long-term catastrophic consequences.”[44] It could not only “seriously degrade or shut down a large part of the electric power grid in the geographic area of EMP exposure near instantaneously, it could also lead to functional collapse of grids beyond the exposed area, as electrical effects propagate from one region to another.”[45]

When cut off from the communication, financial, and other society- supporting functions provided through critical infrastructures dependent upon electrical grids, “emergency response efforts are jeopardized, and fuel reserves for back-up systems and stocks of food and medicine will quickly be exhausted. The maintenance of a reasonable standard of health will not be possible without the rapid recovery of the economies critical industries. Prolonged disruption of these systems puts the survival of the population and the prospect of economic recover into question.”[46]

In addition to the terrestrial impacts that an EMP strike from space or high altitude could convey upon the civilian population, its impact upon our critical space infrastructure, which is interdependent with our terrestrial infrastructure, is also worth considering.[47]47

According to the Defense Threat Reduction Agency, “there is little question that unhardened satellites are vulnerable to high altitude nuclear explosions.”[48] It is also consensus that “any country or organization with sufficient technology, missile lift, and guidance capability can damage or destroy a satellite in orbit using a number of different weapons and kill mechanisms.”[49] These can include everything from reversible attacks using radiofrequency jamming and lasers, to irreversible kinetic effects such as anti-satellite missiles and nuclear detonations.[50]

Strategists should leverage the proposed framework for space deterrence analysis throughout the vertical escalation dynamics, and at all thresholds, to ensure the proper foundations to develop an effective Defense Space Strategy.

Experts say that the use of a FOBS to execute an EMP strike upon the United States’ critical infrastructure by North Korea is more likely than a standard ICBM strike because such an attack “does not require an accurate guidance system because the area of effect, having a radius of hundreds or thousands of kilometers, is so large. No reentry vehicle is needed because the warhead is detonated above the atmosphere.”[51] This accessibility to technology for EMP from space makes for a very serious situation should a nation not deterred by traditional methods of deterrence and coercion gain the capacity to employ such technology. One of these nations of concern is North Korea.

According to the House Committee on Homeland Security, the North Koreans achieved what many thought impossible: they detonated a thermonuclear weapon. Following this test, the North Koreans released a technical report entitled, “The EMP Might of Nuclear Weapons” describing a capability similar to what Russia and China have called “Super-EMP” weapons.[52] North Korea also made a public statement after its thermonuclear test: its new weapon of “great destructive power” can “be detonated at high altitudes for super-powerful EMP attack according to [North Korean] strategic goals.”


Due to the changes in the strategic environment of space from one of perceived sanctuary to one of purposeful interference, testing of kinetic weapons, and the deployment of FOBS systems in Russia and perhaps North Korea, it becomes apparent that “thinking about the unthinkable” in space power contexts is warranted again. Strategists should leverage the proposed framework for space deterrence analysis throughout the vertical escalation dynamics, and at all thresholds, to ensure the proper foundations to develop an effective Defense Space Strategy and posture for the US Space Force and US Space Command. The next article in the series tests the framework by analyzing a non-peer adversary (North Korea) to see if the methodology enables understanding for the creation of an effective strategy and posture for the potential space power crises of the second nuclear age.


  1. Paul Bracken, The Second Nuclear Age: Strategy, Danger, and the New Power Politics (New York: Times Books, 2012), 10–11.
  2. Bracken, Second Nuclear Age, 1.
  3. Ibid., 2.
  4. Roberta Wohlstetter, Pearl Harbor: Warning and Decision (Palo Alto, CA: Stanford University Press, 1962), vii.
  5. Kerry M. Kartchner and Michael S. Gerson, “Escalation to Limited Nuclear War in the 21st Century,” in On Limited Nuclear War in the 21st Century, ed. Jeffrey Larsen and Kerry M. Kartchner (Stanford, CA: Stanford Security Studies, 2014), 145.
  6. Herman Kahn, Thinking about the Unthinkable in the 1980s (New York: Simon and Schuster, 1983), 19.
  7. Bracken, The Second Nuclear Age, 81.
  8. Lawrence Freedman, Deterrence (Wiley, 2004), 22.
  9. Kerry M. Kartchner, “Strategic Culture and WMD Decision Making,” in Strategic Culture and Weapons of Mass Destruction: Culturally Based Insights into Comparative National Security Policymaking, ed. Jeannie L. Johnson et al. (New York: Palgrave Macmillan, 2009), 55.
  10. Kartchner and Gerson, “Escalation to Limited Nuclear War,” 165
  11. Ibid.
  12. Ibid.
  13. Ibid., 166.
  14. Joshua Stowell, “The Problem with Russia’s Nuclear Weapons Doctrine,” Global Security Review Online, 13 February 2018/
  15. Loren Thompson, “Ukraine Dilemma: U.S. Can’t Prevent Russian Annexation Without Better Missile Defenses,” Forbes.
  16. High threshold deals with the higher nuclear threshold levels of the Space Power Escalation Ladder.
  17. Christopher Stone, Reversing the Tao: A Framework for Credible Space Deterrence, (CreateSpace Publishing, 2016), 56.
  18. James Finch, “Bringing Space Crisis Stability Down to Earth,” Joint Force Quarterly 76 (1st Quarter 2015): 18
  19. Stone, Reversing the Tao, 56.
  20. Bracken, Second Nuclear Age, 233.
  21. Stone, Reversing the Tao, 57.
  22. Keith Payne, Fallacies of Cold War Deterrence (Univ. Press of Kentucky, 2001) 187.
  23. Ibid., 51.
  24. DoDM 3020.45-V1, Defense Critical Infrastructure Program, DoD Critical Asset Identification Process (CAIP), 24 October 2008 (Change 1, 23 May 2017), 23.
  25. Stone, Reversing the Tao, 59–62.
  26. Ibid., 62–63.
  27. Keith B. Payne, Laser Weapons in Space: Policy and Doctrine (Boulder, CO: Westview, 1983) is one example of a scholarly work that examines high energy lasers deployed in space. High energy lasers could also be deployed terrestrially.
  28. Ibid., 1.
  29. Eileen M. Walling, High Power Microwaves: Strategic and Operational Implications for Warfare (Maxwell AFB, AL: Air University Press, May 2000), 1.
  30. Stone, Reversing the Tao, 64.
  31. Dana J. Johnson et al., Space Weapons, Earth Wars (Santa Monica, CA: RAND Corporation, 2002), 55.
  32. Sun Zhaoli, Science of Strategy, (Beijing: Academy of Military Science, Military Science Press, 2013), 240. Note: This is the most current version of the Academy of Military Science’s document from 2013, not to be confused with the Chinese National Defense University documents with a similar title.
  33. Thomas C. Riddle, Nuclear High Altitude Electromagnetic Pulse-Implications for Homeland Security and Homeland Defense (Carlisle Barracks, PA: USAWC Strategy Research Project, 2004), 2.
  34. Jack Liu, “A North Korean EMP Attack-Not Likely,” 38 North Online, 5 May 2017.
  35. William R. Graham. Report of the Commission to Assess the Threat to the United States from EMP Attack: Critical National Infrastructures (Washington, D.C.: Government Printing Office, 10 July, 2008), vi.
  36. Liu, 2017.
  37. Ibid.
  38. Riddle, Nuclear High Altitude Electromagnetic Pulse-Implications, 3.
  39. David Stuckenberg, Novel High Altitude Delivery Platforms for Weapons of Mass Destruction/Mass Effect (Washington, D.C.: American Leadership and Policy Foundation, March 2016), 2.
  40. House, Electromagnetic Pulse (EMP): Should This be a Problem of National Concern to Private Enterprise, Businesses Small and Large, As Well As Government? Hearing before the Committee on Small Business, Subcommittee on Government Programs and Oversight, 106th Cong. 1st Sess, 1999.
  41. Ibid.
  42. House, Threat Posed by Electromagnetic Pulse (EMP) Attack, Committee on Armed Services, 110th Cong, 1st sess, 2008, 9.
  43. Article 36, Economic Impacts of a Nuclear Weapon Detonation, International Steering Group of the International Campaign to Abolish Nuclear Weapons (London: United Kingdom, March 2015), 1.
  44. Ibid., 2.
  45. Ibid.
  46. Article 36, Economic Impacts of a Nuclear Weapon Detonation, 2–3.
  47. Stone, Reversing the Tao, 47.
  48. Defense Threat Reduction Agency, A Technical Report in Support of the EMP Commission (Washington, D.C.: Department of Defense, August 2010), 2.
  49. Ibid., 2.
  50. Stone, Reversing the Tao, 47.
  51. Pry, “Empty Threat or Serious Danger,” 4.
  52. Ibid., 1.

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