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solar storm
Could solar activity and its interaction with the Earth’s magnetic field be a more dangerous source of EMP than nuclear weapons? (credit: NASA)

The EMP threat: fact, fiction, and response (part 2)

<< page 1: the real threat


Both the 2008 NAS study and the EMP commission offer useful advice on how to address the vulnerabilities of our infrastructure. These can be divided into monitoring, hardening and response functions.

Space weather monitoring

Continued monitoring of the space environment is essential, but is seriously under-resourced. NASA’s Advanced Composition Explorer (ACE) satellite, which monitors energetic particles in the solar wind from a vantage point between the Earth and Sun (about 1.5 million kilometers sunward of Earth), was launched in August 1997 and is, according to the NAS report, “well beyond its planned operational life” with no plans on the books for a replacement even though “the requirement for a solar wind monitor… is particularly important”. The 12-year-old satellite, as well as another even older one named SOHO, “can fail any time, no one knows,” says Michael Hesse, director of the modeling center at Goddard Space Flight Center [26].

Continued monitoring of the space environment is essential, but is seriously under-resourced.

Even with the current instrumentation in place and working, fully one-third of major storms arrive unheralded and almost one-quarter of the warnings turn out to be false alarms, according to the Space Weather Prediction Center (SWPC) [26]. Backup ACE and SOHO satellites should be funded and built as soon as feasible to offer critical lead time of impending geomagnetic storms. Although the Chinese are planning a similar monitoring satellite as part of their KuaFu space weather project, it will not be launched for several years. Encouragingly, the NASA Authorization Act of 2008 (Section 1101) charges the Office of Science and Technology Policy to work with NOAA, NASA, other federal agencies, and industry to develop a plan for sustaining solar wind measurements from an L1-based spacecraft. The urgency of this directive cannot be overstressed.


As the likelihood of a geomagnetic storm far exceeds that of an incapacitating multi-megaton EMP strike, it is sensible to give priority to investing in that hardening that would protect the electrical grid from E3 (and geomagnetic) type disturbances, as compared to E1. To quote the NAS study [25], “With respect to the entire grid, remedial measures to reduce GIC levels are needed and are cost-effective. The installation of supplemental transformer neutral ground resistors to reduce GIC flows is relatively inexpensive, has low engineering trade-offs, and can produce 60-70 percent reductions of GIC levels for storms of all sizes.” Improved education and situational awareness of grid operators is also called for: “regional system operators require initial and continuing training to understand their assigned roles and responsibilities in protecting the power system during solar events using new tools.” Instituting new design codes that would help reduce geomagnetically induced current (GIC) flows in the power grid during a storm are also called for.

Dr. Radasky and Mr. Kappenman have also outlined similar avenues for hardening the grid against E3 and geomagnetic storms for the House Homeland Security Subcommittee on Emerging Threats, Cybersecurity, and Science and Technology. Other experts advocate improved cabling (e.g. industrial RS-485 cabling) in combination with improved external transient voltage suppressors to protect against the faster pulses. Specific methodologies for protecting against the lower priority fast EMP transients have been outlined in Cold War era (1984) NAS report “Evaluation of Methodologies for Estimating Vulnerability to Electromagnetic Pulse Effects”. [27] Of course, protecting and hardening critical infrastructure from geomagnetic storms (and EMP) would also offer protection against some cyber-threats, sabotage, and natural disasters, like severe storms or hurricanes.

However, any modernization and hardening of the electrical grid should also be done with an eye towards future renewable power sources that may eventually be fed into the grid. Last year’s stimulus bill specifically allocates $11 billion to DOE for “for smart grid activities, including to modernize the electric grid.” And a recent NAS study, “America’s Energy Future: Technology and Transformation” proposes an “expansion and modernization of the nation’s electrical transmission and distribution systems [that] would enhance reliability and security, accommodate changes in load growth and electricity demand, and enable the deployment of new energy efficiency and supply technologies, especially intermittent wind and solar energy”. It would be sensible if such improvements in the electric grid should were focused, at least partially, on reducing vulnerabilities to geomagnetic storms (and, by extension, EMP). However, hardening the grid, and making it “smarter” may work at cross purposes, and should be carefully coordinated. A peer-reviewed study of the most sensible and secure path for incorporating renewable power sources ought to be a priority.


Some suggestions of the EMP commission regarding the response to an EMP strike (or, strong geomagnetic storms) are also eminently sensible: stockpiling large electrical transformers so they could be moved into place in an emergency would be very useful in case of serious damage to these devices in a geomagnetic storm. The EMP commissioners estimate that it would only take a few years to stockpile the requisite number of transformers if they were ordered in bulk. Further, establishing a domestic supplier of the transformers would also be sensible. At the moment, these large devices are imported.

The vulnerability of some of our infrastructure to nuclear EMP is real; however, the threat is overblown. A much greater threat to the US electricity-grid infrastructure is from a powerful once-in-a-century type solar storm.

Dr. Graham, the chairman of the EMP commission, has stated that “In just a few years we can make significant, affordable improvements to protect society even if an EMP attack is carried out against us” [15]. Indeed, other commissioners such as Dr. Wood and Dr. Pry have also weighed in saying that, “[t]he commission estimates… that we could probably put ourselves into a situation where we could neutralize this particular threat, at least to the extent that it… wouldn’t be a catastrophic, society-destroying threat and we would be able to recover.” Some of the cost estimates have been reasonable, e.g., Dr. Pry has quoted a figure of about $2 billion. Of course, the focus of any such response ought to be on resuscitating the electrical power grid as that is the backbone of modern society. As Dr. Pry has said, “If you get it up, you can eventually recover all the other infrastructures.” Hand-in-hand with such response functions, emergency responders ought to be trained in how to handle a large-scale outage as might be expected from a severe geomagnetic storm. Some hardened back-up communication links may also be useful for coordinating between certain emergency responders nationwide.

NMD to protect from Nuclear EMP?

A proposed way to protect against a nuclear EMP attack has been the controversial idea of implementing a national missile defense [24, 28, 29]. An incidental benefit of hardening our infrastructure is that it would also obviate the need for such an expensive (and, as argued by many experts, an ineffective) missile defense. Once the grid is hardened, and this fact has been made public, there is no further need for NMD: it would be a particularly stupid enemy that would try their hand at a EMP strike against a known EMP-hardened infrastructure, with backups and contingency plans in place.

Notably, EMP commissioners Dr. Lowell Wood and Dr. William Graham are also co-author and advisor, respectively, of the report “Missile Defense, the Space Relationship, and the Twenty-First Century” [29], which strenuously advocates the development and deployment of missile defense capabilities, well beyond the limited systems currently envisioned.


The vulnerability of some of our infrastructure to nuclear EMP is real; however, the threat is overblown. A much greater threat to the US electricity-grid infrastructure is from a powerful once-in-a-century type solar storm. As the response to the geomagnetic threat would also address many of the vulnerabilities raised by the EMP commission, we can effectively kill two birds with one stone. However, the prioritization of our responses should emphasize the threat posed by geomagnetic storms, i.e. addressing the vulnerabilities to E3 type pulse should take precedence over E1 type pulses. Strategies for mitigating the risk from geomagnetic storms should be informed by a peer-reviewed study such as the Cold War era NAS report “Evaluation of Methodologies for Estimating Vulnerability to Electromagnetic Pulse Effects” [27] which provides much insight into how to go about protecting systems from nuclear EMP. An updated version of this peer-reviewed study, but tailored to the real geomagnetic threat, is now overdue.


[1] “EMPty Threat?” Bulletin of the Atomic Scientists, Sept/Oct 2005 p. 50

[2] “The Newt Bomb: How a pulp-fiction fantasy became a GOP weapons craze.” The New Republic, June 3, 2009.

[3] “The Next Fake Threat”.

[4] C. L. Longmire. “On the Electromagnetic Pulse Produced by Nuclear Explosions,” IEEE Trans. on Electromag. Compat., Vol. EMC-20, No. 1, pp. 3-13, February 1978.

[5] Glasstone, Samuel and Dolan, Philip J., The Effects of Nuclear Weapons. Chapter 11, section 11.73. United States Department of Defense. 1977.

[6] see Fig 2.4 in “HEMP Emergency Planning and Operating Procedures for Electric Power Systems”, T.W. Reddoch and L.C. Markel, Electrotek Concepts, Inc, ORNL/Sub/91-SG 105/1

[7] Greetsai, V.N., A.H. Kozlovsky, M. M. Kuvshinnikov, V.M. Loborev, Yu. V. Parfenov, O.A. Tarasov, L.N. Zdoukhov, “Response of Long Lines to Nuclear High-Altitude Electromagnetic Pulse (HEMP),” IEEE Transactions on EMC, Vol. 40, No. 4, November 1998, pp. 348-354.

[8] IEEE Transactions on Power Delivery, Vol. PWRD-1, No. 3, July 1986.





[13] US High Altitude Test Experiences, Herman Hoerlin, LANL Report LA-6405, 1976.

[14] “Did High-Altitude EMP cause the Streetlight Incident?”, C.N. Vittitoe, Sandia Laboratory System Design and Assessment Note 31, June 1989.

[15] Presentation by Dr. William Graham, Chairman of the EMP Commission “Commission to Assess the Threat from High Altitude Electromagnetic Pulse (EMP): Overview”.

[16] A Calculational Model for High Altitude EMP,, Louis W. Seiler, Jr., Air Force Institute of Technology, Wright-Patterson Air Force Base, Ohio, March 1975, p. 31.

[17] Mario Rabinowitz, “Effect of the FAST NUCLEAR ELECTROMAGNETIC PULSE on the Electric Power Grid Nationwide: A Different View”, IEEE Trans. Power Deliv. 2: 1199-1222, 1987 available as:

[18] D. M. Erickson et al., Interaction of Electromagnetic Pulse with Commercial Nuclear Power Systems, Sandia Report, SAND82-2738/2, 1983.

[19] EMP Susceptibility of Integrated Circuits, C. R. Jenkins and D. L. Durgin, IEEE Transactions on Nuclear Science, Vol. NS-22, No.6, December 1975.

[20] Simulating the Exposure of ICs to Voltage Surges Caused by Nuclear Explosions K. A. Epifantsev, O. A. Gerasimchuk, and P. K. Skorobogatov, ISSN 1063-7397, Russian Microelectronics, 2009, Vol. 38, No. 4, pp. 260–272. Pleiades Publishing, Ltd., 2009.

[21] M. A. Uman, M. J. Master, and E. P. Krider. “A Comparison of Lightning Electromagnetic Fields with the Nuclear EMP in the Frequency Range 104 - 107 Hz,” IEEE Transaction Electromagnetic Compatibility, Vol. EMC-24 (4), pp. 410-416, 1982

[22] Chapter 12, John Mueller, “Atomic Obsession: Nuclear Alarmism from Hiroshima to Al-Qaeda”, Oxford University Press, 2010.

[23] “Great geomagnetic storms and extreme impulsive geomagnetic field disturbance events – An analysis of observational evidence including the great storm of May 1921”, John G. Kappenman, Advances in Space Research, Volume 38, Issue 2, 2006, Pages 188-199

[24] “Electromagnetic Pulse (EMP) Attack: A Preventable Homeland Security Catastrophe” by Jena Baker McNeill and Richard Weitz, Heritage Foundation Backgrounder, October 20, 2008.

[25] National Academy of Sciences, “Severe Space Weather Events—Understanding Societal and Economic Impacts Workshop Report”, 2008

[26] Kerr, Richard. “Are we Ready for the Next Solar Maximum? No way, Say Scientists”, Science, 324, p 1640, 2009

[27] National Academy of Sciences, 1984, Evaluation of Methodologies for Estimating Vulnerability to Electromagnetic Pulse Effects.

[28] Brian T. Kennedy, “What a single nuclear warhead could do”, Wall Street Journal, November 24, 2008.

[29] “Missile Defense,the Space Relationship, & the Twenty-First Century”, 2009