High-altitude nuclear explosions

by Wm. Robert Johnston
last updated 28 January 2009

Effects of high-altitude nuclear explosions, summary:

The familiar immediate effects of low-altitude nuclear explosions are flash, blast, and prompt radiation. Effects are significantly different for explosions above most of the atmosphere. Since blast is the shock wave transmitted through air, this is attenuated with height and is absent for explosions beyond the atmosphere. Flash is the visible and infrared light pulse from the fireball formed from heated air. With higher altitude, the fireball formation is significantly altered with consequent effects on flash. Prompt radiation includes ionizing radiation from the nuclear reactions in the warhead and decay of fission products left by the explosion. These radiations, particularly neutron radiation, are significantly attenuated by the atmosphere for low altitude bursts. For explosions above most of the atmosphere, ranges of prompt radiation effects are greater than for atmospheric bursts.

Several effects are relatively unique to high altitude bursts:

Effects of high-altitude nuclear explosions, detail:

(under construction)

See: [7,19,20]

Nuclear tests at high altitudes, summary:

From 1958 to 1962, the U.S. and U.S.S.R. conducted over a dozen nuclear tests in the Earth's upper atmosphere or in space--the highest at an altitude of 540 km. The table below lists information on all tests above 20 km altitude.

nationtest namedatetime (UT)lat. (°)long. (°)alt. (km)locationyield (kt)warheadsources
USA HARDTACK I--Yucca 28 Apr 1958 02:40:00.312.617 N163.025 E26.2Pacific Ocean 1.7W-25, plutonium implosion?4,6,14
USA HARDTACK I--Teak 01 Aug 1958 10:50:05.616.744 N169.533 W76.8Johnston Island3800 W39, thermonuclear, 50% fission4,6,14
USA HARDTACK I--Orange 12 Aug 1958 10:30:08.616.358 N169.536 W 43 Johnston Island 3800 W39, thermonuclear, 50% fission4,6,14
USA Argus I 27 Aug 1958 02:28 38.5 S 11.5 W 200 South Atlantic Ocean ~1.5W-25, plutonium implosion?2,4,6,9,14
USA Argus II 30 Aug 1958 03:18 49.5 S 8.2 W 240 South Atlantic Ocean ~1.5W-25, plutonium implosion?2,4,6,9,14
USA Argus III 06 Sep 1958 22:13 49.5 S 9.7 W 540 South Atlantic Ocean ~1.5W-25, plutonium implosion?2,4,6,9,14
USSR#88 Groza ("Joe 79") 06 Sep 1961 06:00 48.45 N 44.3 E 22.7Kapustin Yar 10.5R-12?11,12,14,25,26,27,28
USSR#115 Grom ("Joe 98") 06 Oct 1961 07:15 48.45 N 44.3 E 41.3Kapustin Yar 40 R-510,11,13,14,25,26,27,28
USSRK PROJECT--#127 K-2 ("Joe 109?") 27 Oct 1961 ? 46.1 N 70.6 E 150 Kapustin Yar 1.2R-12?10,11,14,16,25,26,27,28
USSRK PROJECT--#128 K-1 ("Joe 105?") 27 Oct 1961 ? 46.7 N 69.6 E 300 Kapustin Yar 1.2R-12?10,11,14,16,25,26,27,28
USA DOMINIC I/FISHBOWL--Starfish Prime 09 Jul 1962 09:00 17.2 N169.1 W 399 Johnston Island 1400 W-49, thermonuclear4,6,9,14
USA DOMINIC I/FISHBOWL--Checkmate 20 Oct 1962 07:30 16.0 N169.5 W 147 Johnston Island <20*XW-50X13,4,6,14
USSRK PROJECT--#184 K-3 ("Joe 157") 22 Oct 1962 03:40:45 49 N* 46 E* 290 Kapustin Yar 300 R-12?1,5,8,10,11,14,25,26,28
USA DOMINIC I/FISHBOWL--Bluegill Triple Prime26 Oct 1962 08:59 16.9 N169.2 W 48.2Johnston Island 400 W50, boosted fission3,4,6,7,14
USSRK PROJECT--#187 K-4 ("Joe 160") 28 Oct 1962 04:41:20 47 N 64 E 150 Kapustin Yar 300 R-5M, thermonuclear1,5,10,11,14,15,24,25,26,28
USSRK PROJECT--#195 K-5 ("Joe 168") 01 Nov 1962 09:12 49 N* 46 E* 59 Kapustin Yar 300 R-12?10,11,14,17,25,26,28
USA DOMINIC I/FISHBOWL--Kingfish 01 Nov 1962 11:10 16.6 N169.4 W 96.3Johnston Island 400 W50, boosted fission3,4,6,7,14
USA DOMINIC I/FISHBOWL--Tightrope 04 Nov 1962 06:30 17.1 N169.1 W 21 Johnston Island <20*W313,4,6,14

Notes: The exact yields of shots Checkmate (20 Oct 1962) and Tightrope (4 Nov 1962) are unknown; the U.S. has reported their yields as 0-20 kt. For the K Project shots K-3 and K-5, reported locations from [14] refer to the delivery missile launch site at Kapustin Yar; these missiles travelled downrange towards Sary Shagan before detonation.[15] All shots in the table above were delivered by rocket or missile with the exception of shot Yucca (28 April 1958) which was suspended from a balloon.

The figure below plots altitude versus geographic latitude for all nuclear detonations. High altitude explosions fall in three groups, from left to right: U.S. tests over the South Atlantic (Operation Argus); U.S. tests near Johnston Island in the Pacific Ocean; and Soviet tests near Kapustin Yar (southern Russia near Kazakhstan).

Nuclear tests at high altitudes, detail:

(under construction)

The high altitude nuclear tests included these series:

The table below lists, for detonations at altitudes over 40 km, the duration of the thermal pulse, data on the geomagnetic field at the shot location, and data on any artificial radiation belts produced. [7,19,21,22,23]

shot dataduration of thermal pulse (s)magnetic field data at detonation locationradiation belt production
shotdatealtitude (km)yield (kt)strength (G)declination (°)inclination (°)L valuecharacteristicsinjected electronsdecay time
Teak01 Aug 19587738000.10.33210.630.01.12low altitude<1021few days
Orange12 Aug 19584338000.150.33710.629.61.12low altitude<10211 day
Argus I27 Aug 19582001.5 0.263-25.5-55.31.7narrow band 0-20 days
Argus II30 Aug 19582401.5 0.285-22.6-58.72.1narrow band 10-20 days
Argus III06 Sep 19585401.5 0.256-21.7-58.42.0narrow band 10-20 days
#11506 Oct 19614140 0.4946.965.61.75   
K-227 Oct 19611501.2 0.4736.966.01.8   
K-127 Oct 19613001.2 0.4426.365.71.8   
Starfish Prime09 Jul 19623991400<0.0010.28810.630.01.12wide distribution1.3x10251-2 years
Checkmate20 Oct 1962147<20<0.0010.32010.628.71.1   
K-322 Oct 1962290300 0.4446.365.81.8wide distribution3.6x102530 days
Bluegill Triple Prime26 Oct 1962484000.10.33610.730.51.12   
K-428 Oct 1962150300 0.4746.966.01.8wide distribution1.2x102530 days
K-501 Nov 196259300 0.4947.366.21.75narrow band1.2x102430 days
Kingfish01 Nov 1962964000.150.32810.629.81.12   

The radiation belts from Starfish Prime caused damage to several satellites. Operation of Ariel I became intermittent after 7 days; Traac and Transit 4B both showed significant degradation of output from their solar cells before ceasing operations 36 and 24 days after the detonation, respectively. [19]


  1. Cochran, Thomas B., William M. Arkin, Robert S. Norris, and Jeffrey I. Sands, 1989, Nuclear Weapons Databook Vol. IV: Soviet Nuclear Weapons, Harper and Row (New York, NY).
  2. Defense Nuclear Agency, 1982, Operation Argus, 1958, Report DNA 6039F, Department of Defense (Washington, DC).
  3. Defense Nuclear Agency, 1983, Operation Dominic I, 1962, Report DNA 6040F, Department of Defense (Washington, DC).
  4. Department of Energy, Nevada Operations Office, Dec. 2000, United States Nuclear Tests: July 1945 through September 1992, U.S. DOE (Las Vegas, NV), on line at Nevada Site Office [http://www.nv.doe.gov/news&pubs/publications/historyreports/pdfs/DOENV209_REV15.pdf].
  5. Haave, C. R., A. J. Zmuda, and B. W. Shaw, 1965, "Very low-frequency phase perturbations and the Soviet high-altitude nuclear bursts of October 22 and 28, 1962," Journal of Geophysical Research, 70:4191+
  6. Hansen, Chuck, 1995, The Swords of Armageddon, Vol. 8, Chukelea Publ. (Sunnyvale, CA).
  7. Hoerlin, Herman, Oct. 1976, United States High-Altitude Test Experiences: A Review Emphasizing the Impact on the Environment, Los Alamos Scientific Laboratory (Los Alamos, NM).
  8. Keppler, E., G. Pfotzer, and W. Riedler, 1964, "Radioactive debris from nuclear explosions in high altitudes," Journal of Atmospheric and Terrestrial Physics, 26:429-436.
  9. Norris, Robert Standish, and Thomas B. Cochran, 1 Feb. 1994, "United States nuclear tests, July 1945 to 31 December 1992," Nuclear Weapons Databook Working Paper NWD 94-1, Natural Resources Defense Council (Washington, DC).
  10. Podvig, Pavel, ed., 2001, Russian Strategic Forces, MIT Press (Cambridge, MA).
  11. RFNC-VNIIEF, 1998, USSR Nuclear Tests, Hydronuclear Experiments, Plutonium Inventory, RFNC-VNIIEF (Sarov, Russia), on line at Analytic Center for Non-Proliferation Problems [http://npc.sarov.ru/english/issues/plutonium/plutonium_e.pdf].
  12. Stevens, Jeffry L., David A. Adams, G. Eli Baker, Heming Xu, John R. Murphy, Igor Divnor, V. N. Bourchik, Ivan Kitov, "Infrasound scaling and attenuation relations from Soviet explosion data and instrument design criteria from experiments and simulations," 21st Seismic Research Symposium, on line at SMDC Monitoring Research [http://www.rdss.info/librarybox/srr/srr1999/papers5/stevens.pdf].
  13. Stevens, J. L., I. I. Divnov, D. A. Adams, J. R. Murphy, and V. N. Bourchik, 2002, "Constraints on infrasound scaling and attenuation relations from Soviet explosion data," Pure and Applied Geophysics, 159:1045-1062.
  14. Yang, Xiaoping, Robert North, and Carl Romney, Aug. 2000, "CMR Nuclear Explosion Database (Revision 3)," on line, SMDC Monitoring Research [http://www.rdss.info/database/nucex/report/explosion.pdf].
  15. Zak, Anatoly, 2006, "The 'K' Project: Soviet nuclear tests in space," Nonproliferation Review, 13:143-150.
  16. Zaloga, Steven J., 2002, The Kremlin's Nuclear Sword: The Rise and Fall of Russia's Strategic Nuclear Forces, 1945-2000, Smithsonian Institution Press (Washington, DC).
  17. Zmuda, A. J., C. R. Haave, and B. W. Shaw, 1966, "VLF phase perturbations produced by the Soviet high-altitude nuclear explosion of November 1, 1962," Journal of Geophysical Research, 71:899+
  18. Glasstone, Samuel, and Philip J. Dolan, 1977, The Effects of Nuclear Weapons, 3rd ed., U.S. Dept. of Defense and Energy Research and Development Administration/U.S. Government Printing Office (Washington, DC).
  19. Hess, Wilmot N., 1964, The Effects of High Altitude Explosions, NASA TN D-2402, NASA (Goddard, MD).
  20. Defense Nuclear Agency, 1982, Operation Hardtack I, 1958, Report DNA 6038F, Department of Defense (Washington, DC).
  21. Walt, M., 1977, "History of artificial radiation belts," in The Trapped Radiation Handbook, ed. by J. B. Cladis, G. T. Davidson, and L. L. Newkirk, Report DNA 2524H, Lockheed Palo Alto Research Laboratory.
  22. Spjeldvik, W. N., and P. L. Rothwell, 1985, "The radiation belts," in Handbook of Geophysics and the Space Environment, ed. by Adolph S. Jursa, Air Force Geophysics Laboratory.
  23. Mars, R. E., 13 Nov. 2002, "Contribution of neutron beta decay to radiation belt pumping from high altitude nuclear explosions," Report UCRL-ID-151402, Lawrence Livermore National Laboratory, on line at LLNL [http://www.llnl.gov/tid/lof/documents/pdf/243731.pdf].
  24. --, 28 March 2006, "EMP radiation from nuclear space bursts in 1962," Glasstone Blogspot, on line [http://glasstone.blogspot.com/2006/03/emp-radiation-from-nuclear-space.html]; also Howard Seguine, 17 Feb. 1995, "Memorandum for record," Nuclear Weapon Archive, on line [http://nuclearweaponarchive.org/News/Loborev.txt].
  25. ISS, "Nuclear tests of the USSR, Vol. II," Institute of Strategic Stability, on line [http://www.iss.niiit.ru/sssr2/1_9.htm].
  26. CIA, 25 May 1966, "Impact of a Threshold Test Ban Treaty on Soviet Military Programs," NIE 11-11-66, on line at FAQS.ORG [http://www.faqs.org/cia/docs/73/0001030265/IMPACT-OF-A-THRESHOLD-TEST-BAN-TREATY-ON-SOVIET-MILITARY-PROGRAMS.html].
  27. CIA, 16 May 1962, "The Soviet Atomic Energy Program," NIE 11-2A-62, on line at FAQS.ORG [http://www.faqs.org/cia/docs/89/0000843187/THE-SOVIET-ATOMIC-ENERGY-PROGRAM.html].
  28. CIA, 2 July 1963, "The Soviet Atomic Energy Program," NIE 11-2A-63, on line at FAQS.ORG [http://www.faqs.org/cia/docs/83/0000843188/THE-SOVIET-ATOMIC-ENERGY-PROGRAM.html].

© 2005-2006, 2009 by Wm. Robert Johnston.
Last modified 28 January 2009.
Return to Home. Return to Nuclear Weapons. Return to Physics (including Space Physics). Return to Introduction to a brief discussion of space physics.