Electromagnetic Pulse as a Result of Nuclear Pulse Propulsion

Ben Pearson


Throughout the course of history, many strange and unusual ideas have been discussed. Many of the strangest are in the attempt to fly. People have attempted to fly with devices as simple as a few boards with feathers attached to it, balloons filled with hot air, even specially shaped wings that miraculously allow one to fly. You may have noted that the second and third are a hot air balloon and an airplane. There have been tanks filled with liquid hydrogen and oxygen, both of which are highly explosive, such as in modern chemical spacecraft. There have even been ideas of large cannons to fire a person to the moon or farther, such as Jules Verne theorized. However, if you were to look at the patent of Dr. Stanislaw Ulam filled by the AEC in 1959, you would see perhaps the strangest idea of them all, to launch a spaceship by launching nuclear bombs out of it’s back end repeatedly. The idea was called at that time Project Orion.

I came to study Orion in the year 2001. At first I just looked at existing research, studying its pros and cons. Soon I came to one big problem. There was nothing that I studied that had anything to do with Electromagnetic Pulse shockwaves that would result from the use of so many nuclear bombs. Electromagnetic Pulse is the affect of nuclear weapons that has a tendency to destroy electronics in a large area. It is caused by radiation ionizing the atoms in a band around the earth approximately 20-30 km high. It can be extremely damaging. A 1.4 Megaton bomb launched about 400 kilometers above Kansas would destroy most of the unprotected electronics in the entire Continental United States. However, Electromagnetic Pulse remains almost untested for small nuclear bombs.

Long did I study many things to try to determine if Electromagnetic Pulse would have a large enough effect upon the world to have cause to prevent the launch of an Orion spacecraft. I asked many questions on the Internet relating to this. However, the best response I could get was “EMP is not significant for less than 1 megaton bombs” from the Yahoo Project Orion club. I believed it was significant, but I was largely been unable to find out a way to test my hypothesis. However, I did get some information, mostly on using a very commonly used and applied physics formula known as the Inverse Squared law, which states that the power of a field or charge or many other things varies inversely squared with it’s distance. In order to figure out the many calculations, I built a simulator.

My simulator required a great deal of effort to produce. I had to include issues such as acceleration, figure out where each bomb would be when it exploded, and approximate the damage caused by the Electromagnetic Pulse shockwave. Having little knowledge on converting nuclear force to distance, I had to rely upon flight figures I scrounged over the Internet, as well as a few other places. This was not an easy feat. Web sites, books, reports, all did not like to exactly describe an Orion launch, only giving hints as to what it may do. The details are probably classified. However, I gave this problem serious consideration, and proceeded to design a simulation. I decided to use the most common Orion I read about, the 4000-ton version. I had a few numbers; such as it used 200 bombs to reach an altitude of 125,000 ft. I was trying to figure out the force that it would take the bombs to accelerate the ship at 20 m/s, and did. Then I tried to find a time where it would reach 125,000 ft in 200 bombs. However, I discovered that these results were far from optimal. I decided to rework everything I had to find the most optimal Orion launch, provided that I could only change the time between bombs, and ever bomb would provide a force of approximately 80,000,000 Newtons, which corresponds to an initial acceleration of about 20 m/s2, or roughly double that of gravity. I found that the bombs should be launched in intervals of about 1.1 seconds. In the end with many hours of long work, I came up with the Orion Simulator, which is on the CD that came with this paper.[1] The simulator was based off of Newton’s laws of gravity as well as Newton’s third law of motion. It is true that Newton’s laws of gravity are no longer held to an absolute truth, but they are useful for determining the force of gravity between objects that are not microscopic.

That was all for the physical displacement of Orion. I also had to calculate the damage from the Electromagnetic Pulse. This again was not an easy feat. I took estimations of the power of EMP based off of nuclear test of Starfish Prime during Project Dominic. My main concern with this was the figures I had were 1.4 thermonuclear megaton bombs. I would be basing my figures off of a twenty-kiloton fission bomb. To attempt to resolve this problem, I first guessed that there was a linear relationship between bomb size and power of Electromagnetic Pulse. This is probably false, but I don’t have any better information. Second of all, I used known figures to guess how powerful. According to the Federation of American Scientists, a 1.45 Megaton bomb in Project Dominic did severe damage to a radius of at least 800 miles when launched at a height of 248 miles. When converting these into metric, I have a 1.45 Megaton bomb launched from a height of 400 km and affecting a radius of about 1300 km severely. This is not perfect, because these were done on the Pacific islands, where electronics are still to this day not very reliable. Then I assumed that fission bombs created about the same amount of gamma rays as a thermonuclear bomb, and that about the same amount were ionized and created the electromagnetic pulse shockwaves. This one was really stretching the truth; in all actuality fission bombs create more radiation, and thus do more damage, than thermonuclear bombs. And lastly, I took no consideration at all of the Earth’s magnetic field lines, which can potentially greatly influence the sphere of influence of Electromagnetic Pulse.

I still had a few problems. I needed to make sure that the explosions occurred in a range where nuclear explosions could take place, at a minimum altitude of 30 kilometers. Finally I proceeded to execute the simulation. I tested in circles around ground zero of one kilometer. I started these figures at one kilometer from ground zero, and continued to the range of about 8000 kilometers. This is quite a bit farther than is destructive by Electromagnetic Pulse, but this is what I determined to be the maximum area that has even the slightest effect of Electromagnetic Pulse, as it’s the maximum area that is in line of sight. I had it put a guessed value for Electromagnetic Pulse destructiveness. I know that it is not perfect, but it should be close enough for my purposes. I said a number of 100 would be destructive to most systems somewhat, and the higher the number, the more destructiveness would be affected.



In order to calculate the radius of are affected, I needed a few more formulas than could be provided by my previous experience. I tried to look them up, but could not find anything. So I drew a diagram, and used the laws of trigonometry and geometry to calculate these formulas. I have included these formulas as well as the formulas I used to calculate EMP below.

Note that c=distance from the center as determined by arc length, a=altitude, E=electromagnetic damage index, P=power of the bomb, measured in kilotons, D=damage of EMP on a specific area, d=distance between the ground and the point of the explosion of the bomb,  is the Earth’s Radius, and is equal to , and V is the light of sight from altitude a. Formula 1) is the distance between a point on a circle and a point above it, given the arc length from the closest point to the circle. Formula 2) expresses the linear relationship between bomb size and EMP damage, formula 3) is the inverse squared law of Electromagnetic Power, and formula 4) is the calculations of line of site.

In the end, I determined a radius of 276 kilometers, or about 170 miles, would be affected. The full results are available in the Orion.dat file on the CD[2]. Note that the first number is the distance from ground zero, the second the number of times an Electromagnetic burst damaged the area, even if only minor. The third number is the maximum damage index. The last is the altitude where the maximum damage explosion occurred. That is a large area. There are not many areas where this would be safe, and probably the best would be the Magnetic North Pole. The Magnetic North Pole is convenient for several reasons, not just Electromagnetic Pulse. Relating to Electromagnetic Pulse is its remoteness and reasonably easy access. While there is a slight chance of ice caps melting, as a whole, it is a better launch site then any other in the world, especially in respect to Electromagnetic Pulse.

[1] Will be available on the internet at http://www.geocities.com/brp13/orion.html

[2] Will be available on the Internet at http://www.geocities.com/brp13/orion/ in the same package as the simulator.