February 22, 2009

Project Orion Nuclear Pulse Units, EMP, Fallout and More History



On the Apollo missions, only 1/601 of the mass sent into space returned. An Orion mission to Mars would return 1/2.5 of its mass and a mission to Saturn would return 1/6 of its mass. In 1958 dollars, an Orion mission would have cost 11 cents per kilogram sent into space, while in 2005 dollars, it would cost 70 cents per kilogram (Farmbrough). More mass fraction would be cargo if you send it up one way.

Ben Pearson, Central Arizona College worked out the details of the radiation and EMP. Not problems if launch remote enough. He wrote an Orion simulator.

Orion, in its most researched form, is a 4000-ton ship, 1000 for the ship, 1000 for the pusher plate, 1000 for the bombs, and the last 1000 for payload.

According to Ted Taylor’s biography, a normal fission bomb, such as was dropped on Hiroshima, is shaped in an elliptical shape. This allows the resulting fireball from the nuclear explosion to be in a shape somewhat like a car wheel, so it can cause the maximum damage to an object on the ground. Much heat would be wasted if it were to be shot up. A fission bomb typically includes 5 layers. The outermost mainly a protective layer, but reflects some of the heat from the initial explosion inward, waiting until it can convert the maximum matter into energy. The next layer is of C-4, which is one of the most explosive chemical bombs, and also one of the easiest to shape. This layer is the first part to a nuclear reaction; it explodes simultaneously to implode the ball of plutonium 239. The next layer is a reflective shield, usually made out of Uranium 238, which allows the explosion more time after it reaches critical mass to cause a chain reaction. The next layer inwards is a thin layer of plutonium, shaped again something like a football. The innermost layer contains deuterium and/or tritium, which when heated to extreme temperatures that a simultaneous implosion creates, will fuse together, producing a large surplus of neutrons, allowing the nuclear chain reaction to take place at the exact right time. This is different than the first generation of nuclear bombs such as was dropped on Hiroshima, and was primarily the invention of Ted Taylor.



On the other hand, an Orion fission bomb, or as those who designed them like to call them, pulse unit, is shaped more like a wheel, only very thin. It is classified information, but I believe it is somewhat concave inward, as compared to most bombs being concave outward. It would probably use urea to cause the implosion that would result in the nuclear explosion. Urea is used because this would make the bomb the most efficient it can be, due to urea’s high opacity, which means that it will absorb the most radiation and convert it into kinetic energy, which can be transferred to the spacecraft. Orion pulse units most closely resemble the fission trigger nuclear bombs used in a Hydrogen Bomb, and that is the reason so much is still classified on the subject. A Hydrogen bomb is basically an Orion pulse unit with certain easily light compounds, such as Lithium Hydroxide, pointed at the end of the Orion that is flat. When the fission bomb explodes, it causes the Lithium Hydroxide to fuse together, producing a massive explosion.

The biggest problem at this time was how to allow a plate of metal to survive the almost impossibly high temperatures that the nuclear bomb would create. They erected a machine that would launch extremely hot plasma at an aluminum plate. Right before a test, a person had mistakenly put 4 thumbprints on the plate. Those thumbprints would have gone unnoticed, but they actually were the most resistant of anything of the plate. Where the man had stuck is thumb showed no sign of the normal destruction, where everywhere else was vaporized. By a contamination of the sample was created a way to protect an object even against the destructive power of the nuclear bomb.

The last great challenge was the shock absorber. The shock absorber must be able to handle pressures of up to 50,000 pounds per square inch repeating it self as much as twice a second for as many times as 2000 times in a row.

To calculate the damage of fallout, there is a very important number that must first be obtained. This number is the number of rads a person can absorb at very low dosages before dying. It was suspected to be about 100,000 initially, but now is known to be about 10,000. Using this number, approximately 10000 people have died from radiation poisoning resulting from nuclear tests that did not live near ground zero, as George Dyson states in his book.

Now, how does this relate to Orion? It has been estimated that the total fallout of one launch of Orion would be about 1% of the radiation that had been launched into the atmosphere. This can be reduced by a factor of 10 if launched at the Magnetic North Pole. So, totaling everything up, about 10 people would die every time an Orion was launched.

Now, I don’t want you to go thinking that 10 perfectly healthy people would instantaneously die when an Orion was launched. In all actuality, there would be thousands, if not millions, of people whose lives would be shortened slightly, totaling the lives of 10 people. In other words, if one million were affected, it would shorten their lives by about 3 hours. And it is likely that more than just one million people would be affected, lowering the number more.

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 CD2. 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.

When I started this project I was hoping to come up with a result that would encourage me to be completely unsupportive of Project Orion. However, as I studied, I found that there are so many pros to an Orion launch, and most of the cons are minor, especially providing certain selections in choosing a site for the launch of Orion. Providing that Orion can create nuclear bombs that produce very little to no fallout, and it is launched at the Earth’s Magnetic North Pole, then I support a ground based launch of a Project Orion spaceship. In order for me to fully support it, I would request it to be a development among all industrialized nations, such as the Space Station Alpha. It must also carry replacement satellites or the tools and materials to construct them in case anything is destroyed by the space electromagnetic pulse effect, and is launched at a time where it would be the least bothersome to man-made satellites already in orbit. In other words, its time would need to be at a moment when it is most easily able to avoid satellites, especially the Hubble Space Telescope and the International Space Station.

My reasoning behind the Magnetic North Pole is as follows. All of the magnetic lines come to the poles, so they can’t trap radiation nearly as much as with a launch closer to the equator. It is easily accessible by sea, and very little inhabited. It would reduce Electromagnetic Pulse, fallout, and Space Electromagnetic Pulse. As a whole it would work perfectly for an Orion launch.


Apparently Freeman Dyson later became concerned about repeated use of the pusher plate.

George Dyson's TED Talk on Orion
George Dyson's TED Talk on Orion It does not say how big the super-orion bomb is other than it has to direct 3000 tons of materials per shot. Has good info on the shaping of the blast.





























Tests with 3 pounds of C4 in Each Charge, 4 Charges Per Second











The biggest design above is the "super" Orion design; at 8 million tons, it could easily be a city. In interviews, the designers contemplated the large ship as a possible interstellar ark. This extreme design could be built with materials and techniques that could be obtained in 1958 or were anticipated to be available shortly after. The practical upper limit is likely to be higher with modern materials.

Most of the three tons [3000 tons] of each of the "super" Orion's propulsion units would be inert material such as polyethylene, or boron salts, used to transmit the force of the propulsion unit's detonation to the Orion's pusher plate, and absorb neutrons to minimize fallout. One design proposed by Freeman Dyson for the "Super Orion" called for the pusher plate to be composed primarily of uranium or a transuranic element so that upon reaching a nearby star system the plate could be converted to nuclear fuel.

The source that said 1.4 megatons could have been wrong. I need to find the General Atomic paper on different size Orion designs or the interviews with Dyson.

Enormous transplanetary vehicles were also envisioned, including an 8,000,000 ton vehicle that would have carried a crew of 150 to Saturn and back in three years using 1.4 megaton pulse bombs.

Nuclear weapons data book

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