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Flying Platforms with Nuclear Pulse Propulsion

In the near future, only in a few decades, space travel could look like this: huge flying platforms that are propelled by pure fusion detonations start from earth’s surface and fly nonstop to mars and land there after a few weeks in it’s desert near a building site. A ticket to mars will be affordable for most people. The platforms are made of concrete and construction steel and of 30,000 metric tons mass. The technology is rather primitive but complicated. The more mass the better for the vessels. The power of the fusion detonations is huge. The fuels are liquid deuterium for the fusion pulse units with liquid methane, oxygen and tritium for the pure fusion primary igniters. Pure fusion detonators are possible, there’s a chance that they already secretely exist in the arsenals. The energy of fusion propulsion is 10,000 times more than that of chemical propulsion. This and its side effects makes the tickets up to 50,000 times cheaper. Trips to earth orbit will cost $1000, to the moon and back $5000, to mars and back $20,000, value in currency of 2012. I know that this sounds unbelievable, but I will convince You with physical and engineering arguments in the following text.

In the end of the fiftieth the US conducted a secret Air Force research program, called Orion, to investigate the usage of small nuclear detonations for propelling large spaceships [1]. Most of the information is declassified today. Anything that has to do with the pulse units (the atomic fission detonators) is still classified, because its knowledge could be used by terrorists to build cheap and simple suitcase bombs [2]. Actually I have told You the complete story yet and can stop writing. The rest of the story and it’s influence on the future of mankind You also can investigate by Your own and calculate it. Mathematics is universal, You will get the same results than I did. But if You like I show You in the following text, what I have found out and do the work of investigation and calculation for You.

The scientists of Orion made many progresses in all related fields. Finally it was clear that the spaceship should work, and should be several hundred times more powerful and cheaper than any chemical rocket. The BBC has produced a very interesting television show about Orion [3]. It is a good starting point if You have never heard about Orion and nuclear pulse propulsion before. After the airforce lost interest in the project, NASA adopted the idea and the Orion team developed a mars space ship that could be launched by Saturn V rockets and could land men on mars before 1975. Really! But it was only one side of the medal.

It was also clear at this time that Orion at each start would contaminate the launching and landing site, the atmosphere and – the worsest – the whole magnet field of the earth. The highly radioactive plasma of the engine would be trapped in earths magnet field and stay there for a very long time, accumulating with every launch and continuously contaminating humans and nature near the poles. This is where the magnet field lines end. States like Alaska, Canada, Norway, Sweden, Finland and Russia would have suffered from Orions fallout. Antarctica would have become a nuclear fallout zone. That was all unbearable and the main reason for the permitting of nuclear tests in space by the Partial Nuclear Test Ban Treaty [4][2].

Evolution to a Flying Platform

Let me try to reconstruct the early beginnings of the nuclear pulse space ship as I understand it. It all started with an idea of Stanislav Ulam when developing two stage approaches for using cheap unriched natural uranium 238 in atomic bombs. He soon recognized that the ablation pressure of a natural uranium cylinder that is radiated by a nuclear bomb would press it’s interior strong enough to make a fusion reaction possible that would set free enough neutrons for fissioning U238. Thereby he casually invented the fusion bomb, his colleague at Los Alamos, Edward Teller, was so long looking for. But that this approach could lead to hydrogen bombs of arbitrary destruction power was Teller’s idea, when Ulam presented Teller his work, and so the idea got it’s name: the Teller-Ulam principle [5][6][7][8]. As I understand it: Ulam’s idea is the essential ablation implosion principle, Teller’s idea is the multi staging principle. Ulam also recogniced, that one could use nuclear radiation to heat steel plates that would then ablate and release hot plasma with such a high velocity that they would be heavily accelerated. That was the birth of the nuclear pulse space ship in 1948, I assume. He and another colleague, C.J. Everett, then wrote a classified text about nuclear propulsion with external detonations, this text is meanwhile unclassified, you can download and read it here [9].

Later in 1958 Ted Taylor [43] started a new project at General Atomics a subdivision of General Dynamics. He wanted to develop a nuclear propulsed space ship based on Ulams ideas. He needed a thoerist of high reputation who would calculate some aspects of nuclear detonations for him to satisfy financiers at the Air Force and convinced Freeman Dyson, who was young but already famous at this time because of his works in quantum mechanics, to participate in project Orion for one year. The colaboration of Taylor and Dyson would then become – as Dysons son George describes in his history book about project Orion [2] – one of the most fruitful intellectual colaboration I have ever heard of. Taylor and Dyson were both pure enthusiasts and had the ambitious shared goal: to Mars until 1965, to Saturn until 1970. That was years before Kennedy commited the United States to go to the moon until 1970. They calculated several important aspects and built flying prototypes with conventional explosives. After a short time it became clear to the investors, that Orion could indeed work. It could be possible to launch huge payloads at low cost into space. The investors were militaries and so it was logical what payloads they wanted to launch. It was the time of the big hydrogen bombs and the United States and the Soviet Union overtrumped each other with allways bigger yields up to 50 megatons. An Orion would have make it possible to carry bombs in a gigatons++ yield range into space to irradiate half of the Earth. This was called the doomsday bomb [2][10]. The launcher for that ultimate weapon looked probably similar to the civilian design to transport some hundred astronauts from earth to mars that the following drawing shows.

1) The classic ARPA Air Force Orion nuclear pulse rocket concept. The huge aerodynamic shell is to shield the interior machinery from the hot gas and radiation streaming past outside. The dust of the plutonium decay elements is highly radioactive, Fig [1]

The pusher blade at the bottom had a diameter of 40 m. The space ship was therefor as big and as heavy as a typical office building or a sea vessel. It had a lift off weight of about 4,000 metric tons [1]. That was thought as a minimum size for using nuclear pulse propulsion in an economic manner [2].

The Air Force interest vanished with time. The presentation of the doomsday bomb to president Kennedy was no success, he didn’t like that kind of nuclear retaliation weapons [2]. The trend in nuclear weapons development went from one big hydrogen bomb to many warheads in intercontinental missiles that would destroy countries more effective. The big tests had prooved that the fireballs of super-bombs actually blow off mainly into space and the earth horizon effectively protects neighboring regions [7]. It was forseeable that a treaty would come to prevent atomic detonations in space because of their extreme contamination of earths magnetosphere [2].

Just before Orion would have been canceled the new founded NASA got interested in the project because they soon recognized that Mars voyages with chemical rockets were either technically or at least economically not feasable [2]. NASA decided to use Saturn V rockets as first stages for Orion space ships and so the diameter was limited to 10 meters. A miniature version of the Orion with only several hundred tons start mass was developed and the nuclear pulse effectivity suffered a lot from this small size. Also the neutron radiation exposure of the crew was becoming lethal within the leightweight ship that they had to stay in a storm bunker with thick walls during propulsion phases. The nuclear pulse driven Mars project was cancelled after the Partial Nuclear Test Ban Treaty [4], project Orion was offically terminated 1965. NASA landed men on the moon by using chemical rockets 1969. Nuclear fission reactors with only a fraction of the efficiency of Orion that could avoid the Test Ban, KIWI and NERVA [11][12], had been developed and canceled again 1969, and the last and least option to get to Mars, a chemically propelled space ship was also cancelled and even the chemical moonlandings had also been cancelled 1972, any effort to settle the solar system had been stopped after 15 years work in several big projects in the year 1972, Wernher von Braun left NASA dissapointed and the dreams for going to Mars and Saturn with nuclear pulse rockets went into the archives and people were shaking heads in the future about such weird ideas. The space age went to sleep in 1972 and until today no one has started such efforts again. I think it’s time now, but this time in an economic and very effective way, not that chemical blind alley that actually costs the same but can not carry fivehundred tons machine parts and 300 people crews to their destinations on Mars, Io, Ganymed and Titan.

2a) The NASA variant of Orion from the early 1960s. NASA officials soon recognized that the propulsion power of nuclear detonations could make Mars voyages possible in an affordable level of cost, Fig [1]

A young team of NASA members renewed the idea in the second half of the 1990s. At this time, just before the millenium change, it was modern to speculate how mankind could survive or even prohibit asteroid impacts from outer space. There were even popular movies about that topic [13]. After a short while of thinking and calculating any expert (but a few that would rather sacrifice humanity than using nuclear weapons as a protection shield) knew that only nuclear pulse ships could – first – get to the asteroids fast enough to intercept them early enough and – second – provide the power to tug such massive objects a little with some thousand nuclear pulse detonations to change their trajectory only a little bit, but at least as much that they would miss Earth. George Dyson said during a presentation that NASA decided to preserve the plans just for the case [14].

2b) NASA redesign of the 1990s. Primarily adopted to possibly intercept asteroids heading Earth, no major changes to the 1960s designs, Fig [1]

The old Orion design inspired me to my first own Orion idea for an automatic cheap moon ferry that could shuttle between earth and moon orbit several dozen times just with one fuel load and would therefor cost only a fraction of a chemical ferry. At this time I was planing a big chemical (of course) moon project to bring turbines, drilling rigs and tunnel boring machines to the surface of the moon, and I discovered that such a nuclear Orion like pulse ferry could reduce the overall cost massively. But one of the former Orion veterans told me, that this vessel would contaminate earth’s magnetosphere and most of the fission products would get trapped and a large fraction of them would come down along the magnetic field lines into the atmosphere and finally produce radioactive fallout on the ground. This was definetely a blind alley, as NASA’s Orion was before. I had to learn more about it.

3) Blind Alley: Orion based space launched Moon ferry with bigger shield to increase Isp. Transports fuels in huge spherical tanks and material like two monster-trucks, Fig: Author

I was rethinking anything. I beholded the Orion engine alone without the space ship. Ok, if it was not possible to launch Orion space ships regularly from earth without killing people statistically from decay on earth’s surface, then the only solution to use Orion was to start it only from the moon far away from earths magnetosphere. That had many advantages, too. On moon there is a vacuum. So the pressure shock wave does not apply and only a fraction of the hot streaming plasma that has to be kept away from the machinery, so actually there is no need for a huge nose cone.

2c) The 1960s again: Details of the Orion engine block with a 10m diameter pusher plate, about 2000s Isp and several hundred tons thrust released by nuclear yields of 140t TNT at a 1sec frequency, Fig [1]

On the moon the ship needs landing gears and also some capability to move payloads in that uninhabited dessert. I had to become a little creative. The design of an Orion like space ship now became totally different. It has an Orion drive, of course, but it doesn’t look like an Orion at all.

4) Blind Alley ?: First idea of using the Orion propulsion for flying objects to provide building sites far away and that are more related to drilling platforms than carrier rockets, Fig: Author

Again the same veteran I showed my new idea for a moon based version was not satisfied and seemed a little bit disappointed. Was it because Orion was becoming an ugly monster instead of a beautiful Jules Vernes moon stories reminding space ship? He said the decay and the hot plasma would still be a problem. And I think he forgot the neutrons and gamma radiation.

First I made the massive landing gears retractable that they would not ablate and fly away in all directions. Why not using a dozen heavy retractable gears I thought, mass is not the problem with that drive. With a transmission mechanism with appropriate damping they should even retract by the pushes of the first detonations itself. Then I enlarged the pusher plate to get even more specific impulse out of the detonations and as a side effect stop a lot of the hot plasma that would reach the cranes and towers made of heavy construction steel and particularly the payloads.

After a while it was becoming clear to me that if not the plasma itself, at least the nuclear decay products that the plasma brings with it would become a big problem. Crews would allways have to clean the exteriors of the vehicles and would have to use geiger counters to avoid possible hot zones. Was the veteran right? Did I have to use this cones to prevent deadly nuclear decay products from the payloads. How impractical, how unfunctional, nose cones are allways the first thing expendable rockets through away after they have left the atmosphere. They use it against airodynamic drag forces and friction heat. Because of their limited low energy they have to accelerate as fast as possible and so within the denser atmosphere. Why should an Orion like space drive accelerate so fast? The gravity losses would be only some hundred meters or a kilometer per second more, if one would limit the drag to an lower limit. I didn’t want that cone. It became clear to me: not the cone was the problem but the thing it was needed for: the fission reaction. From the first instant Orion was doomed to a fission decay accumulating hot zone. The metal cone could only prevent the interior to a certain limit from getting contaminated with time. A perfect dense technical object does not exist.

Was there another way? Was it possible to build small fusion bombs? Was it possible to build even pure fusion bombs? Didn’t I read somewhere about the threat of pure fusion weapons? I was investigating that topic and got into the realm of one of mankinds best kept secrets. There were indeed small fusion bombs in history with down to a fraction of a kiloton yield. The so called neutron bombs [15]. They had the aim to kill tank crews through their thick armour with neutron radiation. Normally tanks are relatively invulnerable when attacked with atomic bombs – but neutron radiation stops them by killing any life in them [16]. These neutron bombs are optimized to radiate as much neutrons as possible. But with a small effort it is no bigger problem to reduce the radiation levels to a normal nuclear weapon level. They are very small fusion bombs, but they still use plutonium primaries, so they are small but no pure fusion weapons.

One of the leading experts in building small fusion weapons, the inventor of the neutron bomb, Sam Cohen [17], was 100% convinced that Russia owned such weapons in the beginning of the 1990s and even sold essential components of them to Iraq. He wrote about that topic a few years ago [18]. First I thought it would be only one of these legends. Then I investigated that there are at least half a dozen projects in several countries on the planet that exactly have that goal: the pure fusion detonator. Anyone uses another name for that, of course, pure fusion bomb sounds so ugly. And I recongized that a pure fusion device is not as impossible as some other experts had told the media in the 1990s [19]. Today I think there are at least three different promising approaches to get to a fusion primary that can ignite the next stage. I will pick up again the topic later.

5) Pure Fusion finally makes the platforms possible: Current version of a Flying Platform based on pure fusion bombs with retractable landing gear, Fig: Author

But with pure fusion detonators after all the usage of Orion-like nuclear pulse propulsion ships would become possible! Pure fusion detonators are as clean as possible, so they don’t accumulate and contaminate the magnet field over time. The plasma is still trapped in the field but this doesn’t matter because it contains no radioactive fission products and no particle fallout. The tritium plasma exposure will be very small, probably zero. The space ship will not become a big hot zone of fission decay with time. All other nuclear explosion effects are much better to control. So Orion could become finally a reality. Chemical rockets might become ancient technology in a very short time.

The Platforms

Think completely new about nuclear pulse propulsion. What does such a space ship really need?

  • It needs a lot of mass to protect the payload and the crew from neutrons.
  • It needs a pusher plate with the biggest diameter possible, because diameter is area to the second power and more area means more specific impulse.
  • It needs fusion power, because fusion gives the most specific impulse possible.
  • It needs pure fusion. With pure fusion detonators all problems with accumulating fission decay products do not apply anymore.
  • It needs retractable gears, that can withstand the first pulse detonations of lower yield.
  • It needs a goliath crane to be independent from huge support structures. It’s height above ground will be tremendous, because there has to be a minimum distant to the ground for the explosions.
  • It needs a very reliable bomb feeding and supply system. When the bomb supply stucks the whole vessel crashes.
  • It needs a lot of room for a landing and starting area in the magnitude of ten kilometers radius.

What does a nuclear pulse space ship not neccessarily need?

  • It needs no lightweight materials: no carbon, no titanium, no aluminium, no hardened steel. Construction steel for the moving parts and reinforced concrete for the body as well as cast steel is totally sufficient.
  • It needs no high temperature materials. This sounds strange, but expensive high temperature materials would withstand the hot plasma not better than other materials, it’s because of totally different laws in the temperature ranges of nuclear detonations.
  • It needs no aerodynamic shape. It doesn’t matter if it has to decelerate for a while when starting and landing in earths atmosphere to limit the maximum aerodynamic drag, because it has more than enough energy due to it’s fusion drive.
  • It needs no decay protection hull if it uses pure fusion.
  • It needs no shock wave or hot plasma protection hull if the payload sits within the shadow zone of a massive structure of huge diameter.
  • It needs no special start and landing site.

This means a more appropriate solution for pure fusion power propelled space ships than the classical Orion design may be this: Large massive armored-concrete flying platforms of 30,000 tons lift-off mass or even much bigger will be built. They can start and land autarkical on earth and any other solid celestial body in the solar system. Pure fusion nuclear pulse units in the 1 kT to 50 kT yield range propell them. The high mass of these platforms is necessary to give the detonations an appropriate counterpart and a radiation shield that otherwise would endanger the passengers. The standard version of the platform is as big as a sea vessel but less complex, and it transports all kinds of loads: machine parts, building material, food, vehicles, fuels, even complete buildings and power plants.

That is one of the most interesting aspects of the flying platforms, I think: They are indeed more simple and less complex than ocean ships. This is because they have less moving parts and they don’t need to withstand the huge forces of the waves and the storms far out on the ocean. Space is also extreme, different than the salty and brutal world of huge water forces: cold and hot, vacuum and radiation, but space is much more predictable. This will make spacefaring finally cheaper than seafaring. I know that I may be the only person who believes that at the moment, or at least the only engineer, a person who calculates most things around him. But I’m very sure, actually because I have calculated it. I will present You my calculations in the next chapters before I return to the more interesting aspects.

Think our ancestors hadn’t have the courage to travel the oceans, and we would just begin with that. Today, with all our savety, reliability and quality demands, we would start for the first time sending probes, drones, robots, remote steered research vessels. Seafaring would cost the taxpayer billions every single year. Any time when one of these research ships would get lost, the newspapers were full of it. People would say one must be crazy to try to travel the oceans. Don’t say now I can not compare those things, because our ancestors had the power and skills to go to the ocean, but we don’t have power and skills to go to the planets. You are wrong, we have the power and skills since the 1950s: nuclear power, pulse propulsion space ship designs and appropriate engineering skills. No one needs more to get to the rings of Saturn.

Some Rocketry Basics

Specific impulse is the most important value in rocketry. Performance is measured in a term called ‘delta v’. This is the speed the rocket could reach in a forceless space. It is calculated

delta v = c_e ln(R)

where c_e is the exhaust velocity in m/s and R is the mass ratio of the rocket. Engineers use mostly another term for the exhaust velocity, the ‘specific impulse’, Isp, it is just

Isp = c_e / g

where g is the earth gravity acceleration g = 9.81 m/s2. Isp is in seconds and tells us how long a certain fuel would suffice to hover above earth independent of the mass of the rocket – the longer the better, because the more energy is avalable from the fuel. The mass ratio R is the fraction between start mass and burn-out mass. It can be calculated

R= exp(delta v / c_e)

You can increase the performance of a space ship by either increase mass ratio R or increase specific impulse Isp. At an Isp like a huge pusher plate provides (in the range of 27,000 sec, chemicals have 460 sec maximum) the mass ratio becomes more and more insignificant (R is just above 1) for typical missions between planets. Vise versa, the lower the specific impulse, the more important (higher!) is the weight ratio. Roundtrips to the outer planets have delta v’s in the 100 km/sec range and are impossible to conduct with chemical rockets, because the mass ratio becomes huge.

Staging is the only possibility for chemical rockets to get higher delta v’s at buildable (technical feasible) mass ratios R < 10..20 or economic mass ratios R < 3..5. All mass ratios R > 5 mean sophisticated lightweight constructions and R > 10 is extreme lightweight construction and extreme expensive in developing and building and it is not clear if the machine will work at all. R < 3 means normally no bigger effort during design.

Specific Impulses for monopropellants like hydrazine in satellites are typical Isp ~= 200 sec, for bipropellants like kerosene and oxygen is Isp ~= 300 sec, for hydrogen and oxygen is Isp ~= 400 sec. The most advanced hydrogen engines ever have up to Isp = 460 sec. They are reaching slowly the physical limits. Nuclear fission reactors had Isp ~= 850 sec, and the Orion pulse drive developed by NASA as a Saturn V upper stage had Isp ~= 1800 sec. The first bigger ARPA Air Force Orion designs would have provided approximately Isp ~= 4000 sec. This is the range where it becomes slowly more interesting if one plans voyages to the outer planets.

The thrust force of a rocket can be calculated

F = dm/dt * c_e   = dm/dt * Isp * g

where dm/dt is the mass flow rate of the burned fuel per second. The power of the engine or the jet out of the engine is

P = F * c_e   = dm/dt * c_e^2

with the exhaust velocity c_e. This is simply because mechanical work equals force times distance. The energy we get from the rest mass of matter is

E = f * m * c^2

where f is a fraction constant which depends on the fuel and c is the speed of light. Typical values for f are 0.001 as maximum fission energy from plutonium or 0.006 as maximum fusion energy from deuterium. But practical values of f are much less, more in the 1e-8 range for nuclear reactions and chemicals are not worth to mention here.

Specific Impulse

At fission ca. 0.1% of the mass rest energy is set free. In atomic bombs normally 1% of the plutonium mass undergoes fission, so we get a fraction of 0.001 * 0.01 = 1e-5 of the rest mass of the fuel that is converted into energy, theoretically. If this mass is converted into kinetic energy we get v = sqrt(2 * 1e-5 * 3e5^2 km2/s2) = 1340 km/s. But an atomic bomb consists of more than the pure fission fuel. Even the smallest bombs have masses of at least 20 kg. The Orion bombs were more in the weight class of 200 kg to provide a certain mass for producing thrust. A typical Orion bomb had a yield of 0.03 kT. Then we get for the energy per mass 0.03 kT / 200 kg = 0.03 kT * 4.18e12 J/kT / 200 kg = 6.27e8 J/kg and a fraction for the released rest energy of 6.27e8 J/kg / 3e8^2 J/kg = 7e-9. With this value we get a velocity for the particles in the debris v = sqrt(2 * 7e-9 * 3e5^2 km2/s2) = 35 km/s

During project Orion the physicists had found a way to direct and control the debris of nuclear detonations that their plasma doesn’t propagate spherically but more in a double-cone or a double-club shape. So it was possible to get a specific impulse of

Isp = C * v / g    = 0.5 * 35e3 m/s / 9.81 m/s2 = 1800 sec

with C as the collomination factor. A collomination factor of nearly 0.5 has been achieved theoretically. 1800 sec was a typical lower limit for the NASA Orion spaceships. Speculations about secret military projects around a divice called Casaba-Howitzer [20] and X-ray lasers [21] as well the high miniaturisation grade of modern thermonuclear weapons let us assume that the work on directing nuclear blasts in project Orion was rather successful.

For the pure fusion platforms anything is a little bit different. In a deuterium – deuterium reaction up to 0.6 % of the rest energy of matter can be transformed into kinetic energy. In a fusion bomb normally 50% of the fuel undergoes a fusion reaction, so we get a fraction of 0.006 * 0.5 = 3e-3 of the rest mass that is converted into energy. This means it can theoretically set free kinetic energy with debris of a speed of v = sqrt(2 * 3e-3 * 3e5^2 km2/s2) = 23.000 km/s. We see the value is much better with fusion than with fission (1340 km/s). But practically the standard Teller-Ulam principle in a bomb can not become better than 6 kT/kg = 2.5e13 J/kg [22]. This gives us a fraction for the released rest energy of 2.5e13 J/kg / 3e8^2 J/kg = 2.8e-4. This is a quarter of the theoretical upper limit of fission 0.001 and this is no mere coincidence, because it had once been developed to fission natural uranium U238 and most weapons use a U238 tamper. Unfortunately it is not possible to get into such a high range with pure fusion detonators.

The weight for pure fusion devices will not be of a simple 6 kT/kg or 0.17 kg/kT law. It is more

x = a + b [kg/kT] * (y – c)

where a is the fixed mass for the pure fusion igniter, b is the growing factor, y is the yield of the detonator in kT, c is the yield of the pur fusion igniter in kT. For example we get the following masses for a 1 kT, 10 kT and 50 kT detonator with a 5 tons TNT yield MTF [23] primary pure fusion detonator and some stages to commulate the yields:

x = 1000 [kg] + 10.0 [kg/kT] (1 kT – 0.005 kT) = 1010 kg

x = 1000 [kg] + 10.0 [kg/kT] (10 kT – 0.005 kT) = 1100 kg

x = 1000 [kg] + 10.0 [kg/kT] (50 kT – 0.005 kT) = 1500 kg

Assume the 1 kT device had four stages, then the 10 kT device had five and the 50 kT device had also five but a longer tamper cylinder for the last stage. We see the pulse units of 1kT are of approximately the same weight as the 10 kT devices, because the igniter mechanism owns most of the weight.

Without external electric energy the devices would be more in the 4 t to 5 t mass range [24]. But in the platforms electric energy can be used to preheat and ionize plasma in the MTF devices to extreme limits just before it is fired out of the ship. This electric energy comes from the pusher unit, that includes a huge gas driven generator in the concrete body of the platform and provides several megawatts of electric power. This power level is possible without any problem because the power of the explosion that drives the pusher is in the million megawatt range. Only the raw compression energy for the second stage of the MTF device has to be provided from liquid explosives, I assume this can be achieved with 1 t to 1.5 t devices.

This leads to 1 kT / 1010 kg = 1e-3 kT/kg = 4.2e9 J/kg for the small 1 kT bombs and 10 kT / 1100 kg = 1e-2 kT/kg = 4.2e10 J/kg for the 10 kT yield bombs as well 50 kT / 1500 kg = 0.03 kT/kg = 1.4e11 J/kg for the 50 kT yield detonators. This gives us a fraction for the released rest energy of 4.2e9 J/kg / 3e8^2 J/kg = 4.7e-8 and 4.2e10 J/kg / 3e8^2 J/kg = 4.7e-7, as well 1.4e11 J/kg / 3e8^2 J/kg = 1.5e-6.

With this values for the fraction of usable rest energy of matter we get v = sqrt(2 * 4.7e-8 * 3e5^2 km2/s2) = 92 km/s and v = sqrt(2 * 4.7e-7 * 3e5^2 km2/s2) = 290 km/s, as well v = sqrt(2 * 1.5e-6 * 3e5^2 km2/s2) = 530 km/s. We get

Isp = C * v / g = 0.5 * 92e3 m/s / 9.81 m/s2 = 4700 sec

with a collomination factor of 0.5 for the theoretical raw fusion 1 kT device and

Isp = C * v / g = 0.5 * 290e3 m/s / 9.81 m/s2 = 15,000 sec

for the theoretical raw fusion 10 kT device, and

Isp = C * v / g = 0.5 * 530e3 m/s / 9.81 m/s2 = 27,000 sec

for the theoretical raw fusion 50 kT device.

Thrust

The thrust of the flying platforms can be derived in two different ways. We start again in both approaches with the NASA Orion design as a reference and control.

a) The thrust formula for rockets and any kind of impulse drive is F = dm/dt * c_e and we know now the Isp and so c_e, and we also know the mass flow rate, so we get

F = 200 kg/sec * 1800 sec * 9.81 m/sec2 = 3.5 MN ~ 350 t

for the Orion pulse drive. 200 kg is the mass of the bombs and they are deployed one every second. For a ship mass of 880 metric tons that is launched as an upperstage engine this seems to be a good value. For a 1 kT pure fusion detonator we would get

F = 1000 kg/sec * 4700 sec * 9.81 m/sec2 = 46 MN ~ 4600 t

For a 10 kT pure fusion detonator we would get

F = 1100 kg/sec * 15,000 sec * 9.81 m/sec2 = 150 MN ~ 15000 t

For a 50 kT pure fusion detonator we would get

F = 1500 kg/sec * 27,000 sec * 9.81 m/sec2 = 400 MN ~ 40000 t

b) The second approach to get the thrust is directly from the engine power. But one has to consider collomination factor C, because only a fraction of the yield of the bomb is it’s thrust power source, the other fraction blows off into space

F = C * P / c_e = 0.5 * 0.03 kT/s * 4.18e12 J/kT / 17.5e3 m/s = 3.5 MN

This is because half of the yield can be used for providing the thermal energy. Near the ground at lift-off or landing manouvre this value is doubled (ground effect). This has to be considered. For the platforms we get similarly the same thrusts than with the first way of calculation above.

Comparison of Fuel Consumption

Todays best chemical fuels have Isp 460 sec. This means for 27,000 sec for the platforms a factor of 3,400 times more power per kg fuel. For example to propell a space ship from Earth’s surface to escape velocity one needs a mass fraction

R = exp(12km/4.6km) = 13.6

for the chemical rocket and

R = exp(12km/150km) = 1.083

R = exp(12km/270km) = 1.045

for the platform. This means 92.6% of the chemical rocket is fuel and only 7.7% or 4.3% of the platform is fuel to achieve escape velocity.

Let’s assume the chemical rocket has a payload of 1.4% and a dry mass of 6% – this means an extreme lightweight construction – and a start mass of 1000 t, then we have 926 t fuel for 14 t payload, a factor of 926/14 = 66 as a factor. The platform has a payload of 20,000 t and a dry mass of 10,000 t, it needs 2490 t or 1350 t fuel and the factor is 2490/20.000 = 0.125 or 1350/20.000 = 0.067. This means the platform needs 530 or 1000 times less fuel mass per kg payload. The platforms are additionally robust, primitive, simple – reinforced concrete, cast steel, construction steel.

The chemical rocket would be of course non-reusable at such a low dry mass of only 6% if it could be built at all and it would be very expensive because of extreme leightweight materials that are at least 1000 times more expensive than the fuels.

If one would try to build a reusable chemical rocket that is as rugged and cheap in refurbishment as the platforms he had to provide approximately the same dry mass fraction of 30% in any stage. It had to be a 3-stage rocket, a 2-stage rocket would be impossible to reach the delta v with such mass fractions. It had about 12% payload in any stage and one would get with 14 t payload 68 t fuel for the third stage, and a total mass of 117 t for the third stage. The third stage is the payload of the second stage, so one would get 566 t fuel for the second stage and 975 t total mass for the second stage. The second stage is the payload of the first stage, so one would get 4712 t fuel for the first stage and 8125 t total mass for the first stage. With 8125 t the chemical rocket had a lift of mass of 27% of the flying platforms with 30,000 t lift-off mass. But the platforms have a payload of 20,000 t and the chemical rockets only 14 t. I think this difference shows us impressively the influence of nuclear power in rocketry. Together the three stages of the chemical rocket would have 68 t + 566 t + 4712 t = 5346 t fuel. This is a factor of 5346/14 = 382.

The platform with a factor of 0.125 needs 3000 times less fuel per kg payload than the reusable chemical rocket. The platform with a factor of 0.067 needs 5700 times less fuel per kg payload than the reusable chemical rocket. To compare reusable rockets (we can think the platform as a reusable rocket) with different dry mass percentage values would make no sense. Because the refurbishment cost would differ exponentially with the fraction of the differences of the dry masses, it makes actually no sense to compare two vehicles with different dry masses. So this is a good comparison if the platforms and chemical rockets have the same dry mass percentages. The specific refurbishment effort per kg dry mass should be then approximately the same. The specific refurbishment effort per kg payload still differs of course.

Comparison of Thermal Machine Wastage

One could now complain that the chemical rocket has much more complicated engines with turbo pumps and many more movable parts under extreme hot and also extreme cold conditions. This would make a change of the engines neccessary after a certain time and push the cost of the chemical rocket again. But on the other hand part of the fuel of the nuclear pulse rockets is of rather simple mechanical structures – the bomb shells, and this material is evaporated and lost during the explosions. We can assume both, the engines and the bombs as thermal machines that are wasted with time. The bombs in one second, the engines in several thousand seconds.

The following approach applies for any kind of reusable rocket or space vessel. It compares the specific cost of the thermal machines times the mass of the machines devided by their endurance in seconds and devided by the payload they transport to space during their lifetime. As a formula this gives

ther.ma.waste.spec.cost = (spec.cost.ther.ma. * ther.ma.mass) / (ther.ma.lifetime * total.lifetime.payload)

This formula applies for any kind of machines under thermal stress. So not only for engines but also for heat shields, gas generators, and many other parts that are destroyed from entropy much faster than the normal temperature structures of the rocket. Normally the resulting thermal machine wastage payload specific cost will be much higher than the fuel cost and determines therefor the flight cost of the reusable vehicle besides other factors like operations and maintenance.

Normally a high sophisticated rocket engine of 460 sec specific impulse would have an endurance of about 12000 seconds burning time before it has to be replaced. This can be extracted from the flight history of the SSME engine of the space shuttle [25]. They had an average value of ca. 10 cylces of 1200 sec burning time each, in our case it is 30 cycles of 400 sec burning time for each engine. The specific cost of an engine was $10,000 per kg [25], a typical building cost of complicated devices of today (2012 currency) would be more $15,000 per kg. We take the chemical 3-stage rocket from the last chapter. With a very good thrust/weight ratio of 100 kN/t for the engines we get 972 t mass for the first stage engines, 96 t for the second stage engines and 6 t for the single third stage engine. This is together 972 t + 96 t + 6 t = 1074 t for the engines. So we get for the rocket engines a factor of

ther.ma.waste.spec.cost = (15e6 $/t * 1074 t) / (12000 sec * 30 * 14 t) = 3200 $/sec/t

The raw building cost of a nuclear device (ca. 7% of it’s total lifetime cost when used in military applications [26]) is 1e6 $/t, this is because it has much less parts than a complicated chemical rocket engine. But it is still high because these bombs are probably hand made.

Our pure fusion detonators will of course be produced in an automatic mass production facility. They will use liquid fuels (methane, oxygen, deuterium, tritium) and will need the ships electric generators. Minutes before they are deployed, they will be fueled and seconds before they are deployed and blasted, their plasma in the MTF device will be heated up electrically by a very high current of several mega amperes.

What cost medium complicated machines in mass production? We take a normal import compact car of 1000 kg. It costs about $10,000 for the end consumer. So lower complicated devices like our pure fusion detonator should cost not more than $10,000 / 1000kg = 10 $/kg in mass production. We get for the bombs a factor of

ther.ma.waste.spec.cost =(10,000 $/t * 2490 t) / (2264 sec * 20,000 t) = 0.55 $/sec/t

for 10 kT yield and

ther.ma.waste.spec.cost =(10,000 $/t * 1350 t) / (900 sec * 20,000 t) = 0.75 $/sec/t

for 50 kT yield.

This factor means: to fly a payload of 1 metric ton one second costs with the reusable rocket $3200 and with the flying platforms $0.55 or $0.75 thermal wastage of machines that are exposed to extreme temperatures.

Flight Cost – Buy a Ticket to Mars

Now we can calculate what 1 metric ton costs to accelerate it to Earth’s escape velocity.

For the non-reusable lightweight very expensive single stage rocket with a typical $15,000 per kg (2012 currency) for building the dry mass it is

spec.cost = (60 t * 15e6 $/t + 926 t * 2000 $/t) / 16 t = 56,300 $/kg

For the huge, rugged and simple reusable chemical rocket it is 1200 sec * 3200 $/sec/t = 3,840 $/kg for it’s thermal machine wastaege, plus 5346 t * 2000 $/t / 16 t = 668 $/kg for the fuels and as a sum

spec.cost = 4,508 $/kg

This is very cheap, I think. For the Orion derived flying platform with 10 kT yield pulse loads it is

spec.cost = 2490 t / 1.1 t/sec * 0.55 $/sec/t = 1.25 $/kg

due to the vapourized bomb shells. The cost for the fuels is included in the detonators. And for the Orion derived flying platform with 50 kT yield pulse loads it is

spec.cost =1350 t / 1.5 t/sec * 0.75 $/sec/t = 0.675 $/kg

due to the vapourized bomb shells. The cost for the fuel is included in the detonators.

This means for nuclear pulse platforms with clean pure fusion detonators of simple technology and liquid fuels (e.g. liquid deuterium) in mass production it is possible to get 3000 to 6000 times cheaper into space than with huge compareable simple and reusable chemical rockets or 45,000 to 80,000 times cheaper than with the most expensive non-reusable rockets.

If a trip into space costs today with chemical rockets $50Mio per passenger it would become with pure fusion platforms $625 to $17,000 depending on the circumstances (2012 currency). Space settling for anybody becomes possible with pure fusion nuclear pulse rockets.

The End of the Space Elevator

A delta v of 12 km/s that we calculated is 72 MJ/kg or 20 kWh/kg kinetic energy. So we have at 0.675 $/kg payload cost a energy cost of

energy.cost = 0.675 $/kg / 20 kWh/kg = 0.034 $/kWh

For the chemical reusable rocket it is for comparison only 225 $/kWh. This means the energy cost for the kinetic energy of each passenger in a flying platform is actually cheaper than the same electric energy from Your energy provider would cost. This means, if one would build a so called space tower or space tether or space elevator [27] and had to bring people up into space with electric energy only, the space tower would be more expensive per kg payload than the flying platforms with pure fusion power. The advent of pure fusion bombs seems very near, there is even a good chance that they secretely exist in the Russian arsenals for 20 years. The basic materials for the space tower are not even invented yet.

But this doesn’t matter anymore, because we can calculate now, that it will never be an economic solution, because there exists at least one competitor that will allways be cheaper and is closer to realization. A 100,000 tons fusion propelled platform can be build in a normal dockyard on earth, a 100,000 tons space tether must be transported into geostationary orbit first. I can offer a means of transportation now, if the tether guys will ever built their tether. No, I think the space tether has just died, before it was born. Primary energy from fusion detonations will allways be cheaper than secondary electric energy to propell machines, fundamental physical laws tell us.

If You ever have read somewhere of space elevators to reduce space transportation cost: next time you may laugh about that science fiction ideas made of hypothetical materials and unrealistic assumptions. After the upcoming invention of the pure fusion bomb we will only need a lot of reinforced concrete, construction steel and strong handling robots to bring down space transportation cost – affordable for everyone.

How the Engine works

The fuel in a nuclear pulse engine is not burned continuously but explodes in descrete pulses. Any second a load detonates just below the ship. A damping shield transforms the pushes into a continuous movement. This was tested with chemical prototypes in the late 1950s in project Orion and it worked very well. First there were many people in the atomic physicists community and in the Air Force that thought it would be a crazy idea to get in touch so close with nuclear detonations. But after a while it became clear what is possible and what is not. For example, did You know that a tank is not vulnerable to an atomic bomb that is exploding in striking distance? It’s thick metal armour vapourizes for a fraction of a second a few milimeters and the tank is pushed sidewards and thats it. This is exactly the reason why the Army developed a special anti-tank radiation weapon: the neutron bomb [16]. Or did You know that structures of metal (no living objects of course) survive distances to nuclear bombs of Hiroshima size of less than 10 meters [2]? The BBC has made a TV special on the topic of Orion, where You can here about it from nuclear bomb veterans and where You can also see the chemical prototypes flying [3].

A very nice visualization of a NASA Orion on it’s way to Mars, Fig [28]

When a Orion space ship accelerates in space there is no explosion, no fireball, no sound, no bang only very bright flashes behind the space ship. The artwork above is actually wrong. I don’t know who the artist is. I have found the picture on another website [28] without reference, but I like it a lot, nevertheless. I think it is the best Orion visualization that exists. I don’t like computer renderings, You know. They are a little bit stupid.

Details of the Orion engine block, Fig [1]

In the figure above we see a typical Orion engine. It works as follows: Small loads of 0.02 kT to 0.14 kT are fired by a pneumatic gun through a hole in a pusher shield. The nuclear loads detonate shortly behind the pusher shield and the detonation hits the shield forward. A spring-damper mechanism tranforms the discrete pushes into a continuous forward movement. The frequency of the detonations is 1 sec. With any blast the rocket is accelerated at a maximum by 30 m/s2. This is the highest value the damping mechanism can handle. The ship mass is located at typical Orion between 1000 t and 4000 t. The mass of a single load is between 375 kg and 1500 kg. Most of the pulse load mass is a propellant that is vapourized by the nuclear plasma, for example tungsten or plastics. Only a small fraction of the load is the uranium nuclear bomb, just a little more than the supercritical mass, rawly 1.2kg. It’s bomb yield is between 35 t TNT and 140 t TNT. The specific impulse of the engine is  between 1800 sec with a 10 m diameter pusher plate and 3000 sec with a 20m diameter pusher plate [1].

The drive of the flying platforms is a derived Orion pulse drive, but it has some differences:

  • The bombs are fusion detonators. When Orion had been developed, typical hydrogen bombs were in the megaton yield range and this was much too big.  The research on Orion actually provided many new ideas and calculations that made smaller and more directed atomic bombs possible [2] and therefor prepared the path to smaller hydrogen bombs. Today typical fusion bombs are in the several 10 kT to several 100 kT yield range [29]. But there have been also much smaller fusion bombs. There have been so called neutron bombs with smaller yields than 1 kT [15], they are also Teller-Ulam designs like their big brothers.
  • The bombs are pure fusion detonators. For more than 20 years there are many and good argumented speculations that they allready exist. But if not, they will come. This is sure. There are many feasable approaches to the pure fusion bombs and no physical law that forbids them. If they don’t exist already it is only a question of time that they are available. Any industrial nation in the world can develop them, they don’t need plutonium or enriched uranium and a total control is not possible or not desirable. I have written a text about the fear and the promise of pure fusion energy, You can read it here [30].
  • Because the bombs are pure fusion detonators the engine is very clean. It can lift off from earth and cruise the magnetosphere of the earth and land again on earth without contaminating the planet or space. Any start of a classic Orion would have killed statistically 10 people on Earth [1]. The flying platforms will not kill anybody but maybe once a pilot that is so unlucky that he looses his way and gets into the path of a landing 30,000 t space ship. No one is immune against accidents, but a statistical kill rate plutonium bomb driven space ships had will never be an option.
  • The pulse loads are more bulky. This is because pure fusion detonators are not buildable in a bagpack or suitcase version. That is bad for building compact space vessels, but good for preventing terrorism with stolen nuclear bombs. The detonators are so clumsy and undeployable that terrorists will probably not like them. The detonators use liquid fuels and need huge electric generators for ignition. In project Orion it was allways a big problem how to secure, observe and seal off a mass production of the perfect mini bomb for terrorists, that the Orion pulse loads actually represented. Pure fusion is different and offers the only viable way to nuclear pulse propulsion.

Details of the Orion pulse units. The hatched areas still contain classified information and are therefor not available, Fig [1]

  • Due to fusion reaction, bigger pulse loads, and bigger pusher plates, the specific impulse is much higher than in Orion. The numbers remind more on the first Orion designs with plans for roundtrips in the solar system and the beginning of the settlement of Mars before 1965 [1].
  • The pushers move gas dampers that produce high pressure for power turbines in the megawatt range. They are needed to heat up the first stage of the pure fusion igniters. Here some million amperes heat up a plasma for a fraction of a second that is then during second stage – and behind the space ship – contracted by chemical loads until the fusion reaction begins. If this reminds You on the magnetized target fusion approach (MTF [23][30]), dear reader, then You are right.

In the 1960s the engineers thougth the interior of a nuclear pulse rocket would look like a bottling plant.

  • The Coca-Cola era has ended. The Orion space ships of the 1950s and 1960s and also that of the 1990s – as long as I understand NASA’s 1990s anti asteroid and Jupiter exploration approach – assumed that one had to use a kind of a bottle factory or a bottling plant within the ship that would move all the hundreds of bombs ready for deploying from their magazines to the pneumatic gun. It would be very complicated, because during flight the yield and kind of detonators had to be changeable. So the Orion team hired even consultants from the Coka-Cola company as experts for fast item moving and transporting systems [2]. Today we have other more flexible, more powerful and more reliable methods to move small, big, heavy, different and whatever items very fast and precisely: handling robots of any size and power.

Today it would be more realistic to think the interior of a nuclear pulse rocket like a line of handling robots.

You see project Orion is not at all a past and curious project of only historic relevance. It was the beginning and the first steps on the only accessible path to the outer planets and space travel for the man on the street. For the last decades it had been in a deep hybernation sleep like the interstellar space ships it makes possible. The historian George Dyson, the son of one of the Orion makers and visionaries, works to wake up this sleeping beauty. He does this in a very sympathical and humorous way [14]. I also read his book [2] and was very amazed of the high sophisticated technology of the 1950s, and how sweet and insignificant our small and apparently [31] harmless digital playthings with nice pictures and funny sounds are against real technology where masses are moved.

Advantages of Nuclear Pulse Engines

The nuclear pulse drive differs from the nuclear rocket like a KIWI or a NERVA [11][12] as a Diesel differs from a turbine. It is a non-continuous propulsion. Several descrete explosions are cunducted rather than one continuos flame. This has many advantages.

  • The biggest advantage is the energy concentration. There is nothing known in the universe (only neutron stars and black holes) that has a higher energy concentration than nuclear explosions. Highest energy concentration means the smallest possible structures.
  • But the highest energy concentration also means the pulse drive has the highest possible efficiency. High concentration results in high temperature and this means due to fundamental thermodynamic laws the highest efficiency. The external pulse drive has no burning chamber, that would otherwise melt. That is a big advantage.
  • The highest efficiency results in the highest possible specific impulse Isp. Indeed, there is no other propulsion, and due to the arguments I listed before, there will be possibly never another propulsion method (but using black holes as drive) that can reach the Isp of a nuclear pulse drive. Specific impulses of 0.1% – 0.3% the speed of light are possible with nuclear pulse drives!
  • No refilling. Huge Isp means roundtrips in the solar system without refilling. Start from Earth’s surface, land on Mars, then on Saturn’s Titan, then on Jupiter’s Io and fly back to Earth and land softly where You started only one year before. If the habitat You need for your scientific voyage and 150 contributors traveling with You has an additional mass of 3000 tons – dont care. This is all possible with only one ‘tankful’. Of course – it is a delta v of not even 200 km/s for Your journey – absolutely no problem for an engine I have presented in this text of Isp >> 20,000 sec.
  • Simplicity. No other drive is as simple as an external pulse drive.
  • Simplicity means reliability. It’s a drastic difference, if Your Tokamak superconducting magnet is out of order or a pulse drive bomb deploying mechanics, when You are alone and on Your own on Ganymed’s plains.
  • And simplicity means also lowest cost. External pulse drives have the highest specific impulses and the lowest specific investments at the same time.
  • Precision. The high energy plasma beam from the nuclear detonation can be controlled in a very exact manner. It is in no way a simple explosion in all directions like a chemical explosion. Such a nuclear plasma explosion is more comparable to the cones or clubs of antenna radiation patterns in electrodynamics or electron orbitals in quantum mechanics. It’s absolutely not primitive, vice versa.

Pure Fusion Detonators

The flying platforms rely on the advent of pure fusion detonators. Without pure fusion they make no sense. Without pure fusions they would destroy our environment and kill people with time from radiation contamination. Only with pure fusion bombs Orion like nuclear pulse rockets are viable.

Now, am I a dreamer, an utopian, a mystic, who hopes for things that are not feasable at all, not physically and not economically? What do You think?

Arguments Pure Fusion Detonators already exist

Inertial confinement fusion with chemical explosives has been achieved to this date in two different ways [32]. The first is to compress a region of premixed stochiometric deuterium-oxygen gas in the center of a spherical detonation chamber. The second is to compress a deuterium gas in the second stage of a Voitenko compressor [33][34].

Both methods rely on a precise concentration of the detonation wave in the center point of the detonation chamber. This is achieved by filling the chamber with a stochiometric premixed hydrogen-oxygen gas or deuterium-oxygen gas and igniting it exactly in the center of the chamber with a simple heat wire. The explosion wave of the gas hits the spherical wall on all points exactly at the same time. The wall is covered inside with a thin chemical explosive layer that ignites when getting hit from the explosion wave. Then the detonation wave of the explosive hits the center of the detonation chamber exactly at the same time in a very small volume and triggers the nuclear fusion in this volume of approximately one cubic milimetre.

Ballotechnics are chemicals that burn at the speed of sound like explosives do, but don’t produce a shock wave. The whole energy of the chemical reaction is converted in one instant to heat and not to pressure. To ignite the ballotechnics they have to be exposed to a shock wave, that usually comes from explosives [35]. This technology to ignite fusion reactions is speculative and not approved.

The inventor of the neutron bomb, Sam Cohen [17], thought it would be possible to ignite a deuterium-tritium fusion reaction by means of ballotechnics. He also thought this has been done successfully by the Soviets in the end of the eighteeth. He also thought the mythological substance Red Mercury was actually this soviet ballotechnics chemicals. He also believed that president Boris Yeltsin in a time when russias government was practically bankrupt, allowed to sell this substance for a lot of foreign currency to other countries like Iraq [36]. Cohen also claimed, that terrorists would own approx. 100 pure fusion bombs and Iraq finally owned approx. 50 pure fusion bombs with an unknown yield [17].

This was all Cohens believe. Other reputable nuclear scientists in the world did not agree with him. But if he was true it would mean that the Treaty on the Non-Proliferation of Nuclear Weapons would have become senseless. From now on it would be impossibel to track or control who – or who not – has the ability to build nuclear weapons, because control is built on the supervision of the trade and distribution of uranium-235 and plutonium-239. Let’s assume Cohen was right – just as a mindgame – and no one wanted this to be true. Sometimes groups of people speak as one, when alternatives seem to be absolute unbearable. Did someone did a mathematical calculation that prooves ballotechnics don’t work? Cohen was the leading expert for small thermonuclear weapons and said yes – all other respected experts denied. Chemical explosives do work – but only with a very small mass of deuterium. Let’s assume US President Bush was right when he argued that Iraq was able to build nuclear weapons, although Iraq didn’t have weapon grade fissile substances, as it was found out later. Let’s assume it was more than a simple misinterpretation of the situation. Let’s assume today the trade with ballotechnics is as strictly controlled as plutonium trade. If the latter would be the fact it would be another indicator that ballotechnics possibly work as Cohen claimed, and the pure fusion detonator, the pure neutron bomb, a very small and clean nuclear weapon, already exists.

These are interesting speculations so far, but not more. It is still possible that there have never been a working pure fusion weapon or even an experimental device. But as I said before, pure fusion theories don’t break physical laws. Physically they are feasable, technically difficult of course, practically a question of effort and intend.

Arguments Pure Fusion Detonators will exist soon

In the magnetized target fusion (MTF) a plasma is produced and magnetically confined – both shortly before it is compressed. Because the plasma has to stay in the magnetic confinement only for fractions of a second, the requirements for the confinement are correspondingly low and less costly [23]. In magnetic confinement fusion [37] the requirements were very strict, that lead finally to the expensive Tokamak [38], which was the first to meet the requirements.

Then the compression of the plasma is done via the destructive compression of its container. A thin liner metal around the plasma is compressed from outside and builds up pressure up to the level where fusion starts. Because the target is a plasma that is of high temperature already, the requirements for the pressure levels are not as high as for other inertial confinement fusion methods.

Because the compression occurs very fast, it is possible to allow the plasma to touch the liner walls during compression, without cooling down the plasma too much. This makes the process as simple as thinkable. The compression can occur in many different ways: magnetically, chemically, wire-array Z-pinch, ion-beam, actually with all means the different inertial confinement fusion concepts use.

In every respect magnetized target fusion seems to be a pragmatic compromise between magnetic confinement fusion and inertial confinement fusion that brings the requirements for magnet field accuracy, plasma temperature, implosion pressure to levels where they are less extreme. It seems that magnetized target fusion is a good candidate along with Tokamak reactors for the next break-even after the the Teller-Ulam (“1.”, 1952) and the Layer Cake (“2.”, 1953). It may even overhaule the Tokamaks and become the “3.” on the podium. There is a medium sized MTF research reactor [39] at the Los Alamos National Laboratory [40].

It is possible to combine MTF directly with chemical explosives, ballotechnics, helical-flux generators and other devices that produce extreme currents from chemical loads, and of course classical capacitor banks that are loaded by generators or simply the grid. The MTF has two stages: the first stage, the plasma injector, that produces the extremely hot plasma and moves it to the second stage, the liner implosion system, that compresses the hot plasma to fusion conditions.

There are several methods to supply the plasma injector:

  1. with high current in (e.g. MAGO [24]) supplied by helical-flux generators and similar devices or stationary capacitor banks
  2. with a classic single Z-pinch [41] plasma string supplied by helical-flux generators and similar devices or stationary capacitor banks
  3. with ballotechnics chemicals
  4. maybe with shaped charges chemical explosives that produce hot plasma
  5. maybe with strong ion beams that can heat up the plasma sufficiently supplied by stationary capacitor banks

and there are also many ways to get the implosion of the liner:

  1. with the lorentz force from high current in a metal liner supplied by movable helical-flux generators, etc., or stationary capacitor banks
  2. with chemical explosives either cylindrical or spherical
  3. with a wire-array Z-pinch and the Ulam ablation implosion effect supplied by movable helical-flux generators, etc., or stationary capacitor banks
  4. maybe with strong ion beams and the Ulam ablation implosion effect supplied by stationary capacitor banks

These are all combinations of MTF to get to pure fusion. If the plasma from the first stage is not hot enough to let the implosion of the second stage result in nuclear fusion reactions, the development is still not a blind alley: just put a zero-stage before the first plasma injector and heat up the plasma twice. I think there is no reason, why MTF should not work, finally.

But there are also some speculations that one can reach pure fusion with a classic layer cake [42] approach (I think this is the version Cohen thought it existed [36] and Teller laughed about [35]):

  1. an outer spherical chemical explosive
  2. an inner chemical explosive enveloped by the first
  3. a spherical ballotechnics layer enveloped by the explosives
  4. a deuterium-tritium gas bowl in the middle

The inner explosive fires the ballotechnics that heats up the deuterium-tritium mixture to a hot plasma. The outer explosive that is triggered immedately after the inner amplifies the density maximum in the layer cake again by a certain factor (staggered explosions amplification) and compresses the inner core with the deuterium-tritium core to fusion conditions.

And the wire-array Z-pinch machines in the world also seem to be very good candidates, if their target is a preheated plasma. The division line between wire-array Z-pinch and MTF is becoming very blurry. I prefer to name such an approach an MTF with wire-array Z-pinch second stage.

Properties of Pure Fusion Bombs

The economic settlement of the solar system depends on pure fusion. Options to defend natural desasters, the advent of cheap electric fusion energy to boost worlds prosperity, methods to effectively counter effects of global warming until it’s climax, and deflect growing glaciers in the upcoming ice age after the warming period. This all depends on our possibilities to deploy huge nuclear forces that have measurable effects on the many times bigger forces of nature [30]. Without fusion energy our basic materials supply will ebb soon and humanity will regress to one failed evolutionary experiment of nature. After the next big impact of a celestial body, that our grandchildren of grandchildren will surely not be able to deflect, because we didn’t develop the powers to do so, the chance for a new animal on earth may come to do the neccesary tasks. But there will be no human historian to watch and tell the story.

I think humanity can become a spacefaring society. There is still a strong power of intellect and good will. Of course pure fusion detonators are nothing to play around with. They are nuclear bombs and they can be used as weapons. Very bad weapons, but still weapons. I have listed the properties of pure fusion weapons against those of ‘classic’ nuclear weapons in the next table to provide decision makers with appopriate informations, if there should be a lack.

Properties of Pure Fusion
Todays Nuclear Weapons Pure Fusion Weapons
Gamma Rays yes yes
Neutrons yes yes
Thermal Radiation yes yes
Air Blast yes yes
Underground Shock
Underwater Shock
Fission Products yes no
Neutron-Induced Activity little in air, none in water, much in ground little in air, none in water, much in ground
Uranium and Plutonium Dust yes no
Local Fallout very high no
Worldwide Fallout depending on conflict size low to high no
Long Term Residual Radiation Hazard yes no
Storage and Durability depending on technology medium to good bad to medium
Deployment and Mobility very good (small, light) very bad (bulky, heavy)
Ignitability very good (chemical) depending on technology very bad to very good
Traceability, Discoverability Good (nuclear decay products) very bad
Engineering Requirements medium to high very high
Primary Fuels P239, U235 Deuterium-Tritium
Secondary Fuels Deuterium-Tritium, Deuterium Deuterium-Tritium, Deuterium
Yield Amplification with U238 yes, almost in any applications yes, but: ‘Fission Products, Uranium Dust, Local Fallout, Worldwide Fallout, Long Term Residual Radiation Hazard, Traceability, Discoverability’ all become left table column values
Igniters Chemical Explosives Electric Current, Chemical Explosives, Ballotechnics
Proliferation Controllable if all Countries participate Not controllable
Worst Case Applications Worldwide Nuclear Holocaust, Terrorists Suitcase Bombs Well planed large scale Terrorist Operations
Worst Case Prevention Methods Local Wars to destroy Enrichment Facilities, Economic Hegenomy Worldwide Total Observation, Suppression of many Technologies

If we analyze the table we find out soon, that there are only two key elements to prevent misuse of pure fusion:

  1. Preventing well planed large scale terrorist operations: ships, trains, cargo planes and bigger trucks can deliver these weapons as they also can deliver huge amounts of conventional explosives
  2. Traceability of natural uranium 238 trade: preventing the uranium augmented electrical ignited fusion weapon

The first is done today, regrettably inevitable. The observation of the U238 trade is part of the prevention of highly enriched U235, I assume. This is why I think it is possible. And it must be possible, maybe we have no other choice. Pure fusion weapons will always remain bulky, complicated, and probably with a lot of supplying and igniting machinery around them. This is why they are actually more suitable as nuclear detonators for civilian applications than for warfare or terrorism. I have shown the great chances they provide for mankind in this text as well in a former text about pure fusion bombs [30].

Outlook

It is only a question of time that pure fusion detonators of any kind are available. We, the democrates in the remaining free countries of the world, may have still the choice to lock them away as long as we can, and hope humanity will over a period of decades forget anything about nuclear technology, atomic science, fusion energy, fusion propulsion and nuclear weapons – our nemesis. I can understand such a thinking completely, but I would characterize people with such hopes dreamers, utopians, maybe mystics, who hope for things that are not feasable at all. And this is why I like them.

On the other hand, any bad thing is also a good thing. As more negative power a thing has as more positive it must also have. You don’t need to know much about asian philosphies to realize that. Milleniums of knowledge and experience tell us not to hasitate to question the things deeply and find harmony with the whole universe, not only the things that are apparently good and that we therefor like immediately.

Pure fusion power will come. I don’t believe that it will ever be a practical weapon.

Pure fusion power can open the door to unlimited energy and prosperity, space travel for everyone, settlement of the planets. Some of the simplest things in the universe, that we could have owned for at least the last 45 years, if we had wanted it. But we didn’t. And we still don’t have to. It is our free wish. But if we want to do the next more complicated steps, exploration of extrasolar planets, settlement of the stellar environment, practical investigation of space-time, then we have to do the simple things before.

To build rugged, usable, practical working tools with appropriate power like those presented in this text is only one of many necessary simple first steps.

Ende

Resources and Explanatory Notes

[1] The Orion space ship: http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29

[2] George Dyson; Project Orion – The True Story of the Atomic Spaceship: http://www.amazon.com/Project-Orion-Story-Atomic-Spaceship/dp/0805059857

[3] BBC special on the topic of Orion: http://www.youtube.com/watch?v=v4k_YZAXSEI

[4] Partial Nuclear Test Ban Treaty: http://en.wikipedia.org/wiki/Partial_Nuclear_Test_Ban_Treaty

[5] Stanislaw Marcin Ulam: http://en.wikipedia.org/wiki/Stanislaw_Ulam

[6] Edward Teller: http://en.wikipedia.org/wiki/Edward_Teller

[7] Charles Seife; Sun in a Bottle – The Strange History of Fusion and the Science of Wishful Thinking: http://www.amazon.com/Sun-Bottle-Strange-Thinking-ebook/dp/B001IH6WOM

[8] Teller-Ulam inertial confinement fusion principle: http://en.wikipedia.org/wiki/Thermonuclear_weapon

[9] S.M.Ulam, C.J.Everett; On a method of propulsion projectiles by means of external nuclear explosions: http://handle.dtic.mil/100.2/ADA306631

[10] Doomsday bomb: http://en.wikipedia.org/wiki/Doomsday_device

[11] Nuclear thermal rocket: http://en.wikipedia.org/wiki/Nuclear_thermal_rocket

[12] NERVA nuclear rocket engine: http://en.wikipedia.org/wiki/NERVA

[13] Movies about impacts: Deep impact (http://en.wikipedia.org/wiki/Deep_Impact_%28film%29), Armageddon (http://en.wikipedia.org/wiki/Armageddon_%281998_film%29)

[14] TED Talks: George Dyson on Project Orion: http://www.ted.com/talks/george_dyson_on_project_orion.html

[15] Nuclearweaponarchive.org about neutronbombs: http://nuclearweaponarchive.org/Nwfaq/Nfaq4-3.html

[16] Neutron bomb: http://en.wikipedia.org/wiki/Neutron_bomb

[17] Samuel Cohen: http://en.wikipedia.org/wiki/Samuel_T._Cohen

[18] Sam Cohen writing about pure fusion weapons: http://www.financialsensearchive.com/editorials/douglass/2003/0311.html

[19] Pure fusion weapon: http://en.wikipedia.org/wiki/Pure_fusion_weapon

[20] Casaba-Howitzer, a classified nuclear weapon concept, that works like Orion pulse units (details also classified): http://www.projectrho.com/public_html/rocket/spacegunconvent.php

[21] Project Excalibur, X-ray lasers for SDI: http://en.wikipedia.org/wiki/Project_Excalibur

[22] Nuclear weapon yield and efficiency: http://en.wikipedia.org/wiki/Nuclear_weapon_yield

[23] Magnetized target fusion (MTF): http://en.wikipedia.org/wiki/Magnetized_target_fusion

[24] D.Sagie; I.I.Glass: Explosive-driven hemispherical implosions for generating fusion plasmas

[25] Space Shuttle Main Engind (SSME): http://en.wikipedia.org/wiki/Space_Shuttle_Main_Engine

[26] Nuclear weapons cost: http://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CEIQFjAD&url=http%3A%2F%2Fwww.ippnw-students.org%2FNWIP%2Fpdfs%2Fcosts.pdf&ei=2TR3ULWWHsbWtAb4hICgDA&usg=AFQjCNGP5fXau07CFyxgY7J71v-ciOFYaQ&sig2=2RnHzrRiP4GKXuuZm_Eevw

[27] Space Elevator: http://en.wikipedia.org/wiki/Space_elevator

[28] Nuclear pulse drives: http://orbitalvector.com/Deep%20Space%20Propulsion/Nuclear%20Pulse%20Drives/Nuclear%20Pulse%20Drives.htm

[29] Nuclear weapons archive: http://nuclearweaponarchive.org/

[30] Why mankind must not fear the pure fusion bomb

[31] The 10 most dangerous technologies ever

[32] Sagie; Glass: Explosive-driven hemispherical implosions for generating fusion plasmas

[33] Voitenko Compressor: http://en.wikipedia.org/wiki/Voitenko_compressor

[34] Voitenko compressors at NASA: http://www.hq.nasa.gov/pao/History/SP-440/ch6-15.htm

[35] Ballotechnics: http://en.wikipedia.org/wiki/Ballotechnics

[36] Sam Cohen writing about pure fusion weapons: http://www.financialsensearchive.com/editorials/douglass/2003/0311.html

[37] Magnetic confinement fusion: http://en.wikipedia.org/wiki/Magnetic_confinement_fusion

[38] Tokamak reactor: http://en.wikipedia.org/wiki/Tokamak

[39] Magnetized target fusion at the Los Alamos National Laboratory: http://wsx.lanl.gov/mtf.html

[40] The Los Alamos National Laboratory, where humanities first nuclear detonators have been invented: http://www.lanl.gov/index.php

[41] Z-Pinch: http://en.wikipedia.org/wiki/Z-pinch

[42] Layer cake design: http://en.wikipedia.org/wiki/Boosted_fission_weapon

[43] Theodore Brewster Taylor http://en.wikipedia.org/wiki/Ted_Taylor_%28physicist%29

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Über monstermaschine

Blogger, Diplom-Ingenieur, TU, Raumfahrttechnik, Embedded Systems, Mitglied VDI, DGLR

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