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. The Case For Orion

nuclear systems will be critical to space exploration in the 21st century. But can the public ever be convinced it can be utilized safely?
by Wayne Smith for NuclearSpace.com
Brisbane - Mar 12, 2003
"Orion" was the project name of a spacecraft design study so absurd that it stood absolutely no chance of success from the very outset. The drive mechanism was to be an atomic bomb machine gun. Ridiculous as the idea seems it was still given a shoestring budget and a team of top scientists to work on it. The results of that research which ended about two generations ago are still largely classified, but what is known raises some startling questions.

Authorities at the time were no doubt influenced by many factors in their decision to eventually cancel Orion. Chief among them perhaps, with the bombing of Japan still fresh in peoples minds, was the sheer craziness of it.

Yet the scientists working on the project had no doubts about its feasibility. Years of experimentation had persuaded them it was not only a possible goal but the only really practical method of exploring space.

They talked of sending men to Mars by 1965 and Saturn by 1970. Apollo engineers struggled with weightsaving technologies such as five stage rockets for a moon shot carrying three astronauts.

Meanwhile the Orion planners routinely discussed such endeavours as establishing a large permanent moonbase in a single mission.

The scientists and engineers involved with Orion were no fools. Among their many supporters were Wernher Von Braun. Acclaimed as the father of NASA. Originally opposed to such a bizarre idea he changed his mind after seeing a test model fly using TNT. Reportedly falling out of his chair in surprise at seeing such undeniable evidence of pulse propulsion demonstrated.

The original idea of "nuclear pulse propulsion" is attributed to renowned super genius Stanislaw Ulam.

Steady controlled fusion has been a dream since before the atomic age began but seems as far away today as it was in the time of Professor Ulam. To tap into the enormous energy yields of atomic power he had to consider alternative methods. Realising that nuclear blasts could not be easily contained and therefore presented an engineering nightmare he dispensed with the conventional rocket entirely.

Instead of a chamber he put forward the notion of using a "pusher plate" instead. This was the concept pursued by the Orion team from 1958 until after the signing of the nuclear test ban treaty in 1963. To design Stanislaw Ulam's revolutionary new vehicle with its unheard of thrust and Isp. Even today the idea seems insane but the craziest thing of all is that they actually succeeded.

The ship would have carried many small fission bombs, which would then have been ejected one by one behind the ship and detonated. A reaction mass would have been either incorporated into the bomblets or dropped separately. The explosion vapourising it into a plasma which would then bounce off the pusher plate. Springs and cushioning would support the plate and absorb the impact of the explosion to drive the ship forward.

Back in the early atomic age many daring schemes like this were considered for peaceful applications of nuclear power. One was Plowshares. A shortlived study of how nuclear weapons could be applied to civil engineering projects. Blasting tunnels through mountain ranges was seriously entertained at one point. Other less well intentioned ideas included setting off bombs on the moon to unnerve the Russians.

While many bold suggestions were put forward and explored to some extent we must remember that the leadership of the day remained largely ignorant of how nuclear technology worked.

This remains true to this day. Back in the 1950's even top physicists were still coming to grips with the new state of the art discovery that was fission. Some feared the atmosphere could ignite if we detonated too large a device. This suggestion is now laughed at but back then it was a serious concern. Fear of nuclear power was if anything greater than it is now.

After the demise of Project Orion the team leader Freeman Dyson was quoted as saying "...this is the first time in modern history that a major expansion of human technology has been suppressed for political reasons". Ironically enough the main cause of Orions demise was probably not so much lack of backbone from nervous political leaders.

Although that certainly played a role. It was most likely the Apollo program which was most responsible. When the American Administration set itself the task of putting a man on the moon within a decade it turned the space program on its head.

NASA had been seeking a longterm approach to space travel which would eventually ensure affordable human missions to Mars and beyond. Instead of concentrating on the development of more reusable and practical methods of reaching space they were now encumbered with getting there by the quickest and therefore most expensive means available.

Nuclear power in the forms of projects ROVER and Orion could not meet the deadline of 10 years because they were only just off the drawing board. They were therefore unceremoniously cancelled along with countless other programs. Every available dollar was redirected to Apollo and as a result we now have a flag on the moon.

Nobody has revisited our satellite in over 30 years and there are no serious plans in the pipeline to do so.

So after $11 million had been spent over nearly seven years, Orion died. Its followers, those few individuals who were aware of it and supported the program, saw this as an opportunity lost. The closest we ever came to a true golden space age. Others now decry it as a pipedream which would have sent us all to our graves from the unavoidable fallout. Could it have been safely launched from Earth or are the fearmongers right on this?

Fallout is a serious objection to building and launching Orions. It's caused by debris from the ground being sucked into the fireball of an atomic blast, irradiated and then spewed out of the top. This radioactive plume coalesces in the atmosphere before eventually falling back to earth. It's a mix of isotopes with varying half lives. The most vicious of them are shortlived and are gone in just a few hours.

The milder ones can hang around for millennia. This is called a groundburst. With groundbursts the blast and heat throws debris outwards. The debris sucked into the fireball and turned into fallout comes from the crater scoured in the ground by the energy of the blast.

One answer to avoiding fallout for an Orion launch is ludicrously simple. Use a thick metal launchpad. Its as straightforward as that. The Orion team discovered that a thick metal plate can withstand close proximity nuclear blasts very well.

Evidence of this obtained from nuclear tests was the foundation for further research into the feasibility of a pusher plate. It was discovered that ablation (erosion) of the surface of a pusher plate could also be reduced by coating it with graphite. Coating the launch pad in similar fashion would minimise ablation of the surface and therefore create very little fallout indeed. Airbursts are relatively clean from a fallout point of view.

They do generate some fallout from atmospheric dust and water vapor but not as much as legend holds.

Further reduction of fallout can be achieved by using more state of the art pulse units than those proposed back in the 60's. Over 80% of the atmosphere lies within the first 16km from the ground. Its almost completely gone at around 50km. Lessening the concern of bomb schrapnel as a source of residual fallout would make airbursts cleaner still. Casings could be composed of something less amenable to absorbing blast radiation for a start.

Making atomic weapons is more of an art than a science so designing a cleaner bomb is a very reasonable objective to aim for. Unlike conventional rockets which get more complex and less efficient the larger you build them, an Orion is quite the opposite.

The bigger the better. Efficiency just keeps going up. Instead of several launches we would be best served by constructing very large Orions to lift more payload in fewer missions. Instead of small fission devices we could then use small hydrogen bombs which are about a thousand times cleaner relative to energy yield.

But isn't any level of fallout totally unacceptable?
Thats the commonly held myth. Hundreds of atomic devices were detonated back in the 50's and 60's which would make Orion pulses look like xmas crackers by comparison.

They were used without any attempt to minimise fallout whatsoever. Many thousands of tons of fallout would therefore have been created by any one of them. I hardly need to point out that the World was not destroyed as a consequence. We seem more than prepared to use big dirty nuclear weapons such as 'bunker busters' for war so why not small and relatively cleaner ones for peace?

A study by the Center for Disease Control and Prevention in Atlanta which became public last March is the first to consider the health effects of nuclear detonations. It includes tests by all countries between 1951 and 1962 when open-air testing was finally banned. Public exposure to iodine-131, which can cause thyroid cancer, was included in light of new information obtained after the Chernobyl nuclear accident in Russia.

According to the results obtained, of the 3.8 million Americans born in 1951 who would have been exposed to the highest fallout levels in their most vulnerable early years, atomic tests account for an estimated 1000 additional cancer deaths. Smoking, by comparison, is expected to account for about 250,000 cancer deaths within the same group.

Considering the number and magnitude of tests conducted back in the 50's and 60's the figure of 11,000 total deaths seems small but even that is grossly exagerrated.

All US governmental agencies use the linear-no threshold hypothesis. An outdated model which incorrectly assumes all levels of radiation to be deadly. The latest findings from studies into hormesis give a completely different picture. As to radioactive iodine, it primarily causes thyroid cancer which is easily treatable and thus rarely fatal. Today it is preventable with a pill.

Based on more modern research the calculated environmental impact of an Orion launch might cause a single fatality on a global scale. That however is assuming a 10,000 ton Orion designed with 60's fission bombs and launched from Nevada with no effort to minimise groundburst fallout.

But why take any risk at all? What is there to gain by being daring? Today we have grown accustomed to seeing expensive space missions solely for millionaires and the military elite. Orion won't throw open the doors to space for us mere mortals. Not immediately anyway.

Why worry about bold new tasks when life in the west is relatively comfortable and so many problems exist down here which need solving? What Orion can do is put unimaginably massive payloads into space at low cost.

Something we no longer dream about or seem to desire.
Unparalleled access to space means we can lift the industrial infrastructure necessary to start using natural space resources for the first time. We could then mine asteroids and build fleets of Orions off Earth where environmental impact studies would be of no concern.

The last frontier is after all an endless ocean of positive particulate radiation. Like the Starship Enterprise we would never in all likelyhood try to land Orions on Earth. They would act as interplanetary ferries. We would still need to develop a reusable launch vehicle but it would only need enough fuel to reach orbit. Our newly aquired mining, construction and fuel processing industries in space would ensure that abundant fuel stops in the form of space stations would exist for return journeys. One Orion launch might be all thats necessary to kick off a new age of space exploration.

Perhaps one of the best arguments for allowing nuclear power to increase our foothold in space is provided by Daniel Durda, a senior research scientist at the Southwest Research Institute in Boulder, Colorado.

"The worst scenario I can think of is a multi-kilometer-diameter, long-period comet discovered several months out on an impact trajectory as it is entering the inner solar system," he said. "There is absolutely nothing we could do about it at this point in time. Nothing."

You have only to look at the pockmarked moon to realise we can and do occasionally get hit by large bodies. Survival should be a strong motivator for us even if our exploratory urge has diminished.

There was a time once when we were all about exploration, conquest and colonization. We can now be defined as a civilization that focuses on internal problems that will or can never be completely solved.

A cold shudder or chill goes up my spine looking at old black and white photographs of people, events, machines, inventions, proposals and visionary schemes from the early part of the last century.

To see what could have and should have been is sobering to say the least. That generation of yesteryear believed so firmly in science, technology and the progress of Man in all areas of life, that it is easy to see why they have been called 'The Greatest Generation'. They believed that science (understanding) and technology (application) would lead to a higher standard of living, which it did.

They believed in letting technology solve its own problems. They believed in grand projects of engineering.

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