Nuclear propulsion

I’ve been designing a Mars mission with a nuclear rocket. Admittedly this might be a bit much for a one man operation. It grew out of desire to render a NERVA II rocket engine with blender. Although I’m not known to be detail oriented the things that I try to model should look at least a little bit like they might look if they were actually made some day, so I used “existing” hardware to estimate weight of a spaceship and then plug the numbers in to the rocket equation. After some tuning I came up with a two stage space tug that has about 1.5 Gg of mass at low earth orbit. This contraption should be able to transfer five BA 330 modules and 200 Mg of cargo to Mars orbit.

The propulsion unit for my design. It needs six.
A propulsion unit for my design, it needs six.

Before anyone gives harsh critique on the numbers: this is a very notional design: I’d be happy if the numbers are within an order of magnitude of the correct ones. And did I mention that much of the stuff is sort of vaporware or less real.

Close up of the NERVA II. To show the scale, the big cube is 10^3 m3, the green speck is 0.1^3 m3. The Hydrogen tank is almost 47 m long.
Close up of the NERVA II. To show the scale, the big cube is 10^3 m3, the green speck is 0.1^3 m3. The Hydrogen tank is almost 47 m long.

I like physics, I like rockets and almost anything space related, so for me this type of thinking by doing is fun. What is more surprising is that some quite serious people have thought that this could actually be done. Nuclear rocket engines have been proposed and tested ( “direct” nuclear jet engines too).

“Steady progress was made in engine efficiency and controllability, and in lowering the release of radioactivity” [from here]. Just to make it clear these beasts were no sissy nuclear electrics, the idea was to spray a hot reactor core with hydrogen. Several designs were tested in the atmosphere. The word that surely comes to mind when thinking about this sort of engine test is erosion. One would expect that active parts of the core would be spewed out of the hot end even in normal operation.

There is always the possibility of the not so unlikely turbopump failure. While my limited knowledge suggests that because there is no need for an oxidizer it is a bit easier to design one, the eventual pump failure could still lead to a loss of coolant. Not to worry, they tested (KIWI TNT) what happens if you stop the coolant. Boom.

While my design sketch is a space tug, i.e. it would never be used in the atmosphere thus limiting the release of radioactive substances to the biosphere, these engines were also suggested as upper stages for chemical rockets to boost performance. Then there is of course Project Orion, which from the current viewpoint boggles the mind.

No point, just some perspective.

How can we understand the anti-GMO movement?

 

Should deep anti-GMO ideology be considered a form of religious belief? In a secular Western society, religion is protected but its influence limited. Maybe that is exactly what is needed?

“So should GMO supporters go all the way and label anti-GMO activists as members of a pseudo-scientific lunatic fringe? No. Not all GMO skeptics are lunatics. Also, that approach stops all discussion:  for a science-based person, there can be no compromise with pseudoscience. ….     But what if anti-GMO ideology were classified as a religious belief, rather than pseudo-science? I would argue — though I may be completely wrong — that there is actually more room for compromise then. ….      I don’t believe this could ever work as a social policy. However, it could work as a way for individual people to understand why the “other side” is like it is. Understanding what makes a person tick is better than nothing.”

The environmentalist Mark Lynas (home page, Wikipedia page) has made a public “conversion” from a strong opponent of genetically modified organisms (GMO) to a strong supporter. He feels that GMO will be needed to feed the world’s population, and above all that there are no valid scientific reasons to oppose GMO.  (See Slate article for a summary, and preferably the unofficial transcript for the long full text).

I am in the environmentalist camp, yet Lymas’ text resonates heavily with me. It has started a thought process that probably offends everyone and satisfies no one. Yet it might raise thoughts.

From Lymas’ transcript: “So my message to the anti-GM lobby, from the ranks of the British aristocrats and celebrity chefs to the US foodies to the peasant groups of India is this. You are entitled to your views. But you must know by now that they are not supported by science. We are coming to a crunch point, and for the sake of both people and the planet, now is the time for you to get out of the way and let the rest of us get on with feeding the world sustainably.”

Elsewhere Lymas calls for “peaceful co-existence” between the camps, but he doesn’t make it easy. He calls anti-GMO activists anti-science, even comparing them  to climate change denialists. Neither group, he says, is willing to listen to scientific facts, and there is now overwhelming scientific evidence that GMO is safe in every conceivable way.

Lymas does not really probe the motivations of the anti-GMO group. He considers them ill-informed and irrational.  To my eye, he almost seems baffled by them (even though — or perhaps — it is the group he comes from).

Would the best explanation — and a possible solution — be to consider deep anti-GMO ideology a form of religious belief? In a secular Western society, religion is protected but its influence limited. Maybe that is exactly what is needed?

On what issues is the anti-GMO group right?

It sounds like Lymas has had very much of an epiphany (some might even say quasi-religious conversion experience). There is nothing wrong with that. But it does make one liable to denigrate the beliefs one had earlier. Every movement has some rationale behind it; so does the anti-GMO movement.

For the environmentalist movement in general, a key rationale is the precautionary principle: if a technology has even a tiny risk of causing unknown catastrophic and irreversible damage to the environment or human health, don’t use it.  This is not a bad principle.

However, if only zero risk is allowed, it becomes asphyxiating. It is impossible to prove that something is completely risk-free. Certainly GMO crops may have risks that we have not identified yet. However, this applies to anything new. In fact it applies to anything old as well. It is natural evolution that creates diseases such as Ebola. The world is a risky place.

Even without the precautionary principle, some political and ecological arguments against GMO do make eminent sense. I analyze them in more detail in the Appendix. Summary: GMO skeptics are not the idiots Lymas paints them to be. There are valid reasons to be pragmatically skeptical.

However, there are no good reasons to be dogmatically opposed. When the GMO opposition turns ideological, to be honest, I simply do not understand the arguments.  A vocal faction of the environmentalist movement will never accept GMO, since it is “unnatural” and “can be used wrong”.

I don’t really see why conventional breeding of crops is significantly more “natural”. And conventionally bred crops are already being used “wrong” by replacing traditional varied crops with monocultures, making whole countries potentially vulnerable to single pests or diseases.

I agree that the potential for doing wrong is larger with GMO. However, it is a matter of degree only.  I simply cannot see why GMO should be demonized, compared to conventional breeding.

On what issues is Lymas right?

I will go flat out — and lose many friends in the environmentalist community — by agreeing with Lymas on the key issue. GMO foods may be the only realistic way to solve the global food crisis.

Whatever unknown risks GMO might pose, those risks must be balanced against a known catastrophic and irreversible risk: starvation, and the destruction of even more natural habitats to make farmland to avoid that starvation.

Low-efficiency farming will take up more land, leading to loss of biodiversity and negative climate effects. People will feed themselves by whatever means necessary; if that leads to permanent long-term environmental damage, they will still feed themselves. GMO could allow the large-scale damage to be minimized by improving yields.

Even if GMO foods were to cause some health risks to humans, it is up to individual people or nations to decide whether to take those risks or not.  Someone who is underfed and facing a brutal, nasty and short life simply could not care less if a GMO food might theoretically cause a 0.1% increase in the probability of getting cancer thirty years from now. Without the food, he won’t be alive in any case.

Rich Westerners have all the right to be careful about their personal diet and worry about small hypothetical risks. But we do NOT have the right to decide what people on the edge of starvation should do.  And unless agriculture is made dramatically more efficient, a billion or more people will be chronically near that edge.

While Lymas actively celebrates the technology, I am blasè: GMO is a pragmatic way to a pragmatic goal (avoiding starvation). Just as good toilets are a pragmatic way to avoid epidemics. Important, not glamorous.

Is there any way to reconcile the sides?

So should GMO supporters go all the way and label anti-GMO activists as members of a pseudo-scientific lunatic fringe? No. Not all GMO skeptics are lunatics. Also, that approach stops all discussion:  for a science-based person, there can be no compromise with pseudoscience.

But what if anti-GMO ideology were classified as a religious belief, rather than pseudo-science? I would argue — though I may be completely wrong — that there is actually more room for compromise then.

I emphatically do not consider “religion” to be an insulting label. I personally am a practicing Lutheran, and feel little or no shame about it. Equally emphatically, I believe in the principle of the two magisteria. What we do inside our churches/ mosques/ synagogues/ temples is largely our own business; but outside them, we need to run society on secular and rational lines.

There are certainly clear parallels between strong anti-GMO ideology and religious dietary laws such as kosher or halal. Certain things are forbidden, with some room for interpretation but no room for discussion about the ban itself (pork, blood, alcohol, gene modification). Thinking of anti-GMO attitudes in this way actually makes them much less baffling. They simply are what they are, just as kosher or halal laws are what they are.

Many atheists may consider religion to be just a variant of pseudoscience, but religion is still protected by our society (and by the UN Declaration of Human Rights), whether the atheists like it or not. In a sense, “branding” anti-GMO as a religion could protect both sides. Freedom of religion means that people can practice their religious laws within their own community.  It does not, however, mean that those communities can require the whole of society to adopt those laws.

Western society will not voluntarily accept an Islamic ban on pork or alcohol. In the same way, there is no reason why African society should voluntarily accept a Western ban on GMO foods.

Is this a valid compromise?

No.  No side will accept it. Anti-GMO activists have no unifying features that could form a new religion, and in any case would not accept such a status. Nor would the rest of society be likely to grant it to them, if most of the hallmarks of traditional religion are missing. (Many European countries willingly register various kinds of nature-worshipping or pagan religions which look like traditional religions, but are hesitant about groups like Scientology which do not).

I don’t believe this could ever work as a social policy. However, it could work as a way for individual people to understand why the “other side” is like it is. Not accept, any more than an atheist could “accept” kosher dietary laws if pushed on pushed on him. But understanding what makes a person tick is better than nothing.

 

APPENDIX: WHICH ANTI-GMO CONCERNS ARE VALID?

See e.g. the Wikipedia page on GMO controversies for a balanced summary.  The key to understanding anti-GMO thought is the precautionary principle: if a technology has  even a small risk of causing unknown catastrophic and irreversible damage to the environment or human health, don’t use it.

That is a perfectly valid philosophy, if used in a balanced and reasonable way. I would say that  it is a good thing that it was used in the early stages of GMO research (even if it slowed down that research). It forced scientists to measure and gauge the risks in depth. However, no horrific risks seem to have emerged, and it is now time for the environmentalist movement to reconsider.

However, I do find Lymas to be too flippant about the lack of risks. I continue to see loss of biodiversity as a very potential risk. If the GM organisms are superior, they will eventually mix with the local organisms and either dominate or intermix with them. This will happen whatever artificial safeguards are put in place. The skeptics are in fact right: we do not really know how GM organisms will affect the ecosystem. Most likely the effect will be small; but we just do not know.

Far more problematically: Science and technology do not operate in a vacuum. Politics and business always mix in. Thus, I find it naive to assume that things will be all right as long as the science is “pure”.

GMO crops give awesome power to the patent holders (currently largely Monsanto). Proponents argue that free competition will take care of this issue, that it is possible to put in legal safeguards, and that the situation is as it is because independent researchers have not been able to do research in the area.

I respectfully disagree with this optimism. After researching the Plumpy’Nut case, I have come to the conclusion that if companies can make profit by starving people, they will starve people.

And it is naive to think that universities, for example, would not enforce their patents. For concrete examples in other technology areas, see the example of the University of Wisconsin and the recent case of Marvell vs Carnegie Mellon University. Universities are aggressive about their patents, and trusting the goodwill of “independent” researchers is naive. Hoping that GMO crops would not be patented is also naive. Too much money is at stake.

I do not think any of these risks are clear enough to ban GMO. They would apply to any new technology. However, they are real enough to dampen any naive enthusiasm. We would not really need GMO if we were not overpopulated; we are overpopulated; so we will need GMO; but that is no cause for celebrating GMO. It just is what it is.

Future with driverless cars 6: Zoning, Traffic volume and Externalities

 

This is part six of a series on changes that driverless cars may bring. I expose some of the ideas I have, mostly quite practical things. We moved project troglodyte to it’s own website, so the more patent centric recap of the Google driverless car patents can be found from there.

Below I assume that the problem has been solved completely. Driverless cars can access any part of the road network, function even when there are people darting around and can handle any weather including lots of snow and very slippery conditions. Accident levels are same or lower than currently and people are not scared to use autonomous cars.

See also: Rental vs. taxi, Mass transportation, Pirvate cars, Cargo, Parking and driving empty, Zoning Traffic volume and Externalities

In smaller scale considerable flexibility will be created when parking can be some distance away from destinations. In densely populated areas parking facilities can be concentrated to avoid parking on the streets and the most valuable lots can be used more efficiently. In areas where snow cover makes street maintenance difficult cars can be either automatically moved to allow for removal of the snow or parking on the streets can be prohibited.

Removing parking from some areas makes it possible to create very densely built environments where walking is an attractive alternative for moving from one place to another. Denser areas also strongly support public transportation as the total trip time will be low due to short walking distances.

On a slightly larger scale putting commercial, industrial and residential districts close together would enable efficient sharing of vehicles as the same vehicle could transport several persons during one rush hour because the time driven empty would be short. In case of a city center/suburbia structure, serial sharing would also be possible if the rush hour peak is flat enough, but that would increase the total distance driven due to the long trip back to suburbia to pick up the next person.

In areas where the rush hour traffic is mostly one way and the road has several lanes to both directions using more lanes to the direction that has more traffic would increase capacity with relatively minimal investment to infrastructure. This is already possible with human drivers and even in use, though quite rarely. Using automated cars would make it much more flexible. Depending on how this is implemented it might be  necessary to forbid human driven cars from at least some lanes.

Automated cars can take kids to school. This would make it easier for people to live in very sparsely populated areas as parents would not need to drive their kids to school. Several kids could naturally use the same car when they know each other. As a downside parents might put children to schools that are quite far from their home. While this might have a leveling effect on house prices it would make the kids spend a lot of time travelling. The effect on housing prices is due to the fact that parents are willing to move to areas where good schools are available. This is apparently an important factor creating price divergence between areas.

Overall traffic volume would likely increase as driving would be easier, autonomous vehicles would be able to drive by themselves and new groups of people could use private cars. On the other hand relative price competitiveness of public transportation especially busses would likely increase.

People seem to be fairly bad at estimating how expensive driving is, this is particularly true before they make decisions that affect their driving needs for years to come. So costs of car maintenance, operation and time spent in traffic jams have a delayed effect on behavior. Because of the holding pattern parking problem an environment with many automated cars needs some sort of congestion charge system that is dependent on the distance driven and on the current need of that part of the road network. If electric cars become popular and the price of solar panels keeps plummeting, fuel cost might be close to zero in some cases. This would amplify the unnecessary use of road problem if no separate charge for road use exists.  Knowing that every kilometer is charged might have an effect on how willing people are to use a private car and lead to a lowering of the traffic volume.

The most common externalities of traffic that are affected by automating driving are land use for roads, adding to climate change and noise.

If the traffic volume does not increase significantly then the growth in capacity per road area brought by automation could lower the need for land under roads. It could also be possible to use smaller intersections especially on faster roads as traffic on adjacent lanes could have larger speed differences.

A major contributor for traffic land use change could come from the relocation of parking space to less valuable areas. Increases in popularity of public transportation will likely lead to higher throughput for the road network.

Noise is dependent on the number of cars but also strongly on their speed. Automated cars will follow speed limits so lower speeds can be used in areas where the harm from noise is large. Automated traffic can also lead to less accelerations which produce more noise than steady speed. Automated cars travelling empty can drive very slowly to reduce energy consumption.

Acknowledgment:  Thanks to Laston Kirkland for thoughtful evaluation of these ideas.

Future with driverless cars 5: Parking and driving empty

 

This is part five of a series on changes that driverless cars may bring. I expose some of the ideas I have, mostly quite practical things. We moved project troglodyte to it’s own website, so the more patent centric recap of the Google driverless car patents can be found from there.

Below I assume that the problem has been solved completely. Driverless cars can access any part of the road network, function even when there are people darting around and can handle any weather including lots of snow and very slippery conditions. Accident levels are same or lower than currently and people are not scared to use autonomous cars.

See also: Rental vs. taxi, Mass transportation, Pirvate cars, Cargo, Parking and driving empty, Zoning Traffic volume and Externalities

Driverless cars can park themselves. The driver can be left as close to the destination as she wishes while the car will find a parking spot optimizing the cost and the time it takes for it to be available for the next occupant. Parameters like the usual time the car is next needed can be taken into account when the decision is made.

When there is no need for humans to normally enter the car in the garage, cars can be closer to each other. Cars that have been scheduled for next assignment can move inside the garage as the situation changes so that they can leave as close to optimum time as possible. To enable efficient operation there will need to be a possibility for the car to take instructions from the garage computer or equivalent.

Some lowering of cost may be gained from designing the garages for vehicles only, they will need less ventilation and emergency exits. When no one is around more aggressive fire suppression methods can be either remotely used or automated. Essentially a garage will be a big machine where other machines enter and leave.

Paying for the stay must be automated as well. This may produce some conundrums as the car is in effect buying stuff by itself, but similar safeguards as used for example in Facebook marketing may be used, i.e. a maximum per minute and a maximum for a stay. As the car can move to a next garage parking space may be auctioned continually and if it becomes too expensive the car will leave and find a cheaper place to stay.

Building tunnels is cheaper if human safety does not need to be considered. Automated cars may lead to building of “cars only” infrastructure, where a vehicle carrying passengers may not enter. Empty vehicles could leave a point of interest such as a stadium through a small tunnel that is not equipped with emergency exits etc. This would allow the cramming of more capacity to smaller space in densely built areas.

Acknowledgment:  Thanks to Laston Kirkland for thoughtful evaluation of these ideas.

Future with driverless cars 4: Cargo

 

This is part four of a series on changes that driverless cars may bring. I expose some of the ideas I have, mostly quite practical things. We moved project troglodyte to it’s own website, so the more patent centric recap of the Google driverless car patents can be found from there.

Below I assume that the problem has been solved completely. Driverless cars can access any part of the road network, function even when there are people darting around and can handle any weather including lots of snow and very slippery conditions. Accident levels are same or lower than currently and people are not scared to use autonomous cars.

See also: Rental vs. taxi, Mass transportation, Pirvate cars, Cargo, Parking and driving empty, Zoning Traffic volume and Externalities

Transportation of containers between terminals is an obvious place for automated vehicles. Both the loading and unloading can be automated and the vehicles can create a rolling conveyor belt. Specialized vehicles exactly the length of the standard shipping container will likely be built, these vehicles can form trains on faster roads and thus lower their energy consumption considerably.

For cargo travelling shorter distances and requiring manual unloading upon delivery drivers might still be necessary, although they might not actually drive the vehicle. But even here a driver may not be needed. With some development it might for example be possible to unload a truck using its own truck mounted crane by remote control. The crane operator sits in an office and directs the crane using cameras and a communications link. There might still be problems like how to judge how good the support is for the vehicle when the crane needs to move a heavy load far away from the truck.

Remote operation might also be usable when the environment at the delivery or loading point is not easily standardized. Examples might be a quarry or a landfill. The vehicle would be autonomous on the road network, but remotely controlled when when the environment is difficult. This would make it possible for one driver to control several vehicles. The same operator could also control the loading equipment for example a wheel loader.

For light cargo: delivery of pizzas, groceries, stuff bought from the net etc. automated vehicles can be a real revolution. A suitably equipped vehicle may quite easily open a container when a code is given and the customer can take what was delivered. Significantly, driverless cars may make it cheaper to order a carton of eggs from the store than to drive there and buy them. Products for several customers can be delivered in the same run and the cost divided between the receivers whereas when driving to the store you pay for the whole trip. Currently in many cases the cost of the delivery vehicle driver tips the balance the other way.

It may be a bit futuristic to think that specialized pizza vehicles able to make the product would drive around the suburbs, but it is by no means impossible. Making of a pizza is not that difficult and delivering it fresh instead of 30 minutes old may make all the difference. The pizza would be ordered through the net and the pizza van would start making it so that it is right out of the oven when it arrives at the delivery location.

Acknowledgment:  Thanks to Laston Kirkland for thoughtful evaluation of these ideas.

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