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Energy generation at the Mars, for the martian rovers etc.

Posted by: Ekkehard Augustin - Fri Feb 25, 2005 2:58 pm
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Energy generation at the Mars, for the martian rovers etc. 
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Post    Posted on: Sun Sep 10, 2006 3:51 pm
There is work on projects for radiation shielding equipment for the Moon. If I remember correct there is Centennial Challenges Prize for a technology shielding against the particles of the solar wind.

That equipment will be a reasonable if not really good shield on Mars too because the solar wind isn't that throng there as it s on the Moon - due to the larger distance over which it spreads over a larger area and region.

Against non-particle-radiation there might be filters, limiting outlook to indirect view and the like.

Regarding the nuclear reactors and their lifetime the question is how often they are shutdowned, if they are used at the same levvel allways and son on. May be that they are run at lower levels when low velocity or really no velocity is desired compared to fast velocities.

To shutdown the output of nuclear reactors is not that problem - each power element consists of power beams and control beams. By shifting the control beams between the power beams the output can be reduced easyly.

In opposite to the nuclear reactors civil reactors are run at a relatively constant level because of relatively constant demand for electricity. They are shutdowned for maintenance mainly - and for changing the power elements when they are burnt down.

Settlements - colonies: A settlement is something small compared to a colony and I am checking and challenging the idea of a colony at present.

Anotehr point is that the maintenance requirements of nuclear reactors require a minimum of staff. This means that a nuclear reactor requires a larger population than a solar array. The nuclear reactor has more mechanical parts and its components have a larger weight

Also at least one back-up nuclear reactor would be required because of the shutdowns required when maintenance is to be done or the power elements are to be changed.

And decades isn't sufficient - speaking about colonizing Mars means to speak about centuries if not milleniums of living there including to be born there and to die there. Life like here on Earth - not go there and return later. What I have in mind is the question if that would work - this can't be answered by looking to the Earth where it works since billions of years.

Regarding the power elements Wikipedia says that they consist of 63 to 0 control beams to 263 power beams plus 20 control beams - depending on the type of reactor. There is at least one type of reactor that uses spheres.

A single power beam may have a length of 4.17 m and be 11 mm thick. To this a very thin hull has to be added - less than 1 mm thick.

I am still looking for data about the lifetime of a power element - but the lifetime no doubt is less than a decade. In Germany there are often transports of burnt down power elements causing the Greens and other anti-nuclear people to barr the transportation lines, damaging rails and so on.

The lifetime of a nuclear reactor is limited to a few decades - that's a problem regarding a colony of a lifetime of centuries or even milleniums. But the larger problem is the limited lifetime of the power elements.

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Post    Posted on: Mon Sep 11, 2006 5:40 am
( Quietly banging head on wall... )

I think you mean control & fuel rods.

A small reactor would need much, much less maintenance and assembly than the same number of solar cells, batteries, fuel cells, storage tanks etc.

The mass brought from Earth initially would be 10's or 100's of times less too.


Civil reactors are run at extremely high pressures, temperatures etc, for economic efficiency reasons. Military reactors are designed for alternating periods of very high and very low power and minimum foot print.

Our Mars base reactor would be designed for moderate power, over a long period of time with minimal maintenance and maximum safety.

It might come in a sealed core unit, without much shielding, and a separate heat exchanger/electrical generator. Each massing 5 tonnes or less.

Use a bulldozer to scrape a sloping trench 50 m long, 10 m deep at one end with a 90 degree bend in the middle. Place the core unit at the deep end, on an insulated stand. Connect helium coolant hoses, and control cables. Cover with a light-weight, pre-fabricated, sem-cylindrical shell. (Probably dis-aasembled tanks of the rocket lander). Fill in the trench with dirt previously removed. Run the hoses (on insulated mounts) and cables to the generator unit, just inside the entrance to the tunnel. Switch it on.

The core would provide power for decades, then at the end of its life, either the generator would be removed and the tunnel filled in, or the core could be removed, placed on a rocket and launched at Jupiter. Replace it with a new core brought from Earth or eventually one built on Mars.

Coolant leaks are no problem since helium can't become radio-active. The core would be designed so that even in the worst-case at full power and no cooling, it would never get hot enough to meltdown. It might melt the permafrost, but would then just slowly sink deeper into the ground until it ran out of fuel in however many decades.


Surprisingly, civil reactor are NOT built for maximum safety. If they were, they would be economically less competitive. It is entirely possible to build a gas-cooled reactor, for which meltdown would be impossible, and coolant leaks no danger. But such a reactor would produce much less power for the same capital investment.


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Post    Posted on: Mon Sep 11, 2006 11:44 am
Hello, WannbeSpaceCadet,

Thank You Very Much for the correction - I'm very often unsure which translation is the correct one.

Obviously you and me are thinking about different scales of "population" - you are thinking and talking about a Mars base while I myself am NOT talking about a Mars base but about a real colony of thousands and millions the realism of which I am checking, stressing and challenging.

Such a real colony of thousands and millions would need a civil reactor that has to be economically efficient. Nearly everything in such a colony would have to be economically efficient and as a consequence all technologies have to work economically efficient.

Without that it even would be impossible to trade with Earth.

I am still looking for the lifetimes of power elements but got only very indirect informations up to - which all assist what I said: the lifetime significant less than the lifetime of the reactor itself.



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Post    Posted on: Tue Sep 12, 2006 12:58 pm
Ekkehard Augustin wrote:
I myself am NOT talking about a Mars base but about a real colony of thousands and millions
Even more reason not to rely on Solar power. It is the same reason we on Earth do not rely on solar power. It takes too much collecting area and too many batteries to store power for night time use. Solar may be good enough for a base or small settlement, but as the colony grows from thousands to millions, solar becomes less and less feasible. Solar cannot supply a million people on Mars for the same reason it cannot supply a million people on Earth. In the far future, new technology may alter reality, but the reality now is that solar is too weak a power source on Earth, and even weaker on Mars, and my guess for a future reality is fusion power.


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Post    Posted on: Tue Sep 12, 2006 1:05 pm
If those damned French would just do what they said they would and build my fusion reactor, we'd all be very happy.

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Post    Posted on: Tue Sep 12, 2006 2:06 pm
Hello, spacecowboy,

once there is - or would be - a fusion reactor I at present suppose that I might prefer it.

Regarding use of solar power on Earth, required area and another point the situation and evolution is as follows:

- In Europe the use of solar power as an alternative to nuclear reactors is growing.

- The density of population on Mars never can be close to that of Earth because there is too few water on mars compared to Earth - and so there will be sufficient area be left for solar arrays. This will be no problem.

- The ressources of uranium on Earth are limited while sunlight is not limited for the next four to five billion years.

Because of the last of these three points martian nuclear reactors will require resupply from Earth within periods shorter than ten years. The transportation means costs which to calculate I am interesting in. The reactor itself has to be transported too in components - these costs I want to calculated also. Even the costs of the transporation of the solar array I want to calculate. I will do that in the Financial Barriers section later - but to do so I still have to find the lifetime of power elements and some other numbers.



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Post    Posted on: Tue Sep 12, 2006 5:55 pm
Ekkehard Augustin wrote:
- In Europe the use of solar power as an alternative to nuclear reactors is growing.

Only in Germany. France continues to embrace nuclear. Even in Germany, wind power far surpasses solar, which is not surprising given the northern latitude which severely limits the amount of solar energy reaching the surface. By the way, this web page is interesting: http://www.cslforum.org/germany.htm
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A huge change in its generating infrastructure is on the horizon, as Germany has agreed to phase out nuclear power generation over the next two decades. Replacement will most likely be a mix of gas-fueled and coal-fueled power plants, as well as increases in renewable energy and much greater electricity imports (probably from neighboring France and the Czech Republic).

Ekkehard Augustin wrote:
martian nuclear reactors will require resupply from Earth within periods shorter than ten years.
You keep saying that but it is not true. There are existing reactors that do not need resupply for 30 years and reactors that can run 100 years without refueling are possible according to what I have read in Wikipedia.


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Post    Posted on: Tue Sep 12, 2006 9:53 pm
Solar power power is much more cheaper and safer and you dont need to produce electricity for new york you need to produce energy for 10s to maybe 100s of people. Or We could just bring a massive coal power plant and heat that baby up via mars :wink:.

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Post    Posted on: Wed Sep 13, 2006 8:54 am
Hello, Peter,

the information that the use of solar power is growing in Germany only is quite wrong. There often articles under www.welt.de and in the journal Wirtschaftswoche reporting about growing use of solar power even in spain particularly.

That in Germany wind power surpasses soalr at present simply ois the present state while I am speaking about a growth of the use of solar power - the recognition of a growth of something allways is the result of a comparison between at least two states and consequently one single state (regardless of a present one or a past one) never can be accepted as an argument against growth. By logic.

What's limiting the amounts of sunlight reaching the surface over here in Germany are clouds merely than everything else - as a German living in Germany I know that by experience.

The state of photovoltaic technologies has proceeded that far here that I can buy solar arrays just around the corner of my appartement literally. They are offered from powering the appartement or a complete house down to recharging car batteries by solar power. Even TV can be powered by them. The prices are ranging from between 20 Euros and 30 Euros up to 400 Euros in the concrete small shop I am speaking about here. And I remember times when the prices were significantly higher.

To some degree the degree to which a particular power source is used or growing depends on politics - and what politics favour seldom has to do, what is economical efficient or reasonable. In Europe at least such favours are ruled by ideologies mainly - the only exceptions are libertarian parties here.

This menas that the present stet as well as the growth doesn't have to do with the economical or physical possibilities and opportunities.

Spain in particular has reasons to use solar power that apply to Mars also and I have listed in the post yo are responding to: Spain - and in particular Andalusia - suffers by an increasing lack of water and humidity. Andalusia is very dry and travelling there ten years ago I have seen several rivers dried out and trees having growing out of their beds which in betwwen are dead and dry also. So they can't use water craft. For environmentalist reasons they don't want nuclear rectors - but those reactors need water too - and again it can be argued that there is the lack of water in comparison to Germany etc.

Safety of a nuclear reactor against Cernobyl-like accidents depends on water partially and lack of water tends to reduce safety in so far. Saying this I am thinking of the explosion merely which would mean that suddenly the source of electricity disappears. This is a risk that would be deadly on Mars - a risk that is of larger meaning that nuclear pollution.

Regarding resuply I already said that I have my information from a construction engineer who knows to construct civil nuclear reactors and that I am looking for web-sources about that. And all the reactors that are reported about in german media require periodical resupply after less than ten years. There Castor-transportations again and again - after periods of less than ten years. A Castor is a container for burnt down power elements and they are transported to particular final stores within particular large given up salt mines. The one the german anit-nuclear Greens are focussing their resistance against is a salt mine near Gorleben in the Wendland in Niedersachsen in Northern Germany - around 100 km from Hamburg at the south shore of the Elbe.

In so far you can't be speaking about civil nuclear reactors when you talk about "do not need resupply for 30 years" and "reactors than can run 100 years without refueling". I cannot agree before I know the Wikipedia-sites you are referring to and have read them myself. When I know them and have read them I can and will check what to think then.

A martian colony requires a civil reactor that is economical efficient and as safe regarding explosions as the civil reactor in Stade was.

On Mars more purposes will require electricity than on Earth because a martian colony is significantly more fragile than any settlement on Earth - the reasons are the thin atmosphere, the lack of a planetary magnetic field, the very small ressources of water, the lack of an ecological system etc. ...

I am out on numbers as base for cost calculations to find out the financial barriers - number regarding solar power as well as numbers regarding nuclear power as well as numbers regarding wind power as well as numbers regarding biomass as well as numbers regarding etc. ... - this will enable neutral, objective, topic-oriented and ideology-free comparisons.



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Post    Posted on: Wed Sep 13, 2006 12:04 pm
Ekkehard Augustin wrote:
The state of photovoltaic technologies has proceeded that far here that I can buy solar arrays just around the corner of my appartement literally. They are offered from powering the appartement or a complete house down to recharging car batteries by solar power. Even TV can be powered by them. The prices are ranging from between 20 Euros and 30 Euros up to 400 Euros in the concrete small shop I am speaking about here. And I remember times when the prices were significantly higher.


Things havent moved quite so fast in the UK, although solar panels are easy to get hold of they are still very expensive.

http://www.maplin.co.uk/Search.aspx?cri ... &source=15

This company quotes about £1000 for a panel producing 150 Watts of power (you would need something like 13 of these for an average home on Earth), how much power do the ones you are referring to produce? They also come with a 20 year life guarantee which I would have thought will be considerably reduced when working in a Mars environment. These would also be quite heavy so would cost a lot to transport to Mars.

All of this leads me to suspect that it will probably be necessary to create special solar cells optimised for use on Mars which will obviously come with a much higher price tag.

Another question, am I right in thinking that Mars has periodic dust storms that block out a large percentage of the light reaching its surface for possibly month's at a time? If this is true then I am even less sure that solar power is a good option.

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Post    Posted on: Wed Sep 13, 2006 1:17 pm
Hello, Andy Hill,

I will chack for the Watts the solar panels provide that I can buy round the corner at home but I seem to remeber that they are at least slightly above 150 Watts in the 400-Euro-case - which may be due to governmental subsidies for this alternative source of electricity.

Regarding the dust storms I still think that electricity should be stored into accumulators and condensators for use during dust storms. And it has been checked out yet scientifically if wind turbines might be used or if this is not the case. Plus it might be worth to test if the causes of the dust storms might be used somehow. It is suspected that dust devils are caused by dust grains charged because of their movements and firction to each other.

But I am focussed on accumulators and condensators for those times when no sunlight is available. Regarding the day-night-period electricity might be transmitted from the day-side to the night-side perhaps - in addition to the electricty storages.

The weight of solar cells I am looking for and already found a few numbers - but these informations are too few yet from my point of view. I have to look for more to get a broader spectrum of data and informations.

As far as the lifetime of solar cells on Mars is limited by radiation and particles of the solar wind two technologies might be used to enhance that lifetime:

1. A shield technology against particles of the solar winds is already under development for a permanent manned lunar station. That technology should work on Mars also - and even result in larger reductions of particles there because the particle density there is 4/9 of that on the Moon

2. Regarding Gamma rays, X-rays and UV I remember the filters the cameras of the Cassini-probe are using to get images in infrared only, in UV only or so. Such filters might be used to protect solar cells against such radiation perhaps.

Another point might be that solar cells are optimized for that fraction of the spectrum of sunlight that is available on the earthian surface - another optimization might be possible for use on Mars. Then UV might be the best source there - and using it might mean that Uv doesn't reduce the lifetime no more.

The costs and the price never should be taken absolutely here - they allways have to be traded of against the costs and prices of the alternatives. And the opportunity costs have to be taken into account also - in principle these are part of the discussion already when I am or was mentioning that uranium and water are limited ressources that can or/and will determine the fate of each trial to establish a viable colony of a lifetime of hundreds or even thousands of years while sunlight will be available for billions of years yet. The death of the colony because of no more or too few uranium in the far away future is part of the opportunity costs of using uranium etc. while the abundant availability of sunlight means that this part of the opportunity costs of sunlight as power source is coverging to zero. To consider these opportunity costs is very essential if colonization of Mars or another planet in the solar system is considered...



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Post    Posted on: Wed Sep 13, 2006 3:21 pm
Ekkehard Augustin wrote:
But I am focussed on accumulators and condensators for those times when no sunlight is available. Regarding the day-night-period electricity might be transmitted from the day-side to the night-side perhaps - in addition to the electricty storages.


These would need to be huge/heavy to store enough energy to supply a colony for a few months and would need to be produced on Mars rather than transported. One alternative might be to use excess power during sunlight months to split water using electrolysis into H2 and O2 and stored in underground tanks, this could then be recombined using fuel cells to provide energy during dark months.

Ignoring obvious problems like boil-off it makes sense to use this method as any surplus could also be used as rocket fuel and the only by-product is water. It will also propably be easier to transport liquid gases rather than transmit power around Mars if fuel levels run low.

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Post    Posted on: Wed Sep 13, 2006 3:26 pm
Ekkehard Augustin wrote:
all the reactors that are reported about in german media require periodical resupply after less than ten years.
That is no proof that all possible reactor designs require such frequent service. I have already posted links to operating reactors that can run 30 years without changing out fuel elements. There are many current and proposed designs that overcome this problem. Do not limit your thinking to one particular type of reactor.


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Post    Posted on: Thu Sep 14, 2006 7:34 am
Hello, Andy Hill,

I have no problem with accumulators produced or to be produce on Mars. But the accumulator for the car I posted about seems to be not that a problem of weight I think.

But there is a way to store solar energy for use in times when there is no sunlight I forgot yesterday - like I posted some time ago there is the method to use sunlight to split zincoxide. The zinc and oxygen got that way can be brought together again later and their chemical reaction can be used to generate electricity - so Zincoxyde can be used as electricity storage also and this directly from sunlight. The zincoxyde can be stored easyly and might be a very good backup for times when there is a dust storm hiding the sun.

I also have been looking to the specifications of one of the solar panels I can buy round the corner of my appartement:

Code:
system voltage             12 Volt DC
performance                 41 Wp (+/- 10%)
daily performance (average) ca. 205 Wh/day (in summer)
idle voltage                18 Volt DC
minimum voltage             16.8 Volt DC
maximum current             2.3 Ampere
minimum currect             2.0 Ampere
dimensions                  1022 mm * 450 mm * 34 mm
weight                      6.1 kg


That panel explicitly includes an accumulator and can be used to power TV, radio, a caravan or trailer, a campmobile, a summerhouse and the like.

The area obviously is 0.4599 m^2. So the area of 720 m^2 the additionaly solar arrays of the ISS have would require 1565.6 of them. Per day these 1565.6 units would generate 320948 Wh = 320.948 kWh which are 117146020 Wh per year or 117146.020 kWh per year. The last number is nearly ten times what von Beecken gets by cooling his panels.

The weight of the 1565.6 panels would be 9550.16 - the weight of 2.66 CXVs.

These numbers I could use in the Financial Barriers section But I prefer to look for alternative numbers because it might be that that solar panel isn't at the current state of the technology.

The numbers are reasonable in my eyes.



Hello, Peter,

you are using the word "proof" again - I didn't use anything here as a proof. If you maintain the thought that I do then that's your subjective and arbitrary interpretation and you know that I view that as a very inacceptable and bad behaviour. In short you are focussing too much on "proof" - real proofs do exist in mathematics only.

As far as I remember your links don't link to informations about civil reactors. There are good reasons that non-civil reactors aren't used to provide electricity to homes, the public and civil purposes. These reasons wil be valid on Mars the more and so I can't accept non-civil reactors as a proper power source althought they are acceptable for science and space vehicles. But they are not acceptable for a colony on Mars that is a civil one and where the people would be living like in Hamburg, New York or Tokyo.



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EDIT:

Hello, Andy Hill,

I may have misunderstanding you yesterday or mixing something because I couldn't have the look to the solar panel in that shop prior to my answer - I had in mind the Wh per day while you were speaking about Watts but not about Wh. In so far I was wrong regarding the price.

In between I am looking for informations about solar panles from several producers and found a price of a bit less than 900 Euros for a 190 Watts-panel. That price is valid if 200 panels are bought.


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Post    Posted on: Thu Sep 14, 2006 12:50 pm
*senses another Peter vs. Ekke fight starting* First off: proof exists in engineering as well: if it works as well as or better than you anticipated, it's a Good Design. If it blows up in your face or falls apart, it's a Bad Design. Each and every engineer has to be trained to focus entirely on proof, otherwise people die. That's what our jobs are all about.

Now, on to reactors. You're right, there is one very good reason that non-civil reactors aren't used in civilian purposes: they're too damn expensive, because the quality of the craftsmanship is too high. If you want training in how to design or maintain a nuclear reactor, you work for the Navy. Period. Not a civilian power company, because the Navy trained all the guys working for that civilian power company. Military reactors are still better and safer than civilian ones for one simple reason: they have to stand up to the stress of combat.

Finally, the reasons that civilian reactors are designed the way they are will be completely invalid on Mars: you don't need to worry about people living next door to them, because you've got plenty of space. You don't need to worry about exposing them to higher levels of radiation, because any habitat has to be built to withstand the present Martian background radiation, and no reasonably efficient reactor design could possibly raise radiation levels in the habitat above background levels (especially not if it's several miles away). You certainly don't have to worry about someone complaining that it's too ugly, like you do here on Earth. A Martian design will be completely and totally different from a terrestrial design. Hell, we're talking about building these things into the ground, with all kinds of gadgets like Stirling Engines to get the power out of them. Most people wouldn't even know it's a reactor.

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