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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: Mon Sep 25, 2006 9:30 am
Hello, WannabeSpaceCadet,

I can't agree to what you say.

The main point is the abundancy of sunlight in comparison to the limited ressources of uranium on Earth and to tha fact that up to now no uranium resources are known on Mars or even the Moon.

The second main point is that power is required for hundreds and thousands of years - talking about a real colony.

The second main point is that the people staying on Earth by billions won't be willing to mis the uranium they need on Earth - unless they switch completely to solar power to cover 100% of the worldwide electricity demand.

Solar cells could be produced easyly on Mars once the equipment is there - there already is an idea to produce solar cells on the Moon out of lunar silicates robotically.

Up to now I have no particular amounts of solar cells in mind except for the one calculation where the amount of solar cells delivered from Earth were the weight of less than three CXVs - less than 10,800 kg or less than 10.8 tons.

I am not sure that the lifetime of solar cells can't be increased - I am looking for more detailed informations.

The solar panels I can buy around the corner as well as the solar arrays I can buy elsewhere in Germany that are more efficient than the one I listed the specifications of aren't necessaryly those I would carry to Mars - they are at present those I can get data about. I suppose that there are other solar arrays that are more efficient than those - this too I am looking for more informations about. ...

From what did you conclude that I had in mind to send 95 tonnes of solar panels and that they produce 52,000 kWh per year? Did you calculate it from the data about the one panel offered round the corner of my appartement? How did you calculate the numbers?

The link Peter listed doesn't include no numbers about weight or kWhs - from what did you conclude or from where did you get the numbers regarding that? From what do you conclude that the people on Earth would be willing to miss 70 tonnes of uranium?

I remember a look to the electricity requirements of Germany - I will have to check it by calculations but the data don't assist what you say. A colony on Mars no way would be limited to people just living there - they would need an industry there which also would consume huge amounts of electricity. The shields against the particles of the solar wind will require a lot of electricity and to terraform the areas within covered craters electricity will be required.

Additionally the recent nuclear reactor malfunction in Sweden resulted in articles in german newspapers and journals informaing the public that reactors under maintenance or switched off automatically in case of malfunctions require electricity to avoid explosions and accidents. On Earth this is not that much of a problem because there are huge nets of reactors - the electricity infrastructure - and a lot of accumulators and batteries but on Mars there is no net and two reactors will be too few and a significant set of batteries would be required.

I suppose that at least a few misunderstandings are involved in the recent discussion - ...



Dipl.-Volkswirt (bdvb) Augustin (Political Economist)

EDIT:

Because I mentioned abundancy of sunlight and limited ressources of earthian uranium and because I doubted if the earthian people would be willing to miss those 70 tonnes you mentioned, WannabeSpaceCadet I had a look to Wikipedia (german) to find out the amount of uranium economically minable:

1.73 mio tonnes - 3.17 tonnes for sure vs. 11.28 including suspected minable ressources

440 nuclear reactors worlwide needing 68,000 tonnes per year (EU 20,000 tonnes)

25 - 47 years until the world running out of economically minable uranium vs. 166 years including suspected minable ressources - this time will be reduced if the capacities are increased.

I will have to read much more - but these numbers don't favor the use of earthian uranium on Mars because of the limited amounts.


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Post    Posted on: Mon Sep 25, 2006 6:45 pm
Ekkehard I used your numbers for 1565.6 solar panels, but I see I slipped a decimal point. It would only be 9.5 tonnes. This changes the advantage of the nuclear reactor to only 168 times as much power for the same weight.

If the abundance of sunlight was the key factor, then solar power would be the economic choice here on Earth. In fact it would be 2.25 times more economic than on Mars! But it isn't the first choice here, is it?

Uranium is pretty much everywhere. The "economically minable" reserves are economical under the current market conditions. As they are exhausted, lesser grades will become economical. Besides which, I think the people of Earth might be willing to spare 0.001% of their uranium to keep a million Martian colonists going for 1000 years.

Since you are postulating a colony of millions of people on Mars, I will postulate large scale mining of the Asteroid belt (just next to Mars and a lot easier to get to from Mars than LEO is from Earth). There must be billions of tonnes of uranium there.

Alternately, nano-bots could extract minute traces from other ores. The little guys could even separate the 235 from the 238 for us too.


Reallistically, to get a big colony to Mars, fusion power will be needed.
So fusion reactors, fueled with deuterium from Martian polar ice cap water, will be used to power it. If you can't accept that because that technology is not available, then you can't accept a large Mars colony we also don't have the technology to establish.


We could establish a small Mars base/settlement, with today's technology, so power solutions for that are sufficient for a small base are all that need be dicussed.

Solar panels would be sufficient for a short term stay, with limited capabilities. But a small reactor would allow a very long term stay, with hugely more capabilities.


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Post    Posted on: Tue Sep 26, 2006 5:55 am
Hello, WannabeSpaceCadet,

if I remember correct I have calculated the 9.5 tonnes myself earlier and agree to that number - but it still is unclear to me where you got the numbers about SSTAR.

The difference in the degree of being economical between Mars and Earth regarding solar power is no valid argument against the use of solar power on Mars - valid arguments only can be differences between power sources on Mars or between locations on Mars.

Which source is the first choice on Earth to a large degree is determined by politics, economics, culture and not that much by engineering, technology and the like.

Market conditions are no proper criterion here because the time horizon regarding a colony is several hundred to several thousand years while market conditions can be approximated or estimated for a few decades maximum. This is one of the essential reasons why all the alternative power sources should continue to be considered here in parallel - no one should be ruled out but trade-offs are reasonable and the results of the trade-offs can cahnge from time to time.

If people will be willing to spare 0.001% of uranium or not is an opinion - no problem with opinions but they don't work as arguments because each one here is free to have and apply a different opinion (like me myself).

The mining of asteroids hasn't been considered sufficiently yet - it's far from that. There already is one thread about it in this section and it will be interesting to proceed there. Up to now I can't remember no information that uranium has been found there - but there are physical arguments that it might be rare out there.

Regarding fusion power I already answered to spacecowboy that I would or might prefer it - but no numbers are available about it that I could apply. Please remember - I want to do calculations about required investments and costs in the Financial BArriers section. This I can't do for power sources I have no commercial and no sufficient numbers else about. This causes limitations to some or a few power siurces - limitations that no way mean that I am against the remaning power sources.

I am discussing technologies here - but I am interested that the technologies are economically feasable on Mars. Fusion power for example is working already on Earth but it isn't economical yet because more power has to be consumed to get power by fusion - which is a loss economically and because of this anargument agaisnt fusion power at present in real life and according to the researchers.



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Post    Posted on: Wed Sep 27, 2006 2:05 pm
I am looking for more informations about the solar arrays of the ISS. Among others there is the link iss-solar-arrays.information.dyndns.dk .

The article lists the following data:

Quote:
... The power management and distribution subsystem disburses power at 160 volts of direct current (abbreviated as "dc") around the station through a series of switches. ...


Quote:
... To meet operational requirements, dc-to-dc converter units step down and condition the voltage from 160 to 120 volts dc to form a secondary power system to service the loads. ...


Quote:
... With all eight arrays installed, the complete Space Station is large enough to cover a football field. Because the Space Station needs very high power levels, the solar arrays will require more than 250,000 silicon solar cells. ...


Quote:
... The complete power system, consisting of U.S. and Russian hardware, will generate 110 kW (kilowatts) total power, about as much as 55 houses would typically use. Approximately 46 kW will be available for research activities. ...


The article includes a table implicitly providing data I am interested in.



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Post    Posted on: Sat Sep 30, 2006 10:37 am
As I pointed out earlier, the possibility of a large scale Mars colony (> 100,000 people) is at least many, many decades in the future. The power generation technologies that will be available then cannot be reasonably estimated, but will almost certainly include fusion or better.

So there is absolutely no point in talking about what current technologies could be used by a Mars colony.

For a near term base or small settlement it is reasonable, but we have already covered that.


Last edited by WannabeSpaceCadet on Mon Oct 02, 2006 7:46 am, edited 1 time in total.



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Post    Posted on: Sat Sep 30, 2006 4:16 pm
Yes - such a colony will be decades in the future if - anf only if - the privates don't get there earlier even than a manned Mars mission by NASA. This possibility has alread been mentioned in one thread. Not by me but by one or two others - rpspeck perhaps but I am far from sure.

But even in the case of decades the considerations does make sense - regardless of when a colonization might take place it is required to know what the requirements of investments are. Thuis menas that it has to be known into which alternative ressources could be invested and what the installation of the required equioments to use those sources require.

Based on that calculations can be done - and these calculations then can be updated each time when something has been improved, invented and so on. Then it can be ssen if the requirements - in dollars - are increasing or if they are decreasing.

I might say more about that but want to cease that here and I also don't want to talk about those economics in this thread.

But there is also another reason to consider the generation of electricity on Mars here and now - it is interesting to find out how realistic the science fiction ideas and stories are that use, include or consider colonization. None of those SF I have read use fusuon and it seems that in Star Trek the Mars isn't colonized - only the arestationary orbit has been used to build the Enterprise above Utopia Planitia.

SF, the thread about popularizing the Mars, the idea that the private might get to the Mars -all together more than sufficient to consider martian electricity generation. In my eyes - of course others can think about it differently but this doesn't mean that nobody must talk about it.



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Post    Posted on: Mon Oct 02, 2006 8:06 am
OK, now you're using Star Trek and 'realistic' in the same paragraph. Them's fightin' words. :lol: And a contradiction in terms.

Star trek is mostly very poor science. They tend to make up pseudo-scientific explanations & solutions to problems, like the ever faithful "reverse the polarity". I've posted more details in Space Entertainment & Humour.

Try reading Red Mars, Green Mars & Blue Mars by Kim Stanley Robinson, for a more realistic look at technology.

I can't think of a single SF movie or TV show that is 'hard' SF.
Alien & Aliens come close, if you ignore the bit about an alien that can gestate in a human host. :lol:


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Post    Posted on: Mon Oct 02, 2006 12:13 pm
I was speaking about fidning out, how realistic it is - which means to doubt if it is realistic. In Star Trek Mars isn't colonized - in so far it will not be unrealistic regarding the colonization of Mars because

a) regarding Mars nothing has been done that might be unrealistic

and

b) it doesn't mean or say yet that Mars couldn't be colonized.

Rgearding the books you mentioned they might look realistic - even to me perhaps - but this isn't sufficient because the relation between the economic requirements and the economic possibilities isn't known.

That relation involves the generation of electricty on Mars also. ...



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Post    Posted on: Mon Oct 02, 2006 5:36 pm
WannabeSpaceCadet wrote:
OK, now you're using Star Trek and 'realistic' in the same paragraph. Them's fightin' words. :lol: And a contradiction in terms.
*cheers*

WannabeSpaceCadet wrote:
Star trek is mostly very poor science.
That could very well be the understatement of the decade.

WannabeSpaceCadet wrote:
Try reading Red Mars, Green Mars & Blue Mars by Kim Stanley Robinson, for a more realistic look at technology.
More realistic, but not perfect by any means if I remember correctly.

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Post    Posted on: Mon Oct 09, 2006 10:53 am
In between I found additional informations about solar cells already in use. And this time they are solar cells used on Mars.

The article "Mars rover enjoys mysterious power boost" ( www.newscientist.com/article.ns?id=dn6566 ) says that
Quote:
Opportunity’s 1.3 metres of solar cells provided about 900 watt-hours per day when the mission began in January 2004
- a number that completes the numbers already available to me. I will do something by it later.

Of course the article also tells a number related to the martian dust that gathered on Opportunity's solar cells:
Quote:
but that level had dropped to between 500 and 600 by June as dust slowly accumulated on the horizontal panels and as winter advanced.
- I seem to rememver that I already mentioned in another thread that solar panels futurely used on Mars should be non-horizontal - if they are used away from the equator at least. The reason was that the sun there never will be in the zenith.

Furthermore the article says that the power increased
Quote:
- to more than 700 watt hours per day –
again later.

...



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Post    Posted on: Wed Oct 18, 2006 12:12 pm
Hello, Andy Hill,

a bit more than a month ago you wrote

Quote:
Here's an article quoting NASA as saying that it would have been possible to use solar power for the Cassini probe instead of nuclear. It goes on to say that even out as far as Neptune solar power is an alternative due to advances in solar technology, perhaps this indicates that solar power is more viable on Mars than originally thought.

I now the article is obviously from the anti-nuc groups but does anyone have anymore information on these advances? I had thought that Nuclear was really the only sensible option for any Martian colony numbering over a couple of dozen people but perhaps I'm mistaken.

http://www.sunvalleyonline.com/news/art ... ticle=2445

.

It doesn't fit completely or directly into that but hile preparing another post for this thread I found an article under www.wissenschaft.de that says that some scientists found a wy or chance to increase the efficiency of solar cells via transformation of the low-frequency-section of the spectrum of the sunlight.

The green light is shifted to the blue part. This is done by applying a combination of two molecules that absorb photons of the green light and combine them to photons of the blue section of the spectrum.

The central component of the applied principle consist of a so-called non-linear absorption process by which two photons are absorbed by a molecule in parallel. This shifts one of the molecues electrons to a higher level of energy than in the case of he absorption of only one photon. When the electron later returns into the lower energy level a few fractions of a second later one single photon is emitted which as the added-on enegry of the two original photons.

Originnally and formerly this was possible only by using very intensive light which forced the application of lasers.

But now this has been achieved via a trick. Two different kinds of molecules have been used the one of which absorbes photons of the green section of the spectrum and transfers that energy then directly to the second kind. These molecules then kept the increased energy state long enough to be able to exchange enrgy between each other

his way some of the molecules of the second kind got an energy that originated from two green photons. around five milliseconds later these molecules emitted this energy as blue light

During that experiment the ouput was 1% only - but the scientists think that the concept can enhance the section(s) of the spectrum that is available for transformation of enegry via solar cells. photons of energies below the actually usable section then can be transfrmed via the molecules into photons the slar cells(s) do absorb.

The article refers to the Max-Planck-Institute of Research of Polymeres, Stanislav Baluchev and his team, and to the Physical Review Letters, Vol. 97, article 143903 ( link.aps.org/abstract/PRL/v97/e143903 ).

By the way - I discussed at least one of the aspects I clarified earlier with one of the posters via PM and perhaps post about it later keeping the confidence of PMs.



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Post    Posted on: Fri Oct 27, 2006 11:23 am
Since there are data avilable about fuel cells I will include the numbers about them also later.

What I am at present doing regarding solar panels isn't ready yet but I should talk now a bit about the aspects discussed via PM.

Physical arguments have been used a few posts earlier when preferences for nuclear reactors were expressed. While I am still missing the sources regarding two of the numbers used there there are reasons why those numbers are no way sufficient to objectively state or underline the hypothesis that nuclear power were more efficient than solar power.

The reasons are as follows:

- The data used are absolute numbers simply. This means that they are NOT considered in relation to the real requirements, demand and so on. Consideration in such relations might show that the absolute numbers are below or a bove demand/requirement - which both mean suboptimality. In the case of "below" additional power source(s) is required while in the case of "above" power would be generated that isn't needed where it is made available - but this surplus might be required elsewhere where it is not available yet. This is meant in terms of Physics.

- The data used don't ask for the requirements elsewhere nor tell about them which means that other data have to be combined to them. These data can be provided from the elsewhere only. This underscores that the data used are local data - with "local" being the mathematical term used in the analysis of mathematical functions. The aspect that the data must be delivered from elsewhere shows that the data used don't take into account sufficiently that the world isn't a mathematical dot but a three-dimensional object with a two-dimensional surface - which means that nowhere in the solar system all data required are available instantaneously or completely.

- There are factors - a lot - Physics don't take into account and can't take into account which is not to be blamed on Physics not on nothing else: It simply is the consequence of (their) nature. These factors are consciousness and psychologic factors. The world is controlled by conscious beings - humans in the case of Earth and the solar system (as far as is known). The solar system can be included because mankind has the technolgies to go to other planets. Humans have desires, requirements, visions, dreams, interests and the like - they conscious of them and try ad struggle to make them reality. Each of them does this of himself and to prevent him from that means to hurt his rights of freedom, his property rights, constitutions of countries - and there are much more reasons not to remove the freedom. Most of this can't be expressed by (cardinal) numbers nor by absolute numbers - the reason why it unreventably is out of the reach of Physics. But it all generates and causes requirements including additionally required electricity.

- Most people don't know Physics and it can't nor mustn't be expected because daily life as well as long-run-requirements of life require knowledges and capabilities that to get takes so much time that too few time is left to learn Physics. It also is required to do work that doesn't have to do with Physics - taking additional time.

- Much closer to the focus - the generation of electricity by the applying the Physics that allow for that generation depends on other physical phenomenons to applied before that generation of electricity: the Physics of building a nuclear recator or a solar panel or a fuel cell, the Physcs to be applied to transport what the nuclear reactor is made of and its fuel, the Physics required to produce the tools and machines of mining fuel (uranium), all the physics required to provide food, potables and cloths for miners, drivers of lorries and workers who build a reactor.

- The relevancy of non-physical factors can be seen easyly by having a look onto the oil markets and exchanges: the prices are very volatile and float from day to day - which the Physics of mining (for example) don't. Also those prices differ all over the world at the same time (Rotterdam, New York, London...).

- To meet all the physical requirements machines are required which consist of materials to be mined. And the physical needs of workers are can be covered only by food which also is matter. The materials and food are traded and have a price - which means that their prices include Physics in their translation into terms of Economics. Along the complete chain of physical requirement/Physics parts, machines, materials are traded according to requirements of Physics - meaning that Economics as completely as possible take into account Physics. Physics is a base, a firm ground Economics "walk" on.

- There is a complete net or web of physical requirements, connections, links around the whole Earth and allover the solar system and the Universe that is taken into account by the complete Economics.

- (not discussed by PM this way) There is no generation of electricity without materials (uranium, solar cells, casing of fuel cells, turbines etc., walls of buildings) while in Physics no energy can be produced nor needs to be produced due to the Main Laws of Thermodynamics. From this it follows that the price, the tariffs charged by electricity companies do NOT have nothing to do with the electricity or energy - they only have to do with the materials (inclduing food) required to be able to deliver electricity. The tariffs and price are NEVER a price for kwhs - charging a tariff on kwhs simply is the only way to make plausible to customers why they need to pay just that amount of cash they are called for to pay. The tariffs and prices are tariffs and prices of materials: the prices of fuel plus the depreciations of the reactors.

Regarding energy and electricity - of course there is transformation of one sort or form of energy into another. and really this is done by electricity companies.

This all deserves its own thread because there have been arguments at this board in other threads - arguments that had no way to do with electricity - that mix definitions, terms, aspect and include misunderstanding. The thread only would improve the understanding and clarify things.



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Post    Posted on: Fri Nov 03, 2006 8:28 am
This morning the newsticker of www.welt.de is reporting that the mechanism has been found by which plants split water into hydrogen and oxygen. The locations and distances of those atoms, the geometry has been found.

Explicitly the finding is of advantage for the hydrogen-technology which some posters already have proposed as electricity-sorce for Mars.

According to the article plants use a combination of one Calcium-atom and four Mangan-atoms that are connected by five oxygen-atoms to split water during the photosynthetic process of altering carbondioxide plus water into glycosis and oxygen.

It's assumed that this finding might be usable to artificially split water into hydrogen and oxygen without getting ne carbondioxide as according to the article is the case at present.

The article refers to the journal Science and Johannes Messinger, Max-Planck-Institute for Bioanorganic Chemistry in Mülheim upon Ruhr.

This would mean that on Mars no plants would be required to generate hydrogen - and the hydrogen got the new way would be a renewable energy source that is driven.

This not only is another way to use solar power - it also uses slar power to simplify the use fo fuel cells on Mars as one alternative to solar arrays.

...



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Post    Posted on: Sun Nov 05, 2006 4:02 pm
As I said earlier accumulators appear to me as one solution to hanlde variations of solar power such as the day-night-cylce, seasons, dust storms, regional variations due to latitudes and hills or mountains, the variations of the forces driving wind-, dust- or other turbines or even to store surplus eöectricity generated by walking and other movements.

For this reason I continue to pay attention to the devlopments of accumulators.

The edition of Wirtschaftswoche of 30th of October 2006 is reporting that a team of engineers of the company Lange-Flugzeugbau in Zweibrücken (Germany) has developed an airplane driven by an electromotor powered by 72 Lithium-Ion-batteries, This motor is used if there is no Thermic – the airplane is a sailing airplane.

Obviously the 72 Lithium-Ion-accus are sufficiently light that the airplane still can use Thermic.



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Post    Posted on: Mon Nov 06, 2006 10:52 pm
Yes lithium-ion batteries are becoming quite efficient. There are a few production sport cars, now entering the market, that use them and have quite reasonable range and performance.

But there is a big difference between; charging overnight from constant mains power for use the next day, and charging during variable lengths and intensity of day for use both at night and 200 to 500 days later in winter.

Some of the factor to consider:

Battery charging efficiency. i.e. how much more power has to go in to get out a 'full charge'.

Battery self discharge rate when charged. i.e. batteries lose charge over time.

Battery life cycle. i.e battery total capacity drops slightly with each charge/discharge cycle. How many cycle before it becomes unusable. Li-Ion usally 300 to 400 cycles.

Battery permanent capacity loss during long term storage at 100% charge. This can be 5% to 10% in a year for Li-Ion.


I'm tempted to write a little Mars Power simulator program. It would allow entry of solar cell & battery performance and quantities, to meet a nominal average power demand. Starting in the middle of martian spring, it would measure the amount of energy collected & used, and indicate power shortages, over several years.

And I wouldn't even throw in a year long dust storm. :wink:


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