Going Solar...the best solution for Mars.

Antius · 2017-06-21 16:18:22

I love the image. Is that a maglev train in the foreground?

On the topic of solar: EROI becomes important when we start making things on Mars. At that point, we are using up whatever finite resources we brought from Earth in the hope of leveraging them into something more productive using Martian resources. For early missions it will matter less, because those missions will be entirely subsidized by Earth. As things scale up into full scale colonies, more and more of what is used on Mars must be manufactured locally. To get high rates of growth, we need high EROI so that we can invest energy in new infrastructure, rather like the city in that image.

Poor EROI of manual pre-industrial agriculture was a big part of the reason why mediaeval living standards were so poor and remained so for so long. There was very little surplus energy to support non-agricultural classes and hence scientific progress was slow. There was no excess wealth to support infrastructure development. It was the development of global trade by Britain and Europe and the harnessing of fossil fuels in the former that provided the energy surplus needed to start the industrial revolution. It just wasn't possible until the discovery of controllable, high-EROI energy sources. It is no accident that modern Western living standards are starting to decline as the EROI of fossil fuel energy sources starts to decline.

If a Martian civilisation is going to grow and prosper in a harsh environment, then high EROI energy sources are key. Without them, there is never enough surplus wealth to expand infrastructure.

Last edited by Antius (2017-06-21 16:23:09)

SpaceNut · 2017-06-21 19:21:25

So only net surplus above the daily use including whether we have dust storms is applied to making the solar panels which starts with the mining, processing and manufacturing of these to which when implemented adds to the surplus energy so long as we do not have a rise in the energy costs to get from nothing to actual working panels from the starting source of surplus energy.

louis · 2017-06-22 05:17:20

1. Don't really understand your point. Yes, something may emerge to derail a mission. But a pre-run mission to the Moon, using weighted suits in a lunar environment will probably tell us enough about the effects of simulated 1G to proceed with the mission.

2. Talking of "mines" and "plants" immediately conjures up images of huge operations because that's the way we do it on Earth, for reasons of cost efficiency. All our major industrial processes can also be conducted on a small scale. For a settlement of 20 you might only need 4000 sq. metres of PV panel, 63 x 63 metres. They could be manufactured over a couple of years at a rate of 6 per day. We are talking about processing maybe something like 10 kgs of material a day to get to something which might mass 3 kgs.

3. As these links show, PV manufacture is already "highly automated".

http://news.mit.edu/2013/solar-cell-man … costs-0905

http://www.appliedmaterials.com/nanochi … ufacturing

I imagine this would be dealt as a batch process, going through the process step by step. This link provides a guide to the basic steps involved.

https://www.solarworld-usa.com/solar-10 … al_growing

I see no reason why this process couldn't be made small scale. Clearly we would need to design a scaled down, bespoke system for the first manufacturing facility on Mars. The furnace for instance might hold 25 pounds of polysilicon rock rather than 250 pounds. The saw could be for just one ingot rather than 16 and so on.

We would then want to attempt to manufacture that, or as much as possible of it, on Mars. The furnace looks very doable. Maybe a diamond saw would be possible...even if we have to import the diamonds from Earth. Probably a lot of the key parts could be 3D printed.
Even if we still importing some of the more technical stuff, if it was 95% manufactured on Mars, that would be a major achievement.

4. The amount of material being processed is minimal and so a high rejection rate would not be a major issue. But there's no reason to think the rejection rate will be higher than on Earth.

5. I favour modest growth in settlements - maybe 50 people after 5 years, 100 after 10 years. If you have the ISRU to make energy, construct habitats, farm and provide life support then there is no real theoretical upper limit, you can just keep expanding. The real limiting factor is rocket launches from Earth and the skill-sets available from potential settlers.

kbd512 wrote:

A few quick points to hand-wave (if no amount of math matters, then surely none of this matters, either, but here it is):
1. Since nobody knows if humans can live on Mars for any substantial length of time and development programs for human space flight systems will precede any actual mission hardware deployment by at least a decade, so either the associated development program may never produce usable mission hardware if we discover in the interim that humans really can't live on Mars permanently because they require 1g or we'll have to wait ten years from whatever point we discover that .38g has no serious health effects.
2. There are no mines or ore refining plants on Mars, so we'd have to ship all materials from Earth, which kinda defeats the purpose of development of these manufacturing plants for Mars until mines and material refinement plants exist. It's one thing to do limited scale repair of existing equipment, which is what Dook and I argued about endlessly because he was fixated on industrial scale manufacturing, but an industrial scale operation is a different animal entirely.
3. There are no robotic PV panel or battery plants here on Earth, so you're either talking about devoting a good number of people to make PV panels and batteries on Mars or development of a major design automation project that most definitely won't be cheap. Any sort of automation automatically increases electrical power requirements, too, which further increases construction costs. It'd be pretty cool to finally make anything in space on an industrial scale, though.
4. The power to run a metals mine or manufacturing plant doesn't exist on Mars and you've selected the technology with the poorest mass-to-output ratio to try to achieve that unless you want to ship all the raw materials from Earth. Actual output from initial operations will likely be poor, to put it mildly. About 50% of the PV cells from SolAero are rejected by NASA's QC process from plants where mass, cost, and available labor are not major obstacles to production, a major reason why these highly efficient PV arrays are so expensive. There have been 150 missions that have a combined output far less than what would be required for a Mars colony and SolAero (formerly EMCORE) has bragged about delivering over a million cells over the course of a couple decades.
5. Given the track record of all the prognostications about what sort of technology we'd have or what we'd be doing ten or twenty years from the present, it seems a little humorous that you think any of this will happen in the span of a few years. Short of some sort of Manhattan Project to colonize Mars, I'll consider everything to be going great if we just manage to get a dozen people to Mars over the next two decades.
In any event, I wish everyone best of luck with the fantastic future colonies on Mars. If we can even set up a starter colony on Mars, I'll consider the mission accomplished and really don't care what powers it so long as it is reliable and reasonably affordable.

Antius · 2017-06-22 05:42:54

The problem with Mars made PV is that there isn't really any margin for inefficiency in the system - the EROI is only 7 under perfect conditions.

PV could be made on a smaller scale, but smaller scale ore processing and manufacturing is inherently less energy efficient. That's just the way it is. It's part of the reason why economy of scale exists. How much less efficient is difficult to say, but hand waving the issue is rather foolish since we don't know. If EROI were higher there might be room for inefficiency, but it is close to the limits of what would be workable under perfect conditions.

Simply assuming defect rates to be the same as Earth ignores the reality that you would be building panels under less than ideal conditions, with mass constraints on equipment and a more limited labour force. There is every reason to believe that this will effect quality and there is no reason at all to assume that it won't. Even Earth defect rates would be problematic, as they eat away at an already weak EROI.

A simple example: If the rejection rate of panels is 15% and the energy consumption of the process is 15% greater than on Earth, then an EROI of 7 turns into an EROI of 5.

Why would colonists tolerate low incomes and slow growth rates if they could do better? That's a bit like asking a man to walk instead of drive just so the world doesn't have to be burdened by his car.

Also, why would you assume a colony to have 50 people? Musk is readily discussing a city of 1million established in less than a century. It is hard to imagine this happening without a lot of Mars manufacturing and a high-EROI energy source to power the expansion.

Last edited by Antius (2017-06-22 05:47:44)

louis · 2017-06-22 05:53:29

I don't doubt the essential validity of EROI in the sense that a negative or very low figure means either economic nemesis or decline.

But it is easy to become bewitched by the EROI explanation. Japan never had access to high EROI fuels like coal and oil before 1860 but it was a very advanced society with much urbanisation, craft work and high levels of literacy. Tokyo had a population of 1.2 million already in 1750. I believe it was the largest city in the world then. London, for all its coal, didn't get above one million until 1810. And the people of Mesopotamia had access to plenty of oil but were in economic decline for centuries before the industrial revolution took hold in Europe.

Clearly food, education, labour productivity and technology are also key factors.

Once we are up and running on Mars, we may well find other energy sources that have a higher EROI e.g. wood burning (once we are getting plants to do the hard work of making oxygen and the wood) or natural gas (methane, which appears to occur naturally on Mars, as on Earth). This chart by the way does not show nuclear to have a very high EROI compared with other energy sources.

https://www.google.co.uk/imgres?imgurl= … YQ9QEIKDAA

My judgement is that solar energy will prove a springboard for Mars ISRU industrialisation.

Antius wrote:

I love the image. Is that a maglev train in the foreground?
On the topic of solar: EROI becomes important when we start making things on Mars. At that point, we are using up whatever finite resources we brought from Earth in the hope of leveraging them into something more productive using Martian resources. For early missions it will matter less, because those missions will be entirely subsidized by Earth. As things scale up into full scale colonies, more and more of what is used on Mars must be manufactured locally. To get high rates of growth, we need high EROI so that we can invest energy in new infrastructure, rather like the city in that image.
Poor EROI of manual pre-industrial agriculture was a big part of the reason why mediaeval living standards were so poor and remained so for so long. There was very little surplus energy to support non-agricultural classes and hence scientific progress was slow. There was no excess wealth to support infrastructure development. It was the development of global trade by Britain and Europe and the harnessing of fossil fuels in the former that provided the energy surplus needed to start the industrial revolution. It just wasn't possible until the discovery of controllable, high-EROI energy sources. It is no accident that modern Western living standards are starting to decline as the EROI of fossil fuel energy sources starts to decline.
If a Martian civilisation is going to grow and prosper in a harsh environment, then high EROI energy sources are key. Without them, there is never enough surplus wealth to expand infrastructure.

louis · 2017-06-22 06:56:57

I agree that it's wrong to assume colonists would be making lithium batteries.

Might they also make wet batteries in basalt lined trenches (within a hab)?

Terraformer wrote:

Why would colonists be manufacturing Li-Ion batteries? We mainly use them on Terra for purposes where a high power-weight ratio is needed, such as vehicles and portable electronics. How would it look if they used NiMH, or Nickel-Iron?

Last edited by louis (2017-06-22 12:51:28)

kbd512 · 2017-06-22 12:18:11

louis wrote:

1. Don't really understand your point. Yes, something may emerge to derail a mission. But a pre-run mission to the Moon, using weighted suits in a lunar environment will probably tell us enough about the effects of simulated 1G to proceed with the mission.

Before you spend billions of dollars making a factory that can operate on another planet, it's a good idea to make sure humans can live there first. That seems like common sense. There won't be a jump to factories on another planet before the first human has set foot on the planet. Right now, Mars is scientifically interesting for understanding our planet and other Earth-like planets. If .38g is no big deal for humans, then it could absolutely be a second home. I just want someone to do a .38g test in orbit for 6 months and then 12 months to see what the effects are before we spend money to build a factory somewhere we can't live.

louis wrote:

2. Talking of "mines" and "plants" immediately conjures up images of huge operations because that's the way we do it on Earth, for reasons of cost efficiency. All our major industrial processes can also be conducted on a small scale. For a settlement of 20 you might only need 4000 sq. metres of PV panel, 63 x 63 metres. They could be manufactured over a couple of years at a rate of 6 per day. We are talking about processing maybe something like 10 kgs of material a day to get to something which might mass 3 kgs.

Even if you only produce a ton of product per year, you still need to process many tons of material to get that ton of product. Gases and liquids are not terribly difficult to process, but metals mining, smelting, and machining are all high level industrial tasks that require quite a bit of energy input, even for relatively small batches. Doable, yes, easy, no.

Determine what the growth rate for the colony will be and then determine how much material you have to process to achieve that. The numbers get pretty large fairly fast. Again, this is to avoid taking something from Earth that's been tested to the nth degree by as many people and machines as we need to throw at the problem to solve it.

louis wrote:

3. As these links show, PV manufacture is already "highly automated".
http://news.mit.edu/2013/solar-cell-man … costs-0905
http://www.appliedmaterials.com/nanochi … ufacturing
I imagine this would be dealt as a batch process, going through the process step by step. This link provides a guide to the basic steps involved.
https://www.solarworld-usa.com/solar-10 … al_growing

I'm quite sure we could improve automation over and above what we already have, but how many humans will be involved, because there are a lot of other critical functions for the colonists to fulfill, too.

louis wrote:

I see no reason why this process couldn't be made small scale. Clearly we would need to design a scaled down, bespoke system for the first manufacturing facility on Mars. The furnace for instance might hold 25 pounds of polysilicon rock rather than 250 pounds. The saw could be for just one ingot rather than 16 and so on.

True. A PV manufacturing plant could be scaled down for use on Mars. Do you have any idea what the tonnages and volumes are for the equipment involved?

louis wrote:

We would then want to attempt to manufacture that, or as much as possible of it, on Mars. The furnace looks very doable. Maybe a diamond saw would be possible...even if we have to import the diamonds from Earth. Probably a lot of the key parts could be 3D printed.
Even if we still importing some of the more technical stuff, if it was 95% manufactured on Mars, that would be a major achievement.

I would like to see a factory on Mars, too... right after we're relatively certain that we can live there permanently.

louis wrote:

4. The amount of material being processed is minimal and so a high rejection rate would not be a major issue. But there's no reason to think the rejection rate will be higher than on Earth.

This seems somewhat contradictory, but within limits, it should work. I imagine there will be some sort of steep learning curve that we have to overcome, after which operations will be relatively easy and routine.

I think I would still want an energy Plan B for the colony. If a fission reactor never needs to be activated to provide power, then great, but if PV output or storage capacity is insufficient then nobody will die because they didn't get the energy they needed to survive. In time, I expect the output from PV cells and the storage capacity of batteries to improve to the point that virtually any place in the inner solar system can use them to provide electrical power, but past experience indicates that this is a slow and steady process. I'd like to see what science and manufacturing provides in the way of PV and battery technology over the course of the next five years or so. If we make some breakthrough improvements, then lots of things become possible.

louis wrote:

5. I favour modest growth in settlements - maybe 50 people after 5 years, 100 after 10 years. If you have the ISRU to make energy, construct habitats, farm and provide life support then there is no real theoretical upper limit, you can just keep expanding. The real limiting factor is rocket launches from Earth and the skill-sets available from potential settlers.

After 50 years, I imagine a colony of 10,000 people or so will be possible and that eventually the venture will become a self-sustaining enterprise undertaken by corporations for profit or exchange of natural resources in space and on Mars to build the things we want to build.

louis · 2017-06-22 13:30:29

kbd512 wrote:

Even if you only produce a ton of product per year, you still need to process many tons of material to get that ton of product. Gases and liquids are not terribly difficult to process, but metals mining, smelting, and machining are all high level industrial tasks that require quite a bit of energy input, even for relatively small batches. Doable, yes, easy, no.

They are all scalable.

kbd512 wrote:

Determine what the growth rate for the colony will be and then determine how much material you have to process to achieve that. The numbers get pretty large fairly fast. Again, this is to avoid taking something from Earth that's been tested to the nth degree by as many people and machines as we need to throw at the problem to solve it.

Clearly they do get pretty large fairly fast but the ability to manage them also increases. There is no reason why a settlement of say 500 shouldn't be capable of building large diggers and earth movers.

kbd512 wrote:

I'm quite sure we could improve automation over and above what we already have, but how many humans will be involved, because there are a lot of other critical functions for the colonists to fulfill, too.

I agree that labour time is a crucial factor. I don't think this could be attempted on the first mission or even the second. Maybe the third. It looks to me like a couple of people could handle a largely automated process. Of course that's a guess on my part. But having been in some very complex facilities where automation rules, it doesn't seem an over-optimistic projection. I think the two people would be mostly involved in monitoring, machine maintenance, removing and inserting items and possibly final assembly.

kbd512 wrote:

True. A PV manufacturing plant could be scaled down for use on Mars. Do you have any idea what the tonnages and volumes are for the equipment involved?

http://3d-micromac.com/wp-content/uploa … CE_web.pdf

This machine has a volume of 8 cubic metres. Weight not given but I am guessing maybe around a tonne? Doesn't state how many wafers it deals with at any one time.

I would hope we could get the whole manufacturing suite in under 10 tonnes.

kbd512 wrote:

I would like to see a factory on Mars, too... right after we're relatively certain that we can live there permanently.

Depends how you look at these things. I think we have already had factories on Mars - rovers gathering and processing regolith for chemical analysis.

kbd512 wrote:

This seems somewhat contradictory, but within limits, it should work. I imagine there will be some sort of steep learning curve that we have to overcome, after which operations will be relatively easy and routine.

I am not sure it will be a steep learning curve on Mars. I would think the steep learning curve will have been done on Earth. But yes,things can and will go wrong. 3D printers will come in handy.

kbd512 wrote:

I think I would still want an energy Plan B for the colony. If a fission reactor never needs to be activated to provide power, then great, but if PV output or storage capacity is insufficient then nobody will die because they didn't get the energy they needed to survive. In time, I expect the output from PV cells and the storage capacity of batteries to improve to the point that virtually any place in the inner solar system can use them to provide electrical power, but past experience indicates that this is a slow and steady process. I'd like to see what science and manufacturing provides in the way of PV and battery technology over the course of the next five years or so. If we make some breakthrough improvements, then lots of things become possible.

There's a good case to be made for nuclear. But it's not one I care to make.

Antius · 2017-06-22 14:01:55

https://en.m.wikipedia.org/wiki/Economi … ring_basis

louis · 2017-06-22 16:30:07

Economies of scale aren't really relevant to the early settlement on Mars owing to (a) lack of demand (b) the cost of exporting mass to Mars and (c) the lack of price inputs on Mars.

There's no point in building a 9GW nuclear reactor facility if you're only using 9 MW. There is a point in using a relatively inefficient small scale version of a machine on Mars if that saves you the cost - and the mass* - of importing it from Earth. Manufacturing on Mars also has the advantage that you don't have to pay rent for land, taxes or licence fees.

* Using up your mass allowance is like an opportunity cost - by choosing to import item X, you deny that mass being applied to items Y, Z etc.

Antius wrote:

https://en.m.wikipedia.org/wiki/Economi … ring_basis

SpaceNut · 2017-06-22 20:27:20

I am wondering if a payload shroud is tough enough to make use of as a shell for panel landings?

Antius · 2017-06-23 03:06:33

Economy of scale applies everywhere. It doesn't cease to apply just because you are on Mars or because it isn't convenient to manufacture in large volumes. The fact that you don't need 9GW of an energy system doesn't mean you escape from the inefficiency of only making 9MW. It will always be less energy efficient to make something like solar panels on a small scale. There will be poorer utilisation of equipment, energy, material resources and labour.

Also, unless your facility can manufacture substantially more than its own weight in products over a realistic lifetime, you might as well import those products directly from Earth.

Last edited by Antius (2017-06-23 03:07:27)

louis · 2017-06-23 05:24:22

Economies of scale do not relate to energy efficiency. They relate to cost .

Here's a typical definition:

"a proportionate saving in costs gained by an increased level of production."

The unit cost of producing electricity for a community of 1000 is higher if you install a 9GW plant as opposed to a 9MW plant. So in fact the usual economies of scale are reversed.

The reason economies of scale apply on Earth because there are very large levels of demand, and even within a static market, firms can steal market share through economies of scale. None of that will apply in the early settlement on Mars. "Fit for purpose" will be a better guide to efficient use of resources.

Antius wrote:

Economy of scale applies everywhere. It doesn't cease to apply just because you are on Mars or because it isn't convenient to manufacture in large volumes. The fact that you don't need 9GW of an energy system doesn't mean you escape from the inefficiency of only making 9MW. It will always be less energy efficient to make something like solar panels on a small scale. There will be poorer utilisation of equipment, energy, material resources and labour.
Also, unless your facility can manufacture substantially more than its own weight in products over a realistic lifetime, you might as well import those products directly from Earth.

Antius · 2017-06-23 06:56:00

louis wrote:

Economies of scale do not relate to energy efficiency. They relate to cost .
Here's a typical definition:
"a proportionate saving in costs gained by an increased level of production."
The unit cost of producing electricity for a community of 1000 is higher if you install a 9GW plant as opposed to a 9MW plant. So in fact the usual economies of scale are reversed.
The reason economies of scale apply on Earth because there are very large levels of demand, and even within a static market, firms can steal market share through economies of scale. None of that will apply in the early settlement on Mars. "Fit for purpose" will be a better guide to efficient use of resources.

Antius wrote:
Economy of scale applies everywhere. It doesn't cease to apply just because you are on Mars or because it isn't convenient to manufacture in large volumes. The fact that you don't need 9GW of an energy system doesn't mean you escape from the inefficiency of only making 9MW. It will always be less energy efficient to make something like solar panels on a small scale. There will be poorer utilisation of equipment, energy, material resources and labour.
Also, unless your facility can manufacture substantially more than its own weight in products over a realistic lifetime, you might as well import those products directly from Earth.

Louis, why do you think it costs more to manufacture small volumes? Could it have something to do with energy and human labour invested in equipment and facilities and the efficient use of them perhaps?

My point is that you cannot exploit economy of scale when you are manufacturing at a small scale. That is the same point you just made, but seem to missing the point I am trying to make. EROI calculated for solar power systems built on Earth, will not be applicable on Mars unless you are building these things on a similar scale, using the same processes under the same conditions. As processes are scaled down, they become inherently less efficient. This is why we don't make steel or cement in small scale batch furnaces any more and why power plants tend to be built in 100MW scales rather than kW scales.

Last edited by Antius (2017-06-23 06:56:57)

louis · 2017-06-23 08:04:21

Economies of scale can certainly relate to energy efficiency delivering lower cost. But not always. You might have a big warehouse with poor energy efficiency - leaking heat - compared with someone shipping goods from their own well insulated home. But if the big warehouse can deliver shipping cost efficiencies,the energy efficiency per unit is likely to be irrelevant.

I also think, as stated, that on Mars smaller scale is the appropriate scale and will cost less than facilities that deliver economies of scale on Earth.

Antius wrote:

louis wrote:
Economies of scale do not relate to energy efficiency. They relate to cost .
Here's a typical definition:
"a proportionate saving in costs gained by an increased level of production."
The unit cost of producing electricity for a community of 1000 is higher if you install a 9GW plant as opposed to a 9MW plant. So in fact the usual economies of scale are reversed.
The reason economies of scale apply on Earth because there are very large levels of demand, and even within a static market, firms can steal market share through economies of scale. None of that will apply in the early settlement on Mars. "Fit for purpose" will be a better guide to efficient use of resources.
"As processes are scaled down, they become inherently less efficient." That is an assumption on your part. Aerogel enables you to benefit from incredible heat efficiency. It's not used much on Earth, because of cost - and that just underlines what you are ignoring, that economies of scale relate to cost. In a mission costing billions we can afford to use the best technologies to ensure energy efficiency, regardless that on Earth they would not deliver economies of scale but would add to unit costs.
Antius wrote:
Economy of scale applies everywhere. It doesn't cease to apply just because you are on Mars or because it isn't convenient to manufacture in large volumes. The fact that you don't need 9GW of an energy system doesn't mean you escape from the inefficiency of only making 9MW. It will always be less energy efficient to make something like solar panels on a small scale. There will be poorer utilisation of equipment, energy, material resources and labour.
Also, unless your facility can manufacture substantially more than its own weight in products over a realistic lifetime, you might as well import those products directly from Earth.
Louis, why do you think it costs more to manufacture small volumes? Could it have something to do with energy and human labour invested in equipment and facilities and the efficient use of them perhaps?
My point is that you cannot exploit economy of scale when you are manufacturing at a small scale. That is the same point you just made, but seem to missing the point I am trying to make. EROI calculated for solar power systems built on Earth, will not be applicable on Mars unless you are building these things on a similar scale, using the same processes under the same conditions. As processes are scaled down, they become inherently less efficient. This is why we don't make steel or cement in small scale batch furnaces any more and why power plants tend to be built in 100MW scales rather than kW scales.

SpaceNut · 2017-06-30 19:35:04

Yes Louis Musk has a solar image and is on the path to something other than LEO I would hope with self funding of his projects. I just wish that the other space giants would wake up and do the same and stop waiting for the gravy train to ask for something to be built. Thats not how the airline industry did it with a federal gravy train, no they all stepped out to prove that they could fly tooo...

For solar I would like to use the payload Shroud to protect a groups of the ATK panels with landing capability housing the batteries as power junctions to create the much larger system to power once they are joined together for maximum kilowatts... Staying within the small currently capable landing tonnage. Yes someday we will do better but we must start no just wait....

So now how many of these landers at what power level do we need to get started even for a short stay mission to start as what we leave will be building blocks for the next longer stay mission.

louis · 2017-07-01 03:51:30

Once people realise you can make money from lunar tourism (that day is fast approaching in my view) then it will probably be like a gold rush but Space X is likely to have a dominant position now as it is going to reap the harvest of revenue from early lunar tourism.

SpaceNut wrote:

Yes Louis Musk has a solar image and is on the path to something other than LEO I would hope with self funding of his projects. I just wish that the other space giants would wake up and do the same and stop waiting for the gravy train to ask for something to be built. Thats not how the airline industry did it with a federal gravy train, no they all stepped out to prove that they could fly tooo...
For solar I would like to use the payload Shroud to protect a groups of the ATK panels with landing capability housing the batteries as power junctions to create the much larger system to power once they are joined together for maximum kilowatts... Staying within the small currently capable landing tonnage. Yes someday we will do better but we must start no just wait....
So now how many of these landers at what power level do we need to get started even for a short stay mission to start as what we leave will be building blocks for the next longer stay mission.

SpaceNut · 2017-07-06 20:30:54

Mars Surface Solar Arrays

IanM · 2017-09-01 20:48:38

https://en.wikipedia.org/wiki/List_of_c … onsumption

Electricity consumption varies widely by country, but let's assume that Martians will consume ~2500 W/person, a relatively high level for a developed country. For a colony of 12, this translates to 30,000 W for the whole colony, or around 3 power systems in SpaceNut's paper. Given that each system would need around 1000 m^2, this means around 3000 m^2 (33,000 sq ft.) for the entire grid. A similar analysis for a colony of 100 yields 25 systems and 25000 m^2 (270,000 sq ft.), but a more sophisticated system would probably be in use by then.

SpaceNut · 2017-10-08 15:13:37

Sumerized discusion:

Oldfart1939 indicated that SAFE-400 fission reactors, would be no problem in rapidly getting those online.
GW Johnson said that the government monopoly on all things nuclear means they wouldn't give Musk any SAFE-400 and that soal would be how Musk would go to mars which would be much to the enjoyment of Lious.
kbd512 said that NASA and DOE are investing in KiloPower. With my echo that I did no feel that anyone other than a Nasa mission would get them. While kbd512 feels that they can since corporate entities have nuclear power plants.

So bump goes the topic to bring it back into focus if we are not getting any nuclear power for a mars mission that is not Nasa Sponsered...

Oldfart1939 · 2017-10-08 16:54:25

I'm not sure that NASA has the power of absolute veto over in-space use of nuclear. The Air Force has primacy in their own area. Seems that the AF is warming up to Musk and SpaceX. Also, if Elon didn't burn his bridges with the Trump administration, NASA could conceivably get overruled. These are simply "random thoughts," and should be considered as such.

GW Johnson · 2017-10-08 18:38:19

USAF and USN can do whatever the hell they want with nuclear power. But civilian use is regulated by DOE, not NASA.

Originally, this was permitted by the Atomic Energy Commission (AEC), but that is now DOE. In the 1950's, many reactor designs used by USAF (such as for the Project Pluto nuclear ramjet) came from the AEC, while USN went their own way, with the best safety record on the planet.

NASA has been funding some stuff with SAFE-400 and Kilopower, but it is DOE that permits actual civilian use of any nuclear reactor technology.

Musk is going to need one of these on Mars to make propellant, if he really builds the BFR/ITS. Its payload delivery is around an order of magnitude shy of the propellant mass needed to rise from Mars and reach Earth. That mass is around 20-25% methane and 75-80% LOX, made from water by electrolysis. The energy efficiency of electrolysis is low, but the technology is very well known and reliable.

You simply ain't going to make 1200+ tons of methane and LOX for one ship with solar on Mars in only two years. They need nuclear, and the bigger the better. That's SAFE-400, which is 400 KW thermal and 100 KW electric. Bigger than that would be even better, but I know of no such projects in the works.

GW

Last edited by GW Johnson (2017-10-08 18:41:00)

Antius · 2017-10-08 19:38:49

At the moment, the sheer administrative and legal ball ache of trying to get a nuclear power reactor from Earth to Mars, has forced Musk to rely on a solar based solution. Maybe Musk can get a reactor from a non-US source ajd launch it from outside the US?

I have been looking into options for building reactors on Mars using local resources. Crude reactors could be built using natural uranium, but this requires that Musk brings a supply of heavy water with him. It would be very difficult to make that on Mars. But assuming the ability to make steel tanks and aluminium tubes, a crude pressurised heavy water reactor (or boiling heavy water reactor) would not be beyond the capabilities of a small Martian base. It would always be easier to build it on Earth and ship it to Mars. Maybe he could launch a non-fuelled reactor and natural uranium separately? Until it is assembled on Mars, it is just a steel tank full of heavy water.

Graphite moderated reactors are a much more challenging prospect, because the minimum critical core size is about 25 feet in a diameter. Calder hall was 30' in diameter and the graphite core weighed about 2000 tonnes. The power plant consisted of 4 units, each generating 200MW heat and 50MW of electrical power. The UK built this in 1956. It generated for nearly 50 years. If Musk intends to build a city of a million people on Mars, then native built Magnox reactors are something that could be produced relatively quickly using native resources and burning natural uranium. But you would need a sizable city to make a 50MW reactor a worthwhile investment. I wondered if it would be possible to build simpler, lower pressure units using graphite powder moderator and natural uranium metal bars houses in aluminium tubes. But there is no way around the minimum critical radius limit, aside from using heavy water. I think a small CANDU type reactor would be more practical.

Last edited by Antius (2017-10-08 19:54:34)

elderflower · 2017-10-09 04:32:32

I would agree that a Candu type reactor would be a better bet than magnox or a boiling water reactor in a big vessel. Candu type don't use heavy pressure vessels. The reason they are not widespread is the up-front cost of filling up with heavy water. Due to the relative abundance of heavy water on Mars this should be more simple but it depends on finding usable water in quantity and having the electric power to separate HDO from H2O. We don't seem to have this until we get a reactor running!
North Korea have, reportedly, copied the old Magnox design for their reactors. Perhaps they will sell a knocked down one to Spacex.

kbd512 · 2017-10-09 09:44:15

Thorium fueled reactors remove the need for heavy pressure vessels, heavy water, large quantities of fissile Uranium, and complicated waste management and fuel reprocessing issues. If the reactor has to be shut down, there is no requirement for active cooling using a power source capable of powering the water pumps 24/7. A reactor core the size of a bus is something that could reasonably be shipped to Mars. Solar concentrators or fission reactors are required to produce the vast amounts of thermal power required for flash evaporation of water, smelting, and chemicals processing. The solar concentrators only produce heat when the sun is shining, absent a molten salt storage tank, but fission reactors produce heat 24/7.

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