Light weight nuclear reactor, updating Mars Direct

louis · 2017-10-05 16:09:37

GW ,

I am assuming not that Space X will rely on 0.38 G to be therapeutic but that they will use 0.38 G to replicate 1 G through weighted suits. It seems to me such an obvious tactic that I can't imagine it won't be pursued. We know from zero G space flight that the negative effects can be greatly ameliorated through exercise. This will be even more the case, as the "exercise" (via weighted suits) will be 24/7 or whatever is the equivalent in a sol as opposed to 2 hours per day, which seems to be the practical limit in zero G.

I would note this approach can be trialled on the Moon with its 0.12 (IIRC) gravity.

I don't accept that the Mars pioneers (let's not call them colonists yet) would refuse to wear weighted suits. Why would they? We wear clothes everyday - they won't feel "heavy"...they will just feel like 1 G clothes. And people who work in industry wear specialist clothing every day. Have you read The Right Stuff? - a great book by Tom Wolfe. When you read about the indignities suffered by the early astronauts, you realise people will put up with a lot if the goal seems important enough. Weighted suits are, in my view, what we call in the UK a "no-brainer".

GW Johnson wrote:

Louis & Oldfart1939:
I don't think artificial gravity issue is either over-hyped or under-hyped. I know for a fact that we humans know nothing about gravity's effects on the body except at the two endpoints: 0 and 1 gee. There has to be a spectrum of increasing deleterious effects as gravity is reduced from 1 to 0 gee, but we know nothing about the shape of those curves between those two endpoints. I say curves (plural) because the various effects likely will not respond the same way. Murphy's Law says so.
What NASA and Musk are "counting on" is that partial gee will be "therapeutic enough" to tolerate the deleterious effects on the moon and on Mars for long exposures, potentially lifetimes. NASA is further counting on exercise and medicines to counter 0-gee effects for long flight time exposures, longer than roughly a year, which is far short of a trip to Mars and back, and trivial compared to a lifetime spent by a colonist.
But we already DO NOT keep people on ISS longer than a year, and preferably not longer than 6 months. There is probably a very good medical reason for that, which they (NASA) don't like publicized, apparently. Because nobody talks about it, except folks like us in discussions like these.
Musk is reducing the 0-gee exposures with higher energy trips: 3 to 6 months, versus a nominal 8.5 months for a min-energy transfer orbit, and that is very smart. But like NASA, he is "counting on" 0.38 gee being "enough" to tolerate the reduced-gee effects. We have precisely ZERO data to support that bet, but it really isn't such a bad bet. Any colonists on Mars are going to live the rest of their lives dealing with whatever the effects of 0.38 gee finally prove to be. Regardless.
So we might as well go out there and start finding out "for sure" what those effects are. While not doing those things we already know are stupid. My bet is there's a whole lot more stupid things we still don't know about, than there are stupid things we already do know about. The "trick" is to uncover them before we commit to lifetimes of exposure.
I know people and their habits and attitudes well enough to know that Mars colonists would probably go to the gym every day to work out, but are very unlikely to wear weighted suits all day, every day. That inherent feeling of confinement from such a suit goes against everything that we are, psychologically.
GW

Last edited by louis (2017-10-05 16:11:46)

RobertDyck · 2017-10-05 17:45:26

Lunar equatorial surface gravity is 1.62 m/s², Earth's is 9.78 m/s². That means the Moon's gravity is 0.165644 that of the Earth. Round off to 3 significant digits, and it's precisely 1/6th.

I've posted before my hypothesis that much of the zero-G medical effects are due to lack of fluid convection within cells. The only remaining effects on the Moon or Mars should be reduced use. So some bone loss, but not nearly as quick as zero-G. And muscle atrophy should be proportionate to use. I don't think weighted suits will be necessary on Mars. In fact, if NASA uses their new Z-2 suit, it means they'll wear 143 pounds (65 kg) when outside. The PXS suit is said to have almost exactly the same mass. So in 38% gravity, a 185 pound man will have 67% of his normal Earth body weight. A 120 pound woman have 83% of her normal Earth body weight.

SpaceNut · 2017-10-05 17:47:02

The problem with a weighted suit is that when you are doing manual labor that you will need that extra lifting capability that you have just reduced by weighing your self down.
As for the lighter weight nuclear reactor the fact that we would need to contract what we would want on mars is the issue as the likes of nasa or contractors are not going to be providing it as COT's for use on Mars mission. This mean custom design which means big bucks.....

GW Johnson · 2017-10-05 18:39:12

If any of you actually read (or saw) "The Right Stuff", then you know the Mercury 7 actually rebelled against the medical guys, and Von Braun's spacecraft designers, on multiple occasions. So the discussions invoking that here, are BS at best.

Wearing a weighted suit 24/7 is first cousin to wearing a straitjacket 24/7. I would not wear the damned thing either! The medical guys and mission control are on Earth. I'm on Mars. What can they actually do to me, if I rebel? So, screw them! What is so hard to understand about that?

What this entire discussion forgets is that there is a whole lot more to microgravity diseases (plural!!!!!) than just bone decalcification, muscle bulk loss, and fluid redistribution effects. Exercise has nothing to do with fluid redistribution effects, only with the bone and muscle losses, as near as we know. So we already "know" that ONLY exercise (in whatever form) is futile. More is obviously required, but what that really is, is still unknown.

Eyesight acuity loss seems to be a fluid redistribution effect, but it is too soon to actually make that claim: that hypothesis is UNPROVEN!

What about the immune system degradation? While demonstrably real, NOBODY KNOWS how that occurs. There is not even a hypothesis. And NOBODY KNOWS what else there is, yet to uncover.

Exercise seems extremely UNLIKELY to have anything to do with eyesight or immune degradation. The weighted suit Louis is so fond of, will do NOTHING for those effects, as best we know. Even if its use could be enforced. Which it cannot be.

So, use full 1-gee artificial gravity while in space, until and unless we know better. And don't leave people on Mars or the moon for the rest of their lives, until we know better. We will know a lot better within a very few years of the first "permanently"-occupied bases on the moon and Mars. Does not that make more sense?

GW

Last edited by GW Johnson (2017-10-05 18:44:06)

SpaceNut · 2017-10-05 18:51:10

Until we try artifical gravity we will not even know if the fluid redistribution is corrected or not nor will we know if it will cure the immune issues either until it is tried. UNtil the experiments of time are also impemented we will not know how long we need the level of gravity or if less will be enough to stave off these issues either.
The ISS was the perfect place to do the controls on this by eliminating radiational effects form the equation leaving just the microgravity to say that the effects of long term exposure for mars as the issue that we can correct via artificail gravity.

GW Johnson · 2017-10-05 18:56:41

Hi Spacenut:

You are quite correct, it must be tried to know "for sure". Success does seem rather likely, though, due to the physics equivalence of acceleration and gravity.

That is why I say use artificial gravity in the transits, so we can evaluate the effects. And keep duty terms fairly short on the moon and Mars, until we can determine just how therapeutic partial gee really is.

There's no excuse not to go because of these concerns. Likewise, there's no excuse not to try out everything we think might help.

GW

Oldfart1939 · 2017-10-05 22:22:52

I mentioned the microgravity effects being overlooked in my earlier comment (post # 148) on Musk's new ideas. There is a helluva big difference between zero g and any gravitational effects. The probable receptor is the inner ear--but possibly the soles of our feet. We just DON'T KNOW. I happen to regard weighted suits as a foolish eyewash idea. That does very little for the receptor-hormonal feedback mechanism that causes the release of osteoclasts from marrow and suppresses osteoblast formation. ANY gravitation will be beneficial--certainly better than none. The combination of hormonal treatments and 0.38 gees will probably keep the Marsonauts reasonably healthy and able to function. The hormonal treatments include Calcitonin and Amylin, drugs currently used to treat osteoporosis. This totally ignores the immune system degradation and fluid distributions. But I believe that the 0.38 gees would solve the fluid problems.

Last edited by Oldfart1939 (2017-10-05 22:38:04)

elderflower · 2017-10-06 04:52:35

I m not sure what this has to do with light weight reactors.
On the subject of low g exposure. We could, without great difficulty, put up a small satellite with, maybe rats, and spin it at a speed to give 0.38g. After a few months the rats could be tested and examined to see what the effects might be. The satellite could be retrieved into the ISS for examination so eliminating any re-entry effects.
I am concerned that Musk's proposals include direct return from Mars to earth without artificial gravity so his pioneers will be subject to 5 or 6 months of zero g on top of 2 or 4 years of 0.38 g. It sounds unnecessarily risky. Why not do the orbital experiment?

RobertDyck · 2017-10-06 08:55:25

I started this discussion thread to update Mars Direct with new technology. The new reactor is lower mass and does exactly the same job, which is good considering life support equipment developed for ISS proved to be higher mass than Dr. Zubrin's estimate. Louis argued to stop doing anything, leave it to SpaceX. Obviously we don't want to just sit on the sidelines. So discussion of Mars architecture continues.

louis · 2017-10-06 09:25:46

I was thinking more of indoor suits - I don't actually think there be will any need for EVAs on Mars though they might be undertaken for PR purposes.

Apologies for getting the lunar gravity figure wrong -I will try and remember 1/6th in future.

RobertDyck wrote:

Lunar equatorial surface gravity is 1.62 m/s², Earth's is 9.78 m/s². That means the Moon's gravity is 0.165644 that of the Earth. Round off to 3 significant digits, and it's precisely 1/6th.
I've posted before my hypothesis that much of the zero-G medical effects are due to lack of fluid convection within cells. The only remaining effects on the Moon or Mars should be reduced use. So some bone loss, but not nearly as quick as zero-G. And muscle atrophy should be proportionate to use. I don't think weighted suits will be necessary on Mars. In fact, if NASA uses their new Z-2 suit, it means they'll wear 143 pounds (65 kg) when outside. The PXS suit is said to have almost exactly the same mass. So in 38% gravity, a 185 pound man will have 67% of his normal Earth body weight. A 120 pound woman have 83% of her normal Earth body weight.

louis · 2017-10-06 09:27:13

You change into a normal work suit in that case. I am not speaking of elaborate space suits here. Just stuff you can step into and zip up.

SpaceNut wrote:

The problem with a weighted suit is that when you are doing manual labor that you will need that extra lifting capability that you have just reduced by weighing your self down.
As for the lighter weight nuclear reactor the fact that we would need to contract what we would want on mars is the issue as the likes of nasa or contractors are not going to be providing it as COT's for use on Mars mission. This mean custom design which means big bucks.....

louis · 2017-10-06 09:32:22

Yes, I did read it. There was something of a rebellion - but it amounted only to not being paraded around a hospital with a tube up your rectum! They still had to suffer all the indignities of that time. Later astronauts had to exist in an environment with fecal matter floating around. The suit will only make you feel like you do on Earth, no more no less. I would imagine it would have weighted shoulder pads and integral belt. You'd probably wear a weighted cap as well, similar to the old flying caps.

I accept that bone decalcification is not the only negative effect of microgravity. A lot is already being done to counter other negative effects (and bone loss) through space medication.

GW Johnson wrote:

If any of you actually read (or saw) "The Right Stuff", then you know the Mercury 7 actually rebelled against the medical guys, and Von Braun's spacecraft designers, on multiple occasions. So the discussions invoking that here, are BS at best.
Wearing a weighted suit 24/7 is first cousin to wearing a straitjacket 24/7. I would not wear the damned thing either! The medical guys and mission control are on Earth. I'm on Mars. What can they actually do to me, if I rebel? So, screw them! What is so hard to understand about that?
What this entire discussion forgets is that there is a whole lot more to microgravity diseases (plural!!!!!) than just bone decalcification, muscle bulk loss, and fluid redistribution effects. Exercise has nothing to do with fluid redistribution effects, only with the bone and muscle losses, as near as we know. So we already "know" that ONLY exercise (in whatever form) is futile. More is obviously required, but what that really is, is still unknown.
Eyesight acuity loss seems to be a fluid redistribution effect, but it is too soon to actually make that claim: that hypothesis is UNPROVEN!
What about the immune system degradation? While demonstrably real, NOBODY KNOWS how that occurs. There is not even a hypothesis. And NOBODY KNOWS what else there is, yet to uncover.
Exercise seems extremely UNLIKELY to have anything to do with eyesight or immune degradation. The weighted suit Louis is so fond of, will do NOTHING for those effects, as best we know. Even if its use could be enforced. Which it cannot be.
So, use full 1-gee artificial gravity while in space, until and unless we know better. And don't leave people on Mars or the moon for the rest of their lives, until we know better. We will know a lot better within a very few years of the first "permanently"-occupied bases on the moon and Mars. Does not that make more sense?
GW

Oldfart1939 · 2017-10-06 09:46:46

Speaking of Nuclear and Thermonuclear power; I had an opportunity to chat a with with a friend last week, who is a senior scientist at Lawrence Livermore National Labs about how close we are to getting a self-sustaining fusion reaction going. Still having problems getting enough energy into the capsules in a tokamak. Other approaches are being tried, but he "couldn't talk about those." Classified.

Re: SAFE-400 fission reactors, he said they would be no problem in rapidly getting those online.

Last edited by Oldfart1939 (2017-10-06 09:47:59)

SpaceNut · 2017-10-06 15:28:58

Good to hear but as I said until someone puts the funds to there mouths intention to use one we will never know what we will need to alter for mars use....

GW Johnson · 2017-10-07 08:38:34

The government has no intention of sending astronauts to Mars any time soon (meaning in our lifetimes), or they would be pouring money into getting SAFE-400 into a form ready to go. QED.

The government monopoly on all things nuclear means they wouldn't give Musk any SAFE-400 items even if they were ready, or any other nuke power equipment, so that he could go with a good power source. If he goes, he embarrasses the government, perhaps fatally.

Musk is going to have to use solar. Louis will like that, but it WILL put a severe crimp in how fast Musk can make return propellant in 1500-ton quantities per ship, and still power his base. Electrolysis is only about 6% efficient energetically.

Methane is useless to you on Mars without LOX, which outweighs the methane by 3.5-to-4 to 1. A lot of people ignore that, but it is true. Basic chemistry.

GW

Last edited by GW Johnson (2017-10-07 08:40:28)

kbd512 · 2017-10-08 10:38:01

NASA and DOE are investing in KiloPower. The next generation life support systems are exceptionally power-efficient, so a 100kW class reactor is not required, and there is no requirement for SAFE-400 for robotic missions, either. There is a requirement for 1kW to 10kW class power sources for robotic missions into deep space and 10kW class modular prime power sources for human exploration missions. ISRU may be required for colonization, so a far more powerful reactor will be required for that purpose. However, there's no need to produce propellant for exploration purposes. It's an unnecessary complication for a mission with a level of complexity that already strains the limits of what we can reasonably achieve. Although Mars mission benefit from a regular day/night cycle, long duration lunar missions mandate nuclear power sources. KiloPower is a win-win-win for high power consumption robotic missions, near term lunar missions, and mid term Mars missions. Apart from general utility, redundancy is the most likely reason why KiloPower development continues and SAFE-400 development has been shelved.

SpaceNut · 2017-10-08 12:25:48

True as you say that "NASA and DOE are investing in KiloPower" but these will not be made avaialbe to anyone else that can launch payloads beyond earth orbit so with that said there is no mars progress and just more kicking the can down the road.
Going back to the moon and creating the infrastructure with Nasa DOE leaves mars on the back burner until they either lose interest or funding which ever comes first. Yes leveraging the Moons nuclear power for Mars is a plus but beyond that little else is being developed that will be Mars other than a deep space habitat.

kbd512 · 2017-10-08 13:28:45

SpaceNut,

Whether or not KiloPower is made available to NGO's is a matter of policy. Since all nuclear reactors that provide utility electrical power are run by corporations, presumably a large and well-funded corporation with political influence, like SpaceX or Blue Origin, can persuade our government to furnish the reactors, at cost, to provide electrical power for life support. Nuclear power is a requirement for long duration lunar missions, so that project has to be funded to achieve the stated lunar exploration program objectives.

Pretending that we know anything about the moon because we took a few scoops of regolith and some interesting looking rocks back to Earth is just silly. There's a lot more science to be done there and it's a lot closer than Mars. If we can live on the moon, then we can surely live on Mars. The moon is just a stepping stone to something better, but NASA is intent on going back there and has sabotaged every other human exploration project. If they didn't sabotage the myriad of projects they've been tasked to complete, then they're no longer competent to run a human space exploration program.

SpaceNut · 2017-10-08 15:14:43

So then again why are we putting solar panels on everything we send into space?

kbd512 · 2017-10-08 16:29:45

SpaceNut,

Name off robotic missions that solar panels couldn't provide the power for. When you do that, you'll invariably note that NASA selected nuclear power sources for those missions. Only human missions require 10's of kilowatts of continuous electrical power. We've never had any such missions executed at greater than 1AU distances. I don't advocate for the use of nuclear power "just because we can". A mission has to first exist that solar panels, batteries, and fuel cells can't adequately service the requirement for. Then and only then should nuclear power sources be selected. Long duration human lunar and Mars exploration missions require fission for surface electrical power. Inner solar system orbital missions of the robotic and crewed variety can still use solar panels and they're adequate for that particular use case. It's going to take a suite of electrical power provisioning technologies to do everything NASA says it wants to do.

GW Johnson · 2017-10-10 14:19:35

From my 1969-vintage Pratt & Whitney vest-pocket aeronautical handbook: for oxygen-methane rocket engines operating at 1000 psia chamber pressure, the optimum mixture ratio oxygen/fuel by mass is r = 3.15, with c* = 6120 ft/sec. For whatever expansion and nozzle efficiency you like, get a thrust coefficient CF and estimate Isp = CF c* / gc in consistent units. That’s another topic.

What is important here is the percentage of a rocket’s propellant load that is methane fuel = 1/(1+r), and that is oxygen = r/(1 + r). At r = 3.15, that is 24.1% methane and 75.9% oxygen, by mass. On the assumption that Spacex’s concept BFR/ITS second stage ITS requires about 1000 metric tons to leave Mars and reach Earth, those percentages say it needs 759 metric tons of oxygen, liquified, and 241 tons of methane, liquified.

Musk says he wants to electrolyze Martian water for oxygen and hydrogen, and use the hydrogen with Martian atmospheric CO2 to make methane. There are energy costs to each of those steps plus the liquifactions, but the “bugaboo” is electrolysis, which is just inherently and horrifyingly inefficient, at something like 6% energy efficiency. I just look at electrolysis here. The rest is smaller change.

According to multiple old chemistry books in my library, hydrogen and oxygen combine to make water plus the heat of its formation: H2 + 0.5 O2 = H2O + 68.3 kcal/ g-mol (of water). Using the stoichiometric coefficients and molecular weights, we find that each unit of water converts to 88.89% of a unit of oxygen, and 11.11% of a unit of hydrogen. To make 759 metric tons of oxygen, 854 metric tons of water must be electrolyzed. The theoretical minimum amount of energy need to do that is the heat of formation: Δhf = (68.3 kcal/gmol)(18 g/g-mol)(1000 g/kg)(1000 kg/ton) = 3.794 x E6 kcal/ton-of-water.

Now, 1 cal = 4.184 J = 4.184 W-sec, so our min energy per ton E/m = 15.88 E9 J/ton-of-water. A J is a W-sec. The actual electrolysis electrical input per ton is this number divided by energy efficiency 0.06: 15.88 E9/.06 = 265 E9 J/ton. We have to electrolyze some 854 tons of water, and we need to do it in roughly 2 years. Now 2 yr = (3600 sec/hr)(24 hr/day)(365 day/yr)(2yr) = 63.1 E6 sec.

Therefore the electric power we need to make only the oxygen from the water by electrolysis (not including the methane reactor, the liquification processes, or keeping the place powered) is:

P = (265 E9 W-sec/ton)(854 tons)/(63.1 E6 sec) = 3.58 E6 W = 3.58 MW = 3580 KW (delivered “24/7”)

Now, one SAFE-400 electric power reactor is 400 KW thermal but 100 KW electric, and it is the electricity we need. It would take some 36 of these units running fully loaded to do just this one job! The “Kilopower” reactors are smaller still, it would take hundreds of them! Your typical marine power plant reactor is a few hundred MW; only one of those would do this job and a whole lot more besides.

Solar power that gets 1KW/m^2 at peak illumination here, would get half that at Mars, because the sun is half as bright that far out. So, 0.5 KW/m^2. To get 3580 KW out of such a solar array requires about 7160 m^2 of panels for just the electrolysis, which inherently cannot produce it “24/7.” Double this estimate for night vs day effects, and then divide that by an average power factor of 0.3 for daytime intensity variation: that means you need ~ 47,700 m^2 of solar panels for just the electrolysis. Double it again to take care of everything else, and you are talking ~ 100,000 m^2 = 0.1 square km (!!!) of panels. That’s an awful lot of panels to ship, unload, and set up! That alone would take a crew of 2-6 much of the 2 years to accomplish, for crying out loud! 100 m^2 / day takes 1000 days!!!

What that tells me is that this mission plan for the 2020’s using ISPP to get home has not yet been all that well thought-out. Putting pencil to paper puts some reality to the ISPP proposals I see bandied-about in these conversations. That reality is very far from the claims. Yet it can be done.

One of those cargo ships needs to have a marine-equivalent nuclear power plant in its belly, rated at (at least) 10 MW, and whose waste heat can be put to use making hot water and steam for more water extraction from a buried glacier, by steam injection down a well.

Processing slightly-damp regolith just ain’t going to cut it! You haven’t got the time (or the power available) to do that, which is processing hundreds of tons to get 50-ish tons of water! You really do need the massive buried glacier. Do a burst of drilling and pipe-fitting, then go do something else while the propellant gets made during those 2 years. Maybe explore? Maybe experiment with greenhouses? Maybe actually construct a small base? Not if you’re driving a bulldozer all day long every damned day!

That reactor startup is a boot-strap process, as some water is needed for cooling when you first land, but that heated cooling water can be used to extract more water from the buried glacier, which cools it off for recirculation. More and more, as time goes by. The rate of boot-strap must be fast, because you only have 2 years to make the propellants! But, the more MW-electric of reactor you bring, the faster you can do this, and maybe actually power 2 ships instead of just one!

But, bear in mind that we are talking tens or hundreds of MW, not tens or hundreds of KW! Wrong ballpark, otherwise, by some 3 orders of magnitude! Any of my assumptions could be off by factors of 2 or 3, or even 10, and this picture simply does not change!

Sorry to have rained on anybody’s parade.

GW

Last edited by GW Johnson (2017-10-10 14:24:58)

kbd512 · 2017-10-10 16:34:08

GW,

Fortuitously, SAFE-400 was designed to scale up to 4MWt. The dimensions of the 4MWt reactor differ little from the dimensions of the 400kWt, but there's a dramatic increase in the mass of the reactor if adequate shielding is taken into account. I estimate that 6 such reactors are required to reliably provide the level of output you indicated was necessary. You're correct in your assertion that none of these solar-powered ISPP schemes have taken scale into account. There's too much magical thinking on the part of these mathematically illiterate people obsessed with these all-solar power proposals.

Forgive my ignorance, but don't regenerative fuel cells (fuel cells run in reverse) produce better efficiencies than straight water electrolysis by using catalyst beds or meshes and process heat? That should lower the input energy requirement and a fission reactor can contribute process heat. Just a thought. I could be way off base here. I'm not very well read on SORFC technology. Maybe Oldfart1939 or SpaceNut could tell us more.

GW Johnson · 2017-10-10 16:53:47

Hi kbd512! I hope you got your hurricane damage under control!

I am absolutely no expert in these things, but the only large-scale process I ever heard of for splitting water is electricity-driven electrolysis. Folks have been trying to improve the efficiency for decades, but there's nothing I ever heard of much different from platinum electrodes in slightly-salty water.

I was thinking a big contained reactor like that in a submarine, with an initial tank of cooling water and some sort of an initial start-up radiator. Like the safe-400, the electricity is about a quarter of the thermal output. You drill the initial well into the buried massive glacier, pipe the cooling water to and from it, and start ramping-up the reactor power. That way, you start getting lots of Martian likely-salty water back up the well, while make 10's to 100's of MW, pretty rapidly. The more Martian water you can clean up, the more coolant you have, and the higher the power at which you can operate your reactor system, getting away from the dink little radiator and using the gigantic buried glacier as your heat sink. That's the bootstrap process.

As for the rest of the raw water, leave it salty, and simply filter the solids out. Feed that straight to the electrolysis plant. Use the natural salts in it as your electrolyte. So what if the efficiency is only 6% with not-exotic industrial technology, you need not mess with energy-consuming high-quality water cleanup measures. There's nothing about this that we haven't had on-the-shelf in one form or another for over 100 years now. Works here; it'll work there.

You'll need a crater or a hole somewhere to dump the really-tough brine waste from the electrolysis plant. We have a "long and glorious" history of knowing how to just dump waste without treating it. That would appear to be exactly how we first get started on Mars. The nuances come later. Besides, as it freezes, the ice is less salty than the liquid. You can "mine" that and process it into what else you need.

GW

Last edited by GW Johnson (2017-10-10 17:02:04)

elderflower · 2017-10-11 03:00:41

...and strange Martian bugs may come up with the meltwater, then everything will come to a halt whilst they are studied.

Oldfart1939 · 2017-10-11 08:23:32

I just picked up on this thread, but it seems to me that the amount of effort GW put into his CORRECT calculations puts the final nail in the coffin of the solar energy farm plans. I did a check on his assumptions but it was too late at night for me to haul out the calculator and repeat the numbers crunch. Re: fuel cell chemistries, there MAY be some slight improvements possible, but not enough to warrant the investment. There will be no order of magnitude improvement, which would be needed to revitalize a solar plan. Sorry Louis! GW didn't even include the weight (mass) of batteries needed in order to make the ISRU fuel system work 25/7. We've all watched the somewhat overly dramatic rendition of what could happen during a massive month long Martian sandstorm as well--National Geographic "Mars.".

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