Settlement design

Noah · 2021-04-07 06:05:11

Hello SpaceNut!
Thank you for welcoming me.

louis wrote:

The larger a structure is the harder it is to build but we will need room to grow and its not easy to stay in a building mode. A key thing of making a building is to give ways to reduce risk as to isolate work zones, processing equipment and many more semi hazardous work areas from main population areas via air locks, shielding doors for blasts and fires. Safe haven pod areas if such things happen.

Good point, with a certain layout in the building we can also reduce the risks of cosmic rays and solar flares.

louis · 2021-04-07 08:18:32

Noah wrote:

I thought it was about 100 metric tons per spacecraft. So 200 t on the first trip and another 200 t 26 months later when the crew arrives (total = 400 tons).
Or did they update the design of the starship?

I think I took this originally from the 2017 presentation which suggested there would be six Starships (then BFRs) over two years:

The two spacecraft, carrying only cargo, would be used to confirm water resources on Mars and identify hazards for future missions. They would also place power, mining, and life support infrastructure for future flights. In 2024, two crew ships and two cargo ships would follow, setting up a production plant to make fuel from the thin Martian atmosphere and begin building a base for future residents.

https://arstechnica.com/science/2017/09 … more-real/

So 6 Starships = roughly 600 tons payload. I take off 100 tons for transit flight requirements and for some possible reduction in payload as the design matures (it normally goes that way!), so I tend to work with 500 tons, but obviously this is still guesswork. However, one thing is clear - this is on a scale hugely beyond the sorts of tonnages we are used to seeing delivered as part of the space programme Only the ISS comes close and that's been put together over decades.

I'm pretty sure I've seen the six Starships figure in another more recent presentation.

3D printers are so amazing. I just bought on a few weeks ago and it’s unbelievable how many possibilities you have with a 3D printer. Currently I’m building a small rocket with my friends and the 3D printer is a mercy.

Yes 3D printers are amazing and the big industrial models can produce large, high quality parts. I would envisage taking at least 20 tons of 3D printers, CNC lathes, industrial robots and a small steel furnace perhaps as well on Mission One

I have seen some concepts where the EVA suits are stored outside and the suits themselves have the airlock built in. This is because some dust particles are so tiny that they cannot be filtered and would be deposited in the lungs.

Yes, I think that's a NASA design.

I envisage EVAs being kept to a minimum on Mission One. MCP suits may be more appropriate than the big NASA space suits.

I think mostly for outside activity you will get into a pressurised rover held in a pressurised air locked chamber. You will need a separate air lock chamber next to the rover's chamber to prevent dust getting into the hab. That will probably involve a direct connection to the rover so you climb directly out of the rover into the next chamber. That way dust would be kept out. But if EVA suits are involved you'll need shower facilities in the non-rover chamber to allow for dust removal.

Last edited by louis (2021-04-07 08:20:48)

louis · 2021-04-07 08:38:04

Noah wrote:

Attractive approach to go back in history.
I agree that it would be risky to build a city with only solar panels. A mix of different types of energy supply looks interesting. To diversify is a good concept in most cases.
E.g. nuclear power and solar cells.

Nuclear power, while it could have a role longer term is problematic for the early Missions for a number of reasons:

1. Elon Musk - a huge proponent of solar power - has never suggested using nuclear power.

2. To carry radioactive material into orbit would complicate the permissions you need to secure.

3. Unlike deployment of solar power, nuclear power deployment is not simple.

4. Do not be misled by statements about the "Kilopower" units being used. This is still an experimental project and no units have been approved for use in space yet, let alone on the Mars surface. Musk is now talking about launching for Mars in a couple of years (unlikely, admittedly) so nuclear power definitely doesn't fit in with that timeline or indeed anything over the next 10 years I would say.

Your concern about the risk of all the energy eggs being in one basket is reasonable but:

(a) Each solar panel is really a separate power station. So if you have 10,000 with you, you have 10,000 separate units. The likelihood of a complete technical failure is small (and you can mix and match a number of different panels from different manufacturers in any case). That is not the case with a nuclear power unit. If it fails, you are losing a huge amount of power.

(b) If you arrive on Mars with a substantial power back up in the form of methane and oxygen (you'll already have quite a bit sloshing around in the tanks but you can bring more as part of your cargo) and you have a couple of methane generators (2 x 10 Kwes) with you, you don't have to worry even if you land in a worst case scenario dust storm.

(c) Dust storms never stop all solar radiation getting through. There is still a lot of ambient light around. Your system will still produce electricity. Dust storms do not stay at peak obscurity in any case - there being feedback mechanisms that lead them to abate. During a really bad dust storm you can probably still harvest anywhere between 20-40% of your normal harvesting of power.

Once your base is established on Mars you will always have plentiful supplies of methane and oxygen available to see you through dust storms and keep artificially lit farming going for instance. So solar power is really a three power option: direct power from PV panels, methane/oxygen power and stored power in chemical batteries.

kbd512 · 2021-04-07 11:24:25

Noah,

Globally, annual consumption of manufactured goods is now more than 14 tons per person, per year. A city on Mars won't produce 14 million tons of anything per year, using photovoltaics and batteries alone. Mind you, we live on a planet with a breathable atmosphere and in societies that are already awash in all the trappings of a technologically advanced civilization, along with relatively cheap and plentiful liquid fuels to burn for energy, that the Earth made for us, long before any of us were born. There isn't one building (not even a mud hut), road, power plant, waste water treatment plant, farm, or anything else AT ALL on Mars. Mars is a completely barren and, so far as we know, lifeless rock with some ice at the poles and kilometers below the surface. In other words, we're quite literally starting from scratch there.

Annual energy usage in the US is 91MWh per capita. It's a safe bet that energy consumption on Mars will be at least as high, if not a LOT higher. That's 91TWh per year, in a place where the air you breathe doesn't require recycling, rainfall waters the crops, and diesel-powered combines harvest quantities of grains that would be utterly impossible to harvest by hand unless every able bodied person on the planet was in the fields for at least a couple months of the year. In short, TAHC (Technologically Advanced Human Civilization, sorry, tired of writing that out), consumes energy like it's going out of style, just to feed ourselves and live indoors with a modicum of comfort.

Bhadla Solar Park in India covers 45km^2 and has an annual output of 34GWh. Ignoring the dust problem, you'd need about 6 Bhadla Solar Parks (270km^2) to provide 91TWh on Mars. In 20 years time, much of that will have to be replaced with brand new solar panels. The plants that produced those solar panels didn't also provide the power to mine the ores, refine the ores, transport them to and from the factory, etc. For this to work, we need to locate / mine / refine enough Silicon, Gallium, Arsenic, Silver, Copper, Aluminum, cover glass, and the list goes on.

NASA says they need a 40kWe nuclear reactor to supply four crew that they send there on an exploration mission, who won't be mining or refining or manufacturing anything at all nor growing crops, which amounts to 10kWe of continuous power. That works out to 87.6MWh per year, which is astonishingly similar to our US annual per capita energy consumption rate of 91MWh. Multiply that by a million, and that's where that 91TWh figure comes from.

Do I think a city maintaining a 270km^2 solar park, merely to survive, along with a mammoth battery system (533,333,333kg to supply 10kWe for 16 hours for 1 million people, at 300Wh/kg at the pack level; despite the fact that nothing close to this has been achieved in electric aircraft here on Earth where the atmosphere serves as the heat sink; 5,333 flights, at 100,000kg per flight, carrying nothing but batteries) is practical in any way, shape, or form?

Not in the least. I can only indulge others in their fantasies to a point, before it becomes a science fiction screen writing exercise, rather than an engineering exercise. This is what engineers call "a pipe dream". The power initially has to come from somewhere, which means this stuff is all coming from Earth. It also means that 147,190,800t (yes 147 million metric tons of propellant) has to be produced here on Earth. If 1/3 of that is LCH4, then that means about 392 tanker loads of the world's largest LNG tanker, Mozah, would be consumed to get the stupid batteries to Mars. We haven't calculated the mass of the solar panels, the Aluminum to connect a 270km^2 solar array to transformers, construction materials for initial habitation, the colonists themselves, food, water, or anything else at all. That 147Mt is ONLY for shipping the batteries to supply 16 hours of power when the Sun don't shine (with no consideration whatsoever given for dust storms).

You won't see a city with a million people on Mars within your lifetime using current chemical rocket technology. You won't see it with nuclear thermal rocket technology, either. Neither are remotely close to being efficient enough for the stated purpose. Furthermore, even if that specific transportation problem gets solved tomorrow, then that city still won't have a million people unless we create some kind of space elevator between Mars orbit and the surface, in order to ferry people and materials to the surface. That's beginning to scratch the surface of the magnitude of the problem. Even if both of those basic transportation problems are adequately addressed, then 38% Earth gravity will need to be acceptable for a human to remain healthy over a human lifetime, because once we send people there, it's even less economical to bring them back. Nobody has any clue how the human body responds to 0.38g, because we haven't done one single test to find out. Until we achieve Star Trek-level technology, engineering reality is going to put a damper on our grand plans, every single time.

Anybody can do some very quick math to figure out just how absurdly impractical some of these proposals are with current technology. If you then invoke "making" anything on Mars, then your energy and therefore landed tonnage requirements, if you'll pardon the pun, literally skyrocket.

91TWh is equivalent to 8.3 of our 1,250MW nuclear reactors running at maximum rated output, 100% of the time. Obviously those won't be shipped to Mars, because we have nothing to ship them with, but we can ship 250MW reactors.

A 250MWe ThorCon Thorium molten salt reactor is around ~383t (includes the reactor itself, primary containment can- represents most of the device's weight and could be omitted if a concrete lined pit was created on Mars, primary loop pump- only major moving part, and 43t of fuel salt). That would require 166 Starship flights just to get that equipment to the surface. It has to be refueled every 8 years, and consumes 19.7% enriched Uranium at a rate of about 30,834.5kg (about 1.62m^3 in volume) per year. In total, resupply requirements are 363.125t per year (~4 Starship flights). If we can't supply that much fuel per year to sustain our city of a million people, then what are the odds that we can supply orders of magnitude more delivered tonnage for solar panels and batteries?

Obviously there are other delivered tonnage requirements, such as Supercritical CO2 gas turbines (far more compact and efficient than ThorCon's proposed "off-the-shelf" steam turbines in terms of the mass and volume of the equipment), and cooling radiator arrays (or we could dump some of that waste heat into Iron Oxide to produce steel, our preferred construction material, or brine tanks to desalinate the copious quantities of potable water to grow crops- and then we keep the salts to resupply the reactors). Mars also has plenty of Iron, various salts, and Thorium, which means eventually we could eventually cut off our Uranium / Thorium fuel salt supply from Earth and refill the reactor with salt and Thorium from Mars, using the existing Th232 converted into U233 to help produce the next batch of U233 from local Th232.

The 10kWe KiloPower reactors that NASA is working on would serve as the "nuclear spark plugs" to provide the initial power to assemble the reactors, produce Sulfacrete containment vessels (simple vertical bore holes ~20m deep), and turning ice into liquid water for decay heat coolant and desalination ponds where we dump the waste heat from the reactor.

If we’re to see a city of a million people on Mars, within our lifetimes, then we need to use Starship to construct a fleet of 5,000t robotic or minimally crewed cargo frigates using solar-electric or nuclear-electric propulsion (I’d go with solar in this case) and 25,000t colonization transports (these would have to be nuclear powered) that can carry 5,000 passengers at a crack. The fleet needs repair yards in LEO and LMO, along with an orbital platform / space elevator on the Mars end to deliver the cargo to the surface of Mars, because these ships are never leaving orbit after they’ve been built. RobertDyck already has a reasonably good design, but I think it needs to be scaled-up. Something along these lines is the only way we’re going to achieve this “beautiful dream” in a human lifetime, and it’ll be the most significant and sustained engineering / technology development challenge humanity has ever faced, up to this point in our history, at that.

tahanson43206 · 2021-04-07 11:52:26

For Noah re update to Post #1

Thank you for attending to the request by Oldfart1939!

Then Temperature regulation must be added to the LSS topic. Staying warm and unfrozen is of great importance!

Just FYI ... I understand you must be overwhelmed by the sheer enthusiasm of the response to your initiative by members.

It is perfectly reasonable to suppose you might have missed someone as you attempted to keep up with the posts.

After a week, I'll go back over the topic to be sure you've had a chance to acknowledge everyone who contributed.

Bravo! This topic already advanced to the second of what I hope will be many pages of useful content.

(th)

kbd512 · 2021-04-07 13:25:40

Noah,

I made some mistakes in that last post by using some figures about Bhadla that I didn't bounce off of multiple sources. That's what I get for not checking. I also thought that 34GWh/yr figure was actually 34TWh/yr, but that clearly wasn't the case (didn't even check, because this entire "solar power for a million people on Mars" absurdity turns out to be an even greater absurdity). According to the "Interesting Engineering" article link below, Bhadla covers 10km^2 and produces 1.3TWh per year. Maybe that's only solar panel surface area. Wiki says it actually covers 45km^2; maybe that figure also includes area for the service roads around the arrays. Since Mars is twice as far from the Sun than Earth is, let's presume we get half of that power, meaning 0.65TWh per 10km^2. That equates to 140km^2 covered in photovoltaic panels. I can't be sure if either source is correct.

One Farm to Rule Them All: The World's Largest Solar Farms

Here are the other stats associated with the Bhadla farm from the "Interesting Engineering" article:

Another claim to the title of the world's largest solar farm comes from India. The solar plant, located in Kamuthi, Tamil Nadu, Southern India is certainly enormous, but is it the world's largest?
The entire project cost an estimated $679 million and has a total peak capacity of 648MW. The installation covers an area of 3.8 sq mi (10 sq km) and kicks out 5.5 kWh/m² (1 m²=10.7 ft²) a day, and an annual generation of 1.3 TWh/yr is thought to be possible — impressive.
The farms consist of 576 inverters, 154 transformers, and almost 4,660 miles (7,500 km) of cables. All in all, the project consumed 30,000 tonnes of galvanized steel, and around 8,500 personnel worked to install around 11 MW a day, in order to set up the plant in the stipulated amount of time.
Amazingly, the facility was completed within just 8 months. It also includes its own robotic cleaning system. This cleaning system is charged using its own solar panel system.

* Note to Louis on your solar-powered Mars colony fantasy: Well, at least Bhadla has its own robotic cleaning solution, but no mention of how the panels are cleaned (but I'm guessing it's using water), how much all that stuff weighs, etc.

91TWh / 0.65TWh = 140 (meaning, 140 of those 10km^2 photovoltaic arrays that produce an equivalent amount of power from similar panels used on Mars; and of course, actual conversion efficiency won't suffer at all from having half as much input TSI or an atmosphere chock full of fine abrasive dust, because "muh green energy fantasy")

So, to build a similar array on Mars that provides 91TWh of electricity, we need 4,200,000t of steel (42,000 Starship flights), 1,050,000km of power cabling, 21,560 power transformers (no idea how big those are), and 80,640 power inverters. Oh, and 1,190,000 people to complete the array in just 8 months, or maybe only 8,500 people to complete the array over a little over 93 years. I turned 40 last year, so I don't think I'll live to see the end of the array construction if ONLY 8,500 workers are devoted to completing the arrays. Whether or not we invoke robots, AI, CNT - 6,000 flights vs CFRP - 12,000 flights vs Aluminum - 24,000 flights vs steel - 42,000 flights, this only becomes slightly less utterly impractical. Every 20 years, you're either replacing a substantial number of panels and recycling the materials or you're importing more from Earth if you don't have a solar panel factory on Mars that's sourcing its materials from Mars.

Elon Musk is selling a dream, not a practical engineering solution to do what he says he wants to do.

If "The Plan" is to use photovoltaics and batteries on Mars to supply power to a scratch-built city of a million people, THEN THERE IS NO PLAN!

This is impractical for much the same reasons that that "solar powered airliner" that Louis was fantasizing about is and always will be utterly impossible. You can invoke, invoke, invoke "magic" until the cows come home, but in the real world the numbers don't change. I invoked 100% efficient thin film 100g/m^2 solar panels and couldn't come close to making his science fiction fantasy work using his "flying Dorito" / lifting body made from CNT composite, in terms of Pavailable vs Prequired (to move at airliner speeds and carry airliner passenger loads). I know engineering reality can be a real drag, but that's life.

Anyway, I'm done wasting my time on this unadulterated absolute nonsense. Fantasize forever, I don't care. If you want a practical engineering solution for supplying power to a city of a million people living on Mars, then that's called "nuclear power", and even that is at the very edge of feasibility. Heck, I wouldn't drop a dime on any of this silliness until we know with absolute certainty that humans can survive in 0.38g, indefinitely, and figure out how to grow crops on Mars. If Elon Musk or NASA wants to prove they're serious about going to Mars, then gravity simulation / human physiology evaluation is the first experiment I need to see. Nobody's doing that because nobody's serious about going. It's all wild fantasy, "selling the dream", such as it were.

tahanson43206 · 2021-04-07 13:54:01

For Noah re kbd512's observations ...

I'm hoping your initiative here is intended to lead to a "real Universe" result, and not just an exercise in contemplation.

The members of this forum (past and present) have been thinking about how to "do Mars" for more than 20 years. It is time for those who will actually be going to Mars, or the many more who will be supporting them in their resolve, to (as kbd512 put it) "get serious".

It remains to be seen whether this topic can evolve in the direction of "real Universe" planning, testing, reworking and ultimately succeeding in the settlement enterprise.

(th)

louis · 2021-04-07 14:04:23

Re post 29:

1. The One Million Person city isn't Noah's target as far as understand it. That target comes from Musk and in my view is crazily over-optimistic on his timescale (I think it was within 30 years).

2. I don't know where you get the world figure of 14 tons - 14,000 kgs - per person per annum for manufactured goods. Given household waste per person in the UK - one of the richer countries - was a mere 392 kgs in 2019, that seems highly unlikely to me. The amount of manufactures required on Mars will be a case of swings and roundabouts. Yes, they will need life support equipment not necessary on Earth but on the other hand, the early colony isn't going to need private automobiles, paper production, oil rigs, ocean going ships, metalled roads, railways, huge airports, rain gutters, pylons, drainage systems etc etc. If I had to guess I would say the overall materials requirement will be a lot less per person than on Earth.

3. Total electricity production on Earth is around 25 TwH (per annum). Of that some 500 GwHs is produced from solar power. That equates to about 1.4 KwH per person per (Earth) day for a million people.

4. Building up solar energy will be related to how many people move there. Every trip to Mars will include PV panel cargo I expect.
But PV manufacture on Mars will also be established. This will be a prime industry on Mars - it might well be the equivalent of the auto industry on Earth. 90% of the mass at least can be sourced on Mars, so hugely reducing the need for PV panel imports.

Last edited by louis (2021-04-07 14:05:23)

louis · 2021-04-07 14:16:32

Didn't see this post before I posted mine querying some of your figures...

I think you are indulging in some fantasies there.

Your per capita power requirements are too large. And whatever Musk might say a million person city isn't going to appear in 3 decades, let alone overnight: way too many questions over health, culture, technical expertise and so on.

Remember also that because of the benign weather on Mars PV installations don't have to be so robust. There's no particular reason to put them on steel frames. We might decide to lay them out on hillsides or we might suspend them from light wires held taut between posts every 20 metres or so. The steel requirements will be hugely less than on Earth.

On Earth solar is already providing over 2% of electricity generation - the equivalent of providing electricity to support 140 million people pro rata across the world.

kbd512 wrote:

Noah,
I made some mistakes in that last post by using some figures about Bhadla that I didn't bounce off of multiple sources. That's what I get for not checking. I also thought that 34GWh/yr figure was actually 34TWh/yr, but that clearly wasn't the case (didn't even check, because this entire "solar power for a million people on Mars" absurdity turns out to be an even greater absurdity). According to the "Interesting Engineering" article link below, Bhadla covers 10km^2 and produces 1.3TWh per year. Maybe that's only solar panel surface area. Wiki says it actually covers 45km^2; maybe that figure also includes area for the service roads around the arrays. Since Mars is twice as far from the Sun than Earth is, let's presume we get half of that power, meaning 0.65TWh per 10km^2. That equates to 140km^2 covered in photovoltaic panels. I can't be sure if either source is correct.
One Farm to Rule Them All: The World's Largest Solar Farms
Here are the other stats associated with the Bhadla farm from the "Interesting Engineering" article:
Another claim to the title of the world's largest solar farm comes from India. The solar plant, located in Kamuthi, Tamil Nadu, Southern India is certainly enormous, but is it the world's largest?
The entire project cost an estimated $679 million and has a total peak capacity of 648MW. The installation covers an area of 3.8 sq mi (10 sq km) and kicks out 5.5 kWh/m² (1 m²=10.7 ft²) a day, and an annual generation of 1.3 TWh/yr is thought to be possible — impressive.
The farms consist of 576 inverters, 154 transformers, and almost 4,660 miles (7,500 km) of cables. All in all, the project consumed 30,000 tonnes of galvanized steel, and around 8,500 personnel worked to install around 11 MW a day, in order to set up the plant in the stipulated amount of time.
Amazingly, the facility was completed within just 8 months. It also includes its own robotic cleaning system. This cleaning system is charged using its own solar panel system.
* Note to Louis on your solar-powered Mars colony fantasy: Well, at least Bhadla has its own robotic cleaning solution, but no mention of how the panels are cleaned (but I'm guessing it's using water), how much all that stuff weighs, etc.
91TWh / 0.65TWh = 140 (meaning, 140 of those 10km^2 photovoltaic arrays that produce an equivalent amount of power from similar panels used on Mars; and of course, actual conversion efficiency won't suffer at all from having half as much input TSI or an atmosphere chock full of fine abrasive dust, because "muh green energy fantasy")
So, to build a similar array on Mars that provides 91TWh of electricity, we need 4,200,000t of steel (42,000 Starship flights), 1,050,000km of power cabling, 21,560 power transformers (no idea how big those are), and 80,640 power inverters. Oh, and 1,190,000 people to complete the array in just 8 months, or maybe only 8,500 people to complete the array over a little over 93 years. I turned 40 last year, so I don't think I'll live to see the end of the array construction if ONLY 8,500 workers are devoted to completing the arrays. Whether or not we invoke robots, AI, CNT - 6,000 flights vs CFRP - 12,000 flights vs Aluminum - 24,000 flights vs steel - 42,000 flights, this only becomes slightly less utterly impractical. Every 20 years, you're either replacing a substantial number of panels and recycling the materials or you're importing more from Earth if you don't have a solar panel factory on Mars that's sourcing its materials from Mars.
Elon Musk is selling a dream, not a practical engineering solution to do what he says he wants to do.
If "The Plan" is to use photovoltaics and batteries on Mars to supply power to a scratch-built city of a million people, THEN THERE IS NO PLAN!
This is impractical for much the same reasons that that "solar powered airliner" that Louis was fantasizing about is and always will be utterly impossible. You can invoke, invoke, invoke "magic" until the cows come home, but in the real world the numbers don't change. I invoked 100% efficient thin film 100g/m^2 solar panels and couldn't come close to making his science fiction fantasy work using his "flying Dorito" / lifting body made from CNT composite, in terms of Pavailable vs Prequired (to move at airliner speeds and carry airliner passenger loads). I know engineering reality can be a real drag, but that's life.
Anyway, I'm done wasting my time on this unadulterated absolute nonsense. Fantasize forever, I don't care. If you want a practical engineering solution for supplying power to a city of a million people living on Mars, then that's called "nuclear power", and even that is at the very edge of feasibility. Heck, I wouldn't drop a dime on any of this silliness until we know with absolute certainty that humans can survive in 0.38g, indefinitely, and figure out how to grow crops on Mars. If Elon Musk or NASA wants to prove they're serious about going to Mars, then gravity simulation / human physiology evaluation is the first experiment I need to see. Nobody's doing that because nobody's serious about going. It's all wild fantasy, "selling the dream", such as it were.

kbd512 · 2021-04-07 16:03:18

Louis,

I truly wish I was indulging something other than what teams of NASA engineers have said their continuous power requirements would be. Maybe you know more than dozens of people who have spent their entire adult lives doing this kind of work for the agency, but I seriously doubt it. Now that painful engineering reality has some real numbers behind it, the prospect of supplying enough energy to sustain a million people on Mars, using solar power alone, is looking pretty bleak, isn't it?

Elon Musk's company, not Elon Musk himself, is developing a rocket that might take people there, at some point in the future. He doesn't know a thing about running a city of a million people. If he does, then what he probably knows best is just how gullible people who know nothing about engineering can be. Ultimately, he's a salesman who is selling his own products (rockets, solar panels, and electric cars). I wish him luck in that endeavor, and I've even purchased his products for my own use. Sadly, waving our magical solar power wand doesn't make the fundamental engineering problems go away. The same holds true here on Earth.

Bhadla is in the middle of a desert. They see wind speeds of 10mph to 15mph, on average. There are no hurricanes or tornados there, and precious little rain. That's why they put it there. Even if you take our own solar panels out of their Aluminum frames, they still weigh over 20 pounds EACH, and produce 300W. Most of that weight is the backer required to prevent those paper thin Silicon wafers from cracking.

Bhadla supplies power to 150,000 homes, so it supplies a maximum of 23,744kWh/home/day, which equates to 989.3Wh/hr. That's enough power to run a few lightbulbs, a laptop, and a few fans to deal with the heat of the desert. My home in Houston (the building I live in and haven't left for over a year now, except to get food) uses about 27MWh of power PER MONTH. I'm using 37.5kWh/hr. That's just the electricity, not the gas, nor the water consumption. There are 5 people living in my home, so 7.5kWh/hr/person. If we toss in the gas and water (which requires power to pump), then we're probably right at that magic 10kWh number that NASA came up with, for people who aren't making or farming anything at all. I don't have to recycle the air that I breathe or the water that I drink, either.

Regarding the weight of materials, I already threw out some ballpark numbers for other framing materials. No matter how you fiddle with the numbers, we're talking about thousands of Starship flights, just for the solar panels. Laying the solar panels in the dirt will only ensure that they're perpetually dirty, due to the static electricity problem, and not producing their rated output, which makes the weight problem even worse. There will then be thousands more for the batteries. So please, come off it already. This is a fantasy. The numbers are what they are. Don't like it? Come up with a more efficient way to run an AC unit, a refrigerator, computers, lights (we use LED lights), waste water treatment, growing crops, fabricating pressurized habitats, etc.

Indoor farming of Cannabis, which literally grows like a... wait for it... weed, is 5,000kWh/kg. The average astronaut is eating 0.71kg of food per day, so if they could actually eat Marijuana, then that's 3.55MWh, per person, per day. That's 1,295,750,000Wh per person, per year, to simply feed them. For a city of a million people, that's 1,295TWh. Now we need an additional 1,992 Bhadla Solar Parks. This was already utterly ridiculous before we considered food production, and the more we factor into what it actually takes, the more and more laughable it becomes. This is me laughing at just how much power we really need based upon what it actually takes to produce a kilo of anything, not you, not the dream of one day using solar power for everything, nor anything else. It blows my mind how much energy we guzzle down, yet still need more! It's bonkers.

If you don't like those numbers, then you tell me how much energy you think will be expended to grow enough food to feed a million people per year. Then provide a real world example where someone actually computed their energy use to produce a kilo of whatever crop, using the method you think will use the least amount of power. Whatever numbers you come up with, that's the absolute bare minimum possible, not in any way representative of what we'd actually use.

Edit:

Can you begin to understand why I stated that this is only marginally feasible using modular nuclear reactors?

We need an additional 182 of those 1,250MWe large nuclear reactors to supply enough power to feed everyone using indoor farming.

For what should be increasingly obvious reasons, some or all of those additional reactors will need to be made on Mars.

Presumably those people also need clothing, pressurized living space, and every other trapping of TAHC to boot.

The only thing they won't be short of, is work.

Last edited by kbd512 (2021-04-07 16:29:53)

kbd512 · 2021-04-07 17:36:27

In the UK, every square meter of grow area to produce a head of lettuce in a heated greenhouse requires 250kWh of energy consumption. In a purpose built vertical indoor farming facility, that figure grows to 3,500kWh/m^2. 98% of that energy usage is associated with artificial lighting. I like fresh lettuce on my hamburgers and in my salads as much as the next guy, but that's a whopping energy consumption rate for an area that will produce a handful of heads of lettuce per year. If we could grow crops in heated surface greenhouses without SPE and GCR radiation killing the crops, then we could shave off an order of magnitude on that energy requirement. The problem is that we can't do that, because plant growth doesn't work that way. BBQ them with proton and heavy ion radiation, and they don't like that very much. Go figure.

To feed 50,000 people a 2,000 calorie per day diet, every day of the year, a study from the students of Dr. Dickson Despommier suggested that a vertical farm building of 30 stories in height with 27,800,000m^2 of usable floorspace would be required to feed 50,000 people in Manhattan, New York, using a combination of natural and artificial lighting (the building would cover one city block). That would obviously be bored into solid rock on Mars, lined with Sulfacrete, and then an inflatable structure used to provide the various levels of the farm. We're talking about aeroponics, for the most part, to reduce the water consumption to tolerable levels and to eliminate the requirement for soil to deliver nutrients. We need 118,628,397m^3 (calculated using 14 feet / 4.2672m, per story) of pressurized volume in which to grow food to feed 50,000 people. NRG Stadium in Houston is 2,548,516m^3, and it seats 72,220 people. The vertical farm is therefore 46.5 TIMES the volume of NRG Stadium. We need 20 of those things to feed a million people, so we need to build the equivalent pressurized volume of 931 NRG Stadiums to feed a million people. The "good news" is that we "only" need to build an additional 56 NRG Stadium's worth of pressurized volume to comfortably house a million people. Each NRG Stadium was "only" 17,274 tons of steel and 160,000 cubic yards of concrete. For anyone who cares, those are good 'ole fashioned American units, not those communist metric units.

At this point, given what I've told y'all thus far, who here thinks I've incomprehensibly understated, in the most "British" way possible, the energy and material requirements, versus overstated anything AT ALL?

You're not arguing with me. I don't come up with any of this. You're arguing with virtually every researcher and engineer with a PhD WHO BOTH STUDIES AND IMPLEMENTS THIS STUFF, FOR A LIVING! I read what the experts have to say about it, then do SIMPLE MATH (which I still screw up sometimes, but it's only add / subtract / multiply / divide- and mostly multiplication when we're talking about feeding a million people).

Now... When're y'all gunna quit all of this ridiculous BS, and "git real"?

Cause that's the only way we're ever gunna "git'r dun"!

Edit:

The embodied energy in the steel and concrete alone, that went into NRG Stadium, amounts to 289,212,552,000Wh / 289GWh. That was the construction materials production energy cost alone, not what it actually took to build the structure. Multiply that by about 1,000, and that's the amount of energy it would take to build a "steel and concrete" city of a million people on Mars, excluding all the energy that goes into "the machines that make the machines". To be perfectly frank with everyone, this is looking really impractical with nuclear fission. If we had nuclear fusion in the bag, then maybe this would be more feasible, but we're talking about a staggering quantity of energy to give everyone a place to live and a meal to eat.

Yeah, I still want to attempt this, because, hey, why not?

Does everyone fully appreciate everything that both our ancestors and this pale blue dot we all live on has gifted to us?

It's long past time that we leave the cradle of life to take our rightful place amongst the stars, preferably before we all kill each other over a stupid patch of dirt on this particular little rock we call home.

Last edited by kbd512 (2021-04-07 18:01:33)

louis · 2021-04-07 17:44:30

kbd512 wrote:

Louis,
I truly wish I was indulging something other than what teams of NASA engineers have said their continuous power requirements would be. Maybe you know more than dozens of people who have spent their entire adult lives doing this kind of work for the agency, but I seriously doubt it. Now that painful engineering reality has some real numbers behind it, the prospect of supplying enough energy to sustain a million people on Mars, using solar power alone, is looking pretty bleak, isn't it?

NASA's methods for assessing mission requirements is absurdly profligate. Essentially they go to each department and say "What do you need?" Unsuprisingly people respond with "The max - plus some more again". Unless you are talking about coms, surface imaging, space medicine or life support (where they have necessary expertise that Space will have to tap into) NASA is pretty much irrelevant to the issue of Mars colonisation.

Elon Musk's company, not Elon Musk himself, is developing a rocket that might take people there, at some point in the future. He doesn't know a thing about running a city of a million people. If he does, then what he probably knows best is just how gullible people who know nothing about engineering can be. Ultimately, he's a salesman who is selling his own products (rockets, solar panels, and electric cars). I wish him luck in that endeavor, and I've even purchased his products for my own use. Sadly, waving our magical solar power wand doesn't make the fundamental engineering problems go away. The same holds true here on Earth.

Musk does have engineering expertise and the story goes it was he himself who resolved numerous glitches in Falcon 1 and got it to fly.

His enthusiasm is needed for this project but it can't cover up his inability to address issues of social organisation adequately. When Musk talks about putting a million people on Mars he's got some naive notion of people giving up their plots in California and moving to this new planet.

He's a very intelligent guy and I am sure that with time he will come to understand the problem but his focus isn't there are the moment.
He doesn't realise that if he puts up 100,000 tickets at $250,000 a time, for anyone to buy, some Saudi multi-billionaire is going to buy them and give them free to 100,000 peasants from the Middle East, SW Asia and elsewhere. They won't be bought by well off people working for tech companies in Silicon Valley who have too much to lose.

Bhadla is in the middle of a desert. They see wind speeds of 10mph to 15mph, on average. There are no hurricanes or tornados there, and precious little rain. That's why they put it there. Even if you take our own solar panels out of their Aluminum frames, they still weigh over 20 pounds EACH, and produce 300W. Most of that weight is the backer required to prevent those paper thin Silicon wafers from cracking.
Bhadla supplies power to 150,000 homes, so it supplies a maximum of 23,744kWh/home/day, which equates to 989.3Wh/hr. That's enough power to run a few lightbulbs, a laptop, and a few fans to deal with the heat of the desert. My home in Houston (the building I live in and haven't left for over a year now, except to get food) uses about 27MWh of power PER MONTH. I'm using 37.5kWh/hr. That's just the electricity, not the gas, nor the water consumption. There are 5 people living in my home, so 7.5kWh/hr/person. If we toss in the gas and water (which requires power to pump), then we're probably right at that magic 10kWh number that NASA came up with, for people who aren't making or farming anything at all. I don't have to recycle the air that I breathe or the water that I drink, either.

A figure for Earth of about 10KwH per person to lead an advanced-economy lifestyle sounds reasonable to me, for Earth.

A good deal of that will be for heating or air conditioning in temperate and tropical parts of the world. Surprisingly large amounts are eaten up by the supersized TVs we watch these days as well.

Given money is not much of a constraint in the early colony, I think we will be designing our habs to be incredibly energy efficient.
So on Mars at least, I can't see huge power being expended on heating and air cooling. Given heat loss is much less on Mars, that will be helpful as well. Of course, on the other hand we need to power our life support systems and they will be energy hungry.

Regarding the weight of materials, I already threw out some ballpark numbers for other framing materials. No matter how you fiddle with the numbers, we're talking about thousands of Starship flights, just for the solar panels. Laying the solar panels in the dirt will only ensure that they're perpetually dirty, due to the static electricity problem, and not producing their rated output, which makes the weight problem even worse. There will then be thousands more for the batteries. So please, come off it already. This is a fantasy. The numbers are what they are. Don't like it? Come up with a more efficient way to run an AC unit, a refrigerator, computers, lights (we use LED lights), waste water treatment, growing crops, fabricating pressurized habitats, etc.

Please remember that - unlike nuclear power stations - we have actually operated solar panels on Mars, very successfully for many years, beyond their manufactured life. We know how they perform in dust, with only minimal potential for cleaning. With a Space X mission we can definitely have robots on permanent duty cleaning the panels.

Indoor farming of Cannabis, which literally grows like a... wait for it... weed, is 5,000kWh/kg. The average astronaut is eating 0.71kg of food per day, so if they could actually eat Marijuana, then that's 3.55MWh, per person, per day. That's 1,295,750,000Wh per person, per year, to simply feed them. For a city of a million people, that's 1,295TWh. Now we need an additional 1,992 Bhadla Solar Parks. This was already utterly ridiculous before we considered food production, and the more we factor into what it actually takes, the more and more laughable it becomes. This is me laughing at just how much power we really need based upon what it actually takes to produce a kilo of anything, not you, not the dream of one day using solar power for everything, nor anything else. It blows my mind how much energy we guzzle down, yet still need more! It's bonkers.
If you don't like those numbers, then you tell me how much energy you think will be expended to grow enough food to feed a million people per year. Then provide a real world example where someone actually computed their energy use to produce a kilo of whatever crop, using the method you think will use the least amount of power. Whatever numbers you come up with, that's the absolute bare minimum possible, not in any way representative of what we'd actually use.

I have never advocated continued, permanent use of artificial lighting for farming. What I have said is that it will be the preferred method in the very early stages, while the colony is certainly less than 10,000 people strong. Beyond that we clearly need to move into natural light farming. So, all your calculations are pretty irrelevant as regards my position - in fact they support my position, that beyond a certain point artificial light farming is untenable with current technology.

Edit:
Can you begin to understand why I stated that this is only marginally feasible using modular nuclear reactors?
We need an additional 182 of those 1,250MWe large nuclear reactors to supply enough power to feed everyone using indoor farming.
For what should be increasingly obvious reasons, some or all of those additional reactors will need to be made on Mars.
Presumably those people also need clothing, pressurized living space, and every other trapping of TAHC to boot.
The only thing they won't be short of, is work.

See above - we will clearly move to natural light farming. Farming in the optimal zones on Mars with "double" seasons and some help from reflectors, will likely be the equivalent of temperate farming on Earth, which is where most of our calories come from.

Development work will need to be done on heating of farm habs. Ideally we will have translucent plastic habs inflated with low pressure concentrated CO2 to aid plant growth. Heating loss may be an issue, certainly requiring some energy input. We may need to have reflective foil blinds to cover the habs internally at night. We might need to use thermogenic plants that release heat at night. We may need to use differential heat engines to generate heat at night.

SpaceNut · 2021-04-07 18:39:36

I think this has drifted enough to no longer being all that helpful to Noah in bring about the outline of what's needed and how soon do we need it.
With the several mars observers still active in orbit and on the ground the answer should be sought out from what does each location proven to have for assets to make use of.

If solar must be with great year round low dust opacity levels.
Must have the mineralogy to build with for building
Must have the chemistry to make stuff that we need
Needs a source for water to be recovered from whether its a brine well, underground aquafer or just in the soils

Of course this is a short list that the explorers of mars must find to make it an optimal site for man

kbd512 · 2021-04-07 19:11:28

Louis,

I'm not attacking your personal Jesus, Louis, I'm pointing out the simple fact that Elon Musk is, amongst other things, a salesman selling solar panels, batteries, electric cars, and rockets. Of course he's going to promote what he's selling. He'd be stupid not to. I can promote my all-electric, no fossil fuels allowed, battery powered rocket, but the damn thing is never carrying a single pound of anything into space, because there's no zero atmosphere for an electric fan to push against, so it's never going into space without fossil fuels, until we either develop electromagnetic launch or beamed energy or teleportation.

If you're making the claim that NASA's estimates are "absurdly profligate", then show your own math to support your claims. Stop making wild assertions backed up by nothing. A few sentences down, you said you agreed with the 10kWh consumption rate. If you agree with that, then start doing the math regarding how many watt-hours of energy you need to produce and/or store that much energy, how much it weighs, therefore how many Starship flights are required. It's not that hard to do and I believe you can do it. There are a few unit conversions involved, but it's all simple multiplication and division that any handheld calculator can do. If you think your calculator is lying to you, then there's the old pencil and paper standby.

If there isn't a nice air-conditioned environment to live in on Mars, do you think anyone except for a handful of eccentrics will ever be going there?

Apart from a submarine (non-yellow variety), name some other places on Earth where they recycle the air we breathe.

Virtually no place recycles water in the same way that it must be recycled on Mars, nor do we recycle Nitrogen, because it's everywhere, all around us, all the time, but only here on Earth.

Yes, in a hard vacuum or near-vacuum, getting rid of waste heat is a much bigger problem than retaining it. That means an air conditioning system is required, with heat exchangers, and a heat exchange fluid, like CO2 or Ammonia or some other refrigerant. All that stuff requires power as well.

Those unclean, unwashed "peasants" who do real work, that hoity-toity types love to sneer at, despite not knowing how to unclog their own toilet or fix their own computer, those are the people who like those giant flatscreen TVs. They associate that with being rich. If you want real workers to go to Mars to do some real work, then these are the people you'll be sending. If you're planning to send robots to do everything, then no people are needed, and this endeavor is a complete waste of time and money.

The solar panels we've operated on Mars cost a million dollars per kilowatt of output. They're hand-built and the components are hand-tested and hand-selected. That's why they last as long as they do. There's no magic there. When everything is perfectly voltage-matched and perfectly wired in a clean room, it can last for quite awhile, even in an austere environment. Something tells me we won't be installing hundreds of gigawatts of panels at those prices, so no, we haven't operated the types of panels that a colonist could ever afford. When you say "we", you also mean NASA, which you ignore when they don't come up with numbers or solutions you like, then act as if what they do is in any way "normal", when they use solar panels that someone like you or I could never hope to afford. The longest serving spacecraft is nuclear powered. It was zipping out of our solar system at incredible speed before I was even born. It's still sending data back to Earth. No solar powered anything has survived as long in service.

Regarding indoor farming, plant biology doesn't care about your assertions or ideology. If you zap them with radiation from a SPE, they're going to die. Shortly after that, the people who were depending on them for food will die. That's how reality works. I'm not pleased about it either, but I acknowledge that that is what will happen. That's why the food farms need to be indoors, so they can be protected from SPEs and GCRs. That's also why the people will be indoors most of the time, to protect them from the same events.

One other thing to note is that the only reason a single building can feed 50,000 people over every day of the year, is that the grow methods used make the food grow much faster than it does in normal sunlight, with a lot less water and no soil. Remove those optimal grow conditions and then you need a lot more pressurized space, water, fertilizer, etc, all of which requires more materials and more energy expenditures. Much like the solar powered airliner, this is another one of those intractable problems that you can't wave a magic wand at to solve. However, if you do have such a wand, then please wave away, because it's an actual problem that needs solving- but please show your math and detail your solution so others can benefit from what you know.

Heating loss is a problem for "farm habs" here on Earth, to the tune of 250kWh per year in the UK. I can promise you that a "farm hab" stuck in a place colder than the coldest places in Antarctica, on a warm (for Mars) summer night, will require even more heating.

Anyway, everything you've brought up is merely circling back on old talking points with little work behind it. Show your math already, or stop making claims without evidence. It won't kill you to do a little leg work on your ideas.

Here's the premise behind "The Vision" or "The Plan":

1. We're sending humans to Mars using Starship or something else approximating existing spacecraft technology. Yes, in the 23rd century humanity will invent Warp Drive, and teleportation, but since none of us will be alive to see that, we're acting as if chemical, nuclear thermal, ion engines, and electromagnetic acceleration are all that we have to work with. If someone invents a teleporter tomorrow, then of course a chemical rocket will be superfluous and all of this will be a comparative cake walk.

2. We're attempting to build a self-sustaining colony of a million people within a human lifetime. What may possibly be achieved a century from now is not relevant to the next ten to twenty years.

3. We're using estimations that experts in their respective fields have come up with to determine the rough sizing or capacity calculations for everything we want to transport or build.

4. We're not invoking technology that doesn't exist. There's no problem with fantasizing about the future, but we're treating this like an engineering exercise, because that is precisely what it will be if we actually send real humans to Mars, as well as precisely what it has been for all of the robots we've sent to Mars.

5. We're not cherry picking particular points that favor our "en vogue" solution while ignoring all of the actual downsides. Basically, we're approaching this from the standpoint that our own lives are at stake and any mistake or miscalculation we make will be the end of us. Maybe someone here thinks a voice-activated, computer-controlled airlock would be a super cool thing to have, but if you're standing behind the airlock in a T-shirt / shorts, and a hard vacuum is on the other side, do you trust a simple mechanical latching device that a human isn't strong enough to unseal, or do you want to play Russian roulette with the computer?

GW Johnson · 2021-04-07 20:23:42

Point 1 -- We do not yet know for sure what the life support power requirements will be. We only know they are "large".

Point 2 -- We cannot yet define what "large" means, precisely because we have not yet sent humans to live on Mars.

Point 3 -- Sending people there, based on assumptions about power needs, is a risk. If the assumptions are wrong, you end up with a dead crew. There is NOTHING that is as expensive as a dead crew.

Point 4 -- because of point 3, it behooves you to estimate high on power needs (and pretty much everything else, too).

Point 5 -- I second kbd512's motion that solar alone will not do this job on Mars. We will need nuclear. And lots of it. Because there are no other credible choices.

Point 6 -- Unlike solar, nuclear is more compact and lighter for the MWe produced, and it is NOT inherently intermittent. Because we ought to send something like 10 times more than minimum estimates, due precisely to the consequences of point 3, nuclear is the prime choice for base load power. If it's too much for the initial base, then so what? The base can grow into it.

GW

RobertDyck · 2021-04-07 21:47:49

GW Johnson wrote:

Point 1 -- We do not yet know for sure what the life support power requirements will be. We only know they are "large".

I have to challenge this point. I agree with your other points. But we know what humans need. Finding all supplies for permanent settlement is an issue. I still think the best plan is a relatively small exploration mission first; something the size of Mars Direct. Prove a greenhouse can grow food, with a mission that has enough stored food that crew are not dependant on it. Do experiments with producing brick from Mars dirt. Do various construction proof-of-concept experiments. Prospect for dirt that has no perchlorates. Prospect for ice. Prospect for other resources: hematite concretions as iron ore, anorthite as aluminum ore, white sand for glass.

Then build a relatively small permanent base; Mars Homestead Project designed for 12 crew. Then that would build habitats and life support for the first 100. Only then would a SpaceX Starship arrive with the first 100 settlers. Then they would build for the next 1,000 settlers. But Elon Musk wants to go massive from day one.

Ps. When I was part of Mars Homestead Project, I found technical details for life support equipment for ISS. That includes power requirements. I think that's a fair estimate. The manufacturer kept moving their web pages, as if they didn't want me to see. I think that's silly considering I was recommended we plan to buy life support equipment from them. They proved it works on ISS, so just buy more for Mars. Doesn't that mean I'm giving them free marketing? But that means I could give you those power requirements. And we can estimate heat requirements from JPL's work with rovers.

louis · 2021-04-08 07:59:37

I am with you on Mission One Robert.

We have a pretty good idea of all the energy requirements.

We certainly have a reasonably good take on energy required to get 6 Starships there and 1 return.

I think a very generous (as in, will probably be a lot less owing to economies of scale) estimate of energy requirement for the first settlement was around 1Mwe constant equivalent (doesn't mean it has to be delivered as a constant necessarily). From memory something like 95% of that would go into methane and oxygen production. I think I ended up concluding that for a solar power architecture, you'd need to produce produce something like 35 MwH of power per sol (to allow for energy storage).

I agree for Mission One it will be essentially proof of concept for growing food - mainly salads I would imagine as has been done on Antarctic bases. So the energy requirement will be very modest - probably no more than something like 125 KwH per sol. Most of the food consumed will be delivered as part of the cargo.

There would be some exploration but a lot of that exploration would be focussed on the essential water ice mining required to get back home.

I think a six person pioneer crew would be pretty occupied managing the mining, methane/oxygen production, monitoring and maintaining life support, rocket maintenance,preparing the rocket for return and communications with Earth .

You could have a larger crew but then you need to take more life support cargo with you in that case.

RobertDyck wrote:

GW Johnson wrote:
Point 1 -- We do not yet know for sure what the life support power requirements will be. We only know they are "large".
I have to challenge this point. I agree with your other points. But we know what humans need. Finding all supplies for permanent settlement is an issue. I still think the best plan is a relatively small exploration mission first; something the size of Mars Direct. Prove a greenhouse can grow food, with a mission that has enough stored food that crew are not dependant on it. Do experiments with producing brick from Mars dirt. Do various construction proof-of-concept experiments. Prospect for dirt that has no perchlorates. Prospect for ice. Prospect for other resources: hematite concretions as iron ore, anorthite as aluminum ore, white sand for glass.
Then build a relatively small permanent base; Mars Homestead Project designed for 12 crew. Then that would build habitats and life support for the first 100. Only then would a SpaceX Starship arrive with the first 100 settlers. Then they would build for the next 1,000 settlers. But Elon Musk wants to go massive from day one.
Ps. When I was part of Mars Homestead Project, I found technical details for life support equipment for ISS. That includes power requirements. I think that's a fair estimate. The manufacturer kept moving their web pages, as if they didn't want me to see. I think that's silly considering I was recommended we plant to buy life support equipment from them. They proved it works on ISS, so just buy more for Mars. Doesn't that mean I'm giving them free marketing? But that means I could give you those power requirements. And we can estimate heat requirements from JPL's work with rovers.

tahanson43206 · 2021-04-08 09:18:00

For Louis, RobertDyck and all who've helped to give Noah a ** really ** impressive start to the introduction of his new topic.

I suspect (without having heard from Noah directly) that he may well be feeling overwhelmed by the variety and strength of the responses to his opening gambit.

Please include in your approach to this topic a sense of the situation .... Noah is a college student who has (I think bravely) jumped into the middle of an ongoing forum with a winning topic. My goal/interest is to assist Noah in developing a path that leads to success in whatever field he approaches, but I admit to a hope that his ambitions include either actually ** going ** to Mars, or (more likely) participating as a professional in the support activities that will permit successful ventures by others on Mars (and elsewhere in the Solar System).

I can't offer any specific advice, and wouldn't even if I could, but I'm hoping the (much older) members of the forum will attempt to assist Noah in gaining what will eventually be a professional level of understanding of the issues at hand, so he can take a place of leadership over research, development and perhaps eventually expedition teams tackling the Mars Settlement problem.

Edit#1: ... inviting feedback from Noah would seem (to me at least) a reasonable tactic to include in helping to build the topic for future readers.

(th)

kbd512 · 2021-04-08 09:24:15

Louis,

Is that 125kWh/sol for six people on Mission One just for the food growing experiments, or for the entire mission?

That's 5.2kW of continuous power, which works out to 867W of continuously available power per person. Orion supplies 2.8kW of continuous power per person, but that's for a crew of four, not six, no ISRU, no food production, no ice mining, and no motorized off-road vehicles to power. SpaceX's Dragon cargo capsule generates 5kWe from its solar arrays, but there's nobody onboard. CAMRAS and IWP are going to consume more power than that to scrub CO2 and filter water.

Mars One figured their daily power consumption for a crew of four with ISRU replenishment of O2 / N2 (MOXIE) / H2O (surface ice collection / melting / purifying), and using CAMRAS (developed for Orion / ISS / new space suits / Mars missions) and IWP, was 356kWh. That works out to 3.7kWh per person to supply the air and water, but no food production. They figured they needed 141.9kWh/day for CAMRAS and IWP alone.

I could understand the 5.2kW being used for the food growing experiment alone, since it would take that much power to grow a head of lettuce and some other greens, or a kilo of hemp for the seeds / oil / fibers. Is this for an outdoor inflatable greenhouse being supplied with pressurization and power some other way, like solar thermal for heating, in addition to the electrical power?

Oldfart1939 · 2021-04-08 10:00:05

We're back to the old question of "how many do we send" in the first expedition. In my estimation, the 4 person crew of the original Mars Direct plan is simply inadequate to do all that's necessary on the first visit to our new second home.
I've given this problem lots of thought, and after I state my number, I'll expand and expound my reasoning.

A hard and fast number is not possible because there will be lots of changes in planning what the first pre-colonization mission will want to accomplish, but I'm going a bit higher than the NASA plan of 7. I figure around 14 would be barely adequate, but 25 might strain the available resources sent in supplies. My number is 17.

There are many reasons to consider a larger mission crew, based on the workload.

Mainly, I'm considering the physical and psychological workloads on the crew. We're expecting these people to be there for over a year between Hohman transfer windows, and operating at a damned near 25/7 workweek. I'm considering fatigue and mental exhaustion will play a role. There will be differences of opinion between members that can often disrupt the desires of the chair warming planners. We're gonna need many different talents in order to "build stuff" for future use in addition to doing science. Housekeeping will become an issue. Equipment maintenance will become an issue. There will definitely need to be time set aside for simply "doing nothing," in order to get the personal batteries recharged. Illness could be an issue, although we need to quarantine everyone for about 3 weeks prior to departure. Injuries sustained through working and exploring need to be considered. We simply need internal backup through numbers

We need to have several teams within this number--teams of compatibles. Everyone will want to go exploring, but there will need to be limits on simply wandering around. This has to be a team effort, and I'm suggesting that no more than 6 be outside and exposed to GCR at one time, with a 6-8 hour outside time limit. Sleeping quarters need to be well protected from Solar flare radiation and from GCR; we need to limit exposure as much as possible; The entire hab should be covered with a decent layer of regolith, and in a lava tube or cave would be ideal (as we've discussed endlessly in the past).

My bottom line is: there will be too much workload for a skeleton crew to accomplish without going bonkers or becoming angry.

More to follow as time permits.

Last edited by Oldfart1939 (2021-04-08 10:04:28)

louis · 2021-04-08 13:31:06

Hi kbd , The 125 KwH was just for an initial, proof-of-concept, artificially lit food growing operation.

I was suggesting the total energy usage excluding methane and oxygen manufacture might be around 50 KwHs constant-average for a six person mission. About 1,230 KwHs per sol. That would include power used in mining and transportation as well as the experimental farm hab. Happy to accept that might be an over-estimate. But they would presumably be using a fair amount of power on things like rocket maintenance as well. They will probably have to bring with them some sort of gantry crane... I'm imagining there will be a fair few robots moving around the place as well.

Last edited by louis (2021-04-08 13:32:12)

louis · 2021-04-08 13:57:55

I'm at the other end of the scale - 6.

Space X appear to be thinking in terms of two human craft for the outward journey, so that's why I opted for 6...would be difficult to go below 3 per craft.

I'm not saying you couldn't go for more people but with 17 I feel that's building in some unnecessary redundancy for Mission One - you would probably end up doing lots of exploration and science which would be nice but not top priority.

The six people would need to be high functioning in more than one discipline. This isn't so unusual. Doctors for instance often excel at other pursuits.

Across the six you want to cover medical skills (including basic surgery), general engineering, software engineering, 3D printer operation, electrical engineering, geological expertise and coms knowledge. That will probably cover it for Mission One. Operations such as the experimental Farm Hab management, robot control and driving on Mars can be taught as specific procedural tasks, using video training and the like, and all personnel will be adept at those tasks.

My vision for Mission One is it would depend a lot on Rovers and robots. I don't envisage there being much EVA surface action. The key task will be to locate, mine and transport water ice. All that can be done using human controlled rovers and robots. You don't need more than a couple of people working on that once you have found a good source. They will basically be supervising from the comfort of their pressurised Rover the work of robot drillers, diggers, lifters and transporters, dislodging soil and ice.

I don't envisage much construction work being involved on Mission One. The habs will probably be self-inflatables (Bigelow-like structures), that can be towed to the desired location by rovers and inflated on site. Probably the methane and oxygen manufacture plant will be the most complicated structure - that might require some assembly.

Overall, while I think the pioneers will be busy enough, I don't think they will be overworked as in a compressed Apollo-style mission, where things would move quickly from one crucial procedure to another. Once water ice has been discovered, life at the base will settle into something of a routine. Yes they should have some break time - probably combining the "breaks" with some off base exploration would be a good way of managing time. Short 2-3 sol exploration missions would be relatively risk free I feel.

I think a low figure - six - has advantages. It will be easier to maintain team unity for one thing and, as you mention, the resource cargo requrement will be at a minimum.

Oldfart1939 wrote:

We're back to the old question of "how many do we send" in the first expedition. In my estimation, the 4 person crew of the original Mars Direct plan is simply inadequate to do all that's necessary on the first visit to our new second home.
I've given this problem lots of thought, and after I state my number, I'll expand and expound my reasoning.
A hard and fast number is not possible because there will be lots of changes in planning what the first pre-colonization mission will want to accomplish, but I'm going a bit higher than the NASA plan of 7. I figure around 14 would be barely adequate, but 25 might strain the available resources sent in supplies. My number is 17.
There are many reasons to consider a larger mission crew, based on the workload.
Mainly, I'm considering the physical and psychological workloads on the crew. We're expecting these people to be there for over a year between Hohman transfer windows, and operating at a damned near 25/7 workweek. I'm considering fatigue and mental exhaustion will play a role. There will be differences of opinion between members that can often disrupt the desires of the chair warming planners. We're gonna need many different talents in order to "build stuff" for future use in addition to doing science. Housekeeping will become an issue. Equipment maintenance will become an issue. There will definitely need to be time set aside for simply "doing nothing," in order to get the personal batteries recharged. Illness could be an issue, although we need to quarantine everyone for about 3 weeks prior to departure. Injuries sustained through working and exploring need to be considered. We simply need internal backup through numbers
We need to have several teams within this number--teams of compatibles. Everyone will want to go exploring, but there will need to be limits on simply wandering around. This has to be a team effort, and I'm suggesting that no more than 6 be outside and exposed to GCR at one time, with a 6-8 hour outside time limit. Sleeping quarters need to be well protected from Solar flare radiation and from GCR; we need to limit exposure as much as possible; The entire hab should be covered with a decent layer of regolith, and in a lava tube or cave would be ideal (as we've discussed endlessly in the past).
My bottom line is: there will be too much workload for a skeleton crew to accomplish without going bonkers or becoming angry.
More to follow as time permits.

RobertDyck · 2021-04-08 14:49:05

Robert Zubrin and his partner David Baker developed the Mars Direct mission plan in the last quarter of 1989 and first half of 1990, presenting to NASA in June 1990. The reason they planned for 4 astronauts is that was NASA's plan. In 1965 NASA developed a plan to use Apollo hardware to go to Mars. Updated in 1968. After Apollo 11 landed on the Moon, the Soviets seriously considered skipping the Moon, going straight to Mars. When intelligence told NASA about this, NASA got serious about Mars. Of course the Soviet plan did go very far. They started with an unmanned probe to Mars, launched on the most reliable launch vehicle they had, Proton, which had a perfect record, no failures. It exploded as soon as it cleared the launch tower. But they didn't give up, launched a backup, also on Proton. It exploded somewhere over Siberia. So they decided to focus on a space station instead: Salyut 1. After Salyut 1, NASA cancelled their Mars plans, built Skylab instead. But NASA's 1965 configuration of Apollo for Mars was the only one they had. It included seats for 4 astronauts. Life support and food would have to be carried by a separate module. So don't criticize Dr Zubrin for choosing 4 astronauts, he got that from NASA.

Pictures in this discussion thread from 2002: Historical: 1965 Mars Flyby CSM

Oldfart1939 · 2021-04-08 15:03:40

Robert-
I'm not being critical of the work of Zubrin and Baker, since they were working on a "maximum bang for the buck" philosophy, and as you said, that is now 30+ years in the rear view mirror. I'm doing my analysis and thought experiment on realities of just how much humans can do over a 1.5 year period, being isolated and away from the normal lives they were leading. I don't think we should be looking for globally gifted geniuses either. One medic on a trip like this is insufficient--what if the medic croaks? We need a big enough team so there is internal backup available.

Louis-
I think that Bigelow-style inflatables will serve only for a short time on the planetary surface. Too much danger from Solar flares, and wear and tear on them. You are expecting too much from a too small crew. The main reason for going there in the first place is exploration and a survey of the readily available resources. Reliance on robots is a bit fanciful, since none exist at this point that can do all that you are asking them to accomplish.

RobertDyck · 2021-04-08 15:17:41

That said, Mars Direct is actually quite spacious. The Ares launch vehicle was designed to have the lift capacity of Saturn V, but made of Space Shuttle parts. Core stage the same diameter as external tank of Shuttle, 5 SSME, pair of SRBs. And upper stage with a single J-2S engine. Third stage of Saturn V used a single J-2 engine, an update in 1979 produced the J-2S. SLS block 2 essentially *IS* Ares, but main engines configured axial. Moving the main engines required cutting new hole in the Mobile Launch Platform for engine exhaust, and filling in the old one for strength, but since Shuttle doesn't fly any more, that's possible. And upper stage with a single J-2X engine, the 21st century version. Today we would use SLS block 2B: with 4 main engines instead of 5, and upper stage with 4 RL10-C3 engines. Mars Direct habitat was designed to have the same outer diameter as the core stage of Ares, which is the same as the Shuttle's ET, which is the same as core stage of SLS. With outer diameter of 8.4 metres, and inside diameter of 8.0 metres (20cm thick walls), that provides floor area of 50.26548 m² = 541 square feet. That's equivalent to a 60-foot class A motorhome with slide-outs. And that's just the upper deck. Lower deck would have airlock, stairway to upper deck, and storage compartment the size of a single-car garage. The storage compartment would hold a Mars rover plus surface science equipment, plus inflatable greenhouse. The rover capable of carrying all 4 astronauts up to 1,000 km one-way, or exploring around the base. The compartment would be packed full during transit from Earth to Mars, but once on Mars it would be unpacked so available as additional space for EVA prep and workshop or lab. The rest of the lower deck would be solid equipment: landing rockets, propellant tanks, legs, life support equipment, etc. The greenhouse would be the same width as a double-car garage, and twice the length. So that's a lot.

I would like to argue for Mars Direct before SpaceX Starship, but Boeing hasn't been able to complete it in reasonable time, nor keep costs reasonable. SLS block 2 is based on Ares, which was based on Shuttle. It was supposed to be very cost effective because it didn't require re-inventing the wheel. At current SLS prices... I don't know.

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