A Lunar Colony

[spacester]

At a solar constant of 1.37 kw/m^2 and 10% efficiency and 26.2 ft^2 = 2.434 m^2 (a 4 ft x 8 ft panel, like a plywood sheet, with 5.8 ft^2 =18.1% dead area), you get 3.334 kw electricity, so you need a bank of 3 of them to generate 10 kilowatts.<br /><br />Keeping it all metric, at a solar constant of 1.37 kw/m^2 and 10% efficiency and 0.73 m^2 (854 cm x 854 cm square, or 27% dead area on a 1m x 1m square) you get 1.000 kw electricity, so you need a bank of 10 of them to generate 10 kilowatts.<br /><br />Agriculture Energy:<br />1 kcal = 1.163 watt-hour<br />6000 kcal/person-day = 6.978 kilowatt-hour/person-day<br />Assume 1% conversion of electricity energy into food energy<br />Assume continuous agriculture: Operation during lunar day & night, half the agriculture area is illuminated at any given time, for 12 hrs on 12 hrs off on any given crop.<br />(6.978 kilowatt-hour/person-day) / (0.01 efficiency * (24 hour/day)) =<br />= <b> 29.1 kw/person</b> continuous electricity requirement for Agriculture<br /><br />WOW I knew it was a big number, but I’m a bit surprised. It reinforces my view that food commodities will be brought in for quite some time – don’t think MREs or freeze-dried, think wheat and rice and corn and barley and pasta and fish food. Yes, the last one is for the fish. <br /><br />Still, that’s only nine “4 by 8” panels per person. Let’s more than double that for total energy per person: 73.3 kw per person or 22 panels per person. We’ve talked about 100 people in the dome, so that’s 2200 panels to generate 7.33 mW.<br /><br />If we want to operate at night just like we do in the day then we need to more than double that capacity to make our LOX and LH2 to get us thru the night in style. Note that this represents an endpoint in my plan: we don’t get there any sooner than about 7 years after the sweepers show up. In the years after opening, the dome would run with a skeleton crew at night, the tourists would be gone and the agriculture would be run at maintenance <div class="Discussion_UserSignature"> </div>

 

[spacester]

Hi rocketman5000, yeah baby, I’m the KING of the long posts, lol.<br /><br />My first payload would be the power lander I’ve referenced, with a bunch or robots piggybacked on it, along with a small glass factory and a small basalt cutting test machine. It would land, the robots would climb down and deploy everything. The mission is to 1)Survey 2) Deploy the glass factory 3) Make a small basalt brick 4) Sweep the building site to get the dust out of the way.<br /><br />Operations would be a bit less than 14 days at a time, and un-powered survival at night would be desired. If that is not feasible, we’ll need to store some thermal energy somehow to keep our robot friends warm and happy.<br /><br />The BBS format is not the most productive way to work these things out, but here we are; I think we should just stay with this thread. I see your point on a separate thread, but I don’t feel like starting it myself . . . <br /> <div class="Discussion_UserSignature"> </div>

 

[rocketman5000]

I like all of the numbers, maybe it will help keep people from scream Nuc vs. Solar. Now to know the mass of those 8800 panels. <br /><br />The 6000 kcal per person seems a little high to me. Is this a number that comes from NASA? Unless I am wrong 3000 would be sufficient for residents and espically tourists. This could be a substatial reduction in energy requirements.<br /><br />Have you thought about the requirements for life support? Is this where you go to the 22 panels per person? <br /><br />As for your sweepers I don't think you would want to run them during the night. but if you were using seperate robots to do tests a RTG could probably keep it running. many sensors require very little power, it is the transmission of the data that would be a little more energy intense. <br /><br />In the posts above you stated mapping the site and testing in a grid pattern. what sort of data were you anticipating. "Soil" composition I would assume and topography, maybe density? <br /><br />An interesting thought about generating heat during the solar night. I assume that you would have to make your hydrogen cryogenic for storage space reasons. Using a heat pump on fluids that have evaporated off to recondense them (LH2 should be cold enough to absorb heat even during th night) could provide a substantial amount of waste heat to keep everyone warm. At least the residents huddling up for the night. Ideally you wouldn't every use your stored energy to provide heat directly as almost every this produces waste heat due to inefficiences. <br /><br />Thinking about energy and the ways to store and save it. A quick search of the temperature of a lunar night and day on google brought up that the maximum temperature during a lunar day is 1360 F and -110 F at night. The lunar soil has large amounts of iron, and can be sintered very easily as discussed earlier in the thread. If the solar energy can be focused to create a large block of heated solid regolith it would provid

 

[mlorrey]

Normally 3000 kcal per person/day is typical on earth, but keep in mind that people on the moon will be working hard in spacesuits, which according to the astronauts was really difficult just to shuffle around and scoop up a few samples. Improved suits may be better, but not likely much better. <br /><br />My cousin did his masters geology work on a summer in Antarctica, and as the low man on the totem pole was in charge of budgeting the food for the expedition, tenting in a katabatic canyon. He budgeted 6000 kcal/day/person and everyone still lost 10-30 lbs each in two months.<br /><br />I therefore believe that this is a reasonable yardstick for a lunar expedition, doing a lot of hard work in spacesuits and terrible HVAC conditions. <br /><br />Frankly, I expect to put tourists to work like slave dogs, just as if they were 'tourists' on archaeological or anthropological expeditions. Why should the professionals have to do all the grunt work?

 

[chriscdc]

AFAIK the recommended amount is 2500Kcals on earth. I'm guessing that as a geologist, your cousin had to drag his equipment and food along with him (to sites of interest) which would hugely increase the cals required. Do you know of the cals required on one of the antarctic research stations?<br /><br />About the space suits, seeing as what makes it harder to move is that the suit is trying to keep the same volume, have there been any designs that featured say an expandable bladder with some kind of artificial muscle (or piston system) that allows it to change its volume when the person moves?<br /><br />You mentioning the antarctic reminded me about something I heard a while back. It was about how you could work too hard, incase you started to sweat, which would lead to getting wet and freezing. But on the moon, you will be using the same suit over and over again which means smells. There needs to be some way cleaning out such equipment, and clothes etc on the moon. I suggest that all clothes either have antibacterial stuff like silver, or TiO2. The TiO2, when the particles are the right size, they react with water and UV to break down carbon molecules.

 

[mlorrey]

<blockquote><font class="small">In reply to:</font><hr /><p>AFAIK the recommended amount is 2500Kcals on earth. I'm guessing that as a geologist, your cousin had to drag his equipment and food along with him (to sites of interest) which would hugely increase the cals required. Do you know of the cals required on one of the antarctic research stations? <p><hr /></p></p></blockquote><br /><br />Actually, all their supplies were airlifted in by helicopter. The caloric budget involved:<br /><br />a) the cost of respiration at high altitude (lunar pressure modules will likely be pressurized to replicate 8500 foot/2500 meter altitudes, which would replicate this).<br /><br />b) the temperature losses (HVAC systems built by government contractors and/or university scientists with pet theories are likely to be highly unreliable, just look at the oxygen converters) expect to snuggle up in a survival suit on a frequent basis.<br /><br />c) moisture losses (in antarctica, it is the dry katabatic winds and the cold that dries you out fast, on the moon it will be HVAC systems).<br />d) work from digging core holes in dirty ice and rock to get ice cores from buried 22 million year old glaciers, wearing survival suits. This was the big drain. I would posit that the work of wearing a lunar space suit and doing real work (mostly geological) outside in prospecting for regolith ores and ice deposits, as well as the hard work of farming in ag modules indoors, will lead to a similar caloric budget.<br /><br />The 2500kcal/day budget is a modern confection of automated industrial and professional work. You have no idea how easy you have it in the modern age. Obesity in the US is a function of not having to work an 'honest days work' from the POV of the earlier centuries.<br /><br />If we are going to go to the expense of sending a human to the moon, and sustaining them there, they'd better make themselves useful. I'd rather send a bunch of construction workers, miners, and farmers who are all prepared to sweat,

 

[chriscdc]

Ah the dust.<br /><br />No weathering apart from micrometeorites means that the partciles aren't smooth. Though in the UV from the sun charges the particles as well as their size means that they will stick very easily. <br />They will slowly erode fabrics, on the outside of the spacesuit. It will scratch metals and sealants between the suits etc. <br /><br />Also the vacuum will cause any lubricants to evaporate. Therefore to reduce any friction between surfaces you will need to make the surfaces as smooth as possible. For this reason it will be ideal to use diamond as the surface interface, only a micron or so needed though chemical deposition shouldnt be too expensive (compared to the overall cost of these suits). <br /><br />Of course the best solution is to reduce the dust spraying up. The best way is not to use wheel transport on open (un-sintered) ground when there are people on foot. No kneeling, unless on special pads and preferably grabbers for lifting rocks rather than using gloves. Cheap foot protectors would also be needed.

 

[mlorrey]

suggest studying regolith geology. There are a lot of round glass beads, round other things. No, there isn't terran weathering, but the radiation from the sun and cosmic space do something similar, sintering particles to each other in microwelds, like a low level microwave plasma oven. Centrifuging regolith in slurry to remove exploitable metals should provide a significant weathering to any jaggedness left, just as with a jewelers polishing centrifuge.

 

[chriscdc]

I'm just going on what they said after the apollo missions. They were outside for hours and it damaged their suits. So there is plenty of jagged particles.<br />I thought the whole point of the microwave sintering was that it gave the particles energy, faster than they can radiate it away and so raising the temperature causing melting etc. <br />Any small particles lying next to one another over time will form bonds, simply because the energy of atoms in bulk is lower than those on the surface. The smaller the particles, the greater this difference. Are you sure that it is in fact the radiation doing that (apart from obviously heat from the sun giving the atoms energy to move and thus more likelyhood of falling of falling into a lower energy state).<br /><br />Yes centrifuging regolith would remove the jaggedness but I fail to see how this relates to unprocessed regolith damaging space suits or vehicles.

 

[mlorrey]

Sintering is the molecular level bonding you are talking about. Sintering results from both exposure to vacuum, and to radiation.<br /><br />You are right that regolith outdoors will be a problem but half of it is that radiation also happens to weaken the bonds of the complex organic chain molecule materials in spacesuits, which makes them prone to damage from other sources.

 

[rocketman5000]

I don't know the stage of development, but doesn't the army have that suit with the artificial muscles? Instead of using them as muscles use the artificial muscles as constrictive bands on the suit. when the astronauts appendage needs to flex in that area the muscle could relax to allow easier movement. I am sure such a suit would require large amounts of power however

 

[chriscdc]

Well either the power comes from you or a machine. A person will be able to do things (overall) with less energy If they don't have to stop every 10 steps to get their breath.<br /><br />Also the efficiency of storing the energy, then using it to do physical work is going to be better than generating the oxygen and food, which you then use to do the extra work.<br /><br />Of course a skin suit would be the best solution, but I don't see the space agencies investing in that before the astronauts begin to strike over it.

 

[josh_simonson]

It might be possible to mitigate dust problems by never bringing the suit inside, instead have a hatch in the top or back from which one can enter and exit the suit while the suit stays outside, or at least in a 'dirty' airlock at all times.

 

[scottb50]

Another option would be a sealed vehicle that docks to a station. With various interchangable manipulators and tools you could work on the surface in a shirt-sleeve environment. Being able to travel around as well as perform work would be a big plus. <div class="Discussion_UserSignature"> </div>

 

[chriscdc]

I'd do something similar. Half the airlock would be behind an plastic sheet that you could then make a seal with. As the dust will mainly be on the boots and legs, you could have a seal around the waist. The torso would go though the hole in the sheet. This won't be a air tight but it would be simple and would keep out the vast majority of the dust.

 

[larrison]

Robot puppets. Tha astronauts wear an exoskeleton suit that controls a robot outside the station. Different workers could wear the suit meaning the robots work day could be 24 hrs long. Also backup robots could be stored for quick replacement when one was damaged, needed servicing or recharging.

 

[scottb50]

Just so there are no muppets, hate those things! <div class="Discussion_UserSignature"> </div>

 

[larrison]

Well... maybe just a frog.

 

[spacester]

{All: I’m really torn between discussing my dome concept and discussing things in more general terms. I try to do both, so my posts are long, and you have to pay attention to see what context I’m using at the moment. Sorry about that, but I figure it beats me beating everybody over the head with my plan. The thing is that this thread has really helped my firm up some major design decisions, and I can move on to new territory, so I thank you and on with the show as it develops . . . }<br /><br />I like the 6000 kcal/day number for all the reasons cited, nice posts! A ‘modern confection of automated industrial and professional work.’ – I like that line, I’ll be stealing it later, lol.<br /><br /><font color="yellow">. . . Frankly, I expect to put tourists to work like slave dogs, just as if they were 'tourists' on archaeological or anthropological expeditions. Why should the professionals have to do all the grunt work? </font><br /><br />Yes! Somebody else who gets that! That’s one of the reasons I like to put “tourists” in quotes. Especially for lunar field work, which I assume will be going on somewhat concurrently with dome construction. Once the dome opens for business, the ‘true’ tourist – the ‘sipping margaritas on the beach’ type – will have a place to stay in lunar gravity for HUGE money. But in the years before that, there will be plenty of ‘adventure tourists’ that will pay big bucks AND do, as you say, the grunt work. They will stay in Scott’s Modules™ <img src="/images/icons/wink.gif" /> and Bigelow Lunar Habitats and whatever else we come up with. <br /><br />Alternatively, none of that happens and the dome project goes forward anyway.<br /><br /><font color="yellow">Ah, the dust.</font><br />A big part of my plan is dealing with the dust. Clearing the site of the loose regolith right off the bat is a strategy that makes sense for a big dome, but of course isn’t an option for general field work. I don’t have a lot of solutions to the dust problem <div class="Discussion_UserSignature"> </div>

 

[chriscdc]

I think it's important to find out the minimum thickness that the sintered regolith need to be. The thickness for people would probably only be 1-5 cm, whilst a heavy vehicle may need to be 10-50cm thick. The last thing you want is for the wheels of a vehicle to shatter the sintered layer like ice, and kick up razor sharp splinters. <br />On the other hand, you don't want to waste energy making the human walkways thicker than needed.

 

[mlorrey]

Thanks. I watched the PBS series "Frontier House" a few years ago, and was entertained by the SoCal family with the nutritionist wife who was frantic that her husband was 'wasting away' on what she considered a full diet, doing frontier grunt work building fencing, farming, etc. They didn't get that the human animal is a beast of burden on the frontier.

 

[rocketman5000]

Assuming that the Astronaut and suit weigh 500 lb. Earth weight, and that the suit has roughly 90 sq. in of boot area (I measured my shoes I have on here at work) the Pressure on the surface will be somewhere around 6 psi. Given that the lunar surface is somewhere around 1/6th the gravity this should equate to a factor of safety of about 6. <br /><br />As I am having problems finding the yeild strength of bulkglass and not fibers I'll have to get back on the required thickness. I'll edit the post later today. At the moment my lunch hour is almost over.

 

[scottb50]

That's why hermetically sealed vehicles will be the safest and most efficient means of exploration on the moon and on Mars. This will assure any outside contaminates have little chance of getting inside.<br /><br />I suppose suits would be needed for some operations, especially tourists, who could say they walked on the moon or Mars. I would think something able to carry three people would be small enough to get pretty much anywhere you could get in a suit. With grapples, shovels and other specialized attachments pretty much anything could be done. <div class="Discussion_UserSignature"> </div>

 

[scottb50]

I've thought of a water spray after docking the vehicles to a Station, the particles could be filtered out and the water recovered. If nothing else anything tracked in would be wet and stand out.<br /><br />I would think walking outside would be a pretty complicated t6o begin with. It would be much easier to simply climb into the vehicle at a docking port, close the hatches, undock and drive off.<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[josh_simonson]

The dust doesn't stay put, it electrostatically levitates around the moon to a height of several hundred meters. Sintering the ground will not prevent more dust from settling out. <br /><br />The dust problem is probably similar to that of sand on scuba equipment. There you simply rinse the gear after use and clean/replace or lubricate the O-rings to maintain good 3000psi seals. The same should be do-able in space, except the outer door on the airlock may be difficult to service. Dust will probably require a 'squishy' seal like an O-ring. A hermetic diamond seal would never seal if there were bits of dust on it.<br /><br />The ultimate airlock seal would use heating elements and some sort of solder to weld the door shut and melt the seal to open it, providing a continuous piece of metal as the seal.