Author Topic: Best Region for a Base/Outpost?  (Read 37972 times)

Offline redliox

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Re: Best Region for a Base/Outpost?
« Reply #100 on: 04/12/2014 11:23 am »
Again guys, talk about the terrain or region that might work best

Or about the approach to take in finding the best terrain/region. I was impressed by the method Vanoutryve et al. used. See e.g.
"An Analysis of Illumination and Communication Conditions near the Lunar South Pole based on Kaguya data"
http://solarsystem.nasa.gov/docs/pr404.pdf

Excellent!  This would be a good example of what I'm referring to.

Malapert "Peak" was used as a study model in "The Moon" book released by Springer at the height of the Constellation era.  It and the nearby Leibnitz Plateau appear to be the 2 spots immediately adjacent to the Lunar south pole high enough to enable near-continuous solar energy and Earth contact.

Specific targets like this are good examples of what to discuss.  Here'd be one question to pose: which offers more, the south or north pole?
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Offline Hop_David

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Re: Best Region for a Base/Outpost?
« Reply #101 on: 04/12/2014 09:14 pm »
If you are having problems with shadows can we find an arrangement in which no more than half the solar panels are shaded at any time?  We just need twice as many poles.

A cylindrical surface would be constantly illuminated, no matter if the sun was in the south, east, north or west. But then the watts per square meter of array would fall by a factor of pi.

Also when a given part of the surface swings between full sunlight and complete shadow, you once again have to deal with destructive temperature swings.

But a cylinder would be more stable than a rotating mast.

And I suppose the panels on the sunside could send heating electricity to the shadow side of a cylinder. Since they're insulated by perfect vacuum. the heating expense may not be high.

« Last Edit: 04/12/2014 09:15 pm by Hop_David »

Offline gbaikie

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Re: Best Region for a Base/Outpost?
« Reply #102 on: 04/12/2014 10:38 pm »
If you are having problems with shadows can we find an arrangement in which no more than half the solar panels are shaded at any time?  We just need twice as many poles.

A cylindrical surface would be constantly illuminated, no matter if the sun was in the south, east, north or west. But then the watts per square meter of array would fall by a factor of pi.

Also when a given part of the surface swings between full sunlight and complete shadow, you once again have to deal with destructive temperature swings.

But a cylinder would be more stable than a rotating mast.

And I suppose the panels on the sunside could send heating electricity to the shadow side of a cylinder. Since they're insulated by perfect vacuum. the heating expense may not be high.

You want the solar panels to be as cool as possible, so it could be cylindrical to radiate the heat from the solar panels. But you want the panels flat, but if conduct enough heat, one add reflectors to increase amount watts per square meter. So double surface area by having curved back, the reflector also can be radiators. Have radiating surfaces so emit most IR, and use metals which conduct heat away from solar panel to radiating surfaces. And have balanced in terms of weight, but turn solar panel to face the sun. 

Offline Andrew_W

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Re: Best Region for a Base/Outpost?
« Reply #103 on: 04/13/2014 01:00 am »
If you are having problems with shadows can we find an arrangement in which no more than half the solar panels are shaded at any time?  We just need twice as many poles.

I read your comment differently to Hop and  gbaikie, to avoid shading of your solar panels when the sun is blocked by distant mountains you need to elevate them further, might be talking kilometers. To compensate with panels at another location I'm pretty sure you'll have to go as far as a different peak, so panels on Shackleton Rim/Connecting Ridge and on Malapert Peak/Leibnitz beta Plateau connected to the same network to supply continuous solar power.
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Offline clongton

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Re: Best Region for a Base/Outpost?
« Reply #104 on: 04/13/2014 01:08 am »
Talking about solar panel design and installation does no good until the fundamental question is answered: "how much continuous electrical power will be required to power the base"? Only then will anyone have any idea how large the array must be.

One needs to know how large the array is before one can design its installation.
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Offline KelvinZero

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Re: Best Region for a Base/Outpost?
« Reply #105 on: 04/13/2014 01:09 am »
(thats very true.. someone come up with a figure and estimate square areas please ;) )

This is a bit off topic except that it is an advantage of setting a base in one of the polar permanently lit regions:

I was thinking there could be some advantage to a wall of flimsy black sheet around your base. As well as holding your solar power panels it would prevent direct sunlight while radiating a bit of heat into all the shadows, evening out the thermal environment. You wouldnt need to worry about losing a rover because you parked it somewhere that moved into shadow, or any of a zillion components that might slowly or suddenly fail due to extreme temperature changes.

Offline clongton

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Re: Best Region for a Base/Outpost?
« Reply #106 on: 04/13/2014 01:25 am »
or any of a zillion components that might slowly or suddenly fail due to extreme temperature changes.

There are no real extreme temperature changes at the poles to speak of. The sun is at a pretty consistent angle of ~1.5 degrees for the entire lunar month, just constantly changing direction. The subsurface temperature, whether in sunlight or shadow,  remains around -110 degrees C, more or less. Inside the permanently shadowed craters is a different story but on the average surface temperatures are fairly constant at the poles.

Has anyone given any serious thought to finding a way to use geothermal energy? Explorers would have to go deep. The moon has an iron-rich core with a radius of about 205 miles (330 km). The temperature in the core is probably about 2,420 to 2,600 F (1,327 to 1,427 C). The core heats an inner layer of molten mantle, but it's not hot enough to warm the surface of the moon. But it's possible to tap that heat source if one could drill deep enough. Then electrical production would be far less difficult and use more well understood steam turbine generators.
« Last Edit: 04/13/2014 01:32 am by clongton »
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Offline gbaikie

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Re: Best Region for a Base/Outpost?
« Reply #107 on: 04/13/2014 02:13 am »
Talking about solar panel design and installation does no good until the fundamental question is answered: "how much continuous electrical power will be required to power the base"? Only then will anyone have any idea how large the array must be.

One needs to know how large the array is before one can design its installation.

If "base" is mining lunar water and making rocket fuel, the question is how rocket fuel can sell per year. Which
could 50 to 1000 tonnes and over time, a lot more.
If base is crew, it seems electrical power need would less than ISS- though experiments and local travel around base is additional power need.
But it seem about 100 KW or about 100 square meters of solar panel. And you also want thermal energy- like solar furnace or simple solar thermal water heaters and lighting from reflected light.

Offline A_M_Swallow

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Re: Best Region for a Base/Outpost?
« Reply #108 on: 04/13/2014 02:45 am »
Talking about solar panel design and installation does no good until the fundamental question is answered: "how much continuous electrical power will be required to power the base"? Only then will anyone have any idea how large the array must be.

One needs to know how large the array is before one can design its installation.

The energy required is a variable - it increase as the base grows and start doing high energy activities like refining locally mined materials.

We may be able to come up with a power generation solution that scales.

Offline KelvinZero

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Re: Best Region for a Base/Outpost?
« Reply #109 on: 04/13/2014 09:23 am »
or any of a zillion components that might slowly or suddenly fail due to extreme temperature changes.

There are no real extreme temperature changes at the poles to speak of. The sun is at a pretty consistent angle of ~1.5 degrees for the entire lunar month, just constantly changing direction. The subsurface temperature, whether in sunlight or shadow,  remains around -110 degrees C, more or less. Inside the permanently shadowed craters is a different story but on the average surface temperatures are fairly constant at the poles.
Im pretty sure you would get extreme temperature changes, though the situation is better than at the equator.

If there are permanently shadowed areas then I expect there are many more areas that are shadowed only half the month. I don't see why these should be much warmer than lunar night at the equator.

parts of your base not in direct line of sight to the ground would get the same extreme temperature changes that you get on vehicles in deep space, between the lit and unlit sides.  I recall this is why the Apollo command module would slowly rotate on its journey to the moon.

Subsurface temperatures dont really count since they would be stable anywhere on the moon, so long as you go deep enough anyway. Shadowed regions on the surface could get much colder than this, but the difference between -110 celsius and direct sunlight could still be pretty extreme.

I don't understand the 1.5 degrees angle figure though Im hardly an expert. The moon as a 5 degree tilt to the ecliptic so I had assumed that exactly at the pole the angle of the sun would vary from +5 to -5 degrees over a year.

Offline gbaikie

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Re: Best Region for a Base/Outpost?
« Reply #110 on: 04/13/2014 09:02 pm »
or any of a zillion components that might slowly or suddenly fail due to extreme temperature changes.

There are no real extreme temperature changes at the poles to speak of. The sun is at a pretty consistent angle of ~1.5 degrees for the entire lunar month, just constantly changing direction. The subsurface temperature, whether in sunlight or shadow,  remains around -110 degrees C, more or less. Inside the permanently shadowed craters is a different story but on the average surface temperatures are fairly constant at the poles.
Im pretty sure you would get extreme temperature changes, though the situation is better than at the equator.

If there are permanently shadowed areas then I expect there are many more areas that are shadowed only half the month. I don't see why these should be much warmer than lunar night at the equator.
They are colder- generally. But since equator nights get down to 100 K, you could say there is lack of room to goes much cooler.
Like on earth, the lunar surface is generally or averages at being mostly level.
If you have steep hill or crater rim which is steep, the slope facing the sun can warm to same temperature as surfaces at equator, and opposite side one has shade.
So within say 100 feet, one could have 400 K and 100 K. One similar situation at equator, but one should have very hot and very cold and being closest to each other as occurring more in polar regions.
But generally it's colder at poles and 1 meter under ground generally in polar region is much colder than Equator. Say it's 250 K equator, and 150 K polar being what I mean by much colder- 100 K or more colder.
So average surface is level, and if somewhere around 85 latitude, making sun 5 degrees above horizon.
And sun 5 degrees above horizon will not heat the level surface much- each square meter get around 1/10th of solar energy because of angle sunlight to surface. So 136 watts rather than 1360 watts per meter- so worse than asteroid Vesta in "noon" sun or colder than Ceres.

So if at a peak of eternal light and on level surface, that level surface will remain very cold in sunlight [sort of brightly lit, but cold], and rock or solar panel facing the sun can be getting 1360 watts per square meter.
Now if have level ground and vertical wall, the vertical wall will warm level surface as much or more than the sunlight- it's at same angle but parts of a rough wall will radiate at more of angle. Or perfect mirror would be like having two suns at a low angle [double the watts per square meter which hits surface- but still be colder than Mars surface in equator at noon.


Offline sdsds

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Re: Best Region for a Base/Outpost?
« Reply #111 on: 04/13/2014 10:24 pm »
One of the reasons I was impressed by the Vanoutryve paper linked in a prior post was how they made "operationally actionable" thermal assumptions. In particular they assumed the thermal control system and batteries would support loitering through periods of darkness lasting up to 55 hours without sustaining damage.

I Am Not A Thermal Engineer, but I have faith in modern thermal engineering design practices. As regards the "illuminated on one side; shadowed on the other" problem, I assume thermal engineers can design, build (and test) equipment that will meet reasonable requirements. Some amount of internal heat transfer is going to occur from the lit side to the dark side; clever design can maximize the usefulness of that. I'm not saying that design work will be easy or cheap; just that it will be valuable!
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Offline clongton

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Re: Best Region for a Base/Outpost?
« Reply #112 on: 04/13/2014 10:35 pm »
One of the reasons I was impressed by the Vanoutryve paper linked in a prior post was how they made "operationally actionable" thermal assumptions. In particular they assumed the thermal control system and batteries would support loitering through periods of darkness lasting up to 55 hours without sustaining damage.

I Am Not A Thermal Engineer, but I have faith in modern thermal engineering design practices. As regards the "illuminated on one side; shadowed on the other" problem, I assume thermal engineers can design, build (and test) equipment that will meet reasonable requirements. Some amount of internal heat transfer is going to occur from the lit side to the dark side; clever design can maximize the usefulness of that. I'm not saying that design work will be easy or cheap; just that it will be valuable!


Also equipment sitting on the surface, unlike spacecraft in the vacuum of space, can take advantage of thermal transfer thru the rigolith. It is going to happen whether or not it is intended. Granted it is not much but the surface *is* a heat sink of sorts and will try to equalize the temperature of anything sitting on it. Smart engineers might find a way to make that contribute to thermal management.
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Online TrevorMonty

Re: Best Region for a Base/Outpost?
« Reply #113 on: 07/22/2014 04:48 am »
These lava caves look like a great place a base, there are hundreds to choose from. At up to 900m across it would be possible to land a Bigelow module in one then drive it inside.

Some of the XPrize Landers in development could land in one and explorer it with a small rover.

http://www.parabolicarc.com/2014/07/21/lunar-pits-shelter-future-explorers-settlers/

Offline redliox

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Re: Best Region for a Base/Outpost?
« Reply #114 on: 07/22/2014 08:32 am »
These lava caves look like a great place a base, there are hundreds to choose from. At up to 900m across it would be possible to land a Bigelow module in one then drive it inside.

Some of the XPrize Landers in development could land in one and explorer it with a small rover.

http://www.parabolicarc.com/2014/07/21/lunar-pits-shelter-future-explorers-settlers/

I doubt NASA would allow a direct landing inside that, and there's always the chance the descent thrusters could cause a cave collapse.

All the same, I think investigating these should be put on the same level of priority as the polar ice.  While landing inside is unwise, sending a crew to investigate and map would be wise, to ensure the pits are stable.  From a nearby surface camp they could eventually send down the material to make an underground habitat.
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Offline Robert Thompson

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Re: Best Region for a Base/Outpost?
« Reply #115 on: 07/22/2014 10:11 am »
Lunar and Martian Lava Tube Exploration as Part of an Overall Scientific Survey A White Paper submitted to the Planetary Sciences Decadal Survey 2013-2022

http://www.lpi.usra.edu/decadal/leag/AndrewWDagaFINAL.pdf
"The size of these rilles and associated topographic ridges (which may represent sections of a tube that have not collapsed) suggest cross-sectional widths on the order of hundreds of meters, lengths of tens of kilometers, and roofs that are meters thick."

Check out the NAIC presentations listed here:
http://forum.nasaspaceflight.com/index.php?topic=22073.msg1159220#msg1159220

I can see Moon Express landing a rover with ground penetrating radar near a carefully chosen skylight. Late 2020's.

Astrobotic is working on this.
http://www.universetoday.com/104705/this-company-wants-to-send-robots-into-lunar-caves/
« Last Edit: 07/22/2014 12:23 pm by Hernalt »

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