Author Topic: Best Region for a Base/Outpost?  (Read 37973 times)

Offline redliox

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Best Region for a Base/Outpost?
« on: 03/11/2014 07:21 pm »
There have been past discussions about the best place for a lunar base/colony/outpost, but since it has been a while I thought to refresh the topic with or without the likelihood of a lunar expedition in the immediate future (ask this question again with the next US president or Congress and I'll bet the chances change once again).

Previously, the Lunar poles garnered attention since the presence of ice is confirmed.  While this is logical for long-term sustained settlement, if we're talking the first 20 years it is not so much.  I state this because it will be some time before we figure out what to do with the ice, partly because we aren't fully certain if it's fluffy space snow or thin veins in a rocky matrix.  Add to that, neither the north or south poles are friendly places to land blindly since they are, for better or worse, crater quagmires.  Regarding the poles, definitely study them both with robots and astronauts but hold off on any fledgling lunar cities.

Without a communication link, the far side is impossible, but should be scouted once some form of network is established.  Any bases established there should devote themselves to astronomy and the geology of the lunar farside, i.e. to science.

Obviously the near side is easy to reach and support, perhaps even "too easy" since Apollo and what robotic landers we sent did explore numerous regions of it.  Still the maria are as easy a landing site to find and their volcanic nature offers plenty in both resource utilization and science.  Any one of them ought to offer some opportunity.

Personally, I would suggest a base on the limb of the moon where it would still be within communications range of Earth yet within scouting range of the unexplored far side.  The Western Hemisphere offers the Ocean of Storms and Mare Oriental whereas the Eastern Hemisphere has Mare Smythii (which has been suggested in some studies), presuming a simplified preference for the equator.

Wherever we land, initially it should be someplace practical yet with opportunities to explore and experiment with ISRU.  Since I specifically refer to the first 20 years of exploration and settlement, it should be assumed most resources will still come from Earth - hence emphasis on easy-to-reach spots.  Unlike Mars, that is an asset, not a weakness during the formative years with the benefit of a nearby Earth.

Bear in mind 3 factors when you make suggestions:
1) Ease of access (both landing and roving)
2) Function
3) Exploration

Again my suggestion would be the westernmost 'shores' of the Ocean of Storms near the equator.  Overall the region may be bland, but numerous craters are half-buried and easier to rove into; not to mention the size of the Ocean implies it has a major role in the near side's history.  Between the lunar craters & mountains and the maria there would be numerous regolith types accessible to testing, with titanium, iron, and illemite plentiful.  Not necessarily the only place to go, but good to begin.
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Offline sdsds

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Offline mdatb

Re: Best Region for a Base/Outpost?
« Reply #2 on: 03/11/2014 07:36 pm »
http://en.wikipedia.org/wiki/Whipple_(crater)

Pros:

-A sunlit plateau that can be used to generate power.
-Ice, which can be used as rocket fuel and water.
-Other craters in the area may have ice

Cons(compared to your suggestion):

-Not as smooth of a driving area.
-Harder to access.
-Might be less endowed with metals.
-Ocean of storms still has a fuzzy origin. Something to explore!
« Last Edit: 03/11/2014 07:45 pm by mdatb »

Online TrevorMonty

Re: Best Region for a Base/Outpost?
« Reply #3 on: 03/11/2014 07:56 pm »
For any base to survive it needs power 24/7. A nuclear power supplied base can be placed anywhere. In case of solar power it needs to be near a pole for higher sunshine hours.  During lunar nights a solar power system will be running on batteries or fuel cells.


Offline rusty

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Re: Best Region for a Base/Outpost?
« Reply #4 on: 03/11/2014 08:59 pm »
The "Best Region for a Base/Outpost" is in LLO, not on the surface. From there, sorties to all regions of interest can be carried out, samples gathered, tests performed and instrumentation laid. Only if that location is worth hanging around for or is ideal for testing surface equipment for other (Mars?) operations should a surface base/outpost be established. From a previous post of mine, the LLO temporarily-manned base/outpost;

For maximum scientific, modular and reuse capability with minimum size, fuel use and cost I've gone with polar LLO, possibly 86 degrees as that appears to be highly stable. I've calculated delta-v at 2.014 for obit between 85 - 103km with inclination/plane change budget of 15 - 10 degrees, respectively, to cover the entire polar regions. The polar regions with their possibility of ice are a must, the far side equator prime for radio telescopes and the Apollo 15 site the most geologically interesting.

All these are readily accessible from the PLO mentioned, as well as much more. Since then I've buttoned down and tweaked the orbit to be elliptical, but the fundamentals and reasons remain: "Anytime return" from all areas of interest, lowest fuel requirements for multi-sortie missions, shortest duration (safest) and smallest craft to LLO return, greatest downmass capability especially if delivered via SEP, etc.

Offline gbaikie

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Re: Best Region for a Base/Outpost?
« Reply #5 on: 03/11/2014 09:38 pm »
There have been past discussions about the best place for a lunar base/colony/outpost, but since it has been a while I thought to refresh the topic with or without the likelihood of a lunar expedition in the immediate future (ask this question again with the next US president or Congress and I'll bet the chances change once again).

Previously, the Lunar poles garnered attention since the presence of ice is confirmed.  While this is logical for long-term sustained settlement, if we're talking the first 20 years it is not so much.  I state this because it will be some time before we figure out what to do with the ice, partly because we aren't fully certain if it's fluffy space snow or thin veins in a rocky matrix.  Add to that, neither the north or south poles are friendly places to land blindly since they are, for better or worse, crater quagmires.  Regarding the poles, definitely study them both with robots and astronauts but hold off on any fledgling lunar cities.
NASA's job is to explore space.
As your post suggests the lunar poles have not been adequately explored despite decades of strong public support and funding of NASA so that NASA can explore space.

What NASA needs to do is explore space in order to lower the cost of doing such thing as space mining and space development [settlements] so these can be developed in the future. And related to this would having rocket fuel made in space from water.

So order for there to lunar water mining, NASA [or someone] must first explore the moon to determine where and how this might be done the most efficiently.
Considering that there could hundreds of billion dollars worth of recoverable lunar water, and that the mining of lunar water makes it possible to make cheaper lunar rocket fuel. Thereby enabling use the Moon for many different things, at significantly lower cost, it seems wise that before NASA does anything else in regard to the Moon [or for that matter, the rest of solar system]  that NASA should be exploring the lunar poles to determine if and where there is minable lunar water.


Offline Andrew_W

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Re: Best Region for a Base/Outpost?
« Reply #6 on: 03/12/2014 06:06 am »
The "Best Region for a Base/Outpost" is in LLO, not on the surface. From there, sorties to all regions of interest can be carried out, samples gathered, tests performed and instrumentation laid. Only if that location is worth hanging around for or is ideal for testing surface equipment for other (Mars?) operations should a surface base/outpost be established. From a previous post of mine, the LLO temporarily-manned base/outpost;

For maximum scientific, modular and reuse capability with minimum size, fuel use and cost I've gone with polar LLO, possibly 86 degrees as that appears to be highly stable. I've calculated delta-v at 2.014 for obit between 85 - 103km with inclination/plane change budget of 15 - 10 degrees, respectively, to cover the entire polar regions. The polar regions with their possibility of ice are a must, the far side equator prime for radio telescopes and the Apollo 15 site the most geologically interesting.

All these are readily accessible from the PLO mentioned, as well as much more. Since then I've buttoned down and tweaked the orbit to be elliptical, but the fundamentals and reasons remain: "Anytime return" from all areas of interest, lowest fuel requirements for multi-sortie missions, shortest duration (safest) and smallest craft to LLO return, greatest downmass capability especially if delivered via SEP, etc.

And when the Sun has one of its hissy fits?
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Offline Andrew_W

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Re: Best Region for a Base/Outpost?
« Reply #7 on: 03/12/2014 06:11 am »
I don't think any other location comes close to the poles in desirability, and that makes it the #1 initial base location to obtain "propriatory" rights.
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Offline redliox

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Re: Best Region for a Base/Outpost?
« Reply #8 on: 03/12/2014 07:10 am »
For any base to survive it needs power 24/7. A nuclear power supplied base can be placed anywhere. In case of solar power it needs to be near a pole for higher sunshine hours.  During lunar nights a solar power system will be running on batteries or fuel cells.

Agreed.  Solar power is obvious with the weakness being lunar night, but inversely a nuclear reactor I don't see happening at least in the first 10 years from a combination of anti-nuke protesting and lack of funding between both NASA and the DOE.  More than likely the base would be similar to the ISS' own early years, being only temporarily occupied during the first few years and abandoned/powered down during the lunar night.  Fuel cells would be the best backup power outside of a massive battery array.

One link between formative and advanced bases could become utilizing polar ice not merely for rocket fuel or drinking water, but fuel cell replenishment.  I could see that happening perhaps year ~18 onward, though hopefully sooner depending on future space ambitions.
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Online TrevorMonty

Re: Best Region for a Base/Outpost?
« Reply #9 on: 03/12/2014 07:49 am »
I don't think powering down base is an option. The extreme cold of lunar night will kill the electronics and other components, a low level of heating will be needed. The Chinese solution is radioactive isotopes for Chang3.

Offline redliox

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Re: Best Region for a Base/Outpost?
« Reply #10 on: 03/12/2014 08:04 am »
I don't think any other location comes close to the poles in desirability, and that makes it the #1 initial base location to obtain "propriatory" rights.

Desirable yes, practical another question.  We don't know how to mine lunar ice and landing on or near a shadowed crater is not easy.  However, landing at one of the mares near the north pole would be possible, and either by rovers or short-range rocket jumps venturing into the polar craters themselves to build up confidence.
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Offline Proponent

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Re: Best Region for a Base/Outpost?
« Reply #11 on: 03/12/2014 09:10 am »
And when the Sun has one of its hissy fits?

Shielding from solar particle events isn't that difficult: the particles, though very numerous during an event, are not of terribly high energies.

Offline Solman

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Re: Best Region for a Base/Outpost?
« Reply #12 on: 03/12/2014 02:02 pm »
For any base to survive it needs power 24/7. A nuclear power supplied base can be placed anywhere. In case of solar power it needs to be near a pole for higher sunshine hours.  During lunar nights a solar power system will be running on batteries or fuel cells.

 Another possibility is beaming power from Lunar polar orbit. I don't know the ideal number and orbital altitude but solar power laser or microwave beaming orbital sats could even provide constant power. This could allow a base to be placed anywhere on the Moon and if the power level was high enough even allow for beam powered rocket propulsion, perhaps using regolith derived oxygen using beamed power, to and from LLO.

 This could also solve the problem of powering ice miners in the permanently shadowed craters. 

Online TrevorMonty

Re: Best Region for a Base/Outpost?
« Reply #13 on: 03/12/2014 05:26 pm »
Pros.
A solar satellite beaming power maybe able to deliver enough power on each pass to keep a hibernating base alive for lunar night.

Cons.
 Solar satellites don't exist so it would have to be developed. Between satellite and ground station this base has suddenly become complicated and expensive.

Offline Andrew_W

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Re: Best Region for a Base/Outpost?
« Reply #14 on: 03/12/2014 08:43 pm »
I don't think any other location comes close to the poles in desirability, and that makes it the #1 initial base location to obtain "propriatory" rights.

Desirable yes, practical another question.  We don't know how to mine lunar ice and landing on or near a shadowed crater is not easy.  However, landing at one of the mares near the north pole would be possible, and either by rovers or short-range rocket jumps venturing into the polar craters themselves to build up confidence.

Apollo went for large flat areas because hitting a predesignated specific landing spot was near impossible, in effect the Mare gave many landing sites. a Lunar base would require multiple flights to one spot, so any single spot a few meters across will do.
 The selected site will be initially marked with beacons by unmanned flights if that's required.
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Offline aero

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Re: Best Region for a Base/Outpost?
« Reply #15 on: 03/12/2014 09:33 pm »
Pros.
A solar satellite beaming power maybe able to deliver enough power on each pass to keep a hibernating base alive for lunar night.

Cons.
 Solar satellites don't exist so it would have to be developed. Between satellite and ground station this base has suddenly become complicated and expensive.

I think the Lunar Space Elevator would be very helpful in this regard. Simply run a power conductor from a Solar Power Station at L1, down the tether to the ground station. It would be a long run but at least the technology is understood. And as I have pointed out before, the tether anchor on the moon does not need to be a single anchor point, rather it could be a single tether from the L1 station down to a reasonable lunar altitude and branch from there, with branches going to a number of bases. Sort of like guy wires on a utility pole, except holding the main tether down instead of holding the pole up.

Add: You might even get fancy and tap off the conductor to power the climbers of the elevator.
« Last Edit: 03/12/2014 09:35 pm by aero »
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Offline rusty

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Re: Best Region for a Base/Outpost?
« Reply #16 on: 03/12/2014 11:04 pm »
Apollo went for large flat areas because hitting a predesignated specific landing spot was near impossible...
False. Apollo 15 was one hairy ride between a mountain and canyon that produced excellent science. Apollo 17 went into a hilly region with serpentine valleys. Suggesting large flat spaces are required is completely incorrect.


Offline Lar

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Re: Best Region for a Base/Outpost?
« Reply #17 on: 03/12/2014 11:19 pm »
I don't think any other location comes close to the poles in desirability, and that makes it the #1 initial base location to obtain "propriatory" rights.

Desirable yes, practical another question.  We don't know how to mine lunar ice and landing on or near a shadowed crater is not easy.  However, landing at one of the mares near the north pole would be possible, and either by rovers or short-range rocket jumps venturing into the polar craters themselves to build up confidence.

We need the water and a rational exploitation architecture will send robotic explorers (perhaps ICE powered) to sort all that detail out and get pilot ISRU water extraction going so of course the poles are going to be first. To me it doesn't even really seem like much of a question. IMHO of course.
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Offline Andrew_W

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Re: Best Region for a Base/Outpost?
« Reply #18 on: 03/12/2014 11:37 pm »
Apollo went for large flat areas because hitting a predesignated specific landing spot was near impossible...
False. Apollo 15 was one hairy ride between a mountain and canyon that produced excellent science. Apollo 17 went into a hilly region with serpentine valleys. Suggesting large flat spaces are required is completely incorrect.


Both Apollo 15 and 17 had target landing sites in places with tens of square kilometers of flattish ground.

A landing near one of the peaks of eternal light above Whipple or Shackleton would mean a far smaller LZ.
« Last Edit: 03/12/2014 11:46 pm by Andrew_W »
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Offline Warren Platts

Re: Best Region for a Base/Outpost?
« Reply #19 on: 03/13/2014 01:57 am »
Amateurs.....
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Offline Solman

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Re: Best Region for a Base/Outpost?
« Reply #20 on: 03/13/2014 02:18 pm »
Pros.
A solar satellite beaming power maybe able to deliver enough power on each pass to keep a hibernating base alive for lunar night.

Cons.
 Solar satellites don't exist so it would have to be developed. Between satellite and ground station this base has suddenly become complicated and expensive.

The essential tech for a solar power sat has all been demonstrated so I doubt it is too much of a problem and it is arguably simpler to leave the power production system in orbit as opposed to locating it on the Lunar surface since you don't have to land it. The surface part of the base is actually simpler than one that must generate its power on the surface.
   
A series of solar power sats could provide continuous power and open up the entire Moon for exploitation while providing BPP, GPS(LPS?), and communication as well as power. Any base involved in ISRU will likely produce oxygen as a byproduct and a craft using beam powered propulsion could use this waste product for propellant which I think is kind of elegant.

The issue it seems to me is whether the intent is to have a base or prepare for large scale activity all over the Moon.

Offline gbaikie

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Re: Best Region for a Base/Outpost?
« Reply #21 on: 03/13/2014 05:28 pm »
Pros.
A solar satellite beaming power maybe able to deliver enough power on each pass to keep a hibernating base alive for lunar night.

Cons.
 Solar satellites don't exist so it would have to be developed. Between satellite and ground station this base has suddenly become complicated and expensive.

The essential tech for a solar power sat has all been demonstrated so I doubt it is too much of a problem and it is arguably simpler to leave the power production system in orbit as opposed to locating it on the Lunar surface since you don't have to land it. The surface part of the base is actually simpler than one that must generate its power on the surface.
   
A series of solar power sats could provide continuous power and open up the entire Moon for exploitation while providing BPP, GPS(LPS?), and communication as well as power. Any base involved in ISRU will likely produce oxygen as a byproduct and a craft using beam powered propulsion could use this waste product for propellant which I think is kind of elegant.

The issue it seems to me is whether the intent is to have a base or prepare for large scale activity all over the Moon.

What could cheaper is using mirrors in lunar orbit to provide artificial sunlight.
"Last February, the Russian space agency attempted to unfurl such a mirror in orbit. It was 83 feet in diameter, and designed to shine a spot of light about 5 miles in diameter in a number of regions in the former Soviet Union, Germany, and the Czech Republic"
http://www.weathernotebook.org/transcripts/2000/02/07.html

But with Moon you don't have light up such large area, so say want a area about size of football field, so something about 1/10th of 83 feet in diameter. So want 100 meter in diameter or smaller.
And you want a bunch of these mirrors- say, 50 of them. With one launch deploying them all in some lunar orbit.
This could be used by LRO right now, by illuminating areas so LRO cameras can see these lit areas.
This can also allow solar power rovers in dark craters.
So the mirrors can provide light, and by using more them focused on one area, can one provide more artificial sunlight so you can harvest this energy at the surface.
So this means the mirrors must controllable in terms where they are in orbit and in terms pointing them.
One could also make them so they are easily recoverable. So they can moved by a space tug to different orbit or planet. Or refueled so they operate for longer periods.

In terms of orbits, it seems you want them spending most of there time one pole. So something like 200 km by 2000 km. And they could used at both poles- so when 200 km the reflected light is stronger and much shorter time period and when at 2000 km it's weaker but are over head for longer period.
And with say 50, 25 of them have 200 km orbital distance above south pole, and other 25, 200 km over north pole.

Offline mdatb

Re: Best Region for a Base/Outpost?
« Reply #22 on: 03/13/2014 07:37 pm »

Offline redliox

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Re: Best Region for a Base/Outpost?
« Reply #23 on: 03/13/2014 08:07 pm »
Bear in mind we're talking about regions of the Moon, not any satellites about it, and on top of that regions that would be beneficial in the short-term.

Regarding lunar satellites, at least in low orbit, they aren't a long-term gig.  LADEE and GRAIL before it were both designed with impact in mind because the gravity field is very lumpy; that is why every retired orbiter sent moonward crashed decades ago.  Stations at the L1 & L2 positions could be useful, but that's probably better put into the Gateway & Skylab II topics; not to mention difficult to setup within 20 years *cough ISS cough*.
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Offline KelvinZero

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Re: Best Region for a Base/Outpost?
« Reply #24 on: 03/14/2014 07:55 am »
Firstly I want to add my vote for a polar region. All the issues have probably been covered by now.

I used to think the base should be in a permanently shadowed region near a permanently lit region so the base has a constant thermal environment and also constant power can be delivered by a cable or such.

However it just occured to me, you could erect a really flimsy wall of solar panels around any base at the poles at put it in permanent shadow. Simplistically one side would get hot and radiate more heat than the other but it is not hard to think of a few tricks to get the heat such as there is from all sides fairly equally.

There was a discussion recently suggesting that just being out of direct line of sight of the sun wont protect you from solar storms, and then of course there are cosmic rays, and rocks kicked up by landers. These suggest to me that a narrow canyon, or cliff face or anything else that cuts off a lot of the sky, but near a flat landing area, might be best. In future it would be buried but we shouldnt underestimate the scale of that when even duplicating apollo is going to be hard.

Offline jtrame

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Re: Best Region for a Base/Outpost?
« Reply #25 on: 03/14/2014 12:44 pm »
Amateurs.....

We have better maps now.  And certainly would have the advantage of better computers & software.

Still, the Apollo 12 landing near the Surveyor was pretty impressive.

Offline Andrew_W

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Re: Best Region for a Base/Outpost?
« Reply #26 on: 03/14/2014 02:46 pm »
Amateurs.....

We have better maps now.  And certainly would have the advantage of better computers & software.

Still, the Apollo 12 landing near the Surveyor was pretty impressive.

Yep, I was too pessimistic earlier, from the Lunar and planetary institute:

Because Apollo 11 landed about 4 miles beyond its planned target, it was deemed important to demonstrate a precision landing capability on Apollo 12. This capability was vital to the success of later, more complex missions. Accordingly, a landing at the Surveyor 3 landing site was planned. This provided both a clear marker for determining the accuracy of the landing as well as an opportunity to return pieces of the spacecraft to Earth to determine the effects of 2 1/2 years in the lunar environment. Also, this landing site offered the possibility of sampling ejecta from the large crater Copernicus, thereby constraining the age of this crater. Finally, this landing site allowed good orbital imaging of the Fra Mauro site that was later explored by Apollo 14.

http://www.lpi.usra.edu/lunar/missions/apollo/apollo_12/landing_site/
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Offline K-P

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Re: Best Region for a Base/Outpost?
« Reply #27 on: 03/14/2014 03:16 pm »
Apollo went for large flat areas because hitting a predesignated specific landing spot was near impossible...
False. Apollo 15 was one hairy ride between a mountain and canyon that produced excellent science. Apollo 17 went into a hilly region with serpentine valleys. Suggesting large flat spaces are required is completely incorrect.


Both Apollo 15 and 17 had target landing sites in places with tens of square kilometers of flattish ground.

Why don't you both try Orbiter simulator with Apollo 15 & 17 landing simulations and judge after that if it was a hairy ride or flat ground...? :)

Offline Robert Thompson

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Re: Best Region for a Base/Outpost?
« Reply #28 on: 03/16/2014 08:35 am »
This is just for gauging rough available area at the Whipple northern peak of eternal light.
Elevation "0 km" corresponds to lunar global average radius, 1737.4km.
(Color depths proportional to each image's dimension. And, the lowest elevation gets higher under higher resolution.)
It's based on Kaguya data and when I get around to it I'll do this with better / higher resolution PDS data. Wrong header on middle one.

http://en.wikipedia.org/wiki/Land_Run_of_1889
"legal settlers could claim lots up to 160 acres (0.65 km2) in size"
« Last Edit: 03/17/2014 01:42 am by Hernalt »

Offline clongton

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Re: Best Region for a Base/Outpost?
« Reply #29 on: 03/16/2014 01:06 pm »
Locate a base where there are good deposits of thorium. Plan on using it to fuel a LFTR.
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Offline Robotbeat

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Re: Best Region for a Base/Outpost?
« Reply #30 on: 03/17/2014 05:45 am »
Locate a base where there are good deposits of thorium. Plan on using it to fuel a LFTR.
I don't think you'd find any place like that on the Moon. Much easier to bring thorium from Earth. Of all the things you'd make from in-situ material, I would imagine fissionables to be at the very bottom, since fissionables are so incredibly value-dense.
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Offline clongton

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Re: Best Region for a Base/Outpost?
« Reply #31 on: 03/17/2014 11:12 pm »
Locate a base where there are good deposits of thorium. Plan on using it to fuel a LFTR.
I don't think you'd find any place like that on the Moon. Much easier to bring thorium from Earth. Of all the things you'd make from in-situ material, I would imagine fissionables to be at the very bottom, since fissionables are so incredibly value-dense.

See attached
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Offline Robert Thompson

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Re: Best Region for a Base/Outpost?
« Reply #32 on: 03/18/2014 07:38 am »
I'm just dumping this here because I can't find a perfectly appropriate spot. Move / delete / etc.

Moonwalking Bill Dunford 2014/03/18 12:42 CDT
http://www.planetary.org/blogs/guest-blogs/bill-dunford/20140317-moonwalking.html

Offline KelvinZero

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Re: Best Region for a Base/Outpost?
« Reply #33 on: 03/18/2014 08:25 am »
Locate a base where there are good deposits of thorium. Plan on using it to fuel a LFTR.
I don't think you'd find any place like that on the Moon. Much easier to bring thorium from Earth. Of all the things you'd make from in-situ material, I would imagine fissionables to be at the very bottom, since fissionables are so incredibly value-dense.

See attached
That graph only talks about 12ppm though.
This link says 6ppm is average for earth soil, and some earth minerals contain up to 12% thorium oxide.

http://en.wikipedia.org/wiki/Thorium#Occurrence

(edit.. actually there was another image there with a map of north america with high values put at about 13ppm, so perhaps 12ppm is comparable. What may matter is the sort of ores they appear in.. I guess it will eventually be possible to mine much deeper on the moon as well. Im totally guessing here )



« Last Edit: 03/18/2014 08:35 am by KelvinZero »

Offline rusty

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Re: Best Region for a Base/Outpost?
« Reply #34 on: 03/18/2014 08:47 am »
Locate a base where there are good deposits of thorium. Plan on using it to fuel a LFTR.
I hope you're joking as it's a bit like saying, "Find Helium3 to build a fusion reactor."

Offline redliox

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Re: Best Region for a Base/Outpost?
« Reply #35 on: 03/18/2014 08:50 am »
An old school document from the 1990 from SEI mentioning six sites studied tentatively - seemed worth adding here:

http://www.lpi.usra.edu/lunar_resources/siteselection.pdf

Outdated yet worth a read.
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Offline redliox

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Re: Best Region for a Base/Outpost?
« Reply #36 on: 03/18/2014 08:53 am »
Locate a base where there are good deposits of thorium. Plan on using it to fuel a LFTR.
I hope you're joking as it's a bit like saying, "Find Helium3 to build a fusion reactor."

Agreed in the sense it's a bit too early to utilize either thorium or helium3...although no harm in digging the stuff up to experiment...just don't expect instant results to help in the immediate future.
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Online TrevorMonty

Re: Best Region for a Base/Outpost?
« Reply #37 on: 03/18/2014 05:10 pm »
Location depends on what the goal of a base is. Since we talking mining now here is a link to Warren's thread on lunar gold deposits.

 http://forum.nasaspaceflight.com/index.php?topic=31377.msg1026635.msg#1026635

Offline redliox

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Re: Best Region for a Base/Outpost?
« Reply #38 on: 03/18/2014 06:10 pm »
Zoomable map of the lunar north pole recently released - since many believe the poles a prime location worth posting here:  http://lroc.sese.asu.edu/gigapan/
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Offline Robert Thompson

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Re: Best Region for a Base/Outpost?
« Reply #39 on: 03/19/2014 01:16 am »

Offline rusty

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Re: Best Region for a Base/Outpost?
« Reply #40 on: 03/19/2014 10:31 am »
Agreed in the sense it's a bit too early to utilize either thorium or helium3 ...
There are a LOT of problems with his suggestion to ...
Locate a base where there are good deposits of thorium. Plan on using it to fuel a LFTR.
This assumes delivery of a complete LFTR and thermoelectric powerplant to the Moon. Of all possible sources of power, Thorium scales down the least. Fission can be as small as a suitcase, pulse-Fusion (plausibly) the size of a cargo container, but I doubt you can make Thorium under 100MWe.

Secondly, his suggestion assumes a massive mining and refining operation for something that could be sent from Earth for decades at a fraction of the mass. Lastly, Thorium requires constant adjustments to maintain operation. It cannot be shut off whenever it isn't needed like a plausible pulse-Fusion and you can not "Set it and forget it" like other forms of Fission. I cannot possibly imagine a worse suggestion for Lunar power, including having to sweep off and/or replace solar panels ever two weeks.

To your point, Redliox; It's by no means "too early to utilize Thorium." In the most literal sense, Thorium power is "shovel ready" and can immediately begin replacing all coal and nuclear powerplants as quickly as it can be mined and the plants built. There have been a number of different methods and designs floating about, but if a reliable and simple one isn't - I'd gladly design the reactor core and circulation systems for free as long as it's going into full production because I believe it's that important and I know it's that easy.

Offline clongton

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Re: Best Region for a Base/Outpost?
« Reply #41 on: 03/19/2014 11:32 pm »


Thought this would interest some:
http://blogs.telegraph.co.uk/finance/ambroseevans-pritchard/100026863/china-going-for-broke-on-thorium-nuclear-power-and-good-luck-to-them/


We developed it and made it work efficiently in the 60's.
Then Nixon killed it because you couldn't make bombs from the waste.
He wasn't interested in electrical power - just weapons.
But the Chinese want it for electrical power, and they're going to get it, because a LFTR just isn't that hard.
These can be made small and modular.
Yes, they can be on the moon and would be safer than the reactors we run today.
And no I didn't assume a full blown mining operation already there.
I was thinking that it would be a good idea to build a base there because EVENTUALLY mining could be done there. The whole moon could eventually be powered by Thorium, fueled from this one place - economically.
« Last Edit: 03/19/2014 11:39 pm by clongton »
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Offline gbaikie

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Re: Best Region for a Base/Outpost?
« Reply #42 on: 03/20/2014 02:03 am »


Thought this would interest some:
http://blogs.telegraph.co.uk/finance/ambroseevans-pritchard/100026863/china-going-for-broke-on-thorium-nuclear-power-and-good-luck-to-them/


We developed it and made it work efficiently in the 60's.
Then Nixon killed it because you couldn't make bombs from the waste.
He wasn't interested in electrical power - just weapons.
But the Chinese want it for electrical power, and they're going to get it, because a LFTR just isn't that hard.
These can be made small and modular.
Yes, they can be on the moon and would be safer than the reactors we run today.
And no I didn't assume a full blown mining operation already there.
I was thinking that it would be a good idea to build a base there because EVENTUALLY mining could be done there. The whole moon could eventually be powered by Thorium, fueled from this one place - economically.

Chinese don't have centuries of coal, and long term [more than 20 years] they will absolutely need nuclear reactors, using thorium is good long term goal.
In terms of lunar bases, I think NASA should spend tens of billions of dollars exploring the Moon- so about 10 years of lunar exploration as major NASA program. But I think the focus of this lunar exploration should be to find minable water.
Without minable lunar water I don't think the Moon is an attractive destination.
Minable lunar water means water which can be profitable mined. And I think it reasonable possibility that the Moon has somewhere around a trillion dollars worth of minable water.
If the Moon doesn't have minable water, there could other locations in space which does have minable water.
Once you get minable water in space [anywhere] then the Moon could be attractive destination.
I would define minable water as being able to ship rocket fuel made from water, to high earth orbit for about the same or lower cost then you ship it from Earth.

So water priced at about $500 per lb at lunar surface. Having water priced at $500 per lb would make manned lunar base a lot cheaper as compared to shipping water from Earth. But more significantly if buy lunar water for 500 per lb on lunar surface, should allow exporting rocket fuel and water to High earth orbit
at price as cheap or cheaper than you ship either from Earth.

Probably you ship 100 tons of water to lunar surface cheaper, than you can mine 100 tons of lunar water, but you might not be able to ship a 1000 tons of water to lunar surface cheaper than mining a 1000 tons of water. And mining water in space is dependent on being able to sell enough water within certain period of time at some price, and it based on idea that not only will able to sell enough water but there will also be future demand of water at roughly the same value.
And it seems the Moon has least amount water needed to be sold over a given period time, as compared to other location in our solar system.

So for example I don't think being able to buy any quantity of water you need for $500 per lb on Mars has same significance. Nor if water was sold at $500 lb per lb at some asteroid.
I think if NASA mined lunar water at sold it for $500, NASA would lose a lot of money. I think if Chinese govt
did this, they would also lose a lot of money. But I think the private sector if they sell lunar water for $500 per lb might be able to make money.
I think it's would be fairly easy for private sector to buy lunar water at $500 per lb, and make  money.
In terms of buying lunar water, small quantities [less than 10 tons] is not really worth it, being required to buy a lot of water [+10,000 tons] [at $500 per lb] is also not worth much. But between 100 to 1000 tons or
at 1 million per tons: 100 million to 1 billion dollar worth of water would be profitable.
So contract for 1000 tons at $500 per lb, and 9000 tons at $250 lb [1 billion and 4.5 billion] would be something desirable. Or Something you make money from.
So that means lunar water mining company needs to spend less than 5 billion over period of say 5 years, and after 5 year be making about 500 to 1000 tons of water per year [roughly] and have a probable future demand for water in range $200 to $300 per lb at 1000 tons of water per year.
Or one spent capital to have company which has far more future value. Assuming you managing company well and have not had any serious bad luck.

Maybe the water will be priced higher- but just mean somewhere around 500 per lb- as compared to say more than $2000 per lb. As $500 per lb allows one to export rocket fuel and water from the Moon.
So maybe 2 billion for first 1000 tons [$1000 per lb] and  3 billion for the 9000 tonnes, could as good as a deal- though there is risk you don't get the remaining 9000 tons at price promised. And of course it's easier
for lunar water miner- because the hard part will be getting to the first 1000 tonnes water mined.

So anyways, if water is available at such prices then base the might able use say 50 tons of water per year, would have lower operating cost.  And because there rocket fuel at surface and in lunar orbit, you significantly lowered cost of doing anything on the Moon. That one can reuse spacecraft is one obvious cost saving. So have cost build and launch lander to lunar orbit- or don't need to have a separate descent and ascent vehicle like the Apollo LEM.
And since there rocket fuel at about same price and water at much lower price available in High earth, the cost of sending people to Mars is lowered.
And Moon is the gateway to rest of solar system.
« Last Edit: 03/20/2014 02:12 am by gbaikie »

Offline rusty

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Re: Best Region for a Base/Outpost?
« Reply #43 on: 03/20/2014 07:03 am »
Locate a base where there are good deposits of thorium. Plan on using it to fuel a LFTR.
I hope you're joking as it's a bit like saying, "Find Helium3 to build a fusion reactor."

The Chinese want it for electrical power, and they're going to get it, because a LFTR just isn't that hard.
These can be made small and modular. ...The whole moon could eventually be powered by Thorium, fueled from this one place - economically.
My apologies. Cleary you're not trying to be funny, you just don't know what you're talking about. Carry on.

Offline JohnFornaro

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Re: Best Region for a Base/Outpost?
« Reply #44 on: 03/20/2014 12:32 pm »
Zoomable map of the lunar north pole recently released - since many believe the poles a prime location worth posting here:  http://lroc.sese.asu.edu/gigapan/

Totally cool.  Thanks for the link!
Sometimes I just flat out don't get it.

Offline JohnFornaro

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Re: Best Region for a Base/Outpost?
« Reply #45 on: 03/20/2014 12:46 pm »
TerraPanStadium.   Not to be confused with Terrapin Station.  I didn't make the file name up.

Excellent foto, apparently at 300dpi, this is the sheet size that you'd need to print the LROC mosaic.

I can hear the announcer:  "First and ten on Whipple Crater!"
Sometimes I just flat out don't get it.

Offline Robert Thompson

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Re: Best Region for a Base/Outpost?
« Reply #46 on: 03/21/2014 12:43 pm »
'Shrapnel' Risk to Future Moon Surface Missions
http://www.astrowatch.net/2014/03/shrapnel-risk-to-future-moon-surface.html

Give us this day our daily FUD.

Offline gbaikie

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Re: Best Region for a Base/Outpost?
« Reply #47 on: 03/21/2014 05:37 pm »
'Shrapnel' Risk to Future Moon Surface Missions
http://www.astrowatch.net/2014/03/shrapnel-risk-to-future-moon-surface.html

Give us this day our daily FUD.

It seems we should have a satellite which can loiter a lot of it's time above a lunar pole, have  designed measure impactors and  impactors from secondaries would exceed the number from the primaries.
So as said "a fresh 18m-wide crater, punched by a 0.3-1.3m-wide space rock" allow them to see "248 small "splotches" extending up to 30km from the primary crater"

So have a satellite designed to see the primary impact, but also have designed to see the "splotches".
So "the Lunar Impact Monitoring Program has recorded more than 300 flashes - including this one - since 2005".
How many primary flashes could you see if one had lunar satellite designed to see them plus the light from their "splotches"?


Online TrevorMonty

Re: Best Region for a Base/Outpost?
« Reply #48 on: 03/21/2014 06:56 pm »
Deeper you can bury the base the better. There was an article on one of the moon threads about creating an underground base using robotic mining equipment.

Offline sdsds

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Re: Best Region for a Base/Outpost?
« Reply #49 on: 03/21/2014 07:11 pm »
To your point, Redliox; It's by no means "too early to utilize Thorium." In the most literal sense, Thorium power is "shovel ready" and can immediately begin replacing all coal and nuclear powerplants as quickly as it can be mined and the plants built.

Here's some very good commentary on the current state of thorium power technology.
http://energyfromthorium.com/2014/03/21/the-molten-salt-reactor-race-will-america-join-the-race/

China looks to be the new front runner, with a hope of being "shovel ready" in 10 years.
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Offline JasonAW3

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Re: Best Region for a Base/Outpost?
« Reply #50 on: 03/21/2014 07:16 pm »
Deeper you can bury the base the better. There was an article on one of the moon threads about creating an underground base using robotic mining equipment.

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 Workin in a Moon Mine, Whoops! I like to Slip now..."
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Offline JohnFornaro

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Re: Best Region for a Base/Outpost?
« Reply #51 on: 03/21/2014 07:37 pm »
To your point, Redliox; It's by no means "too early to utilize Thorium." In the most literal sense, Thorium power is "shovel ready" and can immediately begin replacing all coal and nuclear powerplants as quickly as it can be mined and the plants built.

Here's some very good commentary on the current state of thorium power technology.
http://energyfromthorium.com/2014/03/21/the-molten-salt-reactor-race-will-america-join-the-race/

China looks to be the new front runner, with a hope of being "shovel ready" in 10 years.

It's not the "shovel ready" on the mine so much as it is the "shovel ready" part for the power generation plant.  Before that, ya gotta shovel all the EPA paper work out of the way.
Sometimes I just flat out don't get it.

Offline rusty

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Re: Best Region for a Base/Outpost?
« Reply #52 on: 03/22/2014 10:32 am »
China looks to be the new front runner, with a hope of being "shovel ready" in 10 years.
How do you figure? Does a political mandate and "140 PhDs" somehow guarantee scientific knowledge?

China is by far the farthest behind any pursuing nation and are currently working toward Uranium 233 and HEU-Th, not pure-Thorium. These reactors are solid-fueled, not liquid-based. India has been using this approach for a long time in specialized instances and is working on full-scale (non-HEU) reactors to stretch their Uranium 235. Many other countries have or are experimenting with similar work including the US dating back to the 1960's. But the only pure-Thorium reactor ever built was the experiment at Shippingport around 1980. They started with an irradiated core, then switched to solid Thorium and managed 65MWe.

If you'd like more info than PR sites and blogs, try;
http://www.world-nuclear.org/info/Current-and-Future-Generation/Thorium/

Offline sdsds

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Re: Best Region for a Base/Outpost?
« Reply #53 on: 03/25/2014 03:07 am »
If you'd like more info [...] try;
http://www.world-nuclear.org/info/Current-and-Future-Generation/Thorium/

Thanks for that link! Quoting from it:
Quote
The China Academy of Sciences in January 2011 launched an R&D program on LFTR, known there as the thorium-breeding molten-salt reactor (Th-MSR or TMSR), and claimed to have the world's largest national effort on it, hoping to obtain full intellectual property rights on the technology. The TMSR Research Centre has a 5 MWe MSR prototype under construction at Shanghai Institute of Applied Physics (SINAP, under the Academy) with 2015 target for operation.

Speaking of blogs, the blog post to which I linked above is listed at http://energyfromthorium.com/kirk-sorensens-corner/. Many here on the nasaspaceflight forums hold Kirk Sorensen in high esteem. He was an early contributor to many discussions here. Since kfsorensen endorses Jon Morrow's Mar 21, 2014 post and its reporting of the thorium situation in China, I'm going to believe it is basically correct.

That said, I expect it will be a long, long time before thorium mined on the Moon is used as fuel in any sort of reactor!
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Offline clongton

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Re: Best Region for a Base/Outpost?
« Reply #54 on: 03/25/2014 03:31 am »
Speaking of blogs, the blog post to which I linked above is listed at http://energyfromthorium.com/kirk-sorensens-corner/. Many here on the nasaspaceflight forums hold Kirk Sorensen in high esteem. He was an early contributor to many discussions here. Since kfsorensen endorses Jon Morrow's Mar 21, 2014 post and its reporting of the thorium situation in China, I'm going to believe it is basically correct.

That said, I expect it will be a long, long time before thorium mined on the Moon is used as fuel in any sort of reactor!

Yes, it will be a long time, but not so long as one might think "IF" the LFTR comes into its own here at home. Nobody is going to attempt to build a LFTR on the moon when it isn't already operating commercially here, but once that happens, the benefits of the LFTR over the Pressurized Water reactor will be compelling. And with known deposits of relatively easily obtainable Thorium on the lunar surface, then (again) "IF" we get serious about permanent lunar bases, LFTRs will, imo, likely become the surface power supply of choice over solar, which can operate only 50% of the time and occupy massive amounts of real estate.
« Last Edit: 03/25/2014 09:04 am by clongton »
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Offline Robert Thompson

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Re: Best Region for a Base/Outpost?
« Reply #55 on: 03/25/2014 07:26 am »
Keep talking LFTR.

Dropping a link that is OP
"Choices of Selected Trades for the Cis - lunar One Transportation Architecture", Doug Plata
http://thespaceshow.files.wordpress.com/2014/03/cl1_trades.pdf

Offline Warren Platts

Re: Best Region for a Base/Outpost?
« Reply #56 on: 03/26/2014 01:52 am »
Space Based Solar Power (SBSP) would be best IMO.

A game-changing Moon base will need several tens of megawatts. Now we could put in a nuke plant--if we could figure out a way to cool the thing. Not trivial. It's old fashioned, dinosaur tech if you ask me! 

Or we could use solar.
 
Now of course a peak of permanent light would get pretty much 24-7 light. But, it would be awful to try and set up km2 sets of solar panels that would wind up shading each other. You know, the mass to keep them stood up and moving around 360 degrees per month. Terrible.

So why waste the rocket propellant to land them on the Moon in the first place when they could be set up in orbit at an L-point and the energy beamed to the Moon?

This would be a great trial run for eventual SBSP on Earth. That would be a lot better than nukes IMHO....

YMMV
« Last Edit: 03/26/2014 10:03 am by Warren Platts »
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Offline A_M_Swallow

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Re: Best Region for a Base/Outpost?
« Reply #57 on: 03/27/2014 04:36 pm »
Space Based Solar Power (SBSP) would be best IMO.

A game-changing Moon base will need several tens of megawatts. Now we could put in a nuke plant--if we could figure out a way to cool the thing. Not trivial. It's old fashioned, dinosaur tech if you ask me! 

Or we could use solar.
 
Now of course a peak of permanent light would get pretty much 24-7 light. But, it would be awful to try and set up km2 sets of solar panels that would wind up shading each other. You know, the mass to keep them stood up and moving around 360 degrees per month. Terrible.

So why waste the rocket propellant to land them on the Moon in the first place when they could be set up in orbit at an L-point and the energy beamed to the Moon?

This would be a great trial run for eventual SBSP on Earth. That would be a lot better than nukes IMHO....

YMMV

A megawatt power receiver on the Moon is going to be big and heavy.

Offline RanulfC

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Re: Best Region for a Base/Outpost?
« Reply #58 on: 03/27/2014 07:22 pm »
IIRC, a megawatt power-rectifier antenna would be about a 1km diameter wire grid. Add the suspension poles in (capable of withstanding Lunar gravity instead of Earth) and it sounds like a metric tonn of wire and a couple of tonns max for the poles and conditioning equipment.

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Offline Lar

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Re: Best Region for a Base/Outpost?
« Reply #59 on: 03/27/2014 07:38 pm »
sounds like a fairly complex assembly task.
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Offline rusty

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Re: Best Region for a Base/Outpost?
« Reply #60 on: 03/28/2014 09:20 am »
... Now we could put in a nuke plant--if we could figure out a way to cool the thing. Not trivial. ...
Assuming we'll have some type of robotic bulldozer on the Moon for clearing LZs or roads, mining, etc. burying habs seems a foregone conclusion for protection and insulation. Even if we don't and even if we don't have bulldozers to work with - burying radiators isn't difficult and should be used for habs and power systems.

Offline Warren Platts

Re: Best Region for a Base/Outpost?
« Reply #61 on: 03/28/2014 02:05 pm »
IIRC, a megawatt power-rectifier antenna would be about a 1km diameter wire grid. Add the suspension poles in (capable of withstanding Lunar gravity instead of Earth) and it sounds like a metric tonn of wire and a couple of tonns max for the poles and conditioning equipment.

Randy

On the Moon, since it's in a vacuum, we wouldn't have to have huge microwave rectennas. The power could be beamed directly with lasers, so the footprint of the receiver would be A LOT smaller.
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Offline Andrew_W

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Re: Best Region for a Base/Outpost?
« Reply #62 on: 03/28/2014 06:51 pm »
... Now we could put in a nuke plant--if we could figure out a way to cool the thing. Not trivial. ...
Assuming we'll have some type of robotic bulldozer on the Moon for clearing LZs or roads, mining, etc. burying habs seems a foregone conclusion for protection and insulation. Even if we don't and even if we don't have bulldozers to work with - burying radiators isn't difficult and should be used for habs and power systems.

`I don't get the "burying radiators" bit, soil is a great insulator.
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Offline Solman

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Re: Best Region for a Base/Outpost?
« Reply #63 on: 03/28/2014 08:34 pm »
 Am I correct in saying that rectenna size for microwave power transmission need not be much larger than that for laser provided the size of the broadcasting antenna in Lunar orbit is large?
 I suppose if the rectenna is directly converting the microwaves into electrical power there would be a limit based on the energy the particular diodes can handle but the microwaves could be used by converting them to heat for smelting or even powering a heat engine.
 Opening up the entire Moon for bases and providing communications and positioning seem to be advantages that give a lot of bang for the buck. Large SBSPS sats could provide beam powered propulsion as well.
 Could set a precedent for Mars maybe.
 

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Re: Best Region for a Base/Outpost?
« Reply #64 on: 03/29/2014 06:45 pm »
... soil is a great insulator
Not as good as a vacuum
Wrong.

As the temperature of your radiator increases it radiates more effectively in a vacuum,
http://www.endmemo.com/physics/radenergy.php

At 200C in a vacuum you radiate 2.8kW/m^2
At 400C in a vacuum you radiate 11kW/m^2

Bury it, and you'll melt your radiator.
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Online TrevorMonty

Re: Best Region for a Base/Outpost?
« Reply #65 on: 03/29/2014 07:51 pm »
... soil is a great insulator
Not as good as a vacuum

Earth soil has water in it, which helps its heat conduction. Lunar regolith will be bone dry.
« Last Edit: 03/29/2014 07:52 pm by TrevorMonty »

Offline gbaikie

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Re: Best Region for a Base/Outpost?
« Reply #66 on: 03/29/2014 08:53 pm »
IIRC, a megawatt power-rectifier antenna would be about a 1km diameter wire grid. Add the suspension poles in (capable of withstanding Lunar gravity instead of Earth) and it sounds like a metric tonn of wire and a couple of tonns max for the poles and conditioning equipment.

Randy

On the Moon, since it's in a vacuum, we wouldn't have to have huge microwave rectennas. The power could be beamed directly with lasers, so the footprint of the receiver would be A LOT smaller.

"For lunar communications and navigation, Ely recommends spacing three satellites 120ş apart in the same elliptical orbit at an inclination of 51ş. Each satellite in turn would go screaming down past periapsis (closest approach to the lunar surface) only 450 miles (700 km) above the north lunar pole, but would each linger fully 8 hours of its 12-hour orbit at 5,000 miles (8,000 km) above the horizon over the south lunar pole. In this configuration, two of the three satellites would always be in radio line-of-sight from a South Pole moonbase."
http://science.nasa.gov/science-news/science-at-nasa/2006/30nov_highorbit/

So 75% of orbital time it's above a pole and 2 out of 3 satellite can always above poles. And since at 8000 km from Moon if you want or need to change the orbit, should require little delta-v. The orbit above is stable, though I think it would also work with other similarly highly elliptical orbits with less stability. But for moment I will assume it's this one.

I suggest instead using lasers one can reflect sunlight with flat mirrors. With flat mirrors one concentrate sunlight by overlapping an area with numerous reflected light sources and one use reflected for lighting a section of dark crater.
And this could done with bunch of nanosats with single mirror or larger satellites with an arrays of mirrors.

Now with curved mirror, one can make a mirror shine on area with the same area of mirror, thereby give about same watts per square meter on surface as which reaches the mirror [with some losses- so around 1360 watts per square meter] and with curved mirror one can concentrate the sunlight so it is lighting a smaller area than size of the mirror [and increasing the 1360 watts per square].
So by increasing the curvature and at a certain distance, one increase the concentration of sunlight.  And having "right" curvature at right distance it can be equal the size of area of mirror. And  one flatten this curvature the reflected sunlight will shine on larger area [and depending how much area- it has less watts per square meter].

If have a sphere which is say 16,000 km in diameter it's curvature will a lot less than a sphere 16,000 mm in diameter. Or a square meter section of 16,000 km in diameter sphere will be close to being flat. Or more flat than than a flat earth surface. The curvature of 16,000 km sphere has as it's focus at 4000 km- focus is half of the 8000 km radius.
So you if took a 50 km radius section of this 16,000 diameter sphere, put it in space and had it pointed at the sun, at a 4000 km distance [towards the sun] this 50 km radius disk focuses at this point. And before doing math is would be about same energy as surface of the sun [in theory, it can never exceed this temperature].
So this 100 km diameter disk would fairly flat and can consider it flat [with small error]. So terms of square meter area it's, 50,000 squared: 7.85 billion square meter. With 1360 watts- 1.06 x 10^13 watts per square meter
And surface of sun is:

"entire sun: 3.83 × 10^26 W

unit area of surface:  6.33 × 10^7 W/m2"
http://www.powerfromthesun.net/Book/chapter02/chapter02.html

So it could not be 1.06 x 10^13 watts per square meter. And instead would be somewhere around 6.33 × 10^7 W/m2.  [Though some people might argue one can make it hotter than sun.]

And as one go either direction from focal point you get much larger area than 1 square meter and be get around 6.33 × 10^7 W/m2.

So one could see and measure the amount curvature of the 100 diameter section, but would harder to measure the curvature of a smaller section of it- say 10 meter diameter section of the 100 km diameter part of 16,000 km spherical shape.

And so what I am talking about flat mirrors to reflect onto lunar surface which are about 10 meter or less in diameter or 10 meter by 10 meters square. And they will reflecting sunlight over distance of 8000 km of orbital height of these orbits in reference above.
So I say flat, but it could also be a curved mirror which has 4000 km or more distance focus point as difference between either flat or curved is small, so small in difference that gravitational curvature of space-time could be meaningful factor.
And such precise may be better "managed" by doing something like how Keck telescope manages their
large optical telescope- it's sectional with each section adjustable. Or one has array which maybe 10 by 10 meter but comprised of 100 1 meter square flat mirrors. Or 100 nanosats with 1 meter square flat mirror flying in formation, which could a box or line and each separated by tens or hundreds of meters.
And so whatever design is a lower cost.

Edit: As the moon orbits the earth [and sun] the simple 51 inclination will not work for "all seasons"- it doesn't matter in regard to communication but matters if reflecting sunlight- where want the reflected light must be between satellite and sun. So the orbit reference above could viewed as starting point- literally and/or figuratively.
But generally it seems one would want fair amount a station keeping delta-v for these satellites. And I suppose one could even consider having them re-fuelable.
But I don't tend to think one would want ion thrusters, but I suppose that option would be considered.
So perhaps one stage and test system in something like 51 inclination. And one use fewer satellites.
And in terms operational use, change orbit and use more of them.
« Last Edit: 03/30/2014 08:22 pm by gbaikie »

Offline rusty

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Re: Best Region for a Base/Outpost?
« Reply #67 on: 03/30/2014 12:16 pm »
... soil is a great insulator
Not as good as a vacuum
Replies;
1) Wrong. As the temperature of your radiator increases it radiates more effectively in a vacuum,
http://www.endmemo.com/physics/radenergy.php Bury it, and you'll melt your radiator.
2) Earth soil has water in it, which helps its heat conduction. Lunar regolith will be bone dry.
Re1) Irrelevant link on blackbody radiation as radiators also include thermal conductivity - ie; burying them. I'd be amazed if I thought you'd made that obvious mistake in error, but unsurprised by the comment after questioning the point of burying radiators. The comment on melting is so odd I'm not sure how you devised it.
Re2) The thermal conductivity of Lunar regolith is debatable, as is its water content.
Unmentioned) The point and tradeoffs of burying habitats.
« Last Edit: 03/30/2014 12:17 pm by rusty »

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Re: Best Region for a Base/Outpost?
« Reply #68 on: 03/30/2014 06:22 pm »
Here's a chart showing thermal conductivity through various materials, I'd expect regolith to have conductivity of less than 1W/m/K

http://en.wikipedia.org/wiki/List_of_thermal_conductivities
« Last Edit: 03/30/2014 06:24 pm by Andrew_W »
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Re: Best Region for a Base/Outpost?
« Reply #69 on: 03/30/2014 06:37 pm »
Maybe I should do some of the math for you, if your radiator is at 480K, and if at 1m away the regolith is at 180K you have a temperature gradient of 300K/m, so for each square meter of radiator you'll radiate 300W* in regolith (assuming a generous conductivity of 1W/m/K), compare that to the 3009W* from radiating to a vacuum with the radiators at 480K. As the temperature of the regolith in the vicinity of the radiator increases the heat loss from the radiators will decline until eventually, if you keep pumping heat into them, they'll melt, soon after that your nuclear reactor will also melt.

* On each side of the radiator
« Last Edit: 03/30/2014 07:00 pm by Andrew_W »
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Re: Best Region for a Base/Outpost?
« Reply #70 on: 03/30/2014 07:25 pm »
Stay on topic guys, this is about regions of the moon not so much hardware.  If you talk hardware keep it simple and what goes on the ground, not in say lunar orbit or theoretical items like fusion reactors.

Great info on the thermal chart Andrew, the properties of regolith would be an example of a deciding factor where to land.  By chance is there information on the mineral differences between maria and highlands?
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Offline gbaikie

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Re: Best Region for a Base/Outpost?
« Reply #71 on: 03/30/2014 07:32 pm »
Maybe I should do some of the math for you, if your radiator is at 480K, and if at 1m away the regolith is at 180K you have a temperature gradient of 300K/m, so for each square meter of radiator you'll radiate 300W* in regolith (assuming a generous conductivity of 1W/m/K), compare that to the 3009W* from radiating to a vacuum with the radiators at 480K. As the temperature of the regolith in the vicinity of the radiator increases the heat loss from the radiators will decline until eventually, if you keep pumping heat into them, they'll melt, soon after that your nuclear reactor will also melt.

* On each side of the radiator

This also true with stone, wet dirt, and water. But difference with water is one can design a system to transport warmed water away from a hot surface. So water can pumped away, or in gravity, water will rise because warmer water has less density. Water can be made to radiate more energy because you get the warmed water to more surface area to ultimately radiate it into space.
Metals generally have much higher thermal conductivity. [Copper is 401 whereas Granite is 1.7 - 4.0 W/m/K-
http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html  ]
Air [or any gas] also has low thermal conductivity but similar to water, it can also be transported.
Compacted regolith conducts heat better loose or fluffy regolith, but stone is more compacted and stone is still a poor conductor of heat.

Edit: Of course it should mentioned that if radiate heat into space, that is heat loss and whole idea of thermal power plant is you want to use heat to make electrical power [or something] So burying a nuclear reactor can be a way to increase it's efficiency.
« Last Edit: 03/30/2014 08:17 pm by gbaikie »

Online TrevorMonty

Re: Best Region for a Base/Outpost?
« Reply #72 on: 03/30/2014 09:04 pm »
Heat retention of regolith soil is important part of base design/location as it needs to be buried for radiation protection. What would be useful is knowing temperature fluctuations of something buried at various depths over lunar day cycle.
If a depth can be found where the temperature doesn't fall below -20C then most equipment should be able to hibernate without external heating being required.

Offline Andrew_W

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Re: Best Region for a Base/Outpost?
« Reply #73 on: 03/30/2014 09:25 pm »
Heat retention of regolith soil is important part of base design/location as it needs to be buried for radiation protection. What would be useful is knowing temperature fluctuations of something buried at various depths over lunar day cycle.
If a depth can be found where the temperature doesn't fall below -20C then most equipment should be able to hibernate without external heating being required.

Something on that here:
http://tallbloke.files.wordpress.com/2012/04/lunar-equatorial-surface-temperature_2012.pdf
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Re: Best Region for a Base/Outpost?
« Reply #74 on: 03/30/2014 09:50 pm »
Thanks Andrew for link.

I've just found some results from Apollo 15 tests of regolith temperature at various depth. At 80cm temperature is stable at 250k (-23C).
With an underground base robotic equipment shouldn't require any heating to survive lunar night.

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Re: Best Region for a Base/Outpost?
« Reply #75 on: 04/02/2014 02:47 pm »
Thanks Andrew for link.

I've just found some results from Apollo 15 tests of regolith temperature at various depth. At 80cm temperature is stable at 250k (-23C).
With an underground base robotic equipment shouldn't require any heating to survive lunar night.

On that note Monty, what regions seem to harbor more signs of lava tubes and sky-lit caves?  If a lunar underground is desirable taking note of which spots have caves is prudent.
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Re: Best Region for a Base/Outpost?
« Reply #76 on: 04/02/2014 08:13 pm »
I was thinking more along lines of excavate a trench 2m deep x 1m wide and few metres long. Drop in half round shelter/tunnel and cover it with regolith, similar to how storm drains are laid. The shelter is light aluminum or carbon fibre.

Come night time Rover drivers into shelter and closes entrance off.

 Astrobotics Polaris can excavate 1ton of regolith an hour so it should be able to build this shelter over 48 hrs. The communications relay station would also need to be on a Rover instead of on lander.

While researching Polaris I discovered it can survive a lunar night on surface. There was no information on how it does this, but we can eliminate radioactive isotope heating.

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Re: Best Region for a Base/Outpost?
« Reply #77 on: 04/03/2014 06:26 pm »
Come night time Rover drivers into shelter and closes entrance off.

In case you haven't seen it:

Heather Jones, John P. Thornton, Ramaswamy Balasubramaniam, Suleyman A. Gokoglu, Kurt R. Sacksteder, and William (Red) L. Whittaker, "Enabling Long-Duration Lunar Equatorial Operations With Thermal Wadi Infrastructure," 49th AIAA Aerospace Sciences Meeting, January, 2011

http://www.ri.cmu.edu/publication_view.html?pub_id=6946
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Re: Best Region for a Base/Outpost?
« Reply #78 on: 04/03/2014 08:29 pm »
Thank you Sdsds for article.

They didn't mention the equipment required to create wadi ie fuse regolith. If heat shield is not deployed correctly or damaged the rover is dead.

IHMO the burrow method is more reliable.

 Tried Googling for information on using lunar burrows but keep coming up with Lava tubes.

The article may answered question regarding Polaris. By following sun around pole it should be able to survive.
« Last Edit: 04/03/2014 08:32 pm by TrevorMonty »

Offline rusty

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Re: Best Region for a Base/Outpost?
« Reply #79 on: 04/04/2014 08:22 am »
Here's a chart showing thermal conductivity through various materials, I'd expect regolith to have conductivity of less than 1W/m/K http://en.wikipedia.org/wiki/List_of_thermal_conductivities
In its loose, granular form Regolith has conductivity of between 0.1 and 0.18 W/mK, steadily rising with rising temperature. If Regolith is melted and solidified into stone its conductivity is over 2.5 W/mK, steadily falling with rising temperature. At around 3m below the surface, pressure of 9kPa~1.3psi increases conductivity of loose Regolith to 1 W/mK and though I haven't seen data on this compression of Regolith, I'd assume it would be generally steady across temperature.

So, yes we could probably assume lunar regolith to have thermal conductivity of 1W/mK (note: not W/m/K as you've listed) whether from us burying the radiators alongside habs or compressing the Regolith when installing them around 0.7m below the surface. And as T.Monty mentioned, temperature a few dozen cm below the surface is steady at around 240K to 255K.
« Last Edit: 04/04/2014 09:13 am by rusty »

Offline redliox

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Re: Best Region for a Base/Outpost?
« Reply #80 on: 04/04/2014 09:30 am »
Come night time Rover drivers into shelter and closes entrance off.

In case you haven't seen it:

Heather Jones, John P. Thornton, Ramaswamy Balasubramaniam, Suleyman A. Gokoglu, Kurt R. Sacksteder, and William (Red) L. Whittaker, "Enabling Long-Duration Lunar Equatorial Operations With Thermal Wadi Infrastructure," 49th AIAA Aerospace Sciences Meeting, January, 2011

http://www.ri.cmu.edu/publication_view.html?pub_id=6946

So, after skimming through this, the idea is putting up sets of "hot blocks" a rover sits on to stay warm during the night?  I am unsure how well a generator it could be, but this would give good justification to add even crude lunar foundries to a list of useful items to bring to the Moon for early construction!  Definitely gives thought!
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Re: Best Region for a Base/Outpost?
« Reply #81 on: 04/05/2014 09:07 am »
The spiderfab maybe one solution to building a lunar base. 

http://www.tethers.com/SpiderFab.html

This could build a Dome or tunnel house structure from Trusses then cover with a material and finally with 2-3m of regolith.

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Re: Best Region for a Base/Outpost?
« Reply #82 on: 04/05/2014 02:17 pm »
The spiderfab maybe one solution to building a lunar base. 

http://www.tethers.com/SpiderFab.html

This could build a Dome or tunnel house structure from Trusses then cover with a material and finally with 2-3m of regolith.

SpiderFab is *part* of a solution, you still need excavators and regolith movers. But yes. Strong and low material usage structures to hold the regolith up are key to an underground base. Relatedly, someone just announced the first 3d carbon fiber printer. https://markforged.com/  Whether it can print usefully strong things remains to be seen. We are veering so I will stop. (watch some other mod come and delete this.. it happens :) )
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Re: Best Region for a Base/Outpost?
« Reply #83 on: 04/06/2014 09:16 am »
One advantage to something like the SpiderFab is that once in place, later missions to base can top up a landers payload with extra feed stock for SpiderFab.

I can see a time where any lunar base would have a few expendable landers nearby from previous missions. These landers could be scrapped for materials (eg aluminium) and parts eg fuel tanks for storing ISRU production.

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Re: Best Region for a Base/Outpost?
« Reply #84 on: 04/10/2014 03:13 am »
While researching Polaris I discovered it can survive a lunar night on surface. There was no information on how it does this, but we can eliminate radioactive isotope heating.

Found article from lunar society? about the Astrobotic rovers. The Rover's electronics and batteries are designed to survive a lunar night on surface. Plan is to put to the test late 2015.

On astrbotic's website there was video about engineer testing batteries that could be frozen to extreme temperatures and survive.
« Last Edit: 04/10/2014 03:14 am by TrevorMonty »

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Re: Best Region for a Base/Outpost?
« Reply #85 on: 04/10/2014 05:04 am »
So in the best of circumstances, lunar rovers are going to "survive" through the lunar night; not operate through the night. (Absent some special source of power.) That presents a staffing challenge back on Earth. "Two weeks on; two weeks off" is not an easy work schedule to arrange (without paying staff for the entire month.)

This motivates having two lunar bases, one near each "limb" of the Moon (i.e. almost on opposite sides of the Moon, though each in view of the Earth at all times). During most of the lunar month, one of the two sites is illuminated
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Offline KelvinZero

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Re: Best Region for a Base/Outpost?
« Reply #86 on: 04/10/2014 07:58 am »
probably jumping in out of context again, but in the best of circumstances you would have more money.

If you are posulating two bases you are probably thinking further ahead than the astrobotic rovers. IMO it would not be a great problem for a larger and nuclear powered rover to run night and day. Also IMO (for HSF precursors) the poles are more interesting than other areas hands down, and there are probably large areas there where you can get significantly larger ratios of daytime to night time.

(but the most interesting areas are in those craters, so back to nuclear again)

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Re: Best Region for a Base/Outpost?
« Reply #87 on: 04/10/2014 10:42 am »
 In regards to power for a base I found this but it is bit out of date (note no mention of Lithium Ion batteries)

http://www.ajwm.net/amayer/space/lunapower.html

Did find a good article on Solar powered satellites based in L1, must of Google magic phrase because I can't find it now.

Powering a manned base though a lunar night would require 100KW x 380hr = 38MWh. The bulk of this power is for heating.
Fuel cells generate 1.9MWH electricity per tonne at 75%, the remaining 25% should be heat.  So tonne of LOX & LH should gives us 2.5MWH of electricity and heat. 38MWH/2.5 = 15 tonnes to survive a lunar night.
How much power would be required to convert 15tonnes of water back into LOX & LH is something I don't know but would take a guess at 100+MWH.
« Last Edit: 04/10/2014 10:47 am by TrevorMonty »

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Re: Best Region for a Base/Outpost?
« Reply #88 on: 04/10/2014 06:27 pm »
IMO it would not be a great problem for a larger and nuclear powered rover to run night and day. [...]
but the most interesting areas are in those [polar] craters, so back to nuclear again

Yes, if by nuclear you mean RTG or something similar. The trouble there is availability of Pu-238. Lunar rover missions will be competing with e.g. outer planets science missions for a highly limited supply, at least through maybe 2020 or whenever substantial amounts of new production can be made available. (NB cooperation with Russia -- with its own supply of RTG material -- is probably off the table for awhile.)

ISTM the uncertainty of RTG availability adds prohibitively high costs which would prevent an RTG-based lunar rover proposal from gaining any traction.

Quote
If you are postulating two bases you are probably thinking further ahead than the astrobotic rovers.

A two location mission with smaller rovers isn't necessarily more expensive than a single location mission with a big rover, and even if it were I don't think that means it would be more difficult to fund per se. There's a special -- probably black -- art needed to get a wedge of funding into the budget of an organization. (The big lesson we should be learning from SLS/Orion for example, is that a smaller proposed funding wedge isn't necessarily easier to get approved.)

Quote
Also IMO (for HSF precursors) the poles are more interesting than other areas hands down, and there are probably large areas there where you can get significantly larger ratios of daytime to night time.

Hmm. What's "significantly larger?" On Earth polar regions have asymmetric illumination because the rotational axis is considerably non-perpendicular to the plane of the Earth's orbit around the sun. But that's not so true for the Moon. Do you have values handy for the ratio of day and night at lunar poles?

Quote
in the best of circumstances you would have more money.

:D
« Last Edit: 04/10/2014 06:28 pm by sdsds »
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Re: Best Region for a Base/Outpost?
« Reply #89 on: 04/11/2014 02:59 am »
Quote
Also IMO (for HSF precursors) the poles are more interesting than other areas hands down, and there are probably large areas there where you can get significantly larger ratios of daytime to night time.

Hmm. What's "significantly larger?" On Earth polar regions have asymmetric illumination because the rotational axis is considerably non-perpendicular to the plane of the Earth's orbit around the sun. But that's not so true for the Moon. Do you have values handy for the ratio of day and night at lunar poles?

According to Spudis there are a few areas that are illuminated a little more than 80% of the time.

These place are thought to be -50şC ± 10ş.

However the sunlight grazing angle is very small. The solar arrays would need to be nearly vertical. Vertical arrays are a problem. With the long shadows of the location, it's hard to position the arrays so they don't cast shadows on their neighbors.
« Last Edit: 04/11/2014 03:01 am by Hop_David »

Offline aero

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Re: Best Region for a Base/Outpost?
« Reply #90 on: 04/11/2014 03:56 am »
Quote
Also IMO (for HSF precursors) the poles are more interesting than other areas hands down, and there are probably large areas there where you can get significantly larger ratios of daytime to night time.

Hmm. What's "significantly larger?" On Earth polar regions have asymmetric illumination because the rotational axis is considerably non-perpendicular to the plane of the Earth's orbit around the sun. But that's not so true for the Moon. Do you have values handy for the ratio of day and night at lunar poles?

According to Spudis there are a few areas that are illuminated a little more than 80% of the time.

These place are thought to be -50şC ± 10ş.

However the sunlight grazing angle is very small. The solar arrays would need to be nearly vertical. Vertical arrays are a problem. With the long shadows of the location, it's hard to position the arrays so they don't cast shadows on their neighbors.

They could be mounted on the side of a steep hill/mountain.
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Re: Best Region for a Base/Outpost?
« Reply #91 on: 04/11/2014 04:43 am »
Quote
[polar] areas there where you can get significantly larger ratios of daytime to night time.

What's "significantly larger?" [...] Do you have values handy for the ratio of day and night at lunar poles?

According to Spudis there are a few areas that are illuminated a little more than 80% of the time.

Yes, the so-called peaks of eternal light are special, as are the closely associated permanently shadowed regions. Thanks for linking the Spudis article; he explains the situation very well!

Quote
These place are thought to be -50şC ± 10ş.

Is the implication that the thermal cycling in these locations is relatively benign?

Quote
However the sunlight grazing angle is very small. The solar arrays would need to be nearly vertical. Vertical arrays are a problem. With the long shadows of the location, it's hard to position the arrays so they don't cast shadows on their neighbors.

You're thinking of an array farm, as for a substantial base, not just a single vertical mast like for a rover?
« Last Edit: 04/11/2014 04:45 am by sdsds »
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Re: Best Region for a Base/Outpost?
« Reply #92 on: 04/11/2014 07:51 am »
Arrays would need to be single mast - which shouldn't be too hard in lunar gravity - and built on top of peaks to track the Sun through 360 degrees.
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Offline KelvinZero

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Re: Best Region for a Base/Outpost?
« Reply #93 on: 04/11/2014 12:50 pm »
Re first two points, Im unfamiliar with the issues around availability of radioactive materials. The mention of bases had me thinking more in terms of HSF than planetary science. I have this pet gripe that neither planetary science or HSF want to do precursor missions which I dont really think are the same as science missions. When I was thinking of large rovers I was thinking of things you could land unmanned but could later be part of a manned infrastructure. The scale isnt incredible given Curiosity is the size of a mini cooper but I still think of these things as coming more from the HSF budget.

Quote
Also IMO (for HSF precursors) the poles are more interesting than other areas hands down, and there are probably large areas there where you can get significantly larger ratios of daytime to night time.

Hmm. What's "significantly larger?" On Earth polar regions have asymmetric illumination because the rotational axis is considerably non-perpendicular to the plane of the Earth's orbit around the sun. But that's not so true for the Moon. Do you have values handy for the ratio of day and night at lunar poles?

Nah, I just figured that if there were peaks of eternal light there must be bases around those peaks that you could traverse around in a lunar day, or maybe a sand-dune like wall that lets you hop to the other side as the sun moves around. And modelling the moon as a perfectly spherical cow, 5deg inclination to the ecliptic would mean at least some moderate region of permanent light during the 'summer' for something the height of a rover, and also it could give you milk.

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Re: Best Region for a Base/Outpost?
« Reply #94 on: 04/11/2014 01:29 pm »
Quote
These place are thought to be -50şC ± 10ş.

Is the implication that the thermal cycling in these locations is relatively benign?

Yes. The thermal cycling is much less challenging than the thermal cycling at lower latitudes.

Quote
However the sunlight grazing angle is very small. The solar arrays would need to be nearly vertical. Vertical arrays are a problem. With the long shadows of the location, it's hard to position the arrays so they don't cast shadows on their neighbors.

You're thinking of an array farm, as for a substantial base, not just a single vertical mast like for a rover?

Correct. For substantial ISRU, we'd need a substantial power source. And at that latitude an array farm that doesn't cast shadows on itself is hard. I suppose we could make a very tall array, the 1/6 gravity makes this more doable. But it would have to rotate 360ş each 4 weeks to follow the sun.
« Last Edit: 04/11/2014 01:34 pm by Hop_David »

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Re: Best Region for a Base/Outpost?
« Reply #95 on: 04/11/2014 08:24 pm »
According to Spudis  there are a few areas that are illuminated a little more than 80% of the time.

These place are thought to be -50şC ± 10ş.

However the sunlight grazing angle is very small. The solar arrays would need to be nearly vertical. Vertical arrays are a problem. With the long shadows of the location, it's hard to position the arrays so they don't cast shadows on their neighbors.

This is one reason I see mountainous areas, including the heavily-cratered poles, as a disadvantage logistically.  Plenty of sunlight but sharp angles on sharp terrain.  With 1/6 gravity something like a 100-foot mast tower might be feasible, but in turn there's two problems

1) It might be assembled in 1/6-G, but it will still be launched from Earth at a full 1 G.  Depending on how hefty the support structure is, this might be less cost-effective than a bank of flat solar panels on the ground.
2) Using astronauts to assemble a 100-foot tower would be cumbersome at best even with new suit technology, and telerobotics with human hands might prove time-consuming.  I wouldn't recommend tower construction on the Moon during the first 10 years; possibly after metal production is enabled but not initially because of risking either an astronaut falling off, the tower falling on an astronaut, and because there are simpler solutions requiring less labor.


Again guys, talk about the terrain or region that might work best, not simply "Oh this solar mirror in orbit would blah blah".  This is about using the environment, the landing site, the Moon and identifying the pros and cons of settling here, there, and elsewhere on the Lunar surface (not low orbit, not LaGrange points).  The Moon has a surface area equating to the New World smushed into a rock - we haven't even explored the area of Connecticut up there!
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Re: Best Region for a Base/Outpost?
« Reply #96 on: 04/11/2014 10:58 pm »
According to Spudis  there are a few areas that are illuminated a little more than 80% of the time.

These place are thought to be -50şC ± 10ş.

However the sunlight grazing angle is very small. The solar arrays would need to be nearly vertical. Vertical arrays are a problem. With the long shadows of the location, it's hard to position the arrays so they don't cast shadows on their neighbors.

This is one reason I see mountainous areas, including the heavily-cratered poles, as a disadvantage logistically.  Plenty of sunlight but sharp angles on sharp terrain.  With 1/6 gravity something like a 100-foot mast tower might be feasible, but in turn there's two problems

1) It might be assembled in 1/6-G, but it will still be launched from Earth at a full 1 G.  Depending on how hefty the support structure is, this might be less cost-effective than a bank of flat solar panels on the ground.
2) Using astronauts to assemble a 100-foot tower would be cumbersome at best even with new suit technology, and telerobotics with human hands might prove time-consuming.  I wouldn't recommend tower construction on the Moon during the first 10 years; possibly after metal production is enabled but not initially because of risking either an astronaut falling off, the tower falling on an astronaut, and because there are simpler solutions requiring less labor.


Again guys, talk about the terrain or region that might work best, not simply "Oh this solar mirror in orbit would blah blah".  This is about using the environment, the landing site, the Moon and identifying the pros and cons of settling here, there, and elsewhere on the Lunar surface (not low orbit, not LaGrange points).  The Moon has a surface area equating to the New World smushed into a rock - we haven't even explored the area of Connecticut up there!

It would just need to be a mast, like a yacht mast, and in 1/6g could be hundreds of feet tall. and the rougher terrain means that your higher peaks are higher than they would be on a smoother surface, which increases the time in sunlight.

Another consideration is that a taller mast will suffer less from shading at its top than a shorter mast.
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Offline Hop_David

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Re: Best Region for a Base/Outpost?
« Reply #97 on: 04/11/2014 11:26 pm »
According to Spudis  there are a few areas that are illuminated a little more than 80% of the time.

These place are thought to be -50şC ± 10ş.

However the sunlight grazing angle is very small. The solar arrays would need to be nearly vertical. Vertical arrays are a problem. With the long shadows of the location, it's hard to position the arrays so they don't cast shadows on their neighbors.

Again guys, talk about the terrain or region that might work best, not simply "Oh this solar mirror in orbit would blah blah".

What do you think I'm talking about? The plateaus that receive sunlight 80% of the time are regions of the moon, not orbital blabbity blap blarps, whatever that might be.

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Re: Best Region for a Base/Outpost?
« Reply #98 on: 04/12/2014 08:01 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.

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Re: Best Region for a Base/Outpost?
« Reply #99 on: 04/12/2014 08:18 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

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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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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 »

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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. 

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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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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.

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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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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.

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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.

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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.

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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.


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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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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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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/

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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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