Location of Moon Base - Discuss.

mental_avenger · Apr 20, 2005

Neal agrees, saying a lunar base would serve as a training ground for more ambitious spaceflights. "Having a Moon base allows us to go and hone our skills for other planetary bodies," he told New Scientist. Spoken by someone who obviously has no idea of what the relative conditions are on Earth vs our Moon vs Mars. There are many places on Earth that are far more like Mars than ANY location on the Moon. Not only that, "training" on the Moon will cost thousands of times what it would cost on Earth, be hundreds of times more dangerous, and take a LOT longer. Attempting to use the Moon as a "training ground" would be incompetent, extremely dangerous, and foolhardy. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

mental_avenger · Apr 20, 2005

In the spots supposed to be permanently lit the sun shines from very low angle. That means you have to tilt your solar panel or mirror almost vertical. So in order not to shadow one panel with another you have to stack them vertically and/or order into a row (which you have to slowly rotate to keep towards the sun as moon spins). Excellent observation! That is the point that has been missed by so many moonies. You are absolutely correct, the low angle would preclude any density of the solar collectors. In addition, moving the collectors means maintenance (which will be difficult and expensive) and increased complexity and cost. Equatorial collectors and associated storage would be more practical and more efficient. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

smradoch · Apr 20, 2005

You are terribly wrong. The most problematic is not chilling down to -180C but further chilling and liquifying. Actualy chilling down to -180C is quite easy on Earth. At the Moon you would need either big machinery with some radiators or some chilling loop to the permanently shadowed crater. Just try some calculation how long it will take to liquify considerable amount of oxygen in vacuum by radiation alone or in touch with good izolant like lunar regolith. Do you have any idea what is the thermal capacity and conductivity of regolith and what is the real temperature in polar crater and under the surface of crater? Soil at the surface is cool only because of radiation to the space. I have no information yet what can be the temperature under this thin surface layer.

smradoch · Apr 20, 2005

Yes thats right. But mission to Mars cann't be done with recent technology, while Lunar mission and Lunar base is feasible. Lunar soil and Mars soil is very different, but you can get an idea how difficult it will be to get to Mars and survive. You have no idea yet how difficult it really will be. And how expensive. So the Moon is really good training ground for surface operations. As ISS is good training ground for space travels. Appolo missions showed us that lunar base at that time wasn't really possible. I hope it's possible now, but it woun't be easy it woun't be fast and it woun't be cheap.

smradoch · Apr 20, 2005

To Mental_Avenger: It seems that you aren't realy interrested in Lunar base. Because you would know that the only way is lunar base with PV panels at sun spots and nuclear reactor for real performance and for real testing of technology and mining. Otherwise we can send robots and don't waste time of astronauts.

tap_sa · Apr 20, 2005

"Just try some calculation how long it will take to liquify considerable amount of oxygen in vacuum by radiation alone" As you wish. Let's start with something very modest, how about liquifying one kilogram of oxygen per hour, IMO quite realistic for early ISRU plant production rate. I assume our feedstock is about room temperature so we need to chill it down 200K to the the boiling point, and then remove the heat of vaporization. Oxygen's specific heat capacity is 920J/(kg*K) (NTP) and heat of vaporization is 213kJ/kg. Required energy to chill down and liquify a kilogram of oxygen is there fore 1kg * (200K * 0,92kJ/(kg*K) + 213kJ/kg) = 397kJ How big and powerful radiator would we need? It would have to be able to dispense 397000J/3600s = 110J/s ie. 110W. I don't know enough equations about heat transfer by radiation to calculate how long pipe would you need to dissipate 110 watts but the amount seems very little. If there is someone in the audience who can enlighten us in this area, maybe give a crash course on black body radiation calculations, please do so. "Do you have any idea what is the thermal capacity and conductivity of regolith and what is the real temperature in polar crater and under the surface of crater?" Not precise idea but a general one that regolith's specific heat capasity relatively low and conductivity is very low ie. it makes a good insulator. All references I've seen put the upper limit of temperature at the bottom of polar craters below 90K. Properties of the regolith and what goes on beneath it aren't so important in liquefaction because it would be rather pointless to try to use the soil as a cold sink when we have the perfect option above our heads, space at chilly 3K. Suspend the radiator above ground level, minimize heat conduction from supports, and if you want really, really cold, put radiation insulation below an

smradoch · Apr 20, 2005

Very well, but there is a problem. Rejecting of 110W from black body at temperature of 90 K. It's bilions time less efficient than rejecting of heat from body with temperature around 0 C. Also be carreful of wrapping anything (even mirror) around the radiator, because it can became hot on sunshine and reject heat towards your radiator, which wouldn't be radiator anymore. So forget radiators alla ISS. You would need really big stuff. But again, I think it's possible to do that with some machinery and rejecting heat at much higher temperature. I just want to think realistically. The case with liquid hydrogen will be much worse.

tap_sa · Apr 20, 2005

"Rejecting of 110W from black body at temperature of 90 K. It's bilions time less efficient than rejecting of heat from body with temperature around 0 C" I just educated myself about Stefan-Bolzmann law which appears to answer many of our questions. Emissive power of black body is directly proportional to fourth power of temperature. 2734/904 = 85. Pretty big difference but not billions <img src="/images/icons/wink.gif" /> Now we can try to calculate how big radiator we would need! 110W / ( 5.6704 × 10-8 J/(s*m2*K4) * 90K4 ) = 30m2 This doesn't count the energy recieved from cosmic background radiation (the 3K) and moon itself. Former seems to be negligible, about 4.5 microW/m2 using the S-B law. How much the moon affects, I don't know, but using reflective foil to insulate will definitively help.

najab · Apr 20, 2005

"Having a Moon base allows us to go and hone our skills for other planetary bodies," he told New Scientist. Spoken by someone who obviously has no idea of what the relative conditions are on Earth vs our Moon vs Mars. There are 'planetary bodies' in the Solar System besides the Earth, the Moon and Mars.

smradoch · Apr 20, 2005

Thanks, you are right. Maybe you don't have perfectly black body, but with 30m2 you would be able to liquify good quantity of oxygen. This billions weren't really appropriate number. If it will be placed inside cold crater you don't need any foil. But with hydrogen it won't work. So we need to mine ice in crater, produce O and H by electrolysis using nuclear reactor el and thermal energy, liquify Oxygen in crater with radiators and produce methane (or amonia) from carbon (probably imported?). You will need really well equiped base, but it would be good start for Moon industry.

chmee · Apr 20, 2005

The best arguement for a Moon base before a Mars base is that if something goes wrong, you are only 3 days away from home, as opposed to 6-18 months on Mars. The Moon base can vet out alot of process and techniques that will be valuable for a permanent Mars base such as mining/processing of local regolith, recycling effeciently of the base, self-sustaining replenishment of food, advantages/dis-advantages of varying building/settlement structures, etc etc. And if something goes really wrong, hop into your lunar ascent vehicle and be home in 3 days.

mental_avenger · Apr 20, 2005

Yes thats right. But mission to Mars cann't be done with recent technology, while Lunar mission and Lunar base is feasible. Nonsense. The same technology works for both. The only real difference is the larger payload to Mars due to extended life support. Actually, at the destination, Mars would be easier to live on than the Moon, so there is some payback in that area. Lunar soil and Mars soil is very different, but you can get an idea how difficult it will be to get to Mars and survive. You have no idea yet how difficult it really will be. And how expensive. Yes we do. And by the time we are ready for a manned mission to Mars, we will have all the data we need. So the Moon is really good training ground for surface operations. That is one of the biggest fallacies ever perpetuated by otherwise intelligent people. As pointed out, there are many locations here on Earth that are far better for preparing for Mars than the Moon is. Antarctica, for instance, is much more like Mars than our Moon is. Places like Antarctica, Devon Island, and certain areas of South America will make valid test-beds for Mars colonies. In fact, Scientists have been using Devon Island for testing Martian equipment for years. The fact is, such testing on the Moon would be 1000 times more expensive, hundreds of times more dangerous, and would take many many times longer than the same testing here on Earth. Also, due to major climatic differences, little of the testing on the Moon would be applicable to Mars. Some people have gotten it into their minds that because the Moon is "off Earth", it will somehow be preferable as a testing site for missions to other places "off Earth". That simply is not so. For Mars, at least, there are places on Earth that are more appropriate. It seems that <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

mental_avenger · Apr 20, 2005

There are 'planetary bodies' in the Solar System besides the Earth, the Moon and Mars. That is correct. However, it is unlikely that we will be attempting to colonize any place other than Mars. Most other bodies are too hostile in one way or another to make even a base practical. There would be little point in going to a place where we cannot stay, and no point in staying at a place that has no practical use for human presence. We don't have to get very far from the Sun before the sunlight becomes so faint as to no longer be effective or practical as a source of power. Also, many places are too radioactively hot to even approach, let alone stay. Those two factors eliminate the majority of the other bodies. Venus is too hostile, and Mercury is too deep in the Sun's gravity well. The rest of the bodies, such as the asteroids, are essentially free space, so "training" for them can be done in LEO. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

najab · Apr 20, 2005

>However, it is unlikely that we will be attempting to colonize any place other than Mars.The only person to talk about colonization in this thread is you.

tap_sa · Apr 20, 2005

"If it will be placed inside cold crater you don't need any foil." You may have to in order to reach 90K. My calculation was gross oversimplification, I just calculated how many watts 90K warm black body would radiate per square meter and divided 110 watts with that. In practise the crater walls would heat the radiator. Radiator gets very ineffective when it's temperature cools near ambient, so we may have to deflect most of that moon radiation heat away from the radiator in order to cool it below 90K. Another gross error in my calculation, but luckily to the positive side, is forgetting the fact the liquefaction is two-part process. First we cool down the gas to boiling point and then remove heat of vaporization. In first part oxygen's temperature drops and we start with very warm 290K, meaning first square meters of the radiator would dissipate much more efficiently than that last which are at 90K. To calculate it all properly would need integration over area or something, my math skills are too rusty for that. You are correct that hydrogen would need more than just radiator, active cooling. But it's a lot smaller step from 90K to 20K than from 290K to 20K <img src="/images/icons/wink.gif" /> Btw do we have to store hydrogen as liquid? Don't know how well hydrogen behaves like ideal gas but the pV=rRT tells you that at 90K can store 3.2 times from gas than same volume and pressure at 270K. One cubic meter at 90K/200bar would contain 58kg of hydrogen provided that it doesn't break the ideal gas law too much. "produce methane (or amonia) from carbon (probably imported?)." Nitrogen and carbon could be extracted from the regolith, but they are in rather low quantities, ~100ppm. Patience and fortitude to siphon many tons of dust would be required <img src="/images/icons/smile.gif" /> IMHO these ISRU experiments should be conducted before manned expedi

mental_avenger · Apr 20, 2005

NajaB claims: The only person to talk about colonization in this thread is you. Not so. From the opening post: " US President George W Bush announced a plan in 2004 to build a permanent lunar base from which people can explore the moon, and then go on to Mars." A colony, by definition, is a remote extension of the home country, as opposed to a settlement which indicates independence and a severance from the home country. Tap_Sa posted " First bases might get sufficient power this way but when we start to talk about several megawatts and more, something else is required…………………. eventually it will be megawatt, someday gigawatt etc." That certainly sounds like a colony in the making. It takes a lot of people and equipment to use gigawatts. Flynn said: " Set up a field a couple of miles away (leave plenty of room for expansion………….." Again, expansion indicates more people on the way. As you were saying…………………. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

mental_avenger · Apr 20, 2005

Tap Sa says: Nitrogen and carbon could be extracted from the regolith, but they are in rather low quantities, ~100ppm. Patience and fortitude to siphon many tons of dust would be required The low concentrations and difficulty of extraction will make nitrogen essentially unavailable in usable quantities. Nitrogen will be required for breathing air, plant growth, and certain manufacturing processes. It is easy to forget how much we need nitrogen when we are literally engulfed in a sea of the stuff. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

najab · Apr 20, 2005

A permanent base is not a colony - there are several permanent Antartic bases, but I don't think anyone would describe Antartica as their home. As for for Tap_Sa's comment about gigawatt power usage, note the indefinite modifier "eventually", that could be decades after the Mars colony has been founded.Finally, expansion doesn't necessarily mean that we're talking about a colony, it could easily be taken to mean that the permanent base is expanded - perhaps with industrial equipment.Anyway, no need to get into a pointless argument, I just wanted to point out that a Lunar base is not necessarily pointless.

najab · Apr 20, 2005

Oh (and I know you'll appreciate the irony here), thanks for the perfect example of the Strawman fallacy: flynn asked the question "Where's the best place for a lunar base?", you responded "We shouldn't build a lunar colony, it's a distraction from the goal of Mars, much better to do our tests on Earth" (paraphrasing both of you.)That's a Strawman, isn't it? Misrepresent someone's position so you can tear it apart and make your own (unrelated) point.

tap_sa · Apr 20, 2005

What's the difference between a base and a colony. By Mental_Avenger's definition I don't see any, both are extension of home country (or could we be a little bit international and say home world?). A colony is more selfsufficient than base but still closely tied to home land? IMHO it is highly unlikely that Moon would not be colonized first, chmee gave very good points about moon activity.

najab · Apr 20, 2005

The idea is, as mental_avenger has pointed out numerous times, a colonist is in it for the long haul. A Lunar (or Martian) colonist would be moving to the Moon (Mars) to make her home there. Someone going to a Martian (or Lunar) base, would do their tour of duty and then go home.FWIW, I actually agree with mental_avenger, it makes sense to build a Lunar base, and a Martian colony. The only thing I don't agree with him on is his idea that the first people to step onto Mars should be colonists.

tap_sa · Apr 20, 2005

"it makes sense to build a Lunar base, and a Martian colony" I concur, the sheer length of trip speaks for martian colonists. You don't travel nine months somewhere just to stay a week. Moon and three day trip, totally different.

mental_avenger · Apr 20, 2005

NajaB falsely claims: Oh (and I know you'll appreciate the irony here), thanks for the perfect example of the Strawman fallacy: flynn asked the question "Where's the best place for a lunar base?", you responded "We shouldn't build a lunar colony, it's a distraction from the goal of Mars, much better to do our tests on Earth" (paraphrasing both of you.) That's a Strawman, isn't it? Misrepresent someone's position so you can tear it apart and make your own (unrelated) point. That was incredibly dishonest of you. That is not the sequence, not even close. My comments were directed to specific statements, which I posted in yellow My first comment was in response to Clive Neal's claim that " a lunar base would serve as a training ground for more ambitious spaceflights. "Having a Moon base allows us to go and hone our skills for other planetary bodies," he told New Scientist." It was not in response to any comment by flynn. In the future, before attempting to use terminology you don't understand, perhaps you should do a little research on the meaning. Before accusing someone, you should read the actual record of what was said. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

mental_avenger · Apr 20, 2005

Tap Sa asks: What's the difference between a base and a colony. By Mental_Avenger's definition I don't see any, both are extension of home country (or could we be a little bit international and say home world?). A colony is more selfsufficient than base but still closely tied to home land? A base on the Moon, at least initially, would be a place to rotate in and out of as najaB says. However, unlike a "base" on the Earth, that rotation would be a lot longer. Transportation to the Moon will be very expensive, and we won't be shuttling back and forth. Secondly, if the base is set up to service telescopes, for instance, or for military purposes, it would almost be a necessity for a service community to be established around it. That is, essentially, a colony. It is unlikely that a base of any significant size will be only a base for long. Only a very small base (10-25 people) would remain isolated as just a base. There are two major possibilities. One is that a small base is established to service remotely controlled equipment, such as the telescopes. There is no reason to actually operate the telescopes from the Moon. Such a base will likely be abandoned for long periods of time, and will not produce any of its own necessities. The other possibility is that resource development will begin to supply the needs of the base. This would necessarily be a large operation, required a lot of people and a long term commitment. The result would be a de facto colony. It is unlikely that there will be anything in between those extremes. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

grooble · Apr 20, 2005

Transport will be cheap when my taxi comes online after 2015 but no later than 2040. I could get you to the moon for under $40m

Location of Moon Base - Discuss.

mental_avenger

Guest

mental_avenger

Guest

smradoch

Guest

smradoch

Guest

smradoch

Guest

tap_sa

Guest

smradoch

Guest

tap_sa

Guest

najab

Guest

smradoch

Guest

chmee

Guest

mental_avenger

Guest

mental_avenger

Guest

najab

Guest

tap_sa

Guest

mental_avenger

Guest

mental_avenger

Guest

najab

Guest

najab

Guest

tap_sa

Guest

najab

Guest

tap_sa

Guest

mental_avenger

Guest

mental_avenger

Guest

grooble

Guest

Similar threads

TRENDING THREADS

Latest posts

Share this page