How can lunar resources ever compete with resources harvested from asteroids?

[Oceanbluesky]

It would seem asteroid resources spiraled down to various locations on the lunar surface would be competitive with resources harvested from the lunar poles - especially if they had to be launched from the poles to various locations on the moon.

Why do advocates of lunar resources so rarely discuss asteroid resources? If their intention is to justify humans returning to the moon - why not argue for that directly, rather than use the pretext of requiring humans to mine lunar resources - especially at a supposed profit in comparison to asteroids??

Thanks

[Coastal Ron]

It would seem asteroid resources spiraled down to various locations on the lunar surface would be competitive with resources harvested from the lunar poles - especially if they had to be launched from the poles to various locations on the moon.

We don't have enough information about what resources will have demand in space or for return to Earth in order to know for sure whether resources from asteroids or the Moon will be needed, or that one or the other will be a better source for them.

Pick a mineral or resource and then some debate can start, but since the demand in space is currently zero no answer is going to make sense.

Why do advocates of lunar resources so rarely discuss asteroid resources? If their intention is to justify humans returning to the moon - why not argue for that directly, rather than use the pretext of requiring humans to mine lunar resources - especially at a supposed profit in comparison to asteroids??

It's not surprising that some people want to focus their attention on just one activity or location, and doing what they can to justify that activity or location also makes sense.  My focus has been on advocating for those things that lower the cost to access space, and lots of people have their own favorite interests.

So bottom line is that ignoring other aspects of the same general activity is not unusual.

My $0.02

[sdsds]

It would seem asteroid resources spiraled down to various locations on the lunar surface would be competitive with resources harvested from the lunar poles - especially if they had to be launched from the poles to various locations on the moon.

I think this is a great topic for conversation! But just to check, are you assuming there is a motivation for surface activity at multiple locations on the Moon?

Why do advocates of lunar resources so rarely discuss asteroid resources? If their intention is to justify humans returning to the moon - why not argue for that directly, rather than use the pretext of requiring humans to mine lunar resources - especially at a supposed profit in comparison to asteroids??

This is not such a good topic for conversation IMHO. I recommend though choosing one or the other. Which has your interest more? The one that deals with technical aspects, or the one that deals with human motivations?

[Oceanbluesky]

Thank you for starting such a straightforward level-headed conversation.

Perhaps a discussion of the price of a kilogram of water delivered to LEO/EML1 from the lunar poles could be compared to water delivered from asteroids?

Lunar advocates often speak of jump-starting human expansion throughout the solar system via a cislunar economy, but, if water-ice is available from near-earth asteroids with negligible delta V, wouldn't hydrogen/oxygen fuel electrolyzed from asteroid ice be much more price competitive than lunar ice (assuming there is a market)?

If asteroid water-ice outcompetes the cost of mining lunar ice - even for use on the lunar surface, even actually, at its poles - wouldn't we risk leaving nascent lunar water-ice harvesting facilities as ghost towns before a viable cislunar fuel economy ever became profitable?

Could such a "manned lunar ice mining operation" become another gigantic waste of money and time, like to an extent some view ISS?

thanks again for your thoughts!

[Hop_David]

Lunar advocates often speak of jump-starting human expansion throughout the solar system via a cislunar economy, but, if water-ice is available from near-earth asteroids with negligible delta V, wouldn't hydrogen/oxygen fuel electrolyzed from asteroid ice be much more price competitive than lunar ice (assuming there is a market)?

To he accessible with little delta V, a near earth asteroid must have a semi-major axis close to 1 A.U. In otherwords an earth like orbit. Such a rock would be too warm to have water ice. If it had water, it would be in the form of hydrated clays.

Also launch windows for earth like asteroids are rare, on the order of years or even decades. Trip times are gnerally around half a year. If establishing infrastructure takes multiple trips, it could easily take a century to establish a mine on an asteroid in heliocentric orbit.

In constrast launch windows for the moon are very frequent. Trip time is less than a week. Establishing infrastructure could proceed at a rapid rate.

An asteroid parked in Lunar orbit is a different story. Like the moon, it would enjoy frequent launch windows and trip times around a week. It would also enjoy low delta V.

[redliox]

It would seem asteroid resources spiraled down to various locations on the lunar surface would be competitive with resources harvested from the lunar poles - especially if they had to be launched from the poles to various locations on the moon.

We don't have enough information about what resources will have demand in space or for return to Earth in order to know for sure whether resources from asteroids or the Moon will be needed, or that one or the other will be a better source for them.

Pick a mineral or resource and then some debate can start, but since the demand in space is currently zero no answer is going to make sense.

Quite an excellent point.  I can think of two resources, from the Moon, that would have significance in spaceflight:
-Water
-Silicon

The first step for long term spaceflight and settlement will be finding sources of water.  Mainly, this should just simply be for life support but obviously plenty speak about using it for hydrogen and oxygen.  Initially though, just melting ice and filtering it to drink and bathe with is significant in itself.  Mars has better availability to this resource, but all the same if the Moon has it and you're going that way...use it.

Silicon is mentionable for several reason.  There's circuit boards, but that's a bit far ahead.  If you melt lunar rock you can essentially make slag and cement, and likewise use it for building material.  If you refine things a little further, you can make glass.  This has even greater applications - every crewed ship has a porthole somewhere, and one way to increase solar array efficiency is to put them essentially under a magnifying glass.  Also, unlike aluminum or certainly uranium, you will find it anywhere...but, in space, the Moon is the nearest reliable source.

[Coastal Ron]

Pick a mineral or resource and then some debate can start, but since the demand in space is currently zero no answer is going to make sense.

Quite an excellent point.  I can think of two resources, from the Moon, that would have significance in spaceflight:
-Water
-Silicon

The first step for long term spaceflight and settlement will be finding sources of water.  Mainly, this should just simply be for life support but obviously plenty speak about using it for hydrogen and oxygen.  Initially though, just melting ice and filtering it to drink and bathe with is significant in itself.  Mars has better availability to this resource, but all the same if the Moon has it and you're going that way...use it.

OK good, water.  First we need to determine what the price of water would be if we sourced it from Earth.  Why?  Because all of the water we've been using in space so far has come from Earth, and even the first outposts on the Moon and Mars will use water that has been transported from Earth.

There have been studies done to figure out how much it would cost to start producing water on the Moon, and one such estimated $88B and 17 years to get water production going.  If that is still correct then whatever the cost of delivering water to the Moon would be could be compared to that to see if it makes economic sense to invest in such a capability.

Silicon is mentionable for several reason.  There's circuit boards, but that's a bit far ahead.

Circuit boards are made out of materials like resin, epoxy, woven glass, and copper, so no, mining silicon would not help with that.

Obviously you're thinking of the electronic components that are made (in part) using silicon.  However they are typically made in multi-billion dollar factories, and will likely be one of the last industries that we move off of Earth.  They are too complex - it literally takes the support of a large-sized city to allow a factory like that to run.

If you melt lunar rock you can essentially make slag and cement, and likewise use it for building material.  If you refine things a little further, you can make glass.

Processes that just use what is available on the Moon, like heat, make the most sense.

This has even greater applications - every crewed ship has a porthole somewhere, and one way to increase solar array efficiency is to put them essentially under a magnifying glass.  Also, unlike aluminum or certainly uranium, you will find it anywhere...but, in space, the Moon is the nearest reliable source.

Things that require more than just simple tools and heat will take a lot longer to be developed.  Think about how much we rely upon 1 G of gravity, all the air we need, and pretty much endless supplies of water and other fluids.  Without them we're pretty close to being back to the stone ages again...

[redliox]

If you melt lunar rock you can essentially make slag and cement, and likewise use it for building material.  If you refine things a little further, you can make glass.

Processes that just use what is available on the Moon, like heat, make the most sense.

This has even greater applications - every crewed ship has a porthole somewhere, and one way to increase solar array efficiency is to put them essentially under a magnifying glass.  Also, unlike aluminum or certainly uranium, you will find it anywhere...but, in space, the Moon is the nearest reliable source.

Things that require more than just simple tools and heat will take a lot longer to be developed.  Think about how much we rely upon 1 G of gravity, all the air we need, and pretty much endless supplies of water and other fluids.  Without them we're pretty close to being back to the stone ages again...

Agree on ya there.  Whatever we initially make in space will probably be simple, basically fuel, melt water, and building blocks.  And lord knows in a zero-g refinery I wouldn't want to be the engineer with some 2,000 degree slag ball flying at me in an accident.  At least we'd know where the stuff would fall in gravity.

[Oceanbluesky]

An asteroid parked in Lunar orbit is a different story. Like the moon, it would enjoy frequent launch windows and trip times around a week. It would also enjoy low delta V.

What is the advantage of placing an asteroid in lunar orbit as opposed to a highly elliptical Earth orbit, perhaps requiring less time and effort to alter from an asteroid's native pre-contact orbit?

If such an asteroid can be reached every few months on an elliptical orbit close to its original and if it remains in functional Earth-telespace during most of that time (say less than thirty seconds time delay), wouldn't water-ice, clays, and silicon already in zero g from the asteroid be much more valuable than what we could recover from the moon's gravity well?

And if we were to recover a large boulder of hydrates from an asteroid and place it at EML1 - rather than in lunar orbit - in what ways would resources there be preferable to resources requiring the delta V of a lunar orbit?

Can't asteroid clays offer a reasonable economic source of water from asteroids - as opposed to whatever might be down the moon's gravity well? I've been under the impression Deep Space Industries and Planetary Resources expect to mine water from carbonaceous-c type asteroids...that they anticipate it being mixed with regolith, subsurface, as clays...wouldn't such a find shut down lunar mining of similar materials?

There have been studies done to figure out how much it would cost to start producing water on the Moon, and one such estimated $88B and 17 years to get water production going.  If that is still correct then whatever the cost of delivering water to the Moon would be could be compared to that to see if it makes economic sense to invest in such a capability.

Exactly. And as rockets become reusable initial start-up costs of off-Earth operations will present an even greater hurdle for investors. Still, we might think in the long, long term asteroids with refined ores already in zero g will offer the best sources for basic raw materials in space...if that is true, then should society focus on developing near-Earth asteroids (even though there is not yet a market/infrastructure for any off-Earth resources), since attempting to develop lunar resources might result in our space program trying to make excuses for being stranded on the moon with never-profitable lunar ice mines, like we have been trying to "make work" in LEO for the last several decades?  (Does that concern make sense? ...That we would just create a super expensive lunar ghost-town?)

Thanks again

[gbaikie]

It would seem asteroid resources spiraled down to various locations on the lunar surface would be competitive with resources harvested from the lunar poles - especially if they had to be launched from the poles to various locations on the moon.

We don't have enough information about what resources will have demand in space or for return to Earth in order to know for sure whether resources from asteroids or the Moon will be needed, or that one or the other will be a better source for them.

Pick a mineral or resource and then some debate can start, but since the demand in space is currently zero no answer is going to make sense.

Quite an excellent point.  I can think of two resources, from the Moon, that would have significance in spaceflight:
-Water
-Silicon

I would say first water.
Then Iron {which also has Oxygen in it- though there is somewhere around 25% which is not oxidized- but rust because it has oxygen and because there be a market for Oxygen [if water is first]}
Next would want a good conductor of electricity- both calcium and aluminum work for this in Space environment- calcium metal may cheaper to make]
And then Silicon [pure silicon]. Of course rocks are silicon, unrefined silicon - paving would be needed quite
early. Since pure requires vacuum, the Moon good place to make pure silicon. In terms stuff in space being cheaper than Earth- pure silicon could reach this point before anything else- depending on when there is enough demand for pure silicon in space [ie, large scale SPS].
Also in terms of a race for cheapest product, Mars water might cheaper than many places on Earth- though the rain on Earth is free. Let's limit it to a comparison of ground or reservoir water being cheaper.

The first step for long term spaceflight and settlement will be finding sources of water.  Mainly, this should just simply be for life support but obviously plenty speak about using it for hydrogen and oxygen.  Initially though, just melting ice and filtering it to drink and bathe with is significant in itself.  Mars has better availability to this resource, but all the same if the Moon has it and you're going that way...use it.

You mine lunar water to open the space frontier. You open the space frontier by having markets in addition to the satellite market. Lunar water mining to make rocket fuel should require the least amount investment dollars and quickest means getting return on investment.
First market would be rocket fuel delivery from Earth, which followed by lunar rocket fuel delivered to some portion of entire space rocket fuel market.
Probably asteroids as "destination" will follow lunar related markets. But another market which could develop is exploration for space resource- which could include lunar, space rocks and Mars. And such exploration may be largely about finding the cheapest water in space- Mars certainly a candidate, particularly if want the water at Mars surface [rather exporting rocket fuel- though might consider exporting water in the form of food rather than rocket fuel. [And beer and other alcohol is food- so that is like rocket fuel:) ]. As far food, one probably need demand for food on Mars [settlements] and/or lots of people living off world.

Silicon is mentionable for several reason.  There's circuit boards, but that's a bit far ahead.  If you melt lunar rock you can essentially make slag and cement, and likewise use it for building material.  If you refine things a little further, you can make glass.  This has even greater applications - every crewed ship has a porthole somewhere, and one way to increase solar array efficiency is to put them essentially under a magnifying glass.  Also, unlike aluminum or certainly uranium, you will find it anywhere...but, in space, the Moon is the nearest reliable source.

Yeah, glass is good possible early option. I think the Moon should be the "best place on earth" to put  large telescopes. Or the future answer to "why were telescopes put on mountain tops", is because that was before we went to the Moon.

[Coastal Ron]

Still, we might think in the long, long term...

Though I think it's far too early to be picking winners (asteroids, Moon, Mars, etc.), I do hope we get to that point where we want to make that decision.  I'm not sure if it will happen in my lifetime, but I have my fingers crossed...

[gbaikie]

It would seem asteroid resources spiraled down to various locations on the lunar surface would be competitive with resources harvested from the lunar poles - especially if they had to be launched from the poles to various locations on the moon.

Why do advocates of lunar resources so rarely discuss asteroid resources? If their intention is to justify humans returning to the moon - why not argue for that directly, rather than use the pretext of requiring humans to mine lunar resources - especially at a supposed profit in comparison to asteroids??

Thanks

There is a quick answer. The most expensive rocket fuel in on other planets or the Moon.
So that more of feature than a bug.
Or I would say lunar rocket fuel is worth about $2000 per lb and lunar water is worth about $500 per lb
on the lunar surface. Some or most think it's worth much more, say $10,000 per lb.

Now question is how much is water or rocket fuel worth on a space rock. The answer is it probably needs to be brought to Earth or Mars orbit to have value. Or could even imagine bringing it to Mars or lunar surface.
Assume the impossible in the near term, that rocket fuel made from water from space rocks is as cheap in Earth high orbit as it is as rocket fuel is on Earth [which very cheap- pound per pound much much cheaper than gasoline [not just because of the taxes, but because LOX is cheaper than orange juice or Pepsi soda- or 5 to 10 cents per kg]. Then if exporting this rocket fuel to the lunar surface, than maybe lunar rocket fuel is about $1000 per lb. Or the only thing which going to drive down the price of lunar rocket fuel
is lunar competition. So one could say lunar rocket fuel has a protected market due to physics [rather then governmental laws].
So what is needed in terms of mining lunar water is to export rocket fuel beyond the Moon, but also has it's own "protected" market at lunar surface.

Another aspect of all this is the trick is what requires the least amount of demand for it to be viable.
There are many oceans worth of water in our solar system and a ocean of two in small space rocks. In ultimate sense Earth, Moon, and Mars might import water from Space- because it's simply cheap. But that is more or less centuries into the future. What needed is path to profitable within say 3 to 5 years. You can't spend billions of dollar and hope to get in the black in more than a decade.

And finally nothing is currently viable, because first one needs exploration and that cost is too high.
So NASA should do this exploration.
And if NASA does this exploration to find something profitable/viable to mine, where should NASA explore?

Also you can't have NASA explore every rock, and I strongly believe we should invest millions maybe a billion or two in detecting the location and characteristic of space rocks- if no other reason than one [or more of them] will hit Earth.
But if want to do the through exploration required, one needs to first select a rock which you want NASA to spend billions of dollars to explore.
So rock I pick is the Moon as first rock.
Your turn to pick one rock.

[QuantumG]

Personally, I see non-terrestrial resources being brought to market as a result of a non-economical choice to gain access to those resources. So the question "why go to the asteroids/the Moon?" is orthogonal to the question of which is more competitive.

[Hop_David]

What is the advantage of placing an asteroid in lunar orbit as opposed to a highly elliptical Earth orbit, perhaps requiring less time and effort to alter from an asteroid's native pre-contact orbit?

If you know of such an orbit, please share. I'm all ears.

Orbits high in earth's Hill Sphere are destabilized by the sun. Travel time to the rock would be about a month or two.

EML2 is at a region where earth's gravity, moon's gravity and so called centrifugal force all cancel. Station keeping expense is minimal.

At 450,000 km from earth, EML2 has the same orbital energy as an ordinary orbit with a 1,100,000 km radius. There's a 9 day, 3.5 km/s route from LEO to EML2. There is also an 84 day 3.1 km/s LEO to EML2 route. See the EML2 thread.

Retrograde lunar orbits are stable up to about 40,000 km. 40,000 km retrograde orbits are very stable. We park something there and it'll stay put for centuries. It's also close to EML2.

[Darkseraph]

My ridiculous two cents; Nearly everything on Earth is designed to operate in an environment with gravity, especially, manufacturing, resource extraction and fractional distillation equipment. The Moon has some gravity, and although you must still design for a vacuum, you have kind of one less problem.

When those resources or products made from them are being transported by reusable methods, the energetic advantage of some asteroids will be tiny compared to the operational advantages of the Moon (3 days away, all resources in one location instead of spread out over multiple orbits). You can navigate around the Moon with such advanced yet cheap technology as "Wheels" or their retro oldskool ancestors called "Legs". Just saying. Also, a Mass driver is unlikely to alter the orbit of the Moon in an inconvenient way. A small asteroid, yes it very well could alter it to somewhere you don't want it. 

But I don't believe it is either/or. It is more complex than that. If some of the popular thinking on forums like these prevailed (everyone but SpaceX is finished once they do X!!), the world would be full of single businesses occupying single locations...when in fact it is more like an ecosystem of multiple locations and diverse businesses doing things in different ways.

I for one, think that even if SpaceX fields MCT at the price point they are claiming, the most economically lucrative part of the Solar system will still be within cislunar orbit, not on the surface of Mars. Even if many people decide to go to Mars! And that, the material from asteroids will be sent to platforms in Cislunar orbits...very much like the ARM mission, but on a vaster scale. But the bulk of that material will come from the Moon. That sounds very sci-fi, but if you can lift hundreds of tons cheaply, those can be used to extract hundreds of thousands of tons even more cheaply from the Moon to human platforms that can have the benefits of full Earth gravity, abundant uninterrupted energy, access to a nearby trading partner, real time communications. Also, people can go and return much easier from platform in Cislunar space compared to Mars. So, I don't think it is one or the other, but that for every person who ends up living on Mars, there will be 10 times as many in the space around the Earth, including the surface of the Moon. Some of the ships that transport massive amounts of people to Mars and further out will be constructed in cislunar space (ion propelled centrifugal cyclers) 

//sorry that was a long winded pie in the sky post.

[gbaikie]

Thank you for starting such a straightforward level-headed conversation.

Perhaps a discussion of the price of a kilogram of water delivered to LEO/EML1 from the lunar poles could be compared to water delivered from asteroids?

Yes, I think that is good metric.
So first how much does it cost to ship from Earth.
LEO is about $2000 per kg and can assume high earth is $4000.
But with increased launch from Earth this cost with enough volume could be halved.
So say the price to beat if it involves more than 50,000 kg per year is about 2000 per kg.
For the Moon the price to beat is $1000 to 2000 per kg. Again depending volume of demand-
which for moon the demand is at lunar surface, and lunar orbit, and possibly at  EML1.
With lunar water mining one needs to get to rocket fuel at 4000 per kg. Can't do that, don't
do it.
And when talking about rocket fuel from water, one dealing two components: LOX and LH2-
though might use gaseous hydrogen [maybe]. Lunar water mining could also give methane in sizable
amount- plus other volatiles. But keeping with H2O, which 1 kg Hydrogen for 8 kg of oxygen, and rocket fuel uses about 1 kg of hydrogen for 6 kg of oxygen. Meaning if split water and uses it for rocket fuel
you get surplus of oxygen.
On Earth Liquid Hydrogen is priced about 100 times more  than LOX per kg. And on the Moon there will also be difference between their price. I generally assume the difference would be about 4 to 1.
Or LOX is worth more in comparison to Hydrogen compared to earth. And cost to ship from Earth is based on it's mass rather than what it sold at on Earth. Though Hydrogen is bulky and harder to ship than LOX.
Also Hydrogen as many potential uses on the Moon. The Moon is already oxidized- not much need to oxidize the Moon further [40% of mass of lunar surface is oxygen in some mineral compound].

Anyway is assume LOX is $1000 per kg and Hydrogen is $4000 per kg. One has $6000 per LOX and
$4000 of hydrogen for 7 kg of rocket fuel. Or 10,000 divided by 7 is $1428.57 per kg of rocket fuel.
Question is if rocket fuel is worth 4000 per kg, how much is H2 and O2 worth.
Since value in beginning is dictated by cost to ship rocket fuel from Earth, it's possible that difference
is less than 1 to 4.  Let's say closer to 1 to 2. So keep hydrogen same and double LOX price to 2000.
So that's 12000 + 4000 is 16K divided by 7 is $2285.71 per kg of rocket fuel.

Say you actually want to ship rocket fuel to lunar surface from Earth despite the situation that one is
all about making rocket fuel on the lunar surface, what do you ship to the Moon.
Put numbers on it, say LH costs $15000 per kg and LOX cost $10,000 per kg to ship from Earth- water or rocks/concrete or whatever is $9000, or nothing is cheaper than $9000 per kg from Earth- just to throw it out there or one think that whatever is landed is scrap condition- not vaguely fragile delivery or more than 100 gees can be assumed. But anyway which?
One thing you know is you are going to have shortage of hydrogen. And if you have LOX or oxygen, hydrogen is chemical energy- could made into electrical power or less electrical power is needed to make rocket fuel. So choice seems obvious that hydrogen seems the best buy if you want rocket shipped from Earth and if it's somewhere around this price. Though it's possible that exploration may find H2 not combined with O2 or anything- that is the case, but it's a matter of how much this is the case.
But my assumption is H2 is hard to get and/or expensive to get on the moon.
So initially LOX at $2000 and Hydrogen at 15000 is $3857.14 per kg of rocket fuel. Which close enough
to 4000 per kg.
So with rocket fuel at 4000 per kg, there is no way to ship 2000 kg LOX to EML1 for 2000 or even less 6000 per kg. Though lunar water could worth about $1000 per kg. So 5000 per kg for lunar water requires
a degree of economic wizardry- possible, but $2000 not possible.
So if importing Hydrogen at $15000 and water is $1000, and LOX is $2000 one has reduced price of delivered rocket fuel from earth from 6 times $2000 is 12,000 + 15,000 divided by 7. Or $10714.28
$3857.14 per kg of rocket fuel vs $10714.28 per kg of rocket fuel.
So it's a good start, assuming someone needs rocket fuel at lunar surface and wants to pay 1/2 of the current rate, plus cheaper if buy more per year.
Whether and when one ships lunar rocket fuel- likely first LOX to lunar orbit, is a choice that needs to made at some point and the decision with largely about the future market size one expects.

Lunar advocates often speak of jump-starting human expansion throughout the solar system via a cislunar economy, but, if water-ice is available from near-earth asteroids with negligible delta V, wouldn't hydrogen/oxygen fuel electrolyzed from asteroid ice be much more price competitive than lunar ice (assuming there is a market)?

There is big difference between water and hydrates.
But it's difficult to say much without having the exploration which allows stuff to be known.
But asteroid which pass close to Earth are not low delta-v to get to- a small percentage could be.
And this is largely related to the vector difference of space rock and Earth blue marble.
Or the average impact velocity of space rocks is about 20 km/sec- or that is mostly roughly specking is the vector difference, and minimum space rock impact velocity for Earth is it's escape velocity: about 11 km/sec.
Or if betting, and something hits earth, it's more than 11, most likely around 20 and could be 50 km/sec or
faster [which would be a comet].

[KelvinZero]

It would seem asteroid resources spiraled down to various locations on the lunar surface would be competitive with resources harvested from the lunar poles - especially if they had to be launched from the poles to various locations on the moon.

Why do advocates of lunar resources so rarely discuss asteroid resources? If their intention is to justify humans returning to the moon - why not argue for that directly, rather than use the pretext of requiring humans to mine lunar resources - especially at a supposed profit in comparison to asteroids??

Im a big fan of any scheme that puts ISRU front and center. The asteroid retreval mission sounds like a great way to get to the ISRU stage as cheaply as possible (on the order of $1b or so). For the same price we can also begin investigating the lunar poles with a teleoperated rover. Both are easily affordable, even together.

The third thing we clearly need is confidence in a DSH that can support humans for multiyear missions.

Put these together and we have a very moderate plan of a DSH in high lunar orbit, investigating ISRU with asteroid materials captured with a SEP tug, and likely serving as a base for near realtime teleoperation to a growing international robotic base at the lunar poles to investigate ISRU there.

Whether humans proceed from there to the moon's surface or to Phobos isn't something to get too concerned about IMO. If we are doing just the above we are doing pretty well.

It is very misleading to describe lunar ISRU as a way of getting to mars IMO. I only value mars for it's potential ISRU anyway. Sure, a manned lunar base could lead there, but firstly it would be a big project of its own, practically a town, and secondly if you can find enough volatiles to throw away as rocket fuel you have just proven you do not need to go to mars to begin a self sufficient settlement. Likewise for potential asteroid ISRU. Mars may become an easy target from all this experience but solar system colonisation will already be underway with or without it.

[gbaikie]

It would seem asteroid resources spiraled down to various locations on the lunar surface would be competitive with resources harvested from the lunar poles - especially if they had to be launched from the poles to various locations on the moon.

Why do advocates of lunar resources so rarely discuss asteroid resources? If their intention is to justify humans returning to the moon - why not argue for that directly, rather than use the pretext of requiring humans to mine lunar resources - especially at a supposed profit in comparison to asteroids??

Im a big fan of any scheme that puts ISRU front and center. The asteroid retreval mission sounds like a great way to get to the ISRU stage as cheaply as possible (on the order of $1b or so). For the same price we can also begin investigating the lunar poles with a teleoperated rover. Both are easily affordable, even together.

The third thing we clearly need is confidence in a DSH that can support humans for multiyear missions.

Put these together and we have a very moderate plan of a DSH in high lunar orbit, investigating ISRU with asteroid materials captured with a SEP tug, and likely serving as a base for near realtime teleoperation to a growing international robotic base at the lunar poles to investigate ISRU there.

Whether humans proceed from there to the moon's surface or to Phobos isn't something to get too concerned about IMO. If we are doing just the above we are doing pretty well.

It is very misleading to describe lunar ISRU as a way of getting to mars IMO. I only value mars for it's potential ISRU anyway. Sure, a manned lunar base could lead there, but firstly it would be a big project of its own, practically a town, and secondly if you can find enough volatiles to throw away as rocket fuel you have just proven you do not need to go to mars to begin a self sufficient settlement. Likewise for potential asteroid ISRU. Mars may become an easy target from all this experience but solar system colonisation will already be underway with or without it.

Of course we don't do ISRU on Earth. On earth we farm and mine. And with Moon I think we should mine it, and with Mars I think we farm and mine it.
But the moon and mars requires further exploration. For purpose of mining or farming one needs a specific type of exploration.
Things like 30% of earth is covered by land area. the Polar regions are cold. It rain in California. Or there is .0001% gold or something in Oregon. There streams in Oregon. This does not help much.

And  ISRU is considered as something belonging to exploration. Not fan of ISRU of the Moon. And not big fan of ISRU of Mars. Only a fan of it if it lowers the costs of exploration.
ISRU is like a prototype of a rocket. Not against using prototypes- sometimes they can be useful.

If we had faster than light communication, the one need to give an argument of why we need bases on Mars.
But since we don't and we are very far along with the whole AI thing, I understand why we need bases on Mars. Things like where to put the base and what kind of base, again I need some explanation of the merits of these choices.
So since the Moon is nearby [relative to speed of light] I generally oppose to the requirement of a lunar base for the purpose of exploring the Moon. I think lots of reason for having a base on the Moon, but first need a way to get to the Moon at a low cost. Or commercial lunar water mining is a path towards having lunar bases. But first need the commercial lunar water mining. And let's see how well that goes before get too excited about governmental massive base buildings projects.
Or if I though a lunar base would cost the tax payer less than 1/2 billion dollars per year- that could be tempting. But doesn't seem possible without first having  commercial lunar water mining.

My view is that only significant barrier to commercial lunar water mining is only a matter of the lack of proper exploration. And of course lunar exploration could provide evidence that commercial  lunar water mining not viable at this point in time or within 10 years. But the findings would have overturn scientific papers to rule out commercial lunar water mining. And getting that result would good also. Better particularly for me, but also it will remove some of the junk from science journals and that good for everyone.

[Nilof]

Well, the lunar craters seem to be a really rich source of volatiles. Looking at the LCROSS data, there was also lots of other things such as ammonia and carbon monoxide/dioxide in the plume. While chondrites may have a lot of hydrated minerals and carbon, extracting hydrogen still takes energy, and getting hold of anything with nitrogen in it is hard.

As I see it though, the comparison is mostly about scale. Asteroids definitely should be the first choice on a limited budget such as the current nasa one, since you only need a single Atlas or FH launch to get a really big rock in a lunar DRO. On the other hand, if you scale up to O'Neill type multi-thousand ton architectures which may include mass drivers, the moon becomes more attractive since the potential throughput is much larger.

Of course, if most of the demand in cis-lunar space ends up being on the moon(for example, a bigelow hotel with a swimming pool on the moon), that does improve the prospects of lunar ISRU.

[gbaikie]

I for one, think that even if SpaceX fields MCT at the price point they are claiming, the most economically lucrative part of the Solar system will still be within cislunar orbit, not on the surface of Mars. Even if many people decide to go to Mars! And that, the material from asteroids will be sent to platforms in Cislunar orbits...very much like the ARM mission, but on a vaster scale. But the bulk of that material will come from the Moon. That sounds very sci-fi, but if you can lift hundreds of tons cheaply, those can be used to extract hundreds of thousands of tons even more cheaply from the Moon to human platforms that can have the benefits of full Earth gravity, abundant uninterrupted energy, access to a nearby trading partner, real time communications. Also, people can go and return much easier from platform in Cislunar space compared to Mars. So, I don't think it is one or the other, but that for every person who ends up living on Mars, there will be 10 times as many in the space around the Earth, including the surface of the Moon. Some of the ships that transport massive amounts of people to Mars and further out will be constructed in cislunar space (ion propelled centrifugal cyclers) 

//sorry that was a long winded pie in the sky post.

If "you can lift hundreds of tons cheaply" Earth gets SPS.
Earth low orbit is like having a house on the beach- second home for many [millions].
Housing is cheaper in medium to high orbit- with artificial gravity. "Beach house" at LEO might not have artificial gravity- because they are "beach houses" and microgravity is part of the fun.
So people living in higher orbit would tend to be more permanent residents and retirement communities where one pick the "gravitational force" which you are most comfortable with. So LEO would higher priced
real estate but it's easier and cheaper to go back and forth from Earth. Small apartment might be more numerous.
Anyways Earth orbits seem like it will have higher population. But seem one will tend to have more people living on Earth surface. And living on Ocean seems more likely- as one can get electricity from Space. And suborbital travel can done from the Ocean, so living on Ocean one could be an hour away from anywhere on the planet or orbit.

Edit: so quite quickly Earth could seem like it's under populated though depending how count it, Earth surface population could exceed 10 billion. Though the sky should appear more busy- generally.