SpaceX going it alone to harvest water

[OTV Booster]

This is an outgrowth of https://forum.nasaspaceflight.com/index.php?topic=50806.msg2738114#msg2738114
where harvesting water for propellant struck me as reason enough for SpaceX to continue their lunar endeavors even if they were cut from the Artemis program. ISTM the issue was far enough removed from the discussions intent that it warranted its own discussion.

The topic says it all. Is a lunar mission in SpaceX's long term interest? Does it further their Mars aspirations?

[InterestedEngineer]

This is an outgrowth of https://forum.nasaspaceflight.com/index.php?topic=50806.msg2738114#msg2738114
where harvesting water for propellant struck me as reason enough for SpaceX to continue their lunar endeavors even if they were cut from the Artemis program. ISTM the issue was far enough removed from the discussions intent that it warranted its own discussion.

The topic says it all. Is a lunar mission in SpaceX's long term interest? Does it further their Mars aspirations?

Make it make economic sense.

At $20/kg to LEO for O2 (which is $4M/launch, so a plausible estimate in the long run), would it make sense to mine O2 on the moon and somehow get it into LEO where the primary expenditure would be?

I doubt it.

If there are 1000 flights that need 1000t of LOX per year (mix of Mars and Moon and outer planet destinations) that's 1M tons of LOX in LEO per year which is a cost of $20B/year.

You'd have to not only be able to set up a mine for about 3x the yearly cost (6 year amortization), or $60B, you'd have to deliver LOX to LEO for about $10/kg to match that 6 year amortization.

The deltaV from lunar polar surface to LEO is 5.7km/sec.   that's a mass ratio of 5 for a Raptor style engine.  I note this is about 60% of the deltaV to come from earth surface.  Are you then saving anything?   

Where is the carbon and hydrogen going to come from to get that LOX into LEO?

The current cost of LOX is $0.25 per kg on Earth.  If it's 10x that on the moon and you have to expend 5x that to get it to LEO then it's now $12.5/kg, which makes no economic sense.

It'll be far cheaper to optimize the cost to LEO to get to $10/kg than to implement the very complex process of getting LOX from the surface of the moon to LEO.

Not to mention that anything coming from Luna can effectively be turned into a weapon against Earth since it's almost all downhill.  (An entire book was written on this topic).

The only way LOX production makes sense on the Moon is to directly support a Moon colony, in an identical manner to the proposals for Mars - and mostly for "going home".

[InterestedEngineer]

it'd be cheaper to find a comet that you can capture around Earth and mine it in the orbit which you wish to expend it.

[Vultur]

Moon stuff may be useful for SpaceX's ambitions, if those include "be overall dominant in the space industry".

I don't think it's useful for Mars, specifically, though. Lunar propellant is probably not useful for anything except leaving the Moon - it's probably a bit of a catch-22. (If launch costs are expensive, there's not a large enough market in space to justify setting up the lunar propellant infrastructure. If launch costs are cheap, you can launch propellant from Earth cheaply.)

Until you are approaching the theoretical/physical limits* it's probably more useful to spend the huge amount it'd cost to build the lunar propellant infrastructure on improving your Earth launch costs instead - since you can use that system to launch things other than propellant, too. Also, reducing launch costs is a natural result of optimizing your existing launch system, while the Moon propellant stuff is totally separate

*Which are probably absurdly low. With a very large number of reuses of a large (Starship - scale) vehicle, manufacturing cost per kg is amortized down to nearly nothing. e.g. 1000 flights of a 100,000kg to orbit vehicle... 100,000,000 kg over the lifetime of the vehicle. If the vehicle costs $200M then the vehicle's part of the launch cost is just $2/kg. Propellant cost is not much either if you use cheap fuels like methane/LOx.

[meekGee]

Yup there's no point where Lunar propellant makes sense outside of leaving Luna, and even that's a maybe.

In order to build a Lunar mining base you need SH/SS running full time, and when that happens Earth-sourced propellant will gain even more of an advantage, since once you take away transportation cost, obviously the sourcing itself is a lot cheaper on Earth.

[volker2020]

This is an outgrowth of https://forum.nasaspaceflight.com/index.php?topic=50806.msg2738114#msg2738114
where harvesting water for propellant struck me as reason enough for SpaceX to continue their lunar endeavors even if they were cut from the Artemis program. ISTM the issue was far enough removed from the discussions intent that it warranted its own discussion.

The topic says it all. Is a lunar mission in SpaceX's long term interest? Does it further their Mars aspirations?

Make it make economic sense.

...

The deltaV from lunar polar surface to LEO is 5.7km/sec.   that's a mass ratio of 5 for a Raptor style engine.  I note this is about 60% of the deltaV to come from earth surface.  Are you then saving anything?   

...

While I am inclined to agree about the economics, that at least this point makes no sense, I find a flaw in your argumentation. If you would produce O² on the moon, you would not send it to LEO but more likely send it on a much higher energy rich parking orbit, gaining deltaV in the process and make it much more financial viable. The ratio does change quite a bit.

[meekGee]

This is an outgrowth of https://forum.nasaspaceflight.com/index.php?topic=50806.msg2738114#msg2738114
where harvesting water for propellant struck me as reason enough for SpaceX to continue their lunar endeavors even if they were cut from the Artemis program. ISTM the issue was far enough removed from the discussions intent that it warranted its own discussion.

The topic says it all. Is a lunar mission in SpaceX's long term interest? Does it further their Mars aspirations?

Make it make economic sense.

...

The deltaV from lunar polar surface to LEO is 5.7km/sec.   that's a mass ratio of 5 for a Raptor style engine.  I note this is about 60% of the deltaV to come from earth surface.  Are you then saving anything?   

...

While I am inclined to agree about the economics, that at least this point makes no sense, I find a flaw in your argumentation. If you would produce O² on the moon, you would not send it to LEO but more likely send it on a much higher energy rich parking orbit, gaining deltaV in the process and make it much more financial viable. The ratio does change quite a bit.

True.

But consider that sourcing o2 on earth is free.
Sourcing it on the moon is very difficult.

That's true not only for the O2 you're taking to orbit, but also for the O2 you use to launch it, and the O2 you use to land the empties back.

And yes, rail gun, sure.  So the power to build and operate the rail gun.  And the power to mine the rocks and extract thw oxygen.

And meanwhile earth launch costs approach propellant costs, the bulk of which is O2, which literally grows on trees down here.

If (IF) there's an inflection point, it lies sooo far in the future that you can't discount high ISP drives anymore.

[TrevorMonty]

To benefit from lunar propellant really need hydrolox  US. For SpaceX just not an option.

Blue have design their LV architecture with moon as target hence choice of hydrolox for US, lander and transporter vehicle.

What would be of benefit for Mars transport is extracting O2 or water from Demios or Phobos.
Having some fuel in orbit would make return trip to earth easier.

[redneck]

I don't see SpaceX getting into the Lunar water business at scale. I do see some entrepreneur developing a cost effective extraction method at some point that changes the trades. I don't see Lunar materials making sense in LEO. High Lunar orbit as a provisioning stop on the way elsewhere seems more likely, eventually.

It is not only the cost of Earth launch to LEO with a mature industry. It is also the hassle and pushback from those that dislike spaceflight/Musk/progress/freedom/The US/name it. There are already those that think spaceflight will doom the planet with damage to the atmosphere. It being nearly impossible to reason people out of a position they weren't reasoned into in the first place.

[OTV Booster]

The broad sweep of a concept is in some posts that I plan to bring over later today. In the meantime I'm working on a phone and quoting is beyond painful.

A fast summary:

Yes, it makes absolutely no sense to use lunar propellant ISRU for mars transit in the short term. The mining will have to start small as the techniques are learned and the number of mars bound ships will be too few to justify a massive R&D program.

As production ramps up use the water for moon-earth return and maybe powering lunar facilities and ground transport during the two weeks of dark. As output grows so will the mars fleet.

Some assumptions about mars traffic. The first mission will have two crewed ships of 12 each. Each 12 crew will need three cargo ships. That's eight ships. Further assume that each ship will need three tanker loads for 24 tankers. There will probably also be a depot or two until Mars ISRU is up and running but that is so speculative we should not add it in but need to take note that the propellant needs will most likely be higher for early missions.

Assume the number of crew doubles each synod and the packing density increase 50% until it there are 100 people per ship and ultimately the musk goal of 1000 ships full of people is reached. If the crew/cargo ratio holds steady that's 9333 ships going to mars each synod requiring 25,000 28,000 tanker loads. The numbers are beyond soft but they get the magnitude of the problem across.

The target would indeed be a higher energy orbit than LEO. L1 suggests itself. Rather than crack the water on the moon, send it to L1 for cracking. The thermal environment is benign for cryo and PV gets uninterrupted solar access except during an occasional equinox. Ship sequestered CO2 up from earth. Think of launch cost as a disposal fee.

A lunar rail gun came to mind but Robobeat suggested a sling. Velocity would be low at L1 and a plane change to a halo orbit inexpensive. A sling launch calls for a counter mass to be slung in the opposite direction, which raised a question in my mind of the possibility of a twofer. One direct from the pole and one over far side with some additional boost needed.

Musk Mars transit numbers are probably akin to Must time projections but the number will still be high. At minimum the natural gas quantities needed will be market distorting.

Long long term, even lunar water may not be enough but we can revisit the question in 50 years and discuss Jovian scoop ships.


Edit: corrected a number.

[TrevorMonty]

 There are already those that think spaceflight will doom the planet with damage to the atmosphere. It being nearly impossible to reason people out of a position they weren't reasoned into in the first place.

Damage to upper atmosphere from spaceflight is quite realistic fear.especially when launching 100s of SHLVs every year. Its big unknown that needs to be monitored.

[OTV Booster]

The logistics of connecting a LOX supply line to a lander on the lunar or Martian surface isn’t practical.

Why?

[crandles57]

Probably a silly question, but from low lunar orbit, can you do a Earth gravity assist to help with getting to a trans mars injection orbit?

Probably even sillier, is there a size of comet that is light enough to be able to slowly steer into and maintain a mars cycler obit perhaps with huge solar sails (that also reduce solar induced melting). Could this also be big enough to be able to build a base on it, 'land' and refuel hydrolox rockets during the journey? Does all the ice disappear too quickly?

Useful radiation protection and propellant supply or just way too big a task for centuries?

[InterestedEngineer]

Probably a silly question, but from low lunar orbit, can you do a Earth gravity assist to help with getting to a trans mars injection orbit?

not a gravity assist, but an oberth burn.  Gravity assist is when you entire from outside earth's Sphere of Influence.  Problem is your cargo is coming from Earth and all that deltaV you took to get to the moon you could have used to go to Mars directly (it's really not that much different, in fact lunar surface is MORE deltaV than Mars surface).

If you wanted to get to Mars REALLY FAST you want to refuel in an elliptical orbit.  So from Luna you are braking a whole bunch of LOX to go from circular to elliptical.

If you could somehow use a magnetic or slingshot launch to get directly from Moon to elliptical orbit with Earth you could set up a way station for refueling.  Problem is the fuel is scattered along that elliptical orbit, you want it concentrated so you can rendezvous with it.

Go play KSP for a while you'll get an intuition for these orbital mechanics.

Probably even sillier, is there a size of comet that is light enough to be able to slowly steer into and maintain a mars cycler obit perhaps with huge solar sails (that also reduce solar induced melting). Could this also be big enough to be able to build a base on it, 'land' and refuel hydrolox rockets during the journey? Does all the ice disappear too quickly?

Useful radiation protection and propellant supply or just way too big a task for centuries?

That's not a bad idea really.   But getting the comet into a high earth orbit might be easier.   It doesn't need to be hydrolox, you can use Raptors - comets have plenty of carbon and water.   This would be a fun topic in the Advanced Topics section.

[Mythundare]

To benefit from lunar propellant really need hydrolox  US. For SpaceX just not an option.

I mean, at a 3.6:1 fuel ratio, oxygen is still 78% of the fuel mass for methalox. You don't need to be producing methane for it to be useful. It should enable the HLS to go LEO -> lunar surface -> LEO propulsively (refuelling with methane and oxygen in LEO, and only oxygen on the lunar surface).

Or LEO -> lunar surface -> earth surface, with the heat shield. That would interfere with the mid-ship landing engines, but in a scenario where you have the infrastructure to harvest oxygen you can probably build a basic pad. Actually... in such a scenario the HLS would be so light when landing that it would have to hoverslam pretty hard when landing. So it might need a dedicated landing engine anyways. If I did my math correctly

[TrevorMonty]

To benefit from lunar propellant really need hydrolox  US. For SpaceX just not an option.

I mean, at a 3.6:1 fuel ratio, oxygen is still 78% of the fuel mass for methalox. You don't need to be producing methane for it to be useful. It should enable the HLS to go LEO -> lunar surface -> LEO propulsively (refuelling with methane and oxygen in LEO, and only oxygen on the lunar surface).

Or LEO -> lunar surface -> earth surface, with the heat shield. That would interfere with the mid-ship landing engines, but in a scenario where you have the infrastructure to harvest oxygen you can probably build a basic pad. Actually... in such a scenario the HLS would be so light when landing that it would have to hoverslam pretty hard when landing. So it might need a dedicated landing engine anyways. If I did my math correctly

You will be hauling methane in and out of lunar gravity well. For every 3.6mt of O you burn to lift payload O off lunar surface will need to deliver 1mt of methane to surface. Lot of effort for very little reward. May as well design a hydrolox powered tanker then it can land empty.

[spacenut]

Does the moon even have enough water to seriously mine for rocket fuel? 

Lox I can see due to oxygen being in the soil, but water would be needed for a lunar colony for human use, not broken down into hydrolox rocket fuel.  Break down the soil for rocks and use what water the moon has for the colony as water will be a precious commodity on the moon.  Hydrogen or methane can be brought from earth for rocket fuel, and maybe lox made on the moon since oxygen is has more mass as a liquid than hydrogen or methane. 

[OTV Booster]

The logistics of connecting a LOX supply line to a lander on the lunar or Martian surface isn’t practical.

Why?

Pick your poison:
1) ground transportation to lander on the surface
2) flight transportation of Lox to lander on the ground
3) landing adjacent to a propellant station
4) landing on a launch tower that connects with LOX

It’s a chicken and egg problem.  You cannot land on the moon/Mars until you have enough propellant to return.

Your last paragraph is absolutely true - for the first flight and for subsequent flights until propellant ISRU is in place. When that happens it is no longer true. Then the method of getting propellant to the ship is a matter of engineering/economics/convenience.

[OTV Booster]

Does the moon even have enough water to seriously mine for rocket fuel? 

Lox I can see due to oxygen being in the soil, but water would be needed for a lunar colony for human use, not broken down into hydrolox rocket fuel.  Break down the soil for rocks and use what water the moon has for the colony as water will be a precious commodity on the moon.  Hydrogen or methane can be brought from earth for rocket fuel, and maybe lox made on the moon since oxygen is has more mass as a liquid than hydrogen or methane.

How much and in what concentration are the big questions.


Opinion: basic survival use: hydration, cooking and hygiene, will use but not consume water. Losses will come from air lock cycling residuals and leaks. Industrial processes and products will be a mixed bag and rocket propellant will be total loss.


AIUI hydrogen from solar wind is available in surface rocks, and of course O (and OH?) Don't know about carbon or concentrations. Getting water precursors from rocks would take more infrastructure and energy than raw water but it's not impossible.


Economics is a funny thing. It's sensitive to circumstances. Raw water in time of little infrastructure has more *immediate* value than holding it back for speculative future use. Very short sighted but very human.


With the implicit but unproven assumption that we are going to the moon to stay, it makes a type of sense to use the cheap water now to enable the infrastructure that can harvest the expensive water tomorrow.

[TrevorMonty]

Does the moon even have enough water to seriously mine for rocket fuel? 

Lox I can see due to oxygen being in the soil, but water would be needed for a lunar colony for human use, not broken down into hydrolox rocket fuel.  Break down the soil for rocks and use what water the moon has for the colony as water will be a precious commodity on the moon.  Hydrogen or methane can be brought from earth for rocket fuel, and maybe lox made on the moon since oxygen is has more mass as a liquid than hydrogen or methane.

How much and in what concentration are the big questions.


Opinion: basic survival use: hydration, cooking and hygiene, will use but not consume water. Losses will come from air lock cycling residuals and leaks. Industrial processes and products will be a mixed bag and rocket propellant will be total loss.


AIUI hydrogen from solar wind is available in surface rocks, and of course O (and OH?) Don't know about carbon or concentrations. Getting water precursors from rocks would take more infrastructure and energy than raw water but it's not impossible.


Economics is a funny thing. It's sensitive to circumstances. Raw water in time of little infrastructure has more *immediate* value than holding it back for speculative future use. Very short sighted but very human.


With the implicit but unproven assumption that we are going to the moon to stay, it makes a type of sense to use the cheap water now to enable the infrastructure that can harvest the expensive water tomorrow.

Once there is supply infrastructure in place using Lunar water/fuel means there is ready market for Asteriod water. Its lot easier to great a business case for Asteriod mining when there is existing market for mined resources. ie mt of H2O delivered to EML1 is worth $$mt.

[Vultur]

I don't see SpaceX getting into the Lunar water business at scale. I do see some entrepreneur developing a cost effective extraction method at some point that changes the trades.

Maybe. I am not 100% sure that its being cost effective is possible though.

The energy cost of launch from the Moon is certainly less than that of launch from the Earth. But this is only an advantage in terms of cost-effectiveness if the energy of launch is a significant part of the cost of propellant in orbit. Do we know sufficiently well how the lunar polar ice is physically arranged (glacier sheets, frozen mud, something else?) to be able to determine the energy cost of mining it? If it's not convenient, cost-effective might just not be possible.

Another factor is the lifetime cost of the equipment working in the (probably pretty challenging) lunar polar crater environment.

--

Now, if the concern is that thousands/tens of thousands of tanker launches just won't be allowed (for environmental reasons, etc) then it may make sense. But not for *cost effectiveness* reasons.

And even then, is the Moon the obvious best source? If this is an environment where a massive Mars infrastructure exists, and if you have zero boiloff technology, maybe the propellant gets made on Mars (if easier access to ice + mining/propellant making infrastructure already existing matters more than higher lauhch delta-V requirement). Or maybe Deimos (lower delta V requirement than Moon)..

[OTV Booster]

Does the moon even have enough water to seriously mine for rocket fuel? 

Lox I can see due to oxygen being in the soil, but water would be needed for a lunar colony for human use, not broken down into hydrolox rocket fuel.  Break down the soil for rocks and use what water the moon has for the colony as water will be a precious commodity on the moon.  Hydrogen or methane can be brought from earth for rocket fuel, and maybe lox made on the moon since oxygen is has more mass as a liquid than hydrogen or methane.

How much and in what concentration are the big questions.


Opinion: basic survival use: hydration, cooking and hygiene, will use but not consume water. Losses will come from air lock cycling residuals and leaks. Industrial processes and products will be a mixed bag and rocket propellant will be total loss.


AIUI hydrogen from solar wind is available in surface rocks, and of course O (and OH?) Don't know about carbon or concentrations. Getting water precursors from rocks would take more infrastructure and energy than raw water but it's not impossible.


Economics is a funny thing. It's sensitive to circumstances. Raw water in time of little infrastructure has more *immediate* value than holding it back for speculative future use. Very short sighted but very human.


With the implicit but unproven assumption that we are going to the moon to stay, it makes a type of sense to use the cheap water now to enable the infrastructure that can harvest the expensive water tomorrow.

Once there is supply infrastructure in place using Lunar water/fuel means there is ready market for Asteriod water. Its lot easier to great a business case for Asteriod mining when there is existing market for mined resources. ie mt of H2O delivered to EML1 is worth $$mt.

That's a pattern. There's no market for a product but a visionary inventor/entrepreneur keeps plugging away until it's perfected and builds a market out of an idea.


Fifteen years ago the idea of reusable rockets was an industry joke. Five years ago the idea of a shortage of orbital lift didn't exist. Today we have both with one company adept at reuse, a second coming on line, several in the wings and a bunch of dinosaurs watching an incoming comet not even sure that it's a problem.


Asteroids will absolutely be Earths mining district in 50 years or less. Until then the moon is handy. That brings us back to the point of this discussion.


Will SpaceX/Musk go it alone if necessary to support their Mars ambitions?

[meekGee]

That's a pattern. There's no market for a product but a visionary inventor/entrepreneur keeps plugging away until it's perfected and builds a market out of an idea.


Fifteen years ago the idea of reusable rockets was an industry joke. Five years ago the idea of a shortage of orbital lift didn't exist. Today we have both with one company adept at reuse, a second coming on line, several in the wings and a bunch of dinosaurs watching an incoming comet not even sure that it's a problem.


Asteroids will absolutely be Earths mining district in 50 years or less. Until then the moon is handy. That brings us back to the point of this discussion.


Will SpaceX/Musk go it alone if necessary to support their Mars ambitions?

You could say that IF lunar mining could support a Mars campaign, they would have.

But it can't, so they won't.

That Ceres will become a key asset one day, I don't doubt for a minute, but that (as you say) is some 50 years later.

Will SpaceX go to the moon if not part of Artemis? Not sure. "It's complicated".

Will SpaceX send a water harvester/converter to Ceres within a decade?  That's interesting to me a lot more - since that's a key to so many things.

[redneck]

I don't see SpaceX getting into the Lunar water business at scale. I do see some entrepreneur developing a cost effective extraction method at some point that changes the trades.

Maybe. I am not 100% sure that its being cost effective is possible though.

..

I used the term "At some point" for reasons you point out. I don't see it being cost effective for someone right now to focus exclusively on Lunar water extraction. My "At some point" could be a decade or a century away and very dependent on economics at that time. It could be never.

It will be strongly dependent on proved reserves and available extraction techniques on the moon when we get that far. And on the alternatives available at that time. If a comet as suggested elsewhere in the thread is brought to Lunar orbit, it may be never. Or restrictions on Earth launch could drive the price of Lunar LOX through the roof. Everything is speculative at this point.

[Vultur]

I don't see SpaceX getting into the Lunar water business at scale. I do see some entrepreneur developing a cost effective extraction method at some point that changes the trades.

Maybe. I am not 100% sure that its being cost effective is possible though.

..

I used the term "At some point" for reasons you point out. I don't see it being cost effective for someone right now to focus exclusively on Lunar water extraction. My "At some point" could be a decade or a century away and very dependent on economics at that time. It could be never.

It will be strongly dependent on proved reserves and available extraction techniques on the moon when we get that far. And on the alternatives available at that time. If a comet as suggested elsewhere in the thread is brought to Lunar orbit, it may be never. Or restrictions on Earth launch could drive the price of Lunar LOX through the roof. Everything is speculative at this point.

.

Yeah. I was just saying that its being profitable depends on more than technology development, it probably also depends on the exact state of the water resources on the Moon which we don't know in detail.

Even given an environment where total Earth launch is constrained, the state of/difficulty of accessing Lunar water (vs asteroid water or whatever) would probably determine whether the Moon makes sense as a source vs Mars or Deimos or asteroids. (Comets are probably too delta v intensive.)

[Twark_Main]

Does the moon even have enough water to seriously mine for rocket fuel? 

Lox I can see due to oxygen being in the soil, but water would be needed for a lunar colony for human use, not broken down into hydrolox rocket fuel.  Break down the soil for rocks and use what water the moon has for the colony as water will be a precious commodity on the moon.  Hydrogen or methane can be brought from earth for rocket fuel, and maybe lox made on the moon since oxygen is has more mass as a liquid than hydrogen or methane.

How much and in what concentration are the big questions.


Opinion: basic survival use: hydration, cooking and hygiene, will use but not consume water. Losses will come from air lock cycling residuals and leaks. Industrial processes and products will be a mixed bag and rocket propellant will be total loss.


AIUI hydrogen from solar wind is available in surface rocks, and of course O (and OH?) Don't know about carbon or concentrations. Getting water precursors from rocks would take more infrastructure and energy than raw water but it's not impossible.


Economics is a funny thing. It's sensitive to circumstances. Raw water in time of little infrastructure has more *immediate* value than holding it back for speculative future use. Very short sighted but very human.


With the implicit but unproven assumption that we are going to the moon to stay, it makes a type of sense to use the cheap water now to enable the infrastructure that can harvest the expensive water tomorrow.

See Andy Weir's second book, Artemis. No relation!   

[Slarty1080]

Are SpaceX going it alone to harvest water? Not if they can help it, but I fear they may not be able to help it. No doubt Congress / NASA are going to faff about a lot and will be extremely safety conscious over something like ISRU on Mars. Landing opportunities will be used to test the process in various ways and as the opportunities tick past at some point Elon Musk will realize that his 60th birthday is approaching (or has arrived) and will lose patience.

He won't be entirely reckless, but he will be a lot more adventurous and open to some risk than NASA ever would. At that point he should be able to afford to try it out. Maybe Congress could be persuaded to pay for a lot of the tech development under the guise of a human mission in 2045 or whenever. That way if or when anything goes wrong they can blame Musk for going to early or if it all works out, bask in the reflected glory.

There might even be (depending on the Administration in power) a tacit approval. Just as long as Musk gets enough money to make it easy plus cover for nuclear (if used) and Planetary protection (if there are any questions).

[DanClemmensen]

Maybe Congress could be persuaded to pay for a lot of the tech development under the guise of a human mission in 2045 or whenever.

So far, Congress has been very reluctant to fund SpaceX. Congress funded CRS, CCP, and Artemis. In each case, NASA made competitive contract award. In each case SpaceX made a low bid and won it. for CCP some congressfolks were unhappy it was not sole-source to Boeing. For Artemis, Congress went ballistic when only SpaceX won, so they gave extra money to NASA for what was effectively a directed second-source contract to Blue Origin.

I think the best we can hope for is for congress to allow NASA to contract for transportation services to Mars. In a rational world, Congress would also direct NASA to contract for end-to-end transportation services to the Moon, but the SLS/Orion pork machine is too entrenched.

[freddo411]

This is an outgrowth of https://forum.nasaspaceflight.com/index.php?topic=50806.msg2738114#msg2738114
where harvesting water for propellant struck me as reason enough for SpaceX to continue their lunar endeavors even if they were cut from the Artemis program. ISTM the issue was far enough removed from the discussions intent that it warranted its own discussion.

The topic says it all. Is a lunar mission in SpaceX's long term interest? Does it further their Mars aspirations?

Make it make economic sense.

..snip

The deltaV from lunar polar surface to LEO is 5.7km/sec. 

..snip

The only way LOX production makes sense on the Moon is to directly support a Moon colony, in an identical manner to the proposals for Mars - and mostly for "going home".

Measuring by comparing costs is the right metric.   However, your math is missing an efficient architecture.

A good architecture would be:

Mars bound Starships arrive in LEO, then refuel enough to travel to NRHO or other very high orbit.   
NRHO would host an oxygen propellent depot.   
Starships would refuel there for the Mars transfer orbit.
Starships would use an efficient oberth maneuver to start toward Mars

[InterestedEngineer]

Mars bound Starships arrive in LEO, then refuel enough to travel to NRHO or other very high orbit.   
NRHO would host an oxygen propellent depot.   
Starships would refuel there for the Mars transfer orbit.
Starships would use an efficient oberth maneuver to start toward Mars

That won't work.  You'll spend more fuel de-orbiting from a circular to an elliptical orbit than you would get benefit from the Oberth maneuver.

"always be in elliptical orbit" - including the propellant.

[wes_wilson]

Lunar point to point would be another use case to consider.  Any long term human establishment is going to want to have mobility around the surface.  Absent roads, tunnels, and other infrastructure, Starship P2P may be an efficient mode of moving material around the moon.

[spacenut]

SpaceX's ultimate goal is Mars.  Except for the Artemis lander for the moon, I don't think SpaceX is at all interested in the moon.  Once a colony is established on Mars, SpaceX in the distant future might mine asteroids and will need water harvesting at Ceres.  That is at least 50-100 years out.  Mars is the goal.  Moon is secondary. 

[DigitalMan]

It would be interesting if you could make a hopper that uses kinetic energy to move around, like a frog.

You could potentially take samples with every hop and quickly create a large collection

[DanClemmensen]

SpaceX's ultimate goal is Mars.  Except for the Artemis lander for the moon, I don't think SpaceX is at all interested in the moon.  Once a colony is established on Mars, SpaceX in the distant future might mine asteroids and will need water harvesting at Ceres.  That is at least 50-100 years out.  Mars is the goal.  Moon is secondary.

SpaceX built Crew Dragon in response to NASA's CCP program, but they also offer service to anyone who will pay for it. they have flown twelve crewed CCP missions and seven crewed non-NASA missions.

I suspect that SpaceX will offer private missions to the Moon, assuming they have customers. This will require SpaceX to develop a mission plan that uses only SpaceX vehicles, not SLS/Orion. A mission that uses Crew Dragon to get crew to LEO Is likely too expensive for any customers except governments. I would love to see a mission by four crew, one each from (say) south Korea, Singapore, Indonesia, and Taiwan. Basically a "flags and footprints" mission, just not the flags you were thinking of.

A cost-effective private Moon mission may need to wait until a crewed EDL Starship is certified as part of the Mars development effort. This mission would land as many as 20 crew on the Moon, using the EDL Ship plus an HLS Ship, Depot, and tankers.

[scientist]

Mars bound Starships arrive in LEO, then refuel enough to travel to NRHO or other very high orbit.   
NRHO would host an oxygen propellent depot.   
Starships would refuel there for the Mars transfer orbit.
Starships would use an efficient oberth maneuver to start toward Mars

That won't work.  You'll spend more fuel de-orbiting from a circular to an elliptical orbit than you would get benefit from the Oberth maneuver.

"always be in elliptical orbit" - including the propellant.

This is no longer true once you get far enough that your orbit is at the edge of the body's gravitational influence. See for example Escapade's orbit:

[InterestedEngineer]

Mars bound Starships arrive in LEO, then refuel enough to travel to NRHO or other very high orbit.   
NRHO would host an oxygen propellent depot.   
Starships would refuel there for the Mars transfer orbit.
Starships would use an efficient oberth maneuver to start toward Mars

That won't work.  You'll spend more fuel de-orbiting from a circular to an elliptical orbit than you would get benefit from the Oberth maneuver.

"always be in elliptical orbit" - including the propellant.

This is no longer true once you get far enough that your orbit is at the edge of the body's gravitational influence. See for example Escapade's orbit:

Interesting.  So you'd presumably toss LOX into this orbit and figure out how to rendezvous with it.

Alas there's not a lot of detail on this orbit on the intarwebs.  Perhaps you could find some?  For example wikipedia says:

hen ESCAPADE will change course to dive within 600 km of Earth for a gravity assist and execute its escape burns to place it on a trajectory to Mars

What's the deltaV for that course change?

What's the orbital period around L2?

How hared to rendezvous with LOX given that orbital period?

What happens if the moon's gravitational influence changes this orbit?

[InterestedEngineer]

answering some of the "moon fuel to L1" questions I raised.

It's about 2.7km/sec from lunar surface to EM-L1 halo orbit.   Since the exhaust velocity of a starship is 3.6km/sec that makes it about half the fuel you have to burn from lunar surface to get it to the fuel keeping station at EM-L1.

Now, it's a trivial < 100m/sec burn to de-orbit to an elliptical earth grazing orbit for an Oberth burn, so that's basically rounding error.  That's the huge advantage of a Lagrange point for parking fuel depots.

So the EM-L1 point is a great place to put fuel depots, whether the fuel is from the moon or the earth.  You can get starships to solar escape speeds quite easily.  Mars transits are less than 100 days and this includes a braking burn at Mars to slow down enough for aerobraking to still work.

Now, it's about 3.2km/sec to get fuel from LEO to EML1.   That's about 65% of the fuel used.

If it costs us in the long run $10/kg to get fuel to LEO, it thus will cost us $28/kg to get it to EML1.

So whatever the Moon's LOX production costs are, they'd better be less than 28/2 = $14/kg or it'll never be economically viable.  Probably less than $10/kg to pay for the development cost.

On Earth LOX is about $0.1/kg so the production costs on earth are rounding error.

Think we can get production costs for LOX on the moon to less than $10/kg?

[OTV Booster]

SpaceX's ultimate goal is Mars.  Except for the Artemis lander for the moon, I don't think SpaceX is at all interested in the moon.  Once a colony is established on Mars, SpaceX in the distant future might mine asteroids and will need water harvesting at Ceres.  That is at least 50-100 years out.  Mars is the goal.  Moon is secondary.

Mars is the goal but if the water works out it might be a means to that end.

[OTV Booster]

answering some of the "moon fuel to L1" questions I raised.

It's about 2.7km/sec from lunar surface to EM-L1 halo orbit.   Since the exhaust velocity of a starship is 3.6km/sec that makes it about half the fuel you have to burn from lunar surface to get it to the fuel keeping station at EM-L1.

Now, it's a trivial < 100m/sec burn to de-orbit to an elliptical earth grazing orbit for an Oberth burn, so that's basically rounding error.  That's the huge advantage of a Lagrange point for parking fuel depots.

So the EM-L1 point is a great place to put fuel depots, whether the fuel is from the moon or the earth.  You can get starships to solar escape speeds quite easily.  Mars transits are less than 100 days and this includes a braking burn at Mars to slow down enough for aerobraking to still work.

Now, it's about 3.2km/sec to get fuel from LEO to EML1.   That's about 65% of the fuel used.

If it costs us in the long run $10/kg to get fuel to LEO, it thus will cost us $28/kg to get it to EML1.

So whatever the Moon's LOX production costs are, they'd better be less than 28/2 = $14/kg or it'll never be economically viable.  Probably less than $10/kg to pay for the development cost.

On Earth LOX is about $0.1/kg so the production costs on earth are rounding error.

Think we can get production costs for LOX on the moon to less than $10/kg?

If tanker can deliver 250t of propellant to LEO at $10/kg that's a launch cost of $2.5m. Is that reasonable? In what time frame?


Transfer from LEO to L1 would be a depot, a tanker or something in between to save dry mass. From lunar surface ultimately a sling. Yeah, it's a new system to develop but the utility of lunar propellant kicks in later as the number of mars ships grows, giving both time and incentive for development.


A question on the 100m/sec burn from EM-L1 to mars. Can it be run in reverse to bring a returning mars ship to L1 with ~100m/sec burn? That would be another trade space to look at. With carbon or CO2, lunar water can make methane. Earth needs to get rid of CO2 but it's also dirt cheap on Mars.

[rsdavis9]

The question of local surface transport.

1. Hop from one location to next ala p2p
2. Continuous thrust to stay aloft and then horizontal movement ala 2001 movie 
3. Surface with wheels and batteries and charging stations.

I think 1 and 3 will be the future for both the moon and mars. They both have flat plains across the majority of the surface. They don't have vegetation or liquid erosion to hamper travel. It will have speed limits but the majority will be fairly easy. Charging stations will be solar panel farm and buried insulated batteries. On mars 12-24 hours of battery storage on the moom 14-28 days of storage.

2 might still be used for surveys where slow and close to surface are needed for some sort of scanning. Or very short distances where fuel use is more important.

[InterestedEngineer]

A question on the 100m/sec burn from EM-L1 to mars. Can it be run in reverse to bring a returning mars ship to L1 with ~100m/sec burn? That would be another trade space to look at. With carbon or CO2, lunar water can make methane. Earth needs to get rid of CO2 but it's also dirt cheap on Mars.

Well, you have to run the ENTIRE thing, including oberth burn, in reverse.

If arrival velocity from Mars is 12-14km/sec, then you'll have to do a 1.1 - 3.1 km/sec burn at perapsis to put you on a trajectory for L1-EM, then an L1-EM insertion burn (the latter being pretty small).

Come to think of it, you might be able to aerobrake that small of a deltaV at pretty high altitude and skip back out to space and on to L1.   It'd be a pretty low risk maneuver (after some practice).

And then there's the timing issue - the moon has to be in the right location.  Which affects both directions.  I really haven't done an analysis of how much deltaV it would take to rotate the egress/ingress trajectory from the nominal periapses burn trajectory.  Which if it takes too much deltaV, means your launch windows to extra-earth locations only happens a few days per month.  (this is a great use for KSP btw, you just slide things around and take notes).

I'm curious why though - why would one refuel on the way back from Mars at L1-EM?  Maybe if EDL is truly limited to 8km/sec (I doubt it), you'd refuel so that you could do a pre-EDL rocket braking.  But multiple aerobrake passes probably make more sense and are less of a scheduling headache with regards to the moon.

Perhaps in an emergency it might make sense (as in "we somehow lost too many tiles in deep space and can't repair it" - how often would that happen?  Probably never).

[OTV Booster]

A question on the 100m/sec burn from EM-L1 to mars. Can it be run in reverse to bring a returning mars ship to L1 with ~100m/sec burn? That would be another trade space to look at. With carbon or CO2, lunar water can make methane. Earth needs to get rid of CO2 but it's also dirt cheap on Mars.

Well, you have to run the ENTIRE thing, including oberth burn, in reverse.

If arrival velocity from Mars is 12-14km/sec, then you'll have to do a 1.1 - 3.1 km/sec burn at perapsis to put you on a trajectory for L1-EM, then an L1-EM insertion burn (the latter being pretty small).

Come to think of it, you might be able to aerobrake that small of a deltaV at pretty high altitude and skip back out to space and on to L1.   It'd be a pretty low risk maneuver (after some practice).

And then there's the timing issue - the moon has to be in the right location.  Which affects both directions.  I really haven't done an analysis of how much deltaV it would take to rotate the egress/ingress trajectory from the nominal periapses burn trajectory.  Which if it takes too much deltaV, means your launch windows to extra-earth locations only happens a few days per month.  (this is a great use for KSP btw, you just slide things around and take notes).

I'm curious why though - why would one refuel on the way back from Mars at L1-EM?  Maybe if EDL is truly limited to 8km/sec (I doubt it), you'd refuel so that you could do a pre-EDL rocket braking.  But multiple aerobrake passes probably make more sense and are less of a scheduling headache with regards to the moon.

Perhaps in an emergency it might make sense (as in "we somehow lost too many tiles in deep space and can't repair it" - how often would that happen?  Probably never).

IF (a big if) lunar water works out for propellant production, EM-L1 has advantages over the lunar surface for electrolysis. Good thermal environment, 24/7 PV output and a usable HEEO refueling location. Methane production doesn't work without carbon or preferably CO2. AIUI, the moon is carbon poor. That leaves Earth and Mars.


An argument for earth sourcing is disposal of sequestered CO2. Economic arguments for and against have so many assumptions as to be useless. It's more an exercise in physics and "what if."


The economics of Mars sourcing is just as tenuous. The main benefit is a backhaul load and getting ships back into service. Deadhead is a killer in the transportation industry. What's the point of building reusable rockets if you don't reuse them? There's only so much you can do with thin stainless plate.

[Twark_Main]

All you get is bragging rights

Oh, so only the same reason people amass fortunes and raise armies? Okay then. 

[Vultur]

answering some of the "moon fuel to L1" questions I raised.

It's about 2.7km/sec from lunar surface to EM-L1 halo orbit.   Since the exhaust velocity of a starship is 3.6km/sec that makes it about half the fuel you have to burn from lunar surface to get it to the fuel keeping station at EM-L1.

Now, it's a trivial < 100m/sec burn to de-orbit to an elliptical earth grazing orbit for an Oberth burn, so that's basically rounding error.  That's the huge advantage of a Lagrange point for parking fuel depots.

So the EM-L1 point is a great place to put fuel depots, whether the fuel is from the moon or the earth.  You can get starships to solar escape speeds quite easily.  Mars transits are less than 100 days and this includes a braking burn at Mars to slow down enough for aerobraking to still work.

Now, it's about 3.2km/sec to get fuel from LEO to EML1.   That's about 65% of the fuel used.

If it costs us in the long run $10/kg to get fuel to LEO, it thus will cost us $28/kg to get it to EML1.

So whatever the Moon's LOX production costs are, they'd better be less than 28/2 = $14/kg or it'll never be economically viable.  Probably less than $10/kg to pay for the development cost.

On Earth LOX is about $0.1/kg so the production costs on earth are rounding error.

Think we can get production costs for LOX on the moon to less than $10/kg?

If tanker can deliver 250t of propellant to LEO at $10/kg that's a launch cost of $2.5m. Is that reasonable? In what time frame?

Depends on what kind of cost.

Marginal cost of launching an additional tanker flight, IMO quite possible fairly soon after full rapid/low maintenance reuse is achieved.

Total cost, including amortization of everything including development costs and pad hardware, that's much harder and would require extremely high flight rates.

[OTV Booster]

answering some of the "moon fuel to L1" questions I raised.

It's about 2.7km/sec from lunar surface to EM-L1 halo orbit.   Since the exhaust velocity of a starship is 3.6km/sec that makes it about half the fuel you have to burn from lunar surface to get it to the fuel keeping station at EM-L1.

Now, it's a trivial < 100m/sec burn to de-orbit to an elliptical earth grazing orbit for an Oberth burn, so that's basically rounding error.  That's the huge advantage of a Lagrange point for parking fuel depots.

So the EM-L1 point is a great place to put fuel depots, whether the fuel is from the moon or the earth.  You can get starships to solar escape speeds quite easily.  Mars transits are less than 100 days and this includes a braking burn at Mars to slow down enough for aerobraking to still work.

Now, it's about 3.2km/sec to get fuel from LEO to EML1.   That's about 65% of the fuel used.

If it costs us in the long run $10/kg to get fuel to LEO, it thus will cost us $28/kg to get it to EML1.

So whatever the Moon's LOX production costs are, they'd better be less than 28/2 = $14/kg or it'll never be economically viable.  Probably less than $10/kg to pay for the development cost.

On Earth LOX is about $0.1/kg so the production costs on earth are rounding error.

Think we can get production costs for LOX on the moon to less than $10/kg?

If tanker can deliver 250t of propellant to LEO at $10/kg that's a launch cost of $2.5m. Is that reasonable? In what time frame?

Depends on what kind of cost.

Marginal cost of launching an additional tanker flight, IMO quite possible fairly soon after full rapid/low maintenance reuse is achieved.

Total cost, including amortization of everything including development costs and pad hardware, that's much harder and would require extremely high flight rates.

Yeah, anything other than marginal costs are tricky.


What is a boosters lifetime? F9 experience points towards a long lifetime. And I'd guess lower lifetime refurb costs with non coking engines. Maybe more important, what is the IRS useful lifetime for calculating depreciation?


What is a ships lifetime? A whole different question. It's got a rougher job and there is only the Shuttle as a guide. Personally, I don't expect turnaround to drop below a week, and maybe several weeks, any time this decade. But then, lunar water mining is a next decade issue so maybe the cost comparison has a rough alignment.


The subject of amortized flight rate, with rapid reuse or not, is another guesstimate but I'm somewhat bullish here. Polishing off the initial Starlinks and begin replacing the older ones could be anywhere from 100 to 150 launches per year. A biannual mars effort with more ships each time, DOD launches and servicing space stations. It all adds up. Even with competent competitors there will be a lot of business.

[Vultur]

What is a ships lifetime? A whole different question. It's got a rougher job and there is only the Shuttle as a guide. Personally, I don't expect turnaround to drop below a week, and maybe several weeks, any time this decade. But then, lunar water mining is a next decade issue so maybe the cost comparison has a rough alignment.

Exactly, none of this is super near term.

The question IMO is whether there is any point where it is cost effective to invest in lunar propellant manufacturing rather than scaling up/making cheaper Earth launch.

[rsdavis9]

What is a ships lifetime? A whole different question. It's got a rougher job and there is only the Shuttle as a guide. Personally, I don't expect turnaround to drop below a week, and maybe several weeks, any time this decade. But then, lunar water mining is a next decade issue so maybe the cost comparison has a rough alignment.

Exactly, none of this is super near term.

The question IMO is whether there is any point where it is cost effective to invest in lunar propellant manufacturing rather than scaling up/making cheaper Earth launch.

My guess for anything near earth and maybe beyond the cheapest will be earth for propellant.

Maybe you could argue water and co2 from earth and then in orbit with solar power to process into LOX and LCH4 because somehow power is cheaper in orbit?

[InterestedEngineer]

What is a ships lifetime? A whole different question. It's got a rougher job and there is only the Shuttle as a guide. Personally, I don't expect turnaround to drop below a week, and maybe several weeks, any time this decade. But then, lunar water mining is a next decade issue so maybe the cost comparison has a rough alignment.

Exactly, none of this is super near term.

The question IMO is whether there is any point where it is cost effective to invest in lunar propellant manufacturing rather than scaling up/making cheaper Earth launch.

My guess for anything near earth and maybe beyond the cheapest will be earth for propellant.

Maybe you could argue water and co2 from earth and then in orbit with solar power to process into LOX and LCH4 because somehow power is cheaper in orbit?

transporting CO2 makes no sense - most of the mass is O2.  You might as well convert it to LOX and LCH4 right here on earth.  And then launch it to LEO so we can travel to the moon and other planets.

Oh yeah, that's the plan of record...

[rsdavis9]

What is a ships lifetime? A whole different question. It's got a rougher job and there is only the Shuttle as a guide. Personally, I don't expect turnaround to drop below a week, and maybe several weeks, any time this decade. But then, lunar water mining is a next decade issue so maybe the cost comparison has a rough alignment.

Exactly, none of this is super near term.

The question IMO is whether there is any point where it is cost effective to invest in lunar propellant manufacturing rather than scaling up/making cheaper Earth launch.

My guess for anything near earth and maybe beyond the cheapest will be earth for propellant.

Maybe you could argue water and co2 from earth and then in orbit with solar power to process into LOX and LCH4 because somehow power is cheaper in orbit?

transporting CO2 makes no sense - most of the mass is O2.  You might as well convert it to LOX and LCH4 right here on earth.  And then launch it to LEO so we can travel to the moon and other planets.

Oh yeah, that's the plan of record...

If power is cheaper in orbit then converting h20 to h2 and o2 is cheaper in space. Then react h2 and co2 to produce the methane.

Not clear that power will be cheaper in orbit.

[Vultur]

Also, if cost effectiveness is your goal you wouldn't make methane and LOX from water and CO2 on Earth. Both are already available. Musk mentioned it way back when, but that's for environmental reasons not cost effectiveness reasons.

[OTV Booster]

What is a ships lifetime? A whole different question. It's got a rougher job and there is only the Shuttle as a guide. Personally, I don't expect turnaround to drop below a week, and maybe several weeks, any time this decade. But then, lunar water mining is a next decade issue so maybe the cost comparison has a rough alignment.

Exactly, none of this is super near term.

The question IMO is whether there is any point where it is cost effective to invest in lunar propellant manufacturing rather than scaling up/making cheaper Earth launch.

Transportation costs will drop but will eventually bottom out. The earlier speculation of $10/kg to LEO is probably near the bottom for chemical rockets. Procedures and infrastructure can be cleaned up a bit but these will be small incremental price drops.


One conclusion drawn from 15 years in trucking is that all forms of transportation share common business concerns. And a biggie is deadhead (empty miles). It's all expense and no income. Almost all loads have some. Drop one load then deadhead to the next. Where it hurts is when there is no backhaul.


A way of dealing with no backhaul is taking a load that would otherwise be unacceptably poor paying. A good example is delivering to Miami then grabbing a max gross weight load of beer up to Jacksonville that barely pays for the fuel it consumes. Note: Except during citrus harvest, Florida is a freight poor environment.


Beer is inexpensive by weight and transportation might be as much as 25% of its retail price so the shipper is sensitive to shipping costs. Propellant is exactly that type of load. If it is produced in a freight rich environment (earth) it will be competing for lift with higher dollar freight that is less sensitive to shipping costs.


OTOH, lunar propellant can accept somewhat higher production costs because it fills a backhaul niche. Ships on the moon-earth run can run on lunar propellant and even carry extra to L1 for topping off ships on the earth-moon run. Using the beer hauling model, if the freight costs cover the cost of the fuel consumed to move the load the shipper might not be ahead of the game but they will be less far behind.


If the propellant is flung directly to L1 the total FOB L1 costs (total delivered cost at L1) are even lower and might justify toping up returning freighters for aerobraking to LEO to top off LEO depots.


This model in its full blown form is for the 2040's or later. It expects a mature space transport infrastructure, not one in development. It will not arrive full blown. Step by step. Inch by inch. And it assumes useful quantities of water. It will most likely start with local propellant use for earth return and expand in response to market forces impossible to predict this far out. I can see the canvas. I can see the palette. I do not know what the picture will be.


If Musk is seriously noodling a 50 year mars plan ISTM that investing in lunar propellant production, unless definitively shown to be impractical, is at least as good an investment/venture as the Boring Company.

[Vultur]

What is a ships lifetime? A whole different question. It's got a rougher job and there is only the Shuttle as a guide. Personally, I don't expect turnaround to drop below a week, and maybe several weeks, any time this decade. But then, lunar water mining is a next decade issue so maybe the cost comparison has a rough alignment.

Exactly, none of this is super near term.

The question IMO is whether there is any point where it is cost effective to invest in lunar propellant manufacturing rather than scaling up/making cheaper Earth launch.

Transportation costs will drop but will eventually bottom out. The earlier speculation of $10/kg to LEO is probably near the bottom for chemical rockets. Procedures and infrastructure can be cleaned up a bit but these will be small incremental price drops.

Sure. The question is whether lunar propellant can be made that cheaply. That depends on things we don't really yet know, like the practicality of mining ice from lunar craters (which depends on the nature of the ice - big sheets of nearly pure ice under fairly distinct regolith layers? frozen mud?) and the maintenance costs of equipment working in that environment.

OTOH, lunar propellant can accept somewhat higher production costs because it fills a backhaul niche.

Only if you have a lot of ships going to and returning from the Moon for some other reason. If Moon activity is otherwise limited to science and small bases for geopolitical flag showing, the volume won't be there.

So this only works if there's already large scale activity on the Moon for some other reason; lunar propellant can't be itself the justification for large scale activity on the Moon.

[OTV Booster]

What is a ships lifetime? A whole different question. It's got a rougher job and there is only the Shuttle as a guide. Personally, I don't expect turnaround to drop below a week, and maybe several weeks, any time this decade. But then, lunar water mining is a next decade issue so maybe the cost comparison has a rough alignment.

Exactly, none of this is super near term.

The question IMO is whether there is any point where it is cost effective to invest in lunar propellant manufacturing rather than scaling up/making cheaper Earth launch.

Transportation costs will drop but will eventually bottom out. The earlier speculation of $10/kg to LEO is probably near the bottom for chemical rockets. Procedures and infrastructure can be cleaned up a bit but these will be small incremental price drops.

Sure. The question is whether lunar propellant can be made that cheaply. That depends on things we don't really yet know, like the practicality of mining ice from lunar craters (which depends on the nature of the ice - big sheets of nearly pure ice under fairly distinct regolith layers? frozen mud?) and the maintenance costs of equipment working in that environment.

OTOH, lunar propellant can accept somewhat higher production costs because it fills a backhaul niche.

Only if you have a lot of ships going to and returning from the Moon for some other reason. If Moon activity is otherwise limited to science and small bases for geopolitical flag showing, the volume won't be there.

So this only works if there's already large scale activity on the Moon for some other reason; lunar propellant can't be itself the justification for large scale activity on the Moon.

IMO the mining will be the expensive part, not the purification. There is vacuum and a wicked temperature differential immediately available. We're talking about water, not rare earths.

Mining in the lunar environment will not be easy but the techniques needed to make it work will be extensions of general purpose techniques needed elsewhere on the moon, not something totally new.

What would be the activities that would generate traffic to the moon? It all starts in proving that your national member is bigger than the other guys, and even when that fades into the background it never quite goes away.

Then there is research. A far side radio telescope would be great. Fill in as many blanks here as you wish.

Tourism. It's trite but true. Ever since reading Heinlein's "The Moon is a Harsh Mistress" I've wanted to strap on wings in 1/6g and 6bar pressure. I am not alone.

Exploration. This is the biggie. It's a matter of the human spirit and intertwines with resource development. Are there useful quantities of He3? Will we develop the technology (on earth or moon) to take advantage of it? Are there near pure silicon deposits or rare earths?

By its very nature exploration gives no guarantee that you will find that which you covet. On the flip side chances are high that the unexpected will be found, sometimes pushing economic development in totally unexpected directions.

If we don't explore we won't know what we're missing.

Possibly China's greatest failure was in breaking up their 15th century trading fleets, destroying the records and banning further fleets. There is some controversial evidence that they had reached the Americas. Either way, by turning inward they lost any chance of grabbing a piece of the economic engine that drove Europe for 350-400 years.

If we go to the moon strictly as a pissing contest then huddle down in a continuously occupied but otherwise useless base, we've missed the point.[/quote]

[TrevorMonty]

Certainly the use of chair lifts on the moon will help astronauts in and out of the deep craters.

I just scratch my head with mining equipment such as backhoes and dump trucks.  Search equipment to identify the wet rocks.  Plus the necessary facilities along a mining route.

Don't need to do any material moving to extract top few feet of ice. Just cover area heat and capture vaporised water. Move on and repeat.  No need to drive in and out of craters when hoppers can fly machines in and water out. DV needed to hop 10kms is very low.

[redneck]

Possibly China's greatest failure was in breaking up their 15th century trading fleets, destroying the records and banning further fleets. There is some controversial evidence that they had reached the Americas. Either way, by turning inward they lost any chance of grabbing a piece of the economic engine that drove Europe for 350-400 years.

If we go to the moon strictly as a pissing contest then huddle down in a continuously occupied but otherwise useless base, we've missed the point.

I read the 1421 book on China reaching America. If it happened somewhat close to the way that author suggests, Then China could have had substantial colonies on the American continents starting a century ahead of the Europeans. The question, similar to the Lunar question, is whether it would have been beneficial to the parent country.  I think probably, but not certain.

[meekGee]

Possibly China's greatest failure was in breaking up their 15th century trading fleets, destroying the records and banning further fleets. There is some controversial evidence that they had reached the Americas. Either way, by turning inward they lost any chance of grabbing a piece of the economic engine that drove Europe for 350-400 years.

If we go to the moon strictly as a pissing contest then huddle down in a continuously occupied but otherwise useless base, we've missed the point.

I read the 1421 book on China reaching America. If it happened somewhat close to the way that author suggests, Then China could have had substantial colonies on the American continents starting a century ahead of the Europeans. The question, similar to the Lunar question, is whether it would have been beneficial to the parent country.  I think probably, but not certain.

If we're doing geopolitics, it's a good observation that China didn't lose the race 400 years ago because it allowed the Westerners to steal its technology.

China lost it all because it went stupid and destroyed its own science and technology.

[redneck]

Possibly China's greatest failure was in breaking up their 15th century trading fleets, destroying the records and banning further fleets. There is some controversial evidence that they had reached the Americas. Either way, by turning inward they lost any chance of grabbing a piece of the economic engine that drove Europe for 350-400 years.

If we go to the moon strictly as a pissing contest then huddle down in a continuously occupied but otherwise useless base, we've missed the point.

I read the 1421 book on China reaching America. If it happened somewhat close to the way that author suggests, Then China could have had substantial colonies on the American continents starting a century ahead of the Europeans. The question, similar to the Lunar question, is whether it would have been beneficial to the parent country.  I think probably, but not certain.

If we're doing geopolitics, it's a good observation that China didn't lose the race 400 years ago because it allowed the Westerners to steal its technology.

China lost it all because it went stupid and destroyed its own science and technology.

What makes me nervous is that it could happen here. Going stupid at large even with many brilliant and motivated individuals trying to move forward. That Musk is considered such an anomaly should be a warning sign. The pushback against so many possibilities concerns me as stagnation is possible with similar results as you point out.

Whether it's Mandarins or NIMBYs or pork or antibusiness,  the edge can be lost. I'd be willing to say that the US edge has been dulled already. Not gone, but not what it could be.

[OTV Booster]

Possibly China's greatest failure was in breaking up their 15th century trading fleets, destroying the records and banning further fleets. There is some controversial evidence that they had reached the Americas. Either way, by turning inward they lost any chance of grabbing a piece of the economic engine that drove Europe for 350-400 years.

If we go to the moon strictly as a pissing contest then huddle down in a continuously occupied but otherwise useless base, we've missed the point.

I read the 1421 book on China reaching America. If it happened somewhat close to the way that author suggests, Then China could have had substantial colonies on the American continents starting a century ahead of the Europeans. The question, similar to the Lunar question, is whether it would have been beneficial to the parent country.  I think probably, but not certain.

Looking on the Atlantic side, one of the first paying loads from N. America was timber, especially the mast sized trees, to build more ships.


China faced deforestation too but I'm unsure of the dates. At some point China also faced a silver shortage. Silver was their US$ equivalent. How can a civilization discover two new resource rich continents and it not be an economic boon? The only way I can think of is to play ostrich, head in sand.


That said, I seriously doubt the moon would give any significant payback until the 2040s. Development won't be even so some things will pay off early, some late. If lunar water has anything near economical output I'd expect it to be one of the early ones.


We've had endless discussions about the number of tanker flights and depot repositionings the different lander refueling strategies call for. Get rid of SLS/Orion and go with all SpaceX hardware and it doesn't get better. By the '40s SS will most likely be certified for crewed EDL and propellant ISRU ready to shift into production.


Focusing strictly on lunar surface refueling,  can anybody make an educated guesstimate on the number of tanker loads saved per crewed mission and how much lunar propellant it would take to do it? Because the earth sourced tankers/depots need to accumulate from others before staging higher the lunar production will be less than the total it displaces. Maybe a lot less.

[OTV Booster]

Possibly China's greatest failure was in breaking up their 15th century trading fleets, destroying the records and banning further fleets. There is some controversial evidence that they had reached the Americas. Either way, by turning inward they lost any chance of grabbing a piece of the economic engine that drove Europe for 350-400 years.

If we go to the moon strictly as a pissing contest then huddle down in a continuously occupied but otherwise useless base, we've missed the point.

I read the 1421 book on China reaching America. If it happened somewhat close to the way that author suggests, Then China could have had substantial colonies on the American continents starting a century ahead of the Europeans. The question, similar to the Lunar question, is whether it would have been beneficial to the parent country.  I think probably, but not certain.

If we're doing geopolitics, it's a good observation that China didn't lose the race 400 years ago because it allowed the Westerners to steal its technology.

China lost it all because it went stupid and destroyed its own science and technology.

You been reading the national news lately?

[redneck]

Possibly China's greatest failure was in breaking up their 15th century trading fleets, destroying the records and banning further fleets. There is some controversial evidence that they had reached the Americas. Either way, by turning inward they lost any chance of grabbing a piece of the economic engine that drove Europe for 350-400 years.

If we go to the moon strictly as a pissing contest then huddle down in a continuously occupied but otherwise useless base, we've missed the point.

I read the 1421 book on China reaching America. If it happened somewhat close to the way that author suggests, Then China could have had substantial colonies on the American continents starting a century ahead of the Europeans. The question, similar to the Lunar question, is whether it would have been beneficial to the parent country.  I think probably, but not certain.

If we're doing geopolitics, it's a good observation that China didn't lose the race 400 years ago because it allowed the Westerners to steal its technology.

China lost it all because it went stupid and destroyed its own science and technology.

You been reading the national news lately?

Your point being that concern is warranted?#1 Or that we shouldn't worry about anything?#2  My thought is #1, and there are others that see #2 as the correct vision.

[meekGee]

Possibly China's greatest failure was in breaking up their 15th century trading fleets, destroying the records and banning further fleets. There is some controversial evidence that they had reached the Americas. Either way, by turning inward they lost any chance of grabbing a piece of the economic engine that drove Europe for 350-400 years.

If we go to the moon strictly as a pissing contest then huddle down in a continuously occupied but otherwise useless base, we've missed the point.

I read the 1421 book on China reaching America. If it happened somewhat close to the way that author suggests, Then China could have had substantial colonies on the American continents starting a century ahead of the Europeans. The question, similar to the Lunar question, is whether it would have been beneficial to the parent country.  I think probably, but not certain.

If we're doing geopolitics, it's a good observation that China didn't lose the race 400 years ago because it allowed the Westerners to steal its technology.

China lost it all because it went stupid and destroyed its own science and technology.

You been reading the national news lately?

Your point being that concern is warranted?#1 Or that we shouldn't worry about anything?#2  My thought is #1, and there are others that see #2 as the correct vision.

My point is that worrying about "China stealing out technology" is not only useless, it's actually counter productive.

Musk understood that from the early days of SpaceX, and the sad state of all the competitors (haha foreign and domestic) affirms it.

Even in the car industry, the only somewhat relevant competitor didn't get there because it copied more technology than anyone else.

[redneck]

[quote autho
You been reading the national news lately?


Your point being that concern is warranted?#1 Or that we shouldn't worry about anything?#2  My thought is #1, and there are others that see #2 as the correct vision.

My point is that worrying about "China stealing out technology" is not only useless, it's actually counter productive.

Musk understood that from the early days of SpaceX, and the sad state of all the competitors (haha foreign and domestic) affirms it.

Even in the car industry, the only somewhat relevant competitor didn't get there because it copied more technology than anyone else.

Actually I agree with you about spaceflight and most technology MeekGee. I was replying to the question about reading the national news in general. There are so many that see our country as doomed, and so many others that see the rest of the world as incompetent copiers at best. I think both extremes are counterproductive to the US in particular and the rest of the world in general.

I work and deal with people from many other countries with Hispanics predominating. Very few of them have a problem with me stating that the US is my country and the one i care about with concern about any others way into second place.

[OTV Booster]

Possibly China's greatest failure was in breaking up their 15th century trading fleets, destroying the records and banning further fleets. There is some controversial evidence that they had reached the Americas. Either way, by turning inward they lost any chance of grabbing a piece of the economic engine that drove Europe for 350-400 years.

If we go to the moon strictly as a pissing contest then huddle down in a continuously occupied but otherwise useless base, we've missed the point.

I read the 1421 book on China reaching America. If it happened somewhat close to the way that author suggests, Then China could have had substantial colonies on the American continents starting a century ahead of the Europeans. The question, similar to the Lunar question, is whether it would have been beneficial to the parent country.  I think probably, but not certain.

If we're doing geopolitics, it's a good observation that China didn't lose the race 400 years ago because it allowed the Westerners to steal its technology.

China lost it all because it went stupid and destroyed its own science and technology.

You been reading the national news lately?

Your point being that concern is warranted?#1 Or that we shouldn't worry about anything?#2  My thought is #1, and there are others that see #2 as the correct vision.

Concern is warranted. We are actively perusing the path of China 400 years ago but that is only the latest and most overt aspect of the problem.


Another aspect is that despite rhetoric, education is on a downward spiral. The number of asian names of CEOs, grad students, researchers and high level technology workers is stunning. Don't get me wrong. The ever changing soup of the American population is a source of strength. Mutts are the best dogs.


The scale of the shift tells me that something else (education being only one possibility) is at work. It's hard to pick out cause and effect.


I could extend this rant but it's out of place here.