Let me know when we can “print” an ice excavator and dissociation refinery. I guess some tankage as well. 3-D printers are cute, but they print shapes, not mechanisms that need assembly.

It is true, however, that equipment maintenance at remote sites could potentially benefit from such printing technology, in that spare parts could be created onsite and there might be less need for a large parts depot.

Just to underscore this point, and to help respond to those who worship at the temple of the Moon, including Pastor Spudis…

You might as well take up another poster’s point. God knows you can’t be bothered to defend your own.

…there is NO QUESTION that propellants manufactured on site can be put into space using less of those propellants from the Moon than from the Earth. But the infrastructure costs to enable that functionality on the Moon are enormous.

Compared to say…4-6 years of NASA’s entire budget? Americans will consent to squandering the money anyway, so might well get something useful for our trouble.

Routine manufacture on and supply from the Moon makes sense ONLY when they are used in very large quantities such that the infrastructure costs can be amortized effectively.

You do know we just spent $100 billion on a friggin’ rest stop in LEO that will never recoup its cost in any run. It’s a little late in the day to be whining about the sunk cost in taking a honest step towards establishing a space-faring economy.

So we’re not talking “exploration” here. We’re talking colonization and settlement.

Um, yeah.

Mass emigration of the species into space. Now, colonization and settlement of space are not federal priorities, and not even clearly a cultural priority.

This is a stupid observation. Is space advocacy an exercise sociology now?

Those are words that are so loaded that Congress doesn’t want to touch them with a ten-foot pole.

This is a dumb conclusion, particularly since Congress is more than willing to touch “the Space Station to Nowhere” to the tune of $100 billion.

So they use the word “exploration” instead. That’s a word that doesn’t connote commitment.

Yes, nothing Americans appreciate more than noncommittally flushing $20 billion a year down the drain.

It’s meaningless to talk about economies of ISRU unless it’s clear what you’re going to do with it.

Replenish satellite bunkerage. Pretty damned clear if you ask me.

The Moon worshippers don’t want to be specific about that, because what would justify it involves words that are presently considered dangerous.

Are you kidding? They’ve been as specific as any other advocate of space-based refueling network regardless of its principle source.

The historical template for exploration is one that led seamlessly into colonization and settlement. You just left people behind, and made sure they had a knife, a saw, a hammer, and maybe a crate of nails. A gun and some ammunition would be nice as well. That template doesn’t apply to space exploration.

What does this have to do with the cost of tea in China?

Getting back on topic, a major change in space policy would be one that faces up to the importance of future colonization and settlement. Is that even a long term goal for our nation? If we formally admit that it is, then reaching out to the Moon to develop space travel resources makes some sense.

Can you think of a better reason to be out in space?

…on some timescale.

Presumably one long enough for you to pat yourself on the back and declare victory.

Not at all. Where do I put the Moon off-limits for sourcing supplies, or say that you can’t get them from the Moon at the same time you do from Earth?

In your previous comment: the last two paragraphs following “[t]his gets down to what you want to spend money on.”

As happens here on Earth, local sources of supply at remote locations are usually created because either the long distance sources are unreliable, or they are deemed too expensive.

At some point you need to stop making up your own “laws” of economics. They’re demonstrably flawed. By your reasoning, discovery and production of…say…petroleum increase only when prices do; an assertion which is nonsense on its face.

We don’t have that situation on the Moon today (local consumption), or anywhere close to the Moon (an export market).

What an insight. Shall I point out that there’s no local consumption or export of any propellant depoted on orbit?

As I see it, the only reason to set up propellant sourcing on the Moon is because we really want to create a lot of human activity on the Moon.

Bingo.

That’s a valid goal if the President, Congress and NASA want to do it, but no one is pushing that right now.

Which is a remarkable foolish failing, not principally of the President or Congress, but of NASA and space advocates like yourself.

We all have our favorite programs and departments we like to target, and yours seems to be the Science portion of the NASA budget.

Actually, mine is the entire budget for NASA. However, the Science budget makes for a convenient club to use when you get on your quixotic anti-heavy lift soap box.

However Congress has a longer history of supporting NASA Science than it does in supporting new mega programs like the SLS…

Now you’re just making stuff up.

“800 manned spacecraft in orbit right now? Try again, space cadet.

You must think satellites maneuver through the power of guts and hard work.”

No satellite on orbit uses loh/lox. Rockets and upper stages do but not satellites. They either use hypergolic like hydrazine and nitrogen tetroxide or electric thrusters using xenon (and the like).

Yes, there are some proven established economic laws, such as:
For something to be economically worthwhile, it must recoup the investment put into it and it must also yield something of greater economic value than you could have gotten otherwise.

“No, I’m not. I’ve explicitly noted that the one-time costs are negligible in the long run. Otherwise, you’d be stuck with the ridiculous notion that no new factory could ever be built that could compete against an existing one. “

One time costs would not be “negligible” when they total in the many tens of billions. Such a structure by your own admission would cost many tens of billions of dollars over the next 15 to 20 years. We’re talking 75 to 100 billion dollars using your own numbers. That price will probably go down significantly in about a decade because of the decline in launch costs that I have already mentioned. Best to start lunar ISRU then.

“No, I’m not. I’ve explicitly noted that the one-time costs are negligible in the long run. Otherwise, you’d be stuck with the ridiculous notion that no new factory could ever be built that could compete against an existing one. The point is rendered moot entirely if we consider the opportunity cost imposed by present space policy.”

If you had read what I wrote more thoroughly for comprehension, you would have realized that I am not saying anything as ridiculous as “no new factory could ever be built that could compete against an existing one.” The only thing ridiculous is your assertion that I am saying that. To accurately represent what I was actually saying, I would rewrite your phrase as, “no new factory can be built currently at present launch costs from Earth that could compete against an existing one.” Didn’t you see the part where I said lunar in situ resource utilization will be necessary when it becomes economically feasible to do so?

“We are already spending prodigious amounts on national space policy.”

And wasting it on SLS and MPCV.

“On the order of $5 billion a year for fifteen to twenty years. I wonder where Congress can find that much money?”

It’s not a question of whether or not Congress has the capability of allocating that kind of money over that long a period. The problem is the unlikeliness that it will do so for that long a period of time that is the issue. SLS will almost certainly go down the tubes for that very reason.

It does, actually, at some technology level. I suspect we’re closer to it than many think (e.g., 3-D printers).

“No, it doesn’t, because your falsely presenting two paths forward as mutually exclusive choices.”

Not at all. Where do I put the Moon off-limits for sourcing supplies, or say that you can’t get them from the Moon at the same time you do from Earth?

As happens here on Earth, local sources of supply at remote locations are usually created because either the long distance sources are unreliable, or they are deemed too expensive. We don’t have that situation on the Moon today (local consumption), or anywhere close to the Moon (an export market).

As I see it, the only reason to set up propellant sourcing on the Moon is because we really want to create a lot of human activity on the Moon. That’s a valid goal if the President, Congress and NASA want to do it, but no one is pushing that right now.

“On the order of $5 billion a year for fifteen to twenty years. I wonder where Congress can find that much money?”

We all have our favorite programs and departments we like to target, and yours seems to be the Science portion of the NASA budget. However Congress has a longer history of supporting NASA Science than it does in supporting new mega programs like the SLS, so I think you’re being a little quixotic. Welcome to the club…

The Spudis/Lavoie plan would cost $87B and take 17 years before they projected they would have their propellant operation running, whereas if we use existing assets we could start much quicker and it would take less money up front.

Why wouldn’t you? Considering Spudis-Lavoie presents a conservative, phased space of trades, you’d expect an Earth-sourced depot network to reduce lift costs at any stage in which it’s available and applicable (which, given the payloads described, appears to be all of them).

This gets down to what you want to spend money on.

No, it doesn’t, because your falsely presenting two paths forward as mutually exclusive choices.

But I’ll let supply & demand forces figure that out, with NASA just providing the demand, not the supply.

Are you kidding me? You think NASA’s some sort of force of nature? There’s no letting things play out here. You propose budget priorities, fight for the ones you can make stick and retreat on those that will sink your whole program.

As an astrophysicist, the difference in escape velocity of the Moon versus Earth as a major factor is of course obvious to me. But the laws of economics are as inescapable as the laws of physics.

Setting aside the dubious assertion that economics yields anything remotely universal enough to be considered a law, might help if you actually pointed to specific relationships and highlight their application.

The arguments that pathfinder_01 espouses apply. See my post to Marcel Williams for more illucidation on the subject.

They do not. See my reply to pathfinder.

You are only considering production costs after the infrastructure to produce and transport the end product has been set up.

No, I’m not. I’ve explicitly noted that the one-time costs are negligible in the long run. Otherwise, you’d be stuck with the ridiculous notion that no new factory could ever be built that could compete against an existing one. The point is rendered moot entirely if we consider the opportunity cost imposed by present space policy.

This is the same mistake Marcel Williams makes. Eventually, it will become economically practical (and necessary) to set up lunar resource production infrastructure, but now is not the time.

You understand your argument boils down to “it’s not economically feasible to set up a lunar resource production infrastructure because it’s not economically feasible to do so.” Do you?

Remember the old Aesop fable of the Ant and the Grasshopper.

Do astrophysicists typically appeal to fable when competing for grants?

We can, in a near adolescent impatience for fast gratification, spend prodigious amounts right now with poor return on our investment, or develop what we need to do it practically in the long run.

We are already spending prodigious amounts on national space policy. I’ve proposed reconfiguring outlays already being squandered to the purpose of kickstarting a cislunar propellant economy. And even if the American space program were in the cash constrained circumstances where you rule of thumb might (on a good day) apply, there is no clear halting condition to your endless search and study for less expensive means to achieve the same goal. In fact, the only natural course of action your fable suggests is to fold up the space program and leave it to the market. Who knows? In a century, available liquidity and the known risk of the enterprise might be such that a private concern will make a go for it.

Think about the enormous cost of initially setting up the lunar infrastructure to get a practical system going.

On the order of $5 billion a year for fifteen to twenty years. I wonder where Congress can find that much money?

That expense ends up being amortized in the production as a significant part of the final cost of the fuel.

That represents the highly unlikely case of private enterprise conceiving and executing on their own dime. You can trade time for money, and the biggest tap for risk reduction is the Treasury.