Calliban Postings including links to notable contributions

tahanson43206 · 2024-09-19 10:11:35

For Calliban ... FriendOfQuark1 sent an inquiry about the problem of heating inside a hollowed out asteroid...

I'm sort of warming to the problem Caliban perceives. It isn't an issue for the oilfield. And we don't spend much time (any?) on what the thermal permeability of "rock" (a broad term!!!) is.
I'm a little perplexed though why Caliban perceives a future where things are thermally inefficient. Say a nuclear powered craft produces 1,000 units of power/heat. If the ship is only able to convert 3% of that nuclear heat to "work" you would heat up your "rock" pretty fast. Don't we expect to convert, especially in a more technologically advanced future, a much larger percentage of the theoretical maximum to work? Surely, there is an efficiency level vis-a-vis the volume of 'rock' where the amount of heat the rock radiates out to space is in parity to the amount of heating is being imparted? E.G. surely the hollowed out asteroid radiates a non zero amount of internal heating to the "aether"....?

For Calliban ... I'm looking forward to your answer .... I am hoping you won't be distracted by the efficiency question. I'm hoping you will concentrate on the insulation that an asteroid would provide that would prevent a spacecraft from radiating thermal energy to space.

(th)

Calliban · 2024-09-19 11:30:08

I'm not sure where 3% efficiency comes from. The efficiency of a heat engine has relatively little to do with how high-tech society is. It is a function of the temperature difference between hot source and cold source. Devices can be optimised with better engineering. But the upoer limit to efficiency is set by the Carnot equation.

Regarding geothermal. Heat has accumulated within deep rocks due to some combination of internal radioactive decay (usually mW/m3) and conduction from the mantle. When heat is withdrawn from a unit volume of rock, its temperature will decline. Heat will enter the rock both through internal radioactive decay and conduction from surrounding rocks. Both processes are relatively slow. The first is limited by the half life of radioisotopes within the rock. The second by the temperature gradient and thermal conductivity of the surrounding rocks. But in practical terms, geothermal energy is a form of mining. The resource is finite in human timescales, though it may be relatively vast. Once a volume of rock is drained of heat, it will take a long time to recharge through conduction and radioactive decay.

Regarding the asteroid question, so far as I understand it. Yes. An asteroid in thermal equilibrium will radiate as much energy (in infrared) as it absorbs from the sun. Internally, there will also be some heating from decay of radioactive elements in the rock. So we would expect all asteroids to be warmer in their centres than in their outer crust. The larger the asteroid is, the warmer its centre will be.

Last edited by Calliban (2024-09-19 11:54:21)

tahanson43206 · 2024-09-19 13:37:54

For Calliban re #127

Thanks for taking a first cut at the multiple questions from FriendOfQuark1....

The question about the hollowed out interior of an asteroid came up because I tried to quote what I remember from your posts on the subject....

I had proposed that a spacecraft might dig a cave for itself inside an asteroid to gain protection for severe radiation.

In reply, you warned that the interior of such an asteroid would not meet the needs of the spacecraft for cooling. My recollection is that you warned that the spacecraft would cook itself because the asteroid would not accept the thermal radiation from radiators on the ship.

I've been hoping you might develop that idea further. If you have lost track of that conversation, please let me know and i'll go looking for it.

The problem would presumably be worse if the asteroid is a rubble pile, because thermal energy would have an even harder tune flowing through a rubble pile.

(th)

Calliban · 2024-09-19 14:29:18

That would depend upon the thermal conductivity of the rock, the thickness of the rock and the temperature difference between the surface and the spacecraft. It also depends upon time - does the system reach thermal equilibrium, i.e a stable temperature gradient? Lets assume it does.

This reference discusses thermal conductivity of crustal rocks. This ranges between 2.5 - 4.5W/m.K. Lets assume the latter.
https://onlinelibrary.wiley.com/doi/10. … 21/6630236

Suppose the surface of the asteroid is at a temperature of 200K (-73°C). Suppose your spacecraft is at a temperature of 300K. How much heat would a 10m thick layer of rock conduct away?

Q=kAdT/dX = 4.5 x (300-200)/10 = 45W/m2.

So I would guess it could work, provided you are not too deep within the asteroid. If the rock thickness can be reduced to 1m, then thermal conduction increases to 450W/m2. It does impose limits on the practical power generation for the spacecraft.

The problem disappears altogether if the spacrcraft can transfer heat to a radiator on the surface of the asteroid, via a fluid containing pipe. If that can be done, then limits imposed by thermal conductivity of rock are obviated.

Last edited by Calliban (2024-09-19 14:33:22)

kbd512 · 2024-09-20 10:41:56

This fixation on energy efficiency is debilitating to the very concept of cleaner energy. There has never been an exemplar energy efficiency increase accompanied by a net reduction in energy usage related to the newer and more energy efficient technology. It doesn't matter if we're talking about lights, engines, computers, or higher strength-to-weight ratio materials. Increasing energy efficiency is not wrong as a concept, but it always produces the exact opposite of the intended result. If we make something more efficient to use, the end result is that we use or consume far more of it, but never less.

We burned whale oil. That was highly inefficient, expensive, and we rapidly ran out of whales. We created cheaper incandescent lights, which produced many more lumens of light per Watt of energy consumed, in comparison to whale oil, because they were way more energy efficient and we had a very large coal supply to feed into the steam boilers to produce electricity. In aggregate, because there was no shortage of coal to burn to generate electricity to power those incandescent lights, net energy consumption associated with lighting drastically increased. We invented LEDs and other semi-conductor technology after WWII, which were in turn more efficient than incandescent lights. Unfortunately, they required far more energy input to make each bulb, an electronic vs electrical device, and now everyone leaves their lights on 24/7. No net energy consumption decrease was achieved.

I hear we now have laser-pumped LEDs, which are purported to be 2X more efficient than plain old semiconductors at producing light. It's a mash-up between halogen or fluorescent tech and LED tech. Pretty soon everyone and their dog will have their homes lit up like neon road signs, at all times, from all angles. People will buy even more of these new lights, which require more energy to make than ordinary LEDs since they require another electronic device- a fiber laser. Per-device energy consumption seems very small, and per device, it truly is. We'll put them up everywhere because they don't use much energy. Similar to AI and data center based computing, we'll inevitably go nuts with this, because that is our nature. No net reduction in energy consumption will be achieved. We'll use vastly more light at all times, even when not required or providing material benefit, which is a fine outcome if you actually want more light. Unfortunately, you'd be foolish to believe that any energy will ultimately be saved by our vastly superior laser-pumped LEDs. Incontrovertible historical evidence indicates that all historical energy efficiency increases were also accompanied by dramatic increases in energy consumption.

We made natural gas energy so efficient that we used it to replace coal. Not only do we burn more natural gas now, we burn so much more that our CO2 emissions are markedly higher than they were when we were mostly burning coal, because there are 5X more units of energy output for every unit of energy input. The brilliant blue flame of natural gas may be far more aesthetically pleasing than the sooty exhaust of coal, at least to some people, but superficial appearance is as far as that goes. We are, in point of fact, using so much more, that CO2 levels are increasing faster, not slower, as we burn more gas instead of coal. You can argue that the air is still cleaner, because it is, but reducing CO2 emissions was the stated end goal behind using more gas vs coal. On that metric, the "energiewende" was a miserable failure.

In actual practice, efficiency is a misnomer. That word actually means we discovered a new way to use more energy. What is some specific newer and more efficient energy technology useful at doing? That is the proper question to ask, because we will use more of it, because we can, at least until we cannot. Electricity is very efficient at consuming more and more energy and energy intensive materials. The more electrical and electronic devices you have, the more demand you'll create for additional electrical and electronic devices. In practice, it's an exponential feedback loop. What's the one thing you cannot do when your energy demand continually increases? You can never stabilize consumption rates. If something costs less money, that's ultimately because less energy went into making it, which means more energy / money remains for using it, which means it will see more use.

If we're not actually doing what we claim as the primary reason behind what we're doing, then why do we need to pretend to do it?

Why is it so difficult for us to be honest with ourselves about what we're actually doing, as opposed to what we intended to do?

The thermal systems that Calliban has come up with are all about actually consuming less energy while still satisfying the basic "need" for something (cooking, warmth, food stage, etc).

If they look somewhat unfavorable when compared to something else, then we should come to terms with the fact that natural energy systems, which are simplistic yet durable energy generating and consuming designs by necessity, don't have the same characteristics as higher-energy systems. This is a feature, not a bug.

Heating up crushed rock using direct sunlight might look inefficient compared to, say, a giant wind turbine sending electricity directly down a wire. The difference is that the rock was scooped off the ground, crushing it was the most energy intensive thing we did with it, and because we sourced it locally, we didn't need to ship vast quantities of materials around the world several times so they could be made or assembled in some specific factory that did that one specific job better than anybody else. Let's say that the end use for the energy is a water desalination plant because there's not enough ground water. There are lots of ways to desalinate water, but you can use reverse osmosis or you can flash evaporate it. Either way, the end result is fresh water.

The wind turbine method requires carbon fiber, rare Earth elements, magnets, Copper, Aluminum, control microelectronics, step-up and step-down transformers, a power line, electric motors to power the pumps at the reverse osmosis plant, filters and filter media, and the list goes on. It may or may not theoretically require less energy, but in point of fact if we did that at scale, then it's going to ultimately consume more energy than direct heating of water using concentrated sunlight.

Using the direct sunlight / solar heating method, we have a giant thermal energy store, essentially a pit of crushed rock. We first heat the water as it passes through that giant thermal energy storage pit. The water flows through powered by water pressure, possibly a trompe or possibly steam from the second stage of the plant. The second stage of the plant uses mirrors to flash evaporate the near-boiling water as it enters. Cold salt water is then used to collect the fresh water in the condenser. Very little in the way of moving parts or specialized high tech equipment is required, because heat and pressure are doing the work. There's just not a lot of sophisticated bits of technology to break, short-circuit, or otherwise wear out. As a result, this sort of plant can keep producing fresh water, potentially for centuries. In contrast, many of the components in the high tech method won't last for a year before they need to be replaced or substantially refurbished. Incidentally, this also basically describes how a natural aquifer works. It's an above-ground variant of an aquifer, but it's doing the same thing.

If either method is getting the job done, why are we devoting more energy and more technology to do what nature and natural materials already do at a scale we've yet to match?

Isn't our apparent lack of progress, relative to nature, a sort of "clue" that what we're attempting to do with high technology may be efficient by one arbitrary metric, yet still vastly inferior to the natural way in which high salinity or brackish water becomes fresh water when filtered through an aquifer?

I think it's worth consideration.

tahanson43206 · 2024-09-25 13:27:21

For Calliban re new Topic about water/fluid goods transport...

I'm hoping you will actively develop this idea.

The NewMars archive is bulking up with great ideas you've published.

From my perspective, many of these could become thriving businesses and some could become entire industries.

While I don't pretend to be qualified to participate in the topic itself, I am hoping I can offer encouragement from this perch off to the side.

To begin with, there needs to be a market where slow movement of material over perfectly flat terrain would support your venture.

As it happens, the planet's oceans and lakes, and even some rivers would be ideal locations for your concept.

Vast amounts of slow moving goods flow down the large rivers in the US, and probably in other Nations.

At one time barge canals were profitable. Certainly that was true in the US for a time, and it may still be true in a few locations in Europe and Asia.

The merit of your idea is immunity from weather delays.

A line along the Mississippi River might carry goods down the central corridor of the United States, as just ** one ** example of a potential site for one (or more) of your shipping lines.

(th)

tahanson43206 · 2024-09-26 06:26:41

This is another attempt to encourage development of the enclosed passage transport idea ....

In order for this apparently worthwhile idea to move from the drawing board to reality, there needs to be a market.

There are NO such systems in existence on Earth today, which tells me the benefits of the proposal are not yet recognized.

It falls to the inventor of a major new way of doing things to persuade the customers of the advantages of the proposed system.

In thinking about potential markets, it occurred to me that a variation on the theme might be interesting to some funders.

The essential element of the proposal, as I understand it, is slow movement of goods carried along by a flow of water.

This is also characteristic of the time honored and very practical idea of using flat bottomed boats to move goods on inland waterways, with emphasis on rivers because they have established a natural gravitational flow that humans can harness.

So! Here is my idea/question .... suppose an entrepreneur loaded a small barge with soil, and planted seeds that would grow on the journey South (or downriver) to the market in one or more large cities. The supply of fresh water would be consistent throughout the passage, and sunlight would be abundant although no more reliable than a fixed location plot would see.

At the destination, the crop would be ready for harvest.

This idea would increase traffic on the river(s) where it is implemented. Is there an opportunity? Would there be objections? (no doubt)

The barges would need to be carried back up the river after they have completed their journey, but they could be stacked densely on large traditional barges.

The distinct advantage is that no infrastructure has to be added to implement the floating farm procedure.

(th)

Calliban · 2024-09-26 07:02:04

A floating farm? I suppose it would depend on what you are growing and what advantage there is to growing it in a barge rather than along the river bank. Usually, the barge would ship the finished product. One problem with growing stuff in the barge itself is that food crops generally require a lot of space. It takes hundreds of square metres to feed one person on a meagre diet. In some cases, customers want living plants to ensure freshness. Corriander and basil are often sold as live plants. This is a case where your proposal could have merit, as the plants would continue growing as they were transported.

Rivers are an under-used resource in the US. If goods are carried in the direction of flow of the river, then the energy needed for transportation is effectively free. The goods just go with the flow.

Calliban · 2024-10-01 05:16:24

I have completed some work for the Carnforth district heating project.
https://newmars.com/forums/viewtopic.ph … 81#p226881

The same system can be replicated where ever we have a densely populated town close to the coast. That covers most of the UK population and a significant fraction of European population overall.

tahanson43206 · 2024-10-02 07:40:39

For Calliban re Mechanical SPS ...

Most considerations of SPS focus on the potential for lightweight PV. But in space at Earth orbit, a black body in full sunlight would achieve a temperature of 120°C. The black sky on the other side of the panel, would have a temperature of 20K. A thermodynamic cycle running between two sides of a sun facing panel could achieve efficiency of over 50%. This is something that wouldn't be possible anywhere on Earth. We don't need semiconductor grade materials to build this. Just an iron plate with a layer of insulation seperating the hot and cold sides and some sort of heat transfer fluid. We could use a heavy gas like argon or CO2 as the power cycle fluid. Methanol for cold side heat transfer and sodium for the hot side.

This is the first time i've seen this idea, and I think it deserves support.

However, I am not sure what a topic around this concept should be named.

Please consider a possible title. The topic could attract contributions by members with mechanical engineering or related backgrounds.

We might even be able to attract new members, if the new topic has long term upside potential.

(th)

tahanson43206 · 2024-10-07 06:19:22

For Calliban ....

This post was intended to focus upon the discussion of a practical thermal energy store for the UK, but in re-reading #135 I am reminded of the potential value of your interest in a mechanical SPS, and hope you will continue working on it.

As one of our NewMars members pointed out, the Moon is an almost perfect site for such a system, since the raw material to build it are present (with a bit of scrounging in the case of water) and because the deep cold of open space is readily available.

***
My purpose in opening this post is to attempt to bring together three streams of thought that seem to exist around the UK thermal store concept. At the far extreme we appear to have one member who is obsessed with finding a global solution. At another extreme, we appear to have another member who is interested in finding and executing a solution for a single town in the UK. In the middle we appear to have a member who can think across the entire range.

From my perspective as an observer, I see an opportunity to actually achieve something in the Real Universe, but it will take a miracle to move theoreticians and ideologues from endless discussion of possibilities to actual decisions that an investor can evaluate.

This forum appears (from my perspective) to waste a lot of time lamenting the fact that most people don't buy what this forum is selling. We don't need ** most ** people to achieve success. We need ** one ** person with the means (deep pockets) to build whatever the members of this group decide upon.

I'm hoping the members of this group can (somehow) arrive at a consensus on a thermal energy storage system for one town in the UK, so that the elements of the plan (with realistic numbers) can be prepared for publication.

(th)

tahanson43206 · 2024-10-08 06:19:54

For Calliban re bore holes ...

In a recent post you mentioned the possibility of using bore holes for thermal energy storage.....

Your description of a solution for Carnworth came across to me as potentially attractive to the residents, and therefore potentially achievable.

I'd like to ask again .... is there something useful that could be done with material excavated from those holes?

Update a bit later.... In several posts including a recent one, you have cited the advantage of butane as a working fluid for a town sized thermal energy store. I decided to come back and toss into the mix a question about making butane instead of mining it

It would sure look good on the ledger if the project could sequester a large quantity of Carbon while building the system. I know that low complexity molecules can be made from CO2 and water ...examples would be methanol...

How hard is it to get from the low complexity molecules to more complex ones such as butane?

(th)

tahanson43206 · 2024-10-08 08:24:06

For Calliban re trunk lines for hot / cold water...

https://newmars.com/forums/viewtopic.ph … 13#p227113

The existing roadway system in the UK (and many other Nations) is a logical place for the kind of large scale fluid movement you've described.

The major consideration that seems worth evaluating is where to put the excavated material. A consideration is that heat from fluid below a roadway might keep it clear of snow if snow falls in a particular region.

(th)

tahanson43206 · 2024-10-08 09:06:10

For Calliban re Butane ....

I'm using this topic as a venue to avoid placing my ID over yours in the Butane topic.

Thanks for pointing out that the process that creates butane also creates other useful hydrocarbons.

I agree with your point about energy, but I object to the overtones of the word "cheap".

All energy from the Sun is totally free.

All energy from the Earth's core is totally free.

What I think you are talking about is the open market, in which sellers offer wares at the best price the market will bear.

As a customer, you have the opportunity to shop around to find the best match of the offering with your ability to trade something of value to the other party.

If you look at the market, and you don't see anyone offering the energy you want at the price you are willing to pay, let's go back to point #1.

All energy from the Sun is free, and all energy from the core is free.

if you need some of that free energy, and no one is providing it in the form you want at the price you are willing to pay, then it is up to you to figure out how to flow that free supply into your pockets.

(th)

Calliban · 2024-10-08 09:06:46

The problem with putting pipes under roads is the need to dig up the road to lay the pipe. That destroys the road, at least temporarily.

But excavated material is something we need to think about. The distance from London to Glasgow is 555km in a straight line. Lets say our ring main is 555km long and about 100km wide on average. To bury it, we need to dig a slot some 6m wide and 6m deep. The volume of material excavated is: (555,000 x 2 + 100 x 2) x 6 x 6 = 47,160,000m3. We need to do the same thing for the cold main as well. So that comes to 94,320,000m3. Just under one quarter of the material will be used to fill in around the pipe. Top soil will be put back in place. So the total volume excavated and not put back will be: 94,320,000 x pi/4 = 74 million m3. Or a cube some 420m aside.

What we do with the excavated material will depend on what it is. Rock can be used as building material, once washed and shaped. We have discussed using rock fragments as thermal storage material as well.

tahanson43206 · 2024-10-08 10:02:54

For Calliban re land use....

The US inherited much of it's land use policy from England.

And in the US, control of land has been a significant part of the social compact.

I can hardly imagine England is any less restrictive.

That is why I suggested the roadways. The roadway is dug up and replaced, and the process would be no different from existing maintenace practice.

Sections are completed at a time, and temporary routes are made available during the inconvenience.

After the work is done, a brand new surface is available, and the road has new capabilities id did not have before.

What is more, the land to the side of the roadway has not been disturbed, so ancient feuds are not resurrected, as would certainly be the case if anyone were to imagine building something at any other location.

Look at the disputes in the US over pipelines.

At least your proposal is free of the baggage of a petroleum pipeline, but I'll bet there are human beings who would object for some other reason.

(th)

tahanson43206 · 2024-10-08 18:33:33

For Calliban re space elevator at the Moon....

Nice to see you pitching in on one of Void's topics.

It takes a rare kind of talent to be able to post in one of Void's topics and survive the encounter, so i tip my hat to your skill.

***
Your reading necessarily must concentrate on materials that support your field, which means that you do not have time to read everything.

Accordingly, it is not surprising that you would have missed an answer that goes back at least 50 years, in answer to the ridiculous idea of crawling up a space elevator cable.

The impossibility of ever building a space elevator for Earth has swamped a lot of early ideas, but your support of the concept for the Moon is a welcome addition to conversation in the forum.

In a nutshell, the problem of speed using a space elevator is solved if you simply rotate the ribbon at whatever pace your system can handle.

The length of the cord/ribbon/rope is doubled, but the benefit is more than worth the extra expense.

The length of cord/ribbon/rope to support the counterweight does NOT need to be doubled, because no traffic will be moving on that leg.

It's been a while since I've seen the numbers run on the loop scenario, and in any case the Moon is a more practical venue for the system.

If you feel at all inspired please see if you can find a bit of time to work up a proposal.

As a reminder, a gent named Jerome Pearson did some work in this area. My recollection is that he received NASA funding for a traditional fixed ribbon design.

Your version would be the first in literally decades to offer the loop concept. I'll ** really ** enjoy seeing that concept back in print, even if it is only in the NewMars.com forum.

(th)

tahanson43206 · 2024-10-09 07:24:20

For Calliban re new post in cycler topic ...

https://newmars.com/forums/viewtopic.ph … 32#p227132

Thank you for bringing that topic back into view.

I hope you will have time (and the energy) to take another look at your proposal.

The idea of being stuck in the cycler seems understandable but perhaps a bit dated.

The idea of the cycler is to insure a safe, comfortable and perhaps even enriching experience for a space traveller during the long leg of a journey. However, the "payload" is a human passenger who can be transported by high speed, high acceleration taxi from the cycler to the destination in a few days at most.

Please take another look at the opportunity.

I understand your specialization is NOT deep space navigation, and GW Johnson will no doubt protest that he is not either, but the fact is GW has the best chance of any of our current members in performing a rough estimate of what it would take to deliver a passenger from a cycler to Mars using a high speed taxi.

I will ask GW if he might be willing to take a look at the problem.

What I am imagining is an automated taxi that slowly maneuvers into position to meet the cycler and then pours on the coal to deliver the passenger to Mars quickly. Both plane change and velocity change are required, but the mass to be moved in minimal, because it will consist of just the passenger, space suit and supplies, and a small allocation for baggage.

Meanwhile, the cycler itself will plod along on it's long journey, picking up passengers and dropping them off as needed.

There could be more than one transportation company in the cycler business, with numerous contributing service companies helping.

(th)

tahanson43206 · 2024-10-09 08:37:45

For Calliban re addition of metal cable for Lunar Space Elevator ...

https://newmars.com/forums/viewtopic.ph … 38#p227138

To quote Caliban (or misquote)...

Who needs a mass driver when you have a metal cable?

From biology, we have the concept of wave-like movement of "goods" along a track...

The human esophagus is a muscular tube that moves food from the mouth to the stomach through a series of wave-like muscle contractions known as peristalsis. A snake's esophagus, however, has very little muscle. It relies on the muscles of the entire body to squeeze food through the esophagus into the stomach.Feb 14, 2022
Animal Digestive Systems - Gastrointestinal Society

I'm pretty sure there is an electromagnetic equivalent capability.

It is possible this concept has been applied by someone, somewhere, some time.

(th)

tahanson43206 · 2024-10-09 08:45:11

For Calliban ....

As a follow up....

The NewMars forum now contains announcement of the concept of an "electromagnetic gullet", which can lift material from the surface of the Moon at velocities approaching that of electricity itself.

The second generation Gerard O'Neill mass driver (which I have seen in action at Princeton) employed a set of rings that generated magnetic force to pull (or push ( I don't remember)) the payload bucket along.

Once we have made the mental leap to consider metal cable from the surface of the Moon to L1, then we have (potentially) the ability to turn the entire column into a mass driver.

And the system can be designed so the magnet force is generated inside the column, so the payload encloses the central shaft.

(th)

Searchterm:gullet

Calliban · 2024-10-09 08:59:48

The problem with putting the mass driver in the cable and pushing the payloads up the cable at constant speed, is that the cable then has to support the weight of both the coils and the payloads in the lunar gravitational field. That really limits the rate at which material can be pushed up the tube, because the mass of both of these elements can only be a small fraction of the cable without breaking it. Ideally, we want the payloads to impose no tensile load on the cable. Hence my idea of firing them up the tube. The tube itself keeps the payloads on target through minor adjusting forces from the walls. But it does not have to support the weight of the payloads. An HVDC cable can be relatively light in comparison.

tahanson43206 · 2024-10-09 09:12:14

For Calliban re #146

Thanks for taking up the challenge of using metal for the Lunar Space Elevator.

You are the first human being to seriously entertain this idea, as far as i know, so you own it for the near term.

It's time to put some numbers on the board.

You are not limited to metal for the elevator. You can use all the kevlar you want to provide strength. An option you have (if the idea is valid) is to use plain electric current to accelerate the payload from surface to L1.

Why did you focus on constant acceleration ?

There is no need to worry about the velocity of the payload along the track.

Let's see if your idea can (literally) carry it's own weight in the Lunar scenario.

If it can, you have at the very least, the opportunity to publish before anyone else does.

Or we may discover that there is prior art.

Either way, this forum is once again the site of some interesting ideas.

(th)

Calliban · 2024-10-09 09:28:57

TH, the elevator will need to include both polymers and metallic components. It doesn't have to be a single cable. Most likely, there will be lengths of cable between junction plates. The whole assembly will have multiple strands. But the polymer cable sections need to account for most of the mass, because we rely upon their strength-weight. The tube through which the payloads are fired needs to be metal because it needs to be conducting to be able to guide the payloads.

So far as HVDC cables are concerned, there needs to be about 1mm2 of aluminium cross section per MW transmitted.
http://www.jicable.org/TOUT_JICABLE/2015/2015-A7-1.pdf

That is actually a bit of problem because an aluminium cable 60,000km long will weigh 162 tonnes per MW. So maybe wires are not the way to go afterall.

Last edited by Calliban (2024-10-09 09:35:00)

tahanson43206 · 2024-10-09 09:37:27

For Calliban ....

Why complicate everything with a tube?

I guess it would make sense if it were a pneumatic tube.

You could pump gas into the bottom and lift the payload against Lunar gravity.

If you just take advantage of your meme shattering idea, and use metal (assuming it has the tensile strength) then you can reduce complexity.

We have NOT established that your opening idea is valid.

Please confirm that there is a metal that can withstand the stress of the Lunar Space Elevator application.

We don't need more hand waving at this point.

There is literally only ONE person in this forum who is capable of answering the question.

If it's going to happen, it's going to be up to you to make it happen.

***
It is possible to support metal with stronger carbon based material, if absolutely necessary, but let's see if metal can do the job on it's own.

Update: Here is a link to the work done by Jerome Pearson for NASA in 2005.

https://www.niac.usra.edu/files/studies … earson.pdf

My guess is he has done 99.9% of the work. All you have to do is to compare the tensile strength of metal to the demands of the application, if I am correct in my expectation that Mr. Pearson did the heavy lifting.

(th)

tahanson43206 · 2024-10-09 10:01:11

For Calliban re pneumatic tube for Lunar Space Elevator....

At least a pneumatic tube would be faster than the ridiculous crawler idea.

It would be limited to the speed of sound of the gas chosen to perform the lift, but that is still a decent velocity.

Dropping a payload down the tube could compress the gas for the next lift cycle, while cushioning the ride for the payload.

In fact, that might be a comfortable ride for a human passenger.

(th)

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#126 2024-09-19 10:11:35

Re: Calliban Postings including links to notable contributions

#127 2024-09-19 11:30:08

Re: Calliban Postings including links to notable contributions

#128 2024-09-19 13:37:54

Re: Calliban Postings including links to notable contributions

#129 2024-09-19 14:29:18

Re: Calliban Postings including links to notable contributions

#130 2024-09-20 10:41:56

Re: Calliban Postings including links to notable contributions

#131 2024-09-25 13:27:21

Re: Calliban Postings including links to notable contributions

#132 2024-09-26 06:26:41

Re: Calliban Postings including links to notable contributions

#133 2024-09-26 07:02:04

Re: Calliban Postings including links to notable contributions

#134 2024-10-01 05:16:24

Re: Calliban Postings including links to notable contributions

#135 2024-10-02 07:40:39

Re: Calliban Postings including links to notable contributions

#136 2024-10-07 06:19:22

Re: Calliban Postings including links to notable contributions

#137 2024-10-08 06:19:54

Re: Calliban Postings including links to notable contributions

#138 2024-10-08 08:24:06

Re: Calliban Postings including links to notable contributions

#139 2024-10-08 09:06:10

Re: Calliban Postings including links to notable contributions

#140 2024-10-08 09:06:46

Re: Calliban Postings including links to notable contributions

#141 2024-10-08 10:02:54

Re: Calliban Postings including links to notable contributions

#142 2024-10-08 18:33:33

Re: Calliban Postings including links to notable contributions

#143 2024-10-09 07:24:20

Re: Calliban Postings including links to notable contributions

#144 2024-10-09 08:37:45

Re: Calliban Postings including links to notable contributions

#145 2024-10-09 08:45:11

Re: Calliban Postings including links to notable contributions

#146 2024-10-09 08:59:48

Re: Calliban Postings including links to notable contributions

#147 2024-10-09 09:12:14

Re: Calliban Postings including links to notable contributions

#148 2024-10-09 09:28:57

Re: Calliban Postings including links to notable contributions

#149 2024-10-09 09:37:27

Re: Calliban Postings including links to notable contributions

#150 2024-10-09 10:01:11

Re: Calliban Postings including links to notable contributions

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