Commercial Mining with a Lunar Elevator - Wednesday, February 12, 2014 | 6:00 pm Pacific Time.

[Charles Radley]

Oregon L5 Society and PNW AIAA Joint Event Commercial Mining with a Lunar Elevator By Charles F. Radley Wednesday, February 12, 2014 | 6:00 pm Pacific Time. Midland Library | 805 SE 122nd Ave, Portland, Oregon 97233 The Earth's Moon is a treasure trove of mineral resources, such as precious metals, rare earth elements, Helium-3 and oxygen for propellants. However, the cost of landing on the Moon is currently very high. Using modern fibers we can build a lunar elevator which reduces the cost of lunar landing sixfold. Furthermore, it makes the cost of collecting material from the Moon and sending it to Earth essentially free. The lunar elevator will pay for itself after nineteen payload cycles. The lunar elevator represents a game changing technology which will open up the Moon to commercial mining. Charles Radley is President of the Oregon L5 Society, and an Associate Fellow of the AIAA. He has worked extensively in the space industry since 1981 as a product assurance and systems engineer. He is an adviser to LiftPort Group. ** This event will be streamed online as a Google hangout at this web link:  https://plus.google.com/events/c7g5u2ngrlq1qpnhl8lbmt720ho

[Edward Wilson]

Charles:

Just please admit you'll need a small steel foundry & shop to make the ware parts!

Marry CHristmas and have a Happy New Years

Love

Ed

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[Royce Jones]

You will need beamed energy for propulsion to get the elevator to lunar orbit.

[Edward Wilson]

Royce:

Talk to Dr. Jordan Kare - he's on that one. 

Ed 

[Charles Radley]

We do not need beamed energy for getting to lunar orbit.  Getting from Earth to LL1 is fairly easy, single launch on any number of commercial launch vehicles would easily achieve the mission, for example Delta-IV, Atlas-V, Ariane-5 etc.

The vehicle will inject into transfer orbit which is a few per cent more delta vee than the standard GTO.  A small chemical upper stage will achieve the final injection to rendezvous at the LL1 location.

The elevator package weighs about 11,000 kg which is well within the capability of existing commercial vehicles for injection to LL1 location.

We could use electric propulsion or laser propulsion to improve the payload, but it is not essential.

[Keith Henson]

Royce, a lunar elevator doesn't need to be tapered.  That being the case, why not use a loop and mechanical drive to get the cargo off the moon?

Also, lunar elevators are really not much good for getting to lunar orbit.  However, if the terminal end and counterweight is at 190,000 km off the lunar surface, it's at the top end of a Hohmann transfer orbit to GEO (ignoring plane changes).  Since the likely market is in GEO, it seems like a good idea to put the top end of the elevator there.

Keith

[Royce Jones]

No, you really do need a beamed energy system because you have to move more than a cable. If the cargo is manufactured on the Moon you need a manufacturing plant(s) there. If the cargo is manufactured at GEO you need a manufacturing plant there instead. If the cargo is moving both ways (trade) you need a manufacturing facility(s) at both ends. Moving a piece of string is easy but you need more than a piece of string. If the goal of the lunar elevator is to sit in orbit and do nothing you might be able to do that fairly cheaply but without purpose it would be a waste of time and money. Therefore, you must integrate the elevator into a scenario that gives it purpose. Say for example you wanted to build a Star Ship in lunar orbit. The aluminum, Lunox, etc. could be processed on the lunar surface (or under it) and transported into orbit using the elevator. Constructing the lunar facilities would require moving substantial mass to the Moon. Moving that mass would be hugely expensive, so expensive in fact that it would kill the idea before it got on paper. Therefore, you need a beamed energy system - regardless of the type of lunar facility you wanted to deploy. Maybe you decide to place the manufacturing facilities in GEO to try to reduce costs and just move dirt. You still need to move the facilities from ETO to GEO. Trying to make the elevator appear desirable by not giving it function or purpose is counterproductive. 

[Frank Smith]

If you think to big the project will never get started.  If you think to small there is no point.  The LiftPort proposal tries to reach a balance where there is just enough value to the project to make it worth doing without so much as to make it to expensive.  They will be able to bring moon rocks to Earth for the fist time in half a century.  They will be able to do some surveying.  They will make a soft landing on the moon without rocket or fuel to do so possible.

This is not much but it is more than we have now and should have an acceptable ROI.  The initial lunar elevator does not really enable mining as most think of it but it does allow some things to be accomplished and will pave the way for more.

A beamed energy system would be nice but the initial lunar elevator does not need to wait for one to be developed and operational.  The existence of a LiftPort lunar elevator could help to spur the developmentof a beamed energy system.

[Marshall Eubanks]

Very well put, Frank

[Royce Jones]

A limited mission elevator serving as a proof-of-concept may be viable economically. This of course would depend on several factors, including mass, function, technology, etc. However, without a program for Lunar exploration, apparently dependent on government funding, it is unlikely to be built. This is primarily dependent upon mass to moon requirements for crew/cargo - the current cost limiting factor. The lunar elevator does not substantially improve these factors and its economics primarily work in the opposite direction. Therefore, you need at a minimum a Solar Electric Propulsion (SEP) system to reduce in-space transportation costs and encourage a new lunar program. The technology to do this is readily available, so to is the technology to deploy a beamed energy systems that would cut vehicle mass by some 20-30x and increase speed of service. Without SEP and/or Beamed Energy systems the cost of transport to the Moon any program will remain expensive and kill your plans. With electric in-space transportation your plans could be adapted to support commercial activities, without which you are dependent on a government that is currently $17 Trillion in debt and whose sole interest is social wealth redistribution - with zero interest in space.   

[Edward Wilson]

Royce: 

Dependent on Teck, Inco, Anaconda,Avalon Rare Metals, Mosaic , Rio Tinto or DeBeers' funding and there's the problem solved. Now all we need to do is to keep the lawyers from absconding with the profits!

For the start of a real list see: http://en.wikipedia.org/wiki/Category:Mining_companies_of_Canada which may not be up to date but better than my memory. This list includes the top 9 mining firms in the world now.

Ed

[Charles Radley]

The baseline lunar elevator is designed to transport cargo's weighing 100 kg to and from the lunar surface.

The climber is electric powered, and beamed energy is used to power the climber.

We will need a laser on the lunar surface shining upwards [illuminating the climber]  to begin  the journey from the lunar surface to the LL1 station.

Once the climber is half way to the LL1 station, a second laser at the LL! station will take over and power the climber the rest of the way.

Payloads from the Moon can then be lowered from the LL1 station along the Earthward extending tether, little energy is required for this, no laser would be needed, a small on board solar panel would power the electronics and brakes.

--------

Payloads from Earth would be launched either by commercial chemical rockets to LL1, or to LEO and then transfer from LEO to LL1 by lasers or electric propulsion.

In the early phases, the first payloads from Earth to Moon would be the laser and solar panels to power the return trip of the climber.

Next come kit components of the He3 mining machine and processing plant  to be assembled robotically on the lunar surface.

For the first few climbs from the lunar surface to LL1 the climber would be empty.

Soon after, there would be a simple scooper/rover which would dump raw lunar dirt and rocks into a bucket on the climber, as scientific samples to be returned to Earth an analysed.

Once the He3 miner is working and the volatile processing plant working, then the climber would be loaded with cylinders of lunar Helium (He4/He3 mix), since we will not yet have isotopic separators.

Once isotopic separator kit has been delivered to the lunar surface then the He3 would be separated from He4, and only the He3 shipped back to Earth.

That is how I see the first phase of setting up the initial He3 mining base would play out.

[Royce Jones]

"The climber is electric powered, and beamed energy is used to power the climber."

"Payloads from Earth would be launched either by commercial chemical rockets to LL1, or to LEO and then transfer from LEO to LL1 by lasers or electric propulsion." 

You made my case for me, only you goofed by using lasers instead of microwave.

[Charles Radley]

No Royce, it is you have goofed not I.

Microwaves simply will not work over a distance of 20,000 kilometers, the antennas size will need to be kilometers across, much too big for the 100 kg payload capability.

It will have to be lasers, microwaves are simply not an option.

[Keith Henson]

Charles is right on this point, but I don't think climbers are a good
idea compared to a powered loop.

I worked out an elevator able to lift it's own mass in 100 days. It
came in 19,000 tons of cable, 65,000 tons of counterweight and the
balance power plant and misc. For that it would lift 1000 tons per
day. Scaled down to 1 ton per day it would mass about 100 tons, but
in the context of a power satellite project, that's not useful where
1000 tons per day would be.

[Royce Jones]

Charles, you stated that the laser would be on the lunar surface, is the distance from the lunar surface to the receiver 20,000 kilometers?

[Royce Jones]

Note: Actually you said half-way with another laser at the other end.

[Charles Radley]

The distance from LL1 to the lunar surface is about 50,000 kilometres.

So the half-way point is about 25,000 kilometres.

[Keith Henson]

Royce, the length of a lunar elevator is at least 50,000 km just get
out to L1. The counterweight hangs into the earth's gravity beyond
L1. For 19,000 tons of cable, it takes 65,000 tons at a distance of
190,000 km from the lunar surface. If you make the cable longer, you
can use less counterweight.

Driving the cable mechanically takes a lot less energy plus you don't
have the dead weight of PV and motors.

[Royce Jones]

Ok, 19,000 tons of cable = 19,000,000kg. Therefore, using SEP you would need 316.66 trips at 60,000kg per trip (1Mw SEP Tug). Yeah, you definitely need a beamed energy system, or actually a hybrid Beamed/SEP system. At least for Keith's version.

[Keith Henson]

It's worse. You have to have the counterweight or it just falls down.
I worked it out on a spreadsheet, if you make the cable longer, you
can use less counterweight. If you want the spreadsheet I can
probably find it.

Because this was in the context of a power satellite project, I
figured on borrowing 65,000 tons of power satellite parts for a
temporary counterweight. That would be replaced in 65 days after
startup with regolith and the parts sent back to GEO.

If we had a lunar elevator, it may be worth mining the moon for
oxygen. Current work I am doing uses water in a condensing radiator.
The second stages coming up from LEO have a little extra hydrogen that
could be combined with Lunar oxygen for the condenser fluid.

This would make Rankine cycle power plants an alternative to PV.

If you want to see the radiator draft design, just ask.

[Jim Cline]

Well I am glad that there wasn't a Royce skillfully heckling my efforts decades ago, re such projects. Yet someone playing the devils-advocate can get one to retrace a path more carefully, even going back to more basics to recover deeper foundations. Civilization has been built on a vast array of when-something-was-first-dones, indeed even of the prior when-first-things-thought-of-that-could-be-dones. Oftentimes the only way to silence the hecklers is to actually build one and show it works - although even then the hecklers simply melt into the crowd to go find someone else to force to play buzzword ego games with them. Hecklers also sometimes are skillfully plying for ideas as to how to do something, so as to not have to figure it out for themselves. Another thing is that intellectual property rights is "a two-edged sword" in that nowadays it too often completely loses its original purpose of protecting true originators from the copycats freely snatching business-foundation ideas, and instead is used by rival businesses to block potential competition from happening, by patenting bits and pieces of obviously needed technologies, with no real intent of utilizing that which they patented. It is quite amazing that civilization can develop with such monkeybusiness going on, yet we humans somehow still do achieve. To achieve functioning and profitable innovative space resource, processing and transportation facilities, benevolently supporting civilization, it is necessary to have the mindset of "figuring out how something could be done" instead of too much of the heckler's "why something won't work."

Transferring transportation energy along a very long space transportations structure, has lots of options nowadays. Even beamed-energy has new options for radiant-energy travel as guided by a structure, for example, not bound by the principles across free space distances; think about it. Forty years ago I suggested sun reflector shielded, space-radiated cooled superconductors along the length of the anchored lunar tether through L-1 to transfer earthward electromagnetic vehicle braking energy electrically over the anchored tether's length to help lift more payload-carrying vehicles up from the lunar surface to L-1 - where the material would be processed in zero-gee before continuing on earthward. But now I better like, as Keith mentioned, the use of a pulley loop mechanically driven elevator structure as located from the lunar surface anchoring point up through L-1 out to the dropoff-site at the earthward endpoint pulley site. This option requires that the tether material have an adequate tensile strength-to-density ratio for a constant cross-section system so as to support its own mass as well as support a bootstrap building up of its girth, as well as being able to withstand the rigors of space and varying latched loads and sometimes severe bending around the pulleys at the endpoints. Alternatively, I think I most prefer the entirely different mode of an electric motor in the form of a thin but very large perimeter eccentric hoop anchored on the farside of the Moon and reaching to Earth-Lunar L--1 (or reverse out to L-2). That technique greatly reduces the stress loads on the structure material enabling use of conventional construction materials, as well as minimizes bending of the material; and the high angular velocity of the hoop provides electromagnetically-variable-braking transportation lift energy for vehicles to be lifted up from the Lunar surface to space, and their gentle return back to the Lunar surface.

Anyway, it is really nice to see the discussion ongoing here, after having little but hostility given me in the past four decades for my efforts to get long space structures seriously considered by other people over the past decades. Enjoy!

Jim Cline

[Edward Wilson]

What I see is a design review meeting, at the FEL-0 phase. We're looking for show stoppers only. 

Please just don't forget the steel foundary at the bottom. Has NOTHING to do with the tether as far as I know. However you are mining on the moon, and miners need Ware Parts by the tonne (I figure a minimum 10 Tonne/day(24 Hr) in daylight operation just for digger teeth, bolts and scraper blades. 

Yours

Ed 

[Royce Jones]

Charles, We seldom agree on anything, as least starting out, and then you eventually come around to my way of thinking and all is well in the universe. I do appreciate your thoughts on various subjects as they help me refine my own a bit from time to time. I have never been much of a fan of the space elevator but I was thinking I might include one in the book I am writing about building a Starship. In the book the Starship is constructed in lunar orbit using aluminum mined on the Moon. The Starship also uses Lunox in its Lox Augmented Nuclear Thermal Rockets for thrust augmentation. So a space elevator might be something that I would include, but I have not decided yet. I was hoping you might convince me of the benefits, but it looks like Keith will talk me out it before that happens.  

Royce

[Keith Henson]

Jim, Spectra, with a density of one, will support 4.3 GPa. Untapered,
a lunar elevator through L1 uses about 80% of that. By the time this
is done, nanotubes are likely to be available at perhaps twice or more
of that strength to weight.

Edward, wear parts are not a problem. You get a percent or two out of
the lunar fines of with a magnet. Melted in a solar furnace, they
will make decent steel for digger teeth.

Keith

[Edward Wilson]

I was never sweating the supply of Fe, just the tendency of some to forget the 10 tonne/day you need of the stuff to keep your mine working. That 10 tonne/day is enough to justify a small smelter, and rolling mill complex, and the staff to keep them and the machine shop [night time work] going. The rolling mill is made from the early 10 tonne/day supply. 

You do not want to think about the $$$$ hauling that stuff from Frankfurt!

Ed.

[Jim Cline]

Keith, sounds like using Spectra with adequate uniformity, would need a minimum of nine or ten strands of Spectra for the loop, so as to enable a very small payload to be delivered as demonstration of functionality; then to be able to support the first add-on strand as girth is begun to be built up toward commercial useful capacity. De-spooling the seed loop with the two pulleys needs to start from some point between LL-1 and Earth, and needs to be designed so that a small surplus is at the Lunar pulley bearing mount block mass so as to impact the lunar surface, at that point unbalancing the despooling system and the remainder of the loop with its pulley stretches out toward the Earth until taught, not reaching kinetic energy enough to pluck out the lunar anchoring block.

However, am not cognizant of Leeward's plans, but I get the impression that it is not a loop and may be of tapered configuration (as was my original fiberglas version in ancient history) so at some point some fairly specific configuration needs to be adopted. Otherwise, as in deadlines for writing articles, one can always improve and never get finished enough to submit something for actualization. 

Determining some configuration that seems feasible if not the best, preferably which appears to also have ability to be improved as data comes in, is necessary before risk of committing resources to start bending metal. At that point it becomes important to support best one can, the path that has been chosen, so long as it appears to have a good chance of reaching the large-picture goal, even if it is not the best path.

Ed, yes, it is important to see the full configuration that will bring in the profit and usefulness, while exploring the smaller ways that lead somewhere, hopefully to it.

Jim C

[Charles Radley]

On Thursday, December 26, 2013 7:01:30 PM UTC-8, jedcline wrote:

Keith, sounds like using Spectra with adequate uniformity, would need a minimum of nine or ten strands of Spectra for the loop, so as to

Spectra is rather an old material.

There are at least three newer fiber material with higher strength to weight ratios"

 - M5  (a derivative of Spectra)

 - Dyneema

 - Zylon.

 

[Keith Henson]

I agree with Charles, the work with Spectra was just an engineering
exercise done years ago to see if we were anywhere close to strong
enough material for a lunar elevator.

There are a lot of problems that need solutions for a loop elevator to
work. There needs to be an acceleration/deceleration section of the
last 50 km above the moon which accelerates the payloads to the speed
of the main cable. The variable speed cable needs to be cycled down
to zero speed to attach a load.

Also needed are ways to keep the strands from tangling. For an
elevator from the earth's surface to GEO there is considerable
coriolis effect to keep the strands appart. It's a much smaller
effect with a lunar elevator. Large separations of the up and down
strands might help as would depositing an electric charge on the
strands so they would repel each other.

The elevator also needs high velocity to reduce the static loading.
Is it even possible to wrap a cable around a pulley when it is moving
at 2000 km/hr? That speed would get the transit time from L1 to the
surface down to a day, which seems like the most a person would want
to spend in a space suit.

The power satellite project does not seem to _require_ lunar resources
to make gobs of money. However, when it is going, it offers a huge
market for lunar resources which looks like would offer investment
opportunity and even more profit. The same is true, perhaps even more
so, for mining asteroids.

But I don't usually include either in the main line power satellite
project writeups. They complicate the business plan and raise the risk
factors to the point the whole project looks dicey.

According the Phil Chapman, that's the reason power satellite didn't
get study money back in the late 70s or early 80s.

He tells the story better than I can.

Keith

[Jim Cline]

Against my better judgement I will make another "outsider" comment here. Just like the automobile clutch is used to apply variable coupling between a moving and a non-moving portion of a system, so also one might consider a variable drag coupling between a constant speed loop elevator - perhaps electromagnetic drag - and a payload carrying module, for speeding the lunar-rising modules up the moving loop. Much longer transportation times reduce the loads on the turn around points and pulleys, and the rare uses for human transportation would be made easier by modules built for several days shirtsleeve environment occupancy to and from along the dual pulley vertical elevator. Storing that drag energy in a flywheel on lunar liftoff might enable reverse acceleration of the lunar-arriving vehicles so as to have a gentler arrival.

Coupling a lunar space elevator with Earth's needs for abundant SPS agreed is iffy, and the current proposal as Charles puts it, has other payload products instead. The original O'Neil justification for the 10,000-person space settlements in L-5 so as to build SPS there out of mass launcher delivered lunar materials was a powerful vision even if needing significant modification nowadays. The larger number of potential products and life sustenance modes and transportation variations, the more likely a far-flung colonization effort will succeed, i think.

Jim C

[Edward Wilson]

Jim; Given the recent materials on SBSP and the potential collapse of the terrestrial market for SPS power (potential with every roof covered in PV with a Nu about 3 - 5 % better than we have now (say 35%) a wide variety of products delivered (like the REE and PGM's for said PV's) are an important part of the economic planning. As I posted elsewhere we can look to mining companies (the big 9 had a confreance in Toronto Ont about space mining [with an 800 lb gorrila in the room - legal structure] a year or two ago).

Like your observation about a run up to speed using fly wheels. That will soften the jerk on the cable (assuming it is moving at all), and that is a cable killer (which engineers would rightly be terrified of). 

Yours

Ed Wilson

[Royce Jones]

Ed, I would not be overly concerned about the "collapse of the terrestrial market for SPS power". For details go here:

https://www.createspace.com/4535042

[Edward Wilson]

Neither would I. Possible, so's my winning the lottery, even if I don't buy tickets!

Ed.

[Jim Cline]

Ed,

Glad you liked the idea of storing the controlled slip energy of a rising vehicle from lunar surface on a 2-pulley loop elevator, and using the stored energy to slow the vehicle down as it returns to the lunar surface on the continuous speed 2-pulley loop. And interesting in another way is that I thought it up right then when writing that post.

On the other thread, I am still a fan of putting plentiful SPS in GEO. Maybe am just old-fashioned, and that it was the initial justification for my KESTS to GEO concept's construction. (Yes I know "KESTS to GEO" concept was as popular as was the continental railroad proposal to the conestoga wagon makers; and similarly the RR would not have happened if Lincoln had not enabled it to happen in his effort to transportation-unite the country east-west in the Civil War.) Still, having photovoltaics on some roofs is important as diversified energy sources even with adequate SPS in GEO, so we no longer need fossil fueled power plants in general usage anymore. Something to consider, however, is that when it was suggested to cover the buildings of Los Angeles with photovoltaics so as to run the air conditioners in the heat of the summer, I pointed out that PV panels are very dark in color, and the 70% or so of solar energy not made into electricity, is converted into heating of the air and mounting structure. The thought of Los Angeles, which currently is fairly light colored and reflects much of the incident solar energy, having become a city that is colored black, and thus having to get rid of an extra 70% heat energy with the air conditioners powered with only 30% of the incident solar's energy, ought to be food for thought. And in general, with enough PVs on roofs to power America even just when the sun shines, would similarly raise the heat level of the nation a significant amount. And lots of folks think there is already civilization-caused rising environmental temperatures, disrupting the weather unpleasantly. 

At any rate, yes, the REEs from Lunar resources may well be required for making significant areas of PV's. 

Jim C

[Royce Jones]

Jim; a simple solution for the heat problem would be to install PV-T panels (combined electric/thermal) rather than PV panels. That way the energy is used. PV-T panels can produce 3-4x to total energy of a PV panels for very little additional costs. 

BTW, GEO is not a good place for PowerSats. 

Royce

[Jim Cline]

Hi Royce. Could you elaborate a bit on the PV-T panels? If they are producing 3-4x PV panels alone, then they would produce 2-3X PV energy panels without the PV panels. So why bother with the PV's? Am curious about technology that uses thermal alone at solar incident energy levels, to produce 2 or 3 times PV output. Now, if you are talking heating water or living space along with some electrical energy, sure, plenty of potential co-generation that currently goes unused, there. But Los Angeles in the summer is not interested much in heating their living space, they are desperately trying to get rid of the heat in their living spaces. If it gets a lot hotter due to PVs, is counterproductive and makes the outdoors intolerable in the city. Yet living and working in a city tends to greatly reduce transportation energy required for commutes, thus is necessary. Well, maybe not so much in the spread-out Los Angeles area; they still are trying to make it work using combinations of conventional transportation like light-rail, buses, plus fossil-fueled internal combustion driven cars and trucks.

Now, here in Ephrata WA USA it could be different. At least in the winter. But it tends to be cloudy in the winter, not much solar getting in, for PV electricity nor for captured thermal uses. No way in the summer, already too hot. I have some solar panels on the roof and has been entertaining to figure out how to efficiently use them; I like the emergency ability to recharge my iPod etc and car battery, if we were to lose the hydroelectric power somehow. But long term living energy, is the question. Need those big hydroelectricity power sources; right now, they are what makes life possible in my tiny all-electric tract home here in the winter, is currently 29ºF here and getting colder, requiring staying close to the electric heaters. But the rest of the nation does not have the hydroelectric option. Abundant SPS in GEO would provide hydroelectric equivalent, 24/7.

Also please explain to me a bit about why GEO is not a good place for SPS. It enables their downlink fixed in position, enabling more efficient resonation with rectennas down earthsurface. That the telecommunications sats in GEO fear getting noise-blased by the gigawattt SPS could be a concern but as yet unproven unsurmountable. Without KESTS  efficient electrically powered continuous access to GEO, would be difficult to provide maintanance to abundant SPS in GEO, agreed. But lack of KESTS to GEO access to GEO is simply a business disruption tactic, and when they can make more profit that way, they will switch, as long as they get all the ego credit and financial profit. Then large scale access to near space will totally change including applications such as total recycling of industrial toxins, and all major spaceports will be in GEO. But for now, we have to piddle along with what we can, of course, like PV's and windmills, and nukes waiting for us to wake up again to that kind of future. People-stuff is complicated, and we can only take a step forward from where we are at right at the moment. I think you are a big-picture person like me, but our viewpoints are quite different at this point, I think.

Jim C

[Royce Jones]

PV-T panels use PV cells but also recover much of the waste heat. It can be used for water heating, etc. so they are useful for thermal energy even in the summer and cut total energy costs. PV-T panels are now coming to market. You will see some really interesting PV-T systems coming on the market over the next couple of years. PV-T and PV also work very well together as they can use the same solar cells. PV-T panels have a fairly simple heat recovery system on the back of what would be a normal PV panel so cost per panel is not much different. I can provide you with such panels if you would like to play around with them. 240 Watt electric and 480 Watt Thermal.

GEO is a distance problem that translates into a mass problem, i.e., the transmitter mass, which then translates into a launch cost problem. The benefit of GEO being "downlink fixed in position" is not enough benefit to justify GEO as a location. You can achieve 24/7 power from other locations that are much closer than GEO, therefore, the mass savings make these other locations preferable to GEO due the huge transmitter mass savings. For example, if you place your PowerSat in a sun-synchronous orbit at 5,100 km and 141 degrees (approximate) you would be 7x closer to the Earth and your beam 49x more powerful (beam density). So, lets say you have a 5.8 GHz transmitter at 5 Gigawatt in GEO = mass 6,500,000 kg. If you move it to SS-O 5,100 km you can build a hugely smaller transmitter (49x smaller = 132,000 kg). Now you can even break the PowerSat into 49 smaller PowerSats with the same beam density as the GEO Sat, making them easier to construct and deploy. 

5,100 km is high enough to get good viewing and targeting of the rectenna(s). With today's modern electronics you should get pretty good reception at the rectenna but even with some angle losses you are better off than GEO. 

Royce

[Jim Cline]

Hello again Royce, our chat here may seem to have wandered far from the subject of "commercial mining with a lunar elevator" but perhaps there can be a long path between here and February 12 of next year, so long as they go to the same place. It is a real world out there with many facets.

And debating is something that seems a useless sport to me. Yet am an unwilling veteran of the Q&A sessions after I had presented eight technical papers related to space transportation and utilization, and I somehow survived them, and so I ought to be a bit thick-skinned as a result. However, as an Asperger, I easily lose when drawn into some variation of the old shell game. And tricking someone into an "oops" situation is disrespectful of all concerned, including oneself.

The earlier thread involving possibility of using a flywheel to store energy in a soft grab of a lunar elevator vertical loop and return the energy just before landing back on the lunar surface, changed into the two threads of this conversation between you and I, seeming to have split off into two arenas, both related to solar energy, one very here-now earthy and the other out there, spacey.  I get the feeling that you replied to only a couple words out of each area of my reply to you, but apparently you read enough to see those few words, at least. I will endeavor to play the game, a little bit.

Photovoltaics down here on Earth as you say may produce 20-30% of the solar influx in the form of electrical energy, and the other 70-80% as thermal heating of the PV panels, needing to be transferred somewhere. You have explored co-generation, using the thermal energy constructively. In places and weather where it is clear skies and cold air, conceivably the heat brought off a PV panel might heat some shower water and even warm a room a bit, but probably not reach a high enough temperature to drive a steam turbine. But my real-world struggles as an old man on fixed income in the high desert, where solar panels rated at 45 W take up the slack in one's yearly budget, and take a busy son's limited-time help of a day to help install on a roof slanted toward the south when located at 47º latitude, actually provides only at best a useful tenth of rated current of 1 A per panel during peak sunshine hours of a cloudless day, much less when shaded by the trees. And it took a year to get the wiring from the panels over to the house placed underground from the garage roof; and how to pipe heat through the same obstacles at this point seems even way more struggle: even though in winter, a little heat would be welcome in the house. How to efficiently transfer the heat from the back of the PV panels on the garage roof, over to warm the inside of the nearby house. is harder than getting large enough low resistance wires installed between panels and the house. Yet this kind of real-world thing will need to be dealt with when building, using and maintaining a lunar elevator in a mining operation.

For the other thread, supposedly relating to why GEO is no place for SPS, I am still struggling to contemplate how a sun-synchronous Sun-Earth L-1 satellite or group of satellites, could provide 24/7 energy to any one location on a rotating Earth.  Maybe a huge blast to each of rectennas on the earth surface as they came into view; solar energy converted into RF in space and delivered as a single frequency to resonant rectennas, might indeed briefly provide lots more energy than mere PVs absorbing normal incident solar influx. But, the planet rotates and thus passes into Earth's shadow beyond the aim of a sun-synchronous RF source; and also, to have a group of SPS as RF sources in the sun synchronous position seems to be quite a problem maintaining their phase coordination at the receiving antenna.  That is about where I ended up on that thread. It is thought-provoking, however.

Jim C

[Royce Jones]

"And tricking someone into an "oops" situation is disrespectful of all concerned, including oneself."

You commented about solar PV and then commented about SSP. I simply gave you better alternatives to those you discussed. I have attached a pic to help you better understand a Medium Earth Orbit (MEO) Sun-synchronous Orbit (SS-O). 

No "oops" required. 

Royce

[Edward Wilson]

All: was down for some time so this post is reply to about 4 or 5 each

 

Jim: That something comes up in the writing of a post is a normal occurrence – and that is what makes discussions like this SO VALUABLE! The gems come out of the churn of ideas and that is what makes this activity so enjoyable.

 

On LA, an interesting point, but also consider what happens to the 30% that runs the AC – it is rejected by either convection to the atmosphere, evaporation of water in a cooling tower or radiation (very little) all of that at about 250 F. Also, the other issue is the roads, and a lot of roofs – they are black, and more than 30% of the surface area.  LA is for sure a large heat island, drawing air to it from all around. Will the increase cause more cloud (I think not)? What would be useful is a cooling water system that supplies seawater for cooling towers (5 cycles not 20 as in fresh) – this would put more moisture into the air, and perhaps an evening / nighttime shower.

 

SPS’s in GEO are for earth service – paying off the mortgage. Any place else and the SPA’s plough into orbital mechanics and don’t get signed.  For space service – powering the moon and elsewhere, they’ll be in any orbit that works.

 

Note that when building SPS’s there is also a comm’s section and the receivers are behind the power beam systems. Out going signals can be mastered rather than broadcast if needed. I will note there is plenty of power available for signals.

 

For all of NA to have hydro requires a serious grid upgrade, and that means building an HVDC backbone and splitting the AC grids from 3 to maybe 20 or so. NA currently has about 1/3^rd of its hydro potential developed, but a lot of that is in areas already well served, or too remote from markets. Quebec Hydro generates most of NYC’s power from the James Bay power development most of 1000 miles (not km) away – problem is that the 750+ KV lines run straight down the magnetic latitude lines and so are susceptible to over voltage during a solar storm. That’s why Manitoba’s HVDC lines run at 45 degree to where they are going and tack the whole way – the improved reliability pays for the 1.4 x .6666 x cable cost (.666 because only 2 cables on a bi-pole).

 

Royce: in LA what is the heat used for? That’s always a messy question. I was at a meeting of Environmentalists and prairie food processors. The former asked the latter why they didn’t recover the heat from their chilling plants. The latter asked what could they use it for, they already heated the water for the scalder and that was the only use of heat they had in the plant except for space heating, and that was also off the main chillers.  LA sounds like the same issue writ large, writ very large – other than evaporating sea water to make the air more humid (and hope for a rain storm) I can’t think of anything that needs low grade heat (Can’t even boil the sea water to make fresh w/o a big vacuum cycle and that eats your power).

 

In terms of where the SPS is manufactured a GEO Sync unit comes down from a colony, and it pays their mortgage. A LEO+ SPS is manufactured on earth and is a demonstration / proof of concept project.

 

Query: how are the economics of an SPS in Molynaya Obit? That would be useful as Geo Sync’s poorly serves the area served anyway. It also has bajoom power costs as everything is diesel powered  (33¢/kwh in 1988 and up some since then)

 

I would watch what I do on beam density. Basically you are restricted to something like 3-5 Kw/m² for ground safety reasons – a bird can fly through it and not get cooked. 

[Royce Jones]

Ed, In LA (or elsewhere) you have the solar heat and the carbon heat. Using more of the solar removes the need more of the other. Applications can include hot water for residential, multi-family, hotel/motel, restaurant, etc. 

For an answer to your question about SSP (and much more) you can find all your answers here. 

http://www.amazon.com/Electric-Space-Space-based-Technologies-Applications/dp/1494257807

Royce

[Jim Cline]

Ed: Yes, the sudden inspiration of using a flywheel to store the energy of a soft drag up from the lunar surface to match the constant speed of the pulley band, occurring to me right as I was in middle of responding to the conversation chain, might well be a kind of thing enhanced by discussions like this one. Addressing one's "creative mind" for a possible solution when no conventional answer is at hand, also gets exercised if one writes high-tech science fiction. A kind of "brainstorming" of oneself, perhaps. I found that when I wrote up some of my space transportation and utilizations in the form of sci fi, concepts which I had previously written and presented in peer-reviewed technical papers, suddenly took on a huge array of details as I imagined how people would be building and utilizing real systems based on the concepts. My first four high tech sci fi novels, starting with "Building Up" and "The Ark of 1984's Future" have a huge variety of ideas in them that popped into my head as I was letting the characters utilize the technical concepts to build and use things. The first couple of chapters in "Building Up" focus on building a pulley type space elevator, for example, and was written soon after I had written my SES 2007 technical paper (that I submitted as camera-ready to the conference along with its Powerpoint, but wryly enough ground transportation problems snagged me from presenting in person and thus the paper never got published) but the nitty gritty of the math and techniques were still fresh in my mind when then doing the science fiction story involving people actually utilizing what was in the technical paper. (And it was a lot more fun writing it as sci fi than as a technical paper.) Providing a suitable "playground" for the creative mind is what lets it happen, I think.

Another thought is that robotics will probably play a big role in the initial startup of the lunar space elevator and sample materials delivery to Earth. How autonomous the robotics needs to be is a variable in such a scenario. The robotics could be personable such as portrayed as Hal in A C Clarke's "2001 Space Odyssey." And a related item is that many years ago, maybe over a decade ago, some psychologist programmers got together and wrote a program that would carry on a conversation about psychology, in email or a text chat. The software would look for key words and specific phrases being used by the unsuspecting human on the other end of the conversation, and would then choose among a large set of responses, the ones that seemed to fit best as a compiled response. And the experiment was a success in that people would carry on quite a long conversation before they started becoming suspicious when the software-robot could no longer handle the increasingly specific details that were coming up in the thread, and were then producing increasingly inappropriate responses to the human.

Jim C

[Edward Wilson]

Royce, For the thermal loads you describe you’ll need concentration, not sure if the 60 MW/m2 concentrator I worked on is the right one for the job (took the PV off at step 3 of 5). But mostly you need 60C + for most hot water loads, and I don't see that in the flat (not unless the air is 50C plus).

Yours

Ed