Transfer of energy - HOW?

Gibbon · 2002-06-18 00:45:25

Does anyone know of the transfer of energy by waves (radio, microwave etc.). I heard that the chinese want to create a base on the moon and generate electricity and beam it back to earth. IS THIS POSSIBLE?
If so, it would make sense to create a large solar array situated in permanent sunlight around mars and have a chain of satellites to relay the energy to a base on one of the moons or the surface of mars itself.
Any thoughts?

Byron · 2002-06-18 06:45:16

Does anyone know of the transfer of energy by waves (radio, microwave etc.). I heard that the chinese want to create a base on the moon and generate electricity and beam it back to earth. IS THIS POSSIBLE?
If so, it would make sense to create a large solar array situated in permanent sunlight around mars and have a chain of satellites to relay the energy to a base on one of the moons or the surface of mars itself.
Any thoughts?

Sure it's possible...but the question to ask is, is it practical? People have proposed powersats in space for decades, since it's not such a "difficult" task to render solar energy into the form of microwaves and beam it down to a receiving array on the surface.

The biggest barrier is, of course, the tremendous cost of ANY space enterprise, but another consideration is public opposition to microwave energy being beamed down from space...what if the powersat shifted slightly, and all those microwaves accidently cooked a city or whatever. ??? That gruesome possibility may very well be the show-stopper for LEO microwave powersats; however, on Mars, it could be an entirely different story.

Since there won't be any cheap carbon-based fuels to burn on Mars, solar and nuclear (and hopefully geothermal) energy will be the way to go on Mars, and if the initial infrastructure of mirrors and collectors could be financed and constructed, it would greatly reduce the amount of energy that would have to be produced on the surface through the use of nuclear power plants or whatever. Just keep in mind that it's always going to be more costly to build anything in space as opposed to on the ground (even the Martian surface).

B

Tom Jolly · 2002-06-19 20:55:25

Radio waves are, of course, actually a transfer of energy, otherwise your car radio wouldn't work as it needs a signal of some sort to amplify. Microwave energy, beamed to Earth from a Solar Power Satellite, can be of a tight enough beam that fringe effects of the beam wouldn't hurt anything, in fact, the beam density can be low enough that you could walk through it without killing yourself or even substantially hurting yourself. Beaming from the moon sounds pretty dumb, though. Beam divergence would make the beam nearly unusable by the time it got this far. The studies I've seen are for geosync orbits, which is still pretty far away.

But then, I've always thought SPS was a dumb idea. No matter how efficient you can make it, you can take that same efficiency and employ it on Earth's surface to collect sunlight without any launch costs and with easy access for repairs and replacements. Granted, you might only be functional for 8 hours a day, average, but who cares? The cost per watt to build the thing is a hundred times cheaper; a 100W solar panel costs $500 and weighs 23 pounds. Let's say you could make it out of exotic materials that only weigh a pound, it still costs $10,000 to get to orbit, and THEN you have to build a receiving station anyway, possible at the same cost the ground-based solar panels would have cost.

But, besides the fact that it's totally uneconomical, it would also increase the incident energy arriving on Earth, where ground-based panels wouldn't, and ultimately the conversion of the microwaves into usable energy would result in heat. A brand new mechanism to ensure global warming, as if oil burning wasn't enough.

TJ

Tom Jolly · 2002-06-19 21:03:14

Oh yeah...now that I'm down off my soap box; putting giant reflectors around Mars to heat it up is a wonderful idea; they'd only need to be a few microns thick. Technically, it's "transmitting" light, so you don't really need an RF or microwave receiver, but you would have to wipe the dust off your solar panels on the ground on occasion. The sweet thing about a microwave antenna is that Mars dust would fall through the gaps in the mesh, but now you're talking some expensive transmitter hardware in orbit.

Nice thing about a big reflector in orbit; there's nothing to break!

John_Frazer · 2002-07-11 21:23:58

Byron wrote:

... another consideration is public opposition to microwave energy being beamed down from space...what if the powersat shifted slightly, and all those microwaves accidently cooked a city or whatever.

Forget about it. The beam for an SSPS system is about 1/10 the intensity of sunlight, and it's also in a freq which won't affect anything smaller than ~3 meters (a significant fraction of the wavelength). Buildings will be immune, as will people, airplanes, birds, etc.

Since there won't be any cheap carbon-based fuels to burn on Mars, solar and nuclear (and hopefully geothermal) energy will be the way to go on Mars

Surface-based solar is limited by nightfall. Nuclear must be imported and soft-landed from Earth. Mars seems to be tectonically dead; Not enough geothermal heat to warm much more than a small pool of bacteria (hopefully, and that probably not near where we'd like to build a big base)

... if the initial infrastructure of mirrors and collectors could be financed and constructed, it would greatly reduce the amount of energy that would have to be produced on the surface through the use of nuclear power plants or whatever.

Go to Mars' moons, and finance the entire thing -including future Mars exploration by extracting water for shipment to Earth orbit (the answer to quesations about self-financing Mars exploration).
Build SSPS in Mars orbit, send down materials to roll out rectennae, and have ample power anywhere on Mars. Build the long-term Mars base in orbit, and have fully shielded, full Earth gravity habitation at Mars (which you can never have as easily on Mars itself).

Just keep in mind that it's always going to be more costly to build anything in space as opposed to on the ground (even the Martian surface)

Says who? I can point to lots of other studies which show exactly the opposite.

Get resources from an asteroid or Mars' moons, get any amount of energy you need from the Sun, move tonnages around cheaply, build large things fror use in space, or to be packaged for delivery to the surface, etc.

Tom Jolly wrote:

I've always thought SPS was a dumb idea. No matter how efficient you can make it, you can take that same efficiency and employ it on Earth's surface to collect sunlight without any launch costs and with easy access for repairs and replacements. Granted, you might only be functional for 8 hours a day, average, but who cares? The cost per watt to build the thing is a hundred times cheaper

Right there is where most detractors of SSPS go wrong. Don't forget that the Space industry system is going to be self-financing after not too long (if it's not, then it won't be built) Asteroid metals are a big one, Geo-synch telecommunications arrays are the other: huge antennae and huge areas of solar power collectors will let a few stations cover the entire planet, and pick up a cel phone from the grond. All this will take is wire, concrete, and rolled & stamped metals -all easily produced in an early space manufacturing facility.
Fully 95%+ of the facility and the antennae farms are built from bulk space resources.
Bootstrap the capability, instead of the stupid idea of lifting an entire factory from the Earth -using the even more stupid idea of lifting the entire thing with the Space Shuttle! Here's one: "You want to build a city on Mars? Figure the city weighs a billion tons, and you have to lift it on the Shuttle. Then you have to lift all the chemical fuels to boost it to Mars, and soft land it on Mars, and your Martian city is clearly impossible"
That's the kind of modelling some (unnamed) people use to detract from the space industry concept.

...besides the fact that it's totally uneconomical

only if you use the worst possible (or impossible or at least unlikely) assumptions. Change your models, and the entire outlook turns about.

... it would also increase the incident energy arriving on Earth, where ground-based panels wouldn't...

Earth-based solar requires Earth-based industry; space industry eventually involves no pollution in the biosphere whatsoever! The only effect on the biosphere is the incident energy from the power beams. All other energy intensive and heavily polluting industry is done off-planet...
And that is the part where the potential of space infrastructure and SSPS comes out on top. (Not to mention it stops the need to burn oil, adding to the greenhouse; killing another of the straw men erected to argue against space industry & SSPS)

Not just a multi-planet species, but a space-faring species. Not just crossing space to drop down into another hole, but living in all of space. Far more than just one more tiny planetary surface to expand into.
Far more important to the long-term survival of the species and Gaia than simply plopping tuna cans down on Mars.

Shaun Barrett · 2002-07-12 00:18:06

Hi John!
I agree in principle with much of what you propose ... it sounds like a grand scheme.
But lay off those "tuna cans", will ya!!!
I and a lot of other people happen to be very fond of the idea of "simply plopping" them down on Mars! .... and the sooner the better.

PS. I wish it were as 'simple' as you make it sound.

John_Frazer · 2002-07-20 19:41:57

Shaun Barrett wrote
> I and a lot of other people happen to be very
fond of the idea of "simply plopping" them down on
Mars! .... and the sooner the better.

I agree. Shooting off Mars Direct missions is the ideal thing for now. I can't think of anything as possible in the near-term which would mean as much as this.
I have no problem with a crew of only 4, and letting them take their risks and the glory when they get back.
Only 2 particulars bug me:
1) no escape system on the crew launch. Better to wait an orbit or 2 for the crew to meet the hab in LEO from a Soyuz or 2, than risk the roman candles with absolutely no hope for survival.
Read here about the Shuttle's rotten safety.

In October 1999, former astronaut Michael Coats testified at congressional subcommittee that he personally experienced sitting on the pad during STS-41-D in 1984 while a hydrogen fire was burning below him and knowing he had no way to escape. Only one month after the release of the NASA safety report justifying not having a crew escape system, NASA had to scrub the launch of Space Shuttle Atlantis because of another hydrogen leak. This time there was no fire and no crew on the vehicle. The gambler was lucky this time... but what about next time..

So use Energia or something without roman candles as a first stage. Plenty of ways around it. (Sure, the crew acccepts the risks, but I doubt anybody is selfless enough to risk that, when there are ways around it)

2) No experience with long term exposure to low G. Much is made of Shannon Lucid walking off the Shuttle after a long time on Mir, and other cosmonauts surviving even longer durations. Yes, they made it, but a decade later, they still haven't completely recovered.
I suspect that .38G for 3.5 years will make the crew either permanently crippled or long-term debilitated after they get back. It'll take far more than mice in orbit for 50 days to settle it, and I suspect that it will prove that low G is almost as bad as zero G. (I've got a couple of long-term bets on it) Face it: people who don't get much exercise just aren't as healthy. They'll have to exercise strenuously for several hours every day of a Mars Direct mission, and they'll still have serious long-term health problems.

> I wish it were as 'simple' as you make it sound.

I never say it's simple (I do say that it's not as hard or expensive as the government makes it look). It'll cost lives, several tens of billion$ to start, and a decade or more to show any promising sign for the public that the expense isn't wasted on "flags & footprints", and maybe some stuff being moved around.

I've become attached to a few ideas I've found. ASAP build a spinning 1G fully shielded hab in Mars orbit. Make it possible for crews to stay long-term without any health effects, build up to more crew, with more equipment and landers and fuel depots, allow extensive telerobotic exploration of the planet while crews are rotating in & out. Above all, provide some means of profit... Water! Other chemicals, and easy transport back to Earth orbit -and buyers. (none of this is mine: "Plagiarism is copying from one source, while research is copying from many sources".)

The Diemos Water Company article points out the benefits of going to Mars' moons.
See also the book "Mars 1999" by Brian O'Leary. He suggests that the first Mars mission goes to the moons first, to make fuel and establish the base/chemical extraction factory before comitting to landing. The first and every crew carries a tank of water back to LEO when they return.

See the Bootstrapping space industries article by Bruce Mackenzie. Note especially his spinning station/depot design, and the emphasis on bootstrapping. Ideal for the Diemos orbit Mars base.

This one can't be over estimated
Projects to Employ Resources of the Moon and Asteroids Near Earth in the Near Term
http://permanent.com/

I think it answers many ill-informed objections about space processing, space industries, etc.

Maybe also to the point here, is this:
Didn't Robert Zubrin debunk this whole SPS/space settlements scenario in his book "Entering Space"?
http://members.aol.com/oscarcombs/spacsetl.htm#zubrin

Shaun Barrett · 2002-07-22 22:35:28

Hi John!
Again I find myself in agreement with most of what you say.
Especially the idea of a shielded 1g rotating habitat in Mars orbit. There is no doubt in my mind that 3.5 years in 0.38g will be very detrimental to any astronaut with plans to return to Earth.
I have been advocating spun-up Mars missions for some time now and I think a 900 metre spin radius using cables (at 1 rev per minute), to provide full 1g artificial gravity, is desirable outbound and homebound.
With this and the 1g hab in Mars orbit, we can conduct long-term exploration without condemning our people to chronic debilitating illnesses when they return to Earth.
Perhaps we could rotate the crews from LMO to surface duty every few weeks, so that their bodies never become fully adapted to 0.38g. This will achieve the desired effect of maintaining muscle tone and bone density, with the added bonus that the astronauts will be "super-strong" when on the surface and less prone to tiring.
In the long term, of course, some of the astronauts will volunteer to become permanent Mars residents. Since they will not be returning home to Earth, they can be left on the surface and not required to spend time at 1g in LMO. In my opinion, that will be an irrevocable decision on their part since they will become unable to tolerate Earth's gravity. Going back won't be an option.
I get the impression that some New Mars contributors tend not to take the gravity adaptation problem very seriously. Maybe I tend too much towards the opposite viewpoint. But I think it will be more of a problem than a lot of people realise.

HeloTeacher · 2002-07-23 09:48:45

Just a thought, regarding living in .38G vs 1.0g vs 0.0g.

To my knowledge a person who loses 50 or 75 lbs of extra weight does not suffer a reduced bone density due to the reduced stress on their skeleton.

I believe that these mice may show a reduced bone density in the subsequent generations but otherwise they will be healthy. Just like the future settlers of Mars wil be healthy with consideation of the environment they will be living in.

We'll see...

Merp · 2002-08-24 04:41:16

I don't know if the doom and gloom over 0.38G is justified. 0.38G is greater than 0G by a factor of... (work it out). Its a substantial difference and the truth is we don't have research on long-term low gravity exposure to say either way.

My own feeling is that any (non-zero) gravity well might stop bone decalcification, which is the real demon. As far as I know muscular deterioration is thoroughly reversable, and in 0.38G, 5psi, heavy physical activity environment would probably be negligible.

I agree with Zubrin that hosting humans in LEO just for the purpose of discovering how bad the effects of zero G are is entirely unethical, as is the lack of research into artificial gravity.

--Merp

Josh Cryer · 2002-08-24 21:39:56

Hmm, I didn't realize Zubrin felt that way about LEO, but I totally agree with the sentiment. However, how else is one to learn?

dicktice · 2002-11-05 10:50:54

What about the "vibrating plate" approach I read about in New Scientist Magazine a few months back, in which various animals are placed upon a platform, or plate that can be vibrated at differing frequencies and amplitudes depending on the mass of the animal, to induce muscular stimulation of bone calcification...? I haven't seen anything further, but if it works...what a great alternative to what you all are talking about...!

Palomar · 2002-11-05 11:57:57

*Okay, it's time I swallowed my pride and ask: What is LEO?

Maybe I've missed it somewhere...

--Cindy

TJohn · 2002-11-05 13:12:22

ecrasez_l_infame, I believe it is Low Earth Orbit.

nebob2 · 2002-11-05 13:15:08

Some of the probelm with musculer atrophy is caused by the fact that in 0g there are muscles that are simply not used at all, even in exercise machines. .38g would use these muscles to support the body, if only to a lesser extent.

More research definitly has to be done on the long tern effects of low gravity on mammals. Why not hang a spinning container off the ISS to test the effects on mice for a year or so. It could always be de-spun periodicly to be cleaned and reloaded with food.

dickbill · 2002-11-06 17:53:42

Hi,

From the transfer of energy to biology in 0.38g there is a big jump. I really think that a transfer of energy is a key to Mars colonization. With energy you can do everything, and first, you can go to Mars.

I read that it would be possible to transfer gravitational energy from Jupiter to Mars with a shuttle asteroid/mass, which in return would then decelerate Jupiter and accelerate when approaching Mars...or something like that...Mr Robert Dick will correct me If I am wrong. Anyway, the idea was to use the Jupiter energy field to accelerate asteroids or planets and then transfer that energy to another planet or asteroid. Nothing different here of what do the space probes en route to the stars, except, for example, that the energy released could be used to move distant NH3/icy comets from the kuiper's belt to a Mars crossing orbit and deliver substantial amount of NH3/H20 to Mars, (as said in the KSR trilogy).
Also, maybe that gravitational energy could be transformed/transfered to a remnant Martian magnetic field and ignite a putative Martian iron core to spin, re-creating a magnetic field for Mars. This maybe trough a gravitational resonnance between a Mars vibrational mode (of the crust, iron core ?)at the asteroid passage. That would heat Mars a little...But maybe all this is too dangerous and would destabilize the Mars inclinaison axis on the long term. However, I like the idea to pull the distant icy comets to a Mars crossing orbit.

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#1 2002-06-18 00:45:25

Re: Transfer of energy - HOW?

#2 2002-06-18 06:45:16

Re: Transfer of energy - HOW?

#3 2002-06-19 20:55:25

Re: Transfer of energy - HOW?

#4 2002-06-19 21:03:14

Re: Transfer of energy - HOW?

#5 2002-07-11 21:23:58

Re: Transfer of energy - HOW?

#6 2002-07-12 00:18:06

Re: Transfer of energy - HOW?

#7 2002-07-20 19:41:57

Re: Transfer of energy - HOW?

#8 2002-07-22 22:35:28

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#9 2002-07-23 09:48:45

Re: Transfer of energy - HOW?

#10 2002-08-24 04:41:16

Re: Transfer of energy - HOW?

#11 2002-08-24 21:39:56

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#12 2002-11-05 10:50:54

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#13 2002-11-05 11:57:57

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#14 2002-11-05 13:12:22

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#15 2002-11-05 13:15:08

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#16 2002-11-06 17:53:42

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