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#76 2020-02-16 18:55:11

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,208

Re: New Solar Power Technology

Yes - good news.

This again underlines that we are nowhere near theoretical limits of energy generation from solar power or most efficient methods of producing the energy generation systems. In other words there is huge technological scope for efficiency gains. 

Of course with solar power, it's not just the PV technology that's important, it's also economies of scale, installation cost and associated electrical equipment (including storage). 

If you can achieve overall efficiency gains of 1%, 2% or 3% you will realise huge reductions in cost of the next couple of decades.

All serious analysts agree there is huge scope for further lowering the cost of solar power.

tahanson43206 wrote:

The topic theme is "new" solar power technology ...

The article at the link below is about improvements in "old" technology.

https://www.yahoo.com/finance/news/brea … 00397.html

The Brown study found that the use of perovskite materials (“a broad class of crystalline materials”) can create a much more resilient and durable next generation of solar cells. Science Daily puts it in layman’s terms: “Though perovskite films tend to crack easily, those cracks are easily healed with some compression or a little bit of heat. That bodes well, the researchers say, for the use of inexpensive perovskites to replace or complement pricy silicon in solar cell technologies.” Padture elaborates: "The efficiency of perovskite solar cells has grown very quickly and now rivals silicon in laboratory cells."

Incorporating perovskites into solar cells is not a revolutionary discovery in and of itself. They’ve been used in the technology since 2009, but they haven’t always been efficient or durable. The importance of the Brown researchers’ discovery is that these brittle solar cells can also be fixed more easily than ever before.

Because perovskite is reported to be present on Mars, it is good to see that the material can be "healed" when it cracks.

(th)


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#77 2020-02-17 04:13:06

kbd512
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Posts: 6,252

Re: New Solar Power Technology

Apparently, the virtue signalers are too busy signaling to their fellow signalers that they have no virtue.  Then again, we already knew that.

Don't these environmentalists understand that Tesla is "saving the planet" by chopping the trees down for their next Giga Factory?

I actually think these people are anti-human and want us to live the way we did in the Stone Age- you know, that period of time in our history where life was short, bleak, and brutal.

Tesla ordered by German court to stop cutting down trees for Gigafactory

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#78 2020-02-17 07:44:41

tahanson43206
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Registered: 2018-04-27
Posts: 12,081

Re: New Solar Power Technology

For kbd512 ...

<< grin >> I think this is just good old fashioned American NIMBY, translated to Germany.

The Germans wouldn't care (I'm guessing) if the trees were in the US somewhere.  They just happen to be in their neighborhood.

We had a similar fuss locally, when a large international retailer wanted to cut down some trees so passers-by could see the new store they were building.

It didn't matter the new store would create valuable jobs and bring really neat products into the region.

I guess the store must have won the argument! << grin >> We can see the store from the road.

(th)

Last edited by tahanson43206 (2020-02-17 07:45:17)

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#79 2020-02-17 12:00:43

kbd512
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Posts: 6,252

Re: New Solar Power Technology

tahanson43206,

It's just hard to believe that people who claim to care about the environment don't understand that you have to crack a few eggs to make an omelet.  If I had to guess, this is just the minions of the central government trying to ensure that the East Germans remain poor and dependent on government.  Tesla is there to upset that status quo by providing jobs to those people.  They don't seem to have a problem with clear cutting forests to get at the coal beneath the ground, despite the fact that they could purchase that coal from the US, which has plentiful supplies of a much cleaner grade of coal than the stuff they have.

It's either that or their objection is to having the US-based Tesla Motors Corporation build a factory there to supply them with the cars they'd otherwise import from America.  Since BMW / Mercedes-Benz / VW aren't supplying like-kind products, I don't see what the problem is.  Dependent upon the attitude of the workers towards quality, there should be no difference between a Tesla made in California and one made in Germany.  I've never heard anyone suggest that the Germans don't know how to make cars, so they can make their own Teslas there for the European market.  Everybody can have their own factories in their own countries to supply their people with whatever jobs and products they want.  It's not as if Americans are moving to Germany and replacing local workers, either.

We don't need to ship products around the world several times the way BMW does- first for the raw materials, again for subassembly components, and a final time for the finished vehicles.  Distributed supply chains for raw materials make sense when you can't reasonably source a raw material from within your own country, but that's about it.  Most of the world's Aluminum ore comes from Australia / Brazil / China / Guinea / India, for example, because those are the most economical sources in terms of energy expenditure.  Sending things across the world and back is ridiculously inefficient from an energy consumption standpoint and requires mass quantities of fossil fuels that Germans claim to dislike so much.

Wasn't the entire purpose of the industrial revolution to swiftly produce a bazillion identical copies of the "in-demand" products wherever you happened to plop down the production machinery, hopefully now using minimally skilled labor to boot?

As long as we have to be Team America World Police and since the world's manufacturing base is no longer in a state of utter destruction following another pointless global war, wouldn't it be a lot easier to just protect the exchange of raw materials between countries and reduce the ability of pirates to steal from everyone?  On that note, doesn't it also reduce the chances of conflict when everyone has local access and local benefit producing and consuming the things they want?  Here in America, if a foreign car company wants to set up shop, we only ask them to consider how big their factory is and where it fits with everything else in the surrounding area.  After that, it's a done deal.  The same basic rule should apply everywhere else.

I'm not going back to the way we lived before the Industrial Revolution to appease the tiny minority of our populations who want to be "nature boy" or "nature girl".  In the 21st century, this is what progress looks like.  Everyone has their own factory that produces what they want and thus there's no need to fight over anything for the traditional reason because there's an endless supply of whatever it is that they want.  I'm not really sure what we should do about religious dogma, the other traditional reason people kill each other, but I've noticed that in secular-run societies that religious fanaticism as part of governance policies gradually falls from favor over a century or two.  We'll never live to see the end of that, but in another century or two real progress might be achievable.  However, we have to "get it right" in the here and now for that to happen.

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#80 2020-02-17 13:43:50

tahanson43206
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Posts: 12,081

Re: New Solar Power Technology

For kbd512 ... While I appreciate the thought you put into Post #79, I think you are making the matter overly complicated.

The people who object are trying to preserve ** their ** trees!   The city planners (as I understand it) had already approved the project for economic reasons.

The people who will lose out (as is always true) are those with little power to protect what they and their ancestors have provided for their children to enjoy.

My guess is the local folks will lose the battle, and their trees.

In the United States, depending upon the wisdom or lack of wisdom of the government, an individual land owner can prevail over powerful economic interests, but the exceptions are so rare they make national news.

(th)

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#81 2020-02-17 15:04:17

kbd512
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Posts: 6,252

Re: New Solar Power Technology

tahanson43206,

I hope you're right.  I'm not a fan of imminent domain law, either, but it's been on the books in most countries for quite some time now.  I think the application of the law is overly-broad in many cases, but you can't please everyone all the time and if their community finally gets the jobs they need to become gainfully employed then I view that as better than nostalgia over a few pine trees or buildings.

The Germans took little issue with plowing over churches and the Bavarian Forest to get at the coal underneath it, so why not this, too?

I guess they care more about trees than whether or not their workers can put food on the table without government handouts.  I also thought these communists were all-in on the idea of communal property, but I guess not.  Besides, didn't Tesla promise to plant at least 3 new trees for every tree they cut down?

Personally, if an oil company or an electric car company wants to pay me what I put into my house and drill an oil well on it or build a new car factory, I'm quite willing to get rid of this money pit and give my fellow countrymen the benefit of a new energy source or new source of transport.  Look out everyone, but I think that might actually be a "progressive" idea there.

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#82 2020-02-17 16:10:38

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,806

Re: New Solar Power Technology

He should have combined the plant with solar panel manufacturing and it would have sailed through. Also when enever a place takes down a large area it should also make efforts to repatriate trees to other locations where growth is been burnt or distroyed by other acts of nature...Tree havesting is natural and when its done the acreage is repopulated for the future.

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#83 2020-02-17 19:15:47

louis
Member
From: UK
Registered: 2008-03-24
Posts: 7,208

Re: New Solar Power Technology

Within the next 50 years we will develop an effective technology for orbital solar power to be beamed back to Earth, and then the amount of land given over to energy generation can be reduced a tiny fraction of today (we can dispense with big power stations, coal and gas storage, huge PV arrays, big wind turbines, huge hydro facilities and all the rest). The only problem is, we might be adding heat to the planet...so I guess some we might need some artificial cooling as well. But at least the trees will be spared!


tahanson43206 wrote:

For kbd512 ... While I appreciate the thought you put into Post #79, I think you are making the matter overly complicated.

The people who object are trying to preserve ** their ** trees!   The city planners (as I understand it) had already approved the project for economic reasons.

The people who will lose out (as is always true) are those with little power to protect what they and their ancestors have provided for their children to enjoy.

My guess is the local folks will lose the battle, and their trees.

In the United States, depending upon the wisdom or lack of wisdom of the government, an individual land owner can prevail over powerful economic interests, but the exceptions are so rare they make national news.

(th)


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#84 2020-02-17 19:51:33

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,806

Re: New Solar Power Technology

Where will you dump the heat from the air cooling device?

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#85 2020-02-17 21:32:14

kbd512
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Re: New Solar Power Technology

Louis,

50 years ago they were saying the same thing and 50 years later, that still hasn't happened.  Since our solar and wind advocates are fine with destroying the environment to "save the planet", I take no issue with heating the planet up a little.  I've yet to see any realistic proposals.

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#86 2020-02-17 22:02:27

tahanson43206
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Registered: 2018-04-27
Posts: 12,081

Re: New Solar Power Technology

For Louis re #83

At first reading, I was puzzled at your idea that solar power satellites would heat the planet.  The microwaves used in all designs I have seen have little interaction with the atmosphere, and are chosen for that specific characteristic.  However, upon reflection, I recognize that all the electrical power consumed from an SPS grid will eventually end up as heat in one form or another. 

However, the amount of solar radiation impinging upon the Earth 24*7*365 is surely orders of magnitude greater than even a fleet of SPS could provide.

For kbd512 re #85 ... I agree ... we're still waiting ... Musk might be able to put a dent in the costs of launch from Earth, but I suspect we won't see much happening until Lunar mining becomes robust.  Lunar supply of materials for SPS was considered the ticket back in the 70's, and I think it remains so today.

(th)

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#87 2020-02-17 22:15:03

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 26,806

Re: New Solar Power Technology

Microwave warming happens as it heats the water that is in the air...

The trouble is that the microwave term has a variety of meaning for what frequency and wavelength.

Microwaves are a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter; with frequencies between 300 MHz (1 m) and 300 GHz (1 mm). Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and EHF (millimeter wave) bands.

The walvelength that is long (1) is the one which has less interaction but it has the largest of antenna's to gather the beam as its going to be spreadout by the time it get to the surface of the planet with less energy being captured versus what has been transmitted from space.

Of course its the mass for making the antenna for mars that is the limitation to make solar less plausible for use early on.

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#88 2020-02-17 23:55:35

kbd512
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Posts: 6,252

Re: New Solar Power Technology

tahanson43206,

Since Musk and others are planning on constellations of tens of thousands of satellites in LEO and these space-based solar power stations would sit in GEO and send power back to Earth in the form of high power microwaves, how are we going to send all that juice back when we're dumping power in the same frequency band that those satellites are operating in for telecommunications purposes?  We don't have to fry anything to render it functionally useless, either.

At an industrial / civilization level scale, the best efficiency we seem to get from these mass-manufactured photovoltaics is around 25%.  All the more efficient arrays are absurdly expensive because they have very high scrap rates due to intractable quality control issues.  It's just really difficult to make near-perfect large-scale integrated circuits and always has been, hence the high cost.  To make such an undertaking worth the expense and effort, it has to provide power for some significant chunk of humanity, a truly staggering amount of power, and total efficiency has an enormous effect on launch mass and therefore cost at that scale.

Apart from existing multi-junction cells, the following graph from NREL doesn't inspire much confidence (please note that it took 45 years to achieve the efficiency that the state-of-the-art space-based photovoltaic cells achieved and there haven't been any giant leaps in efficiency in the past few years, much like batteries):

Best Research - Cell Efficiencies

An introductory course into electrical engineering would very swiftly indicate what the fundamental engineering problem with low cell efficiency photovoltaics happens to be.  It limits the size of the individual array elements and requires lots of heavy wiring to overcome resistance.  This means far lighter wiring and far more efficient cells are required.  Why do you think I constantly harp on the requirement for basic research to improve lighter CNT structural materials and wiring?  This is an actual materials science problem that's worth the effort because it has profound knock-on effects relating to nearly every aspect of modern electrified and computerized civilization.

It's always the weight / efficiency / cost of a practical system.  Always!  From here on out, this is the name of the game.  Daydreaming and speculating is loads of fun, but building practical systems that work well is even more fun and actually useful.  This kind of stuff is nearing the realm of feasibility to work on Mars for exploration class missions because it works well enough at limited scale.

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#89 2020-02-18 09:34:56

tahanson43206
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Registered: 2018-04-27
Posts: 12,081

Re: New Solar Power Technology

For kbd512 re #88

Your primary point (as I understand it) is that there exists a potential for interference between moving radio transmitters and their intended receivers, if the operators of transmitters fail to adhere to the requirements of international agreements on allocation of frequencies.

(th)

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#90 2020-02-18 13:34:44

kbd512
Administrator
Registered: 2015-01-02
Posts: 6,252

Re: New Solar Power Technology

tahanson43206,

My argument is that pumping a few tens of watts per square meter of very high frequency microwave energy into a communications satellite the size of a suitcase would not generally be a good thing for its health or operations.  Even heavily shielded satellites in GEO can be and are routinely damaged by bursts of high frequency RF energy from the Sun.  These StarLink satellites are meant to be cost-effective and easily replaceable hardware.  They probably don't have expensive highly EMI resistant chips / circuitry in them, as a function of cost, in much the same way that the redundant computers aboard Falcon 9 / Falcon Heavy don't for the same reason (fault tolerance was achieved through using multiples of low cost commodity hardware and error-correcting software- and that works quite well within limitations).  Resistance to fairly intense and continuous EMI was not likely part of the design specification and their very low altitude shields them from the maelstrom of energy from our magnetosphere's interaction with the Sun that's commonly associated with higher orbits.  In simple terms, there probably aren't very many 170GHz to 300GHz transmitters raining down that kind of power on them.

StarLink is supposed to operate between 40GHz and 75GHz, but that doesn't mean its antenna or any external solar panel electrical connections won't couple radiated power received at higher frequencies.  It shouldn't interfere with the transmitted signal from the satcom relay, but that's not the problem I'm pointing out here.  Basically, anything metal in the satellite will couple the received radiation and produce a voltage that could interfere with StarLink's circuitry without significant shielding and hardening that will drive up the cost and dictate the use of military / aerospace hardware vs COTS hardware.  In order for both pieces of equipment to be useful, they have to be overhead at the same time and sending or receiving RF energy within the same block of "sky" at the same time, so simply moving something out of the way or turning it off is not an option.

None of this is insurmountable, but it will increase the cost and complexity of the design for both systems.  Silly little things like grounding straps require deliberate design choices for StarLink to function as intended when subjected to this additional external RF power source.  I know without a doubt that this problem can be solved since it's a common electrical engineering problem, but at what cost?

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#91 2020-02-18 14:04:30

tahanson43206
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Registered: 2018-04-27
Posts: 12,081

Re: New Solar Power Technology

For kbd512 re #90

My filters prevented me from understanding the problem you are seeing.  Thanks for your persistence.

I am not a communications engineer, but I hang around with them that is << grin >> I'll ask.

One thing your point brings home to me is that the Earth lost out by failing to implement solar power satellites when they were a hot item, decades ago.

At the time, there were no (or very few) LEO satellites to worry about.  If SPS were up and working, then satellite designers would have built in the shielding needed and all would have been well. 

My "reasonably educated" guess is that a Faraday shield around the satellite would protect it from electromagnetic radiation in the regulated range.

From Google:

Spectrum management is the process of regulating the use of radio frequencies to promote efficient use and gain a net social benefit. The term radio spectrum typically refers to the full frequency range from 3 kHz to 300 GHz that may be used for wireless communication.

Spectrum management - Wikipedia

This is interesting (to me in light of the discussion:)

Two space research groups, NASA (USA) and JAXA (Japan), have proposed different working frequency for feasible satellite solar power implementation, i.e., 2.45 and 5.8 GHz respectively [1].Jun 19, 2018

Satellite solar wireless power transfer for baseload ground ...

I would ** like ** to think the Starlink engineers are aware of frequency spectrum allocations, and able to persuade their managers to fund protection against EMR that does not exist today but is under active discussion.  Obviously, I can't speak to what managers will do << grin >>

Edit#1: The question was submitted to a technical forum frequented by radio/communications engineers.  This is a bit of an intrusion on their normal discussions, so I'm hoping for a positive outcome.

(th)

Last edited by tahanson43206 (2020-02-18 19:30:13)

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#92 2020-02-18 18:37:55

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 26,806

Re: New Solar Power Technology

Basically the station recievers can not have any reception of signals for meaning in the same location as they would be overloaded in the inputs for having the same frequency blasting in to them.
The emi hardening is to not let the signal energy disturb the workings of the satelites internals as the energy would pass through them repeatedly killing them in time.

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#93 2020-02-18 19:54:59

kbd512
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Posts: 6,252

Re: New Solar Power Technology

SpaceNut,

In really simple terms, we can't have RF power from the solar power station converted to DC power and messing with the microcircuitry in a way that would either unacceptably interfere with or outright "kill" StarLink's electronics.  This has nothing to do with the frequency used by the solar power station interfering with StarLink's satcom signals.  The frequency stability of gyrotrons can be pretty good and the frequency stability of microwave band telecommunications equipment is extreme.

I don't think a power level of 10W/m^2 to 20W/m^2 would outright "kill" or "cook" the satellite unless too much of that power starts flowing through exposed wiring (solar arrays; the more difficult of the two likely input pathways to solve since they supply input power yet still solvable) or antennas (more exposed wiring, but connected to a high power amplifier that's unlikely to mess with the internal electronics until the power levels are such that other more significant problems begin to occur).  I don't believe FCC would allow power density sufficient to start BBQ'ing things, either.

Heck, for all I know this could actually be an ingenious way to supply power to the StarLink constellation.  It all comes down to the design.  As I said before, contending with these issues won't be cheap even though it's a totally solvable problem.

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#94 2020-02-18 20:59:25

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 26,806

Re: New Solar Power Technology

http://www.ripublication.com/aeee_spl/a … spl_12.pdf
Solar Power Satellites and Microwave Wireless Power ...

https://en.wikipedia.org/wiki/Space-based_solar_power

A considerable fraction of incoming solar energy (55–60%) is lost on its way through the Earth's atmosphere by the effects of reflection and absorption.

https://www.ijser.org/researchpaper/Gen … te-SPS.pdf
Generation and Transmission of Electrical Power through Solar Power Satellite (SPS)

https://core.ac.uk/download/pdf/42956068.pdf
DISTRIBUTION POWER LEVEL BY GSM900 BASE STATION FOR RF ENERGY HARVESTING

https://www.slideshare.net/AmitKumar1135/amit-41557739
microwave transmission slideshow

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#95 2020-02-19 08:46:15

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 12,081

Re: New Solar Power Technology

For kbd512 re #93

Your post ended with an intriguing idea ... A point worth factoring into the thought process for pulling power from SPS systems in GEO is that they are fixed in position, and transmit to fixed locations on Earth.

A satellite in LEO (anywhere below GEO) will inevitably pass through the beams of microwaves at 17,000 miles per hour (or less if higher).

It seems possible that the brief transit time may not be enough to allow for drawing of much useful power.  On the other hand, if the supply of power in the beam is copious, then even a brief transit might be worth exploiting.

I have submitted an inquiry to a radio communications forum, and hope to receive a reply.

For SpaceNut ... I don't know if I can pull this off, but there is a remote possibility someone in the radio communications forum will be interested in the problem of designing an SPS for Mars.  If that were to happen, we would be entering into uncharted territory in the forum, because such a person would not be here to participate in idle discussion.

The rich creative flow of ideas that this forum stimulates does not (by default) lead to concrete decisions that must be made to turn speculation into practice.

(th)

Last edited by tahanson43206 (2020-02-19 09:02:22)

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#96 2020-02-19 10:44:56

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 12,081

Re: New Solar Power Technology

This is a follow up to Post #91

The radio engineering forum is a private group, so I have removed identifying information.  If further communication with anyone who sent a reply is desired, let me know and I'll consider it.

There were four replies.  The first three are brief and I will quote them here.
The fourth is long and somewhat detailed, so I'll post that separately.



Reply from Radio Engineering Forum …

20120218 Technical Design Question

Reply 1 of 3

Hi

A good starting place may be RTCA DO-160 Sections 19, 20, and 21.
Note this is written for aircraft and there may be better documents for
spacecraft but it is a good starting place.

Here is a reference to the document:
https://en.wikipedia.org/wiki/DO-160 

Reply 2 of 3  (from a PhD Electrical Engineer)

I am concerned that solar power transmissions will transmit not only on their assigned frequencies, but also bleed over onto other frequencies, since they are so powerful. It will be very difficult to keep them totally confined to their specific band.  This will cause interference to all kinds of space communications.

Reply 3 of 3

I also read some where that the Starlink system is likely to cause it's own RFI problems. I hope they are paying attention to that as well as whether they will get interfered with by other systems. It feels like "I'm allowed to RFI you but don't dare RFI me"  ???

The original question:

A member of a forum devoted to space development inquired about the risk of Solar Power Satellite radio transmissions to the new Starlink constellation of Internet satellites, and their competitor constellations by other vendors.  I offered to try to find an answer.

I'm hoping the question will be of interest to ** real ** radio engineers who subscribe to this list, or those with appropriate background and experience.

No solar power satellites exist, but both the US and Japan have reserved frequencies for their use.

It is my impression that ordinary Faraday shielding around the electronics in Starlink or other Internet satellites should be able to keep unwanted radio waves out, and I would hope that Starlink engineers would have designed shielding into their systems by default.

Can anyone shed light on this, or perhaps suggest appropriate references for study?

(th)

(th)

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#97 2020-02-19 13:47:58

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 12,081

Re: New Solar Power Technology

This is another follow up from Post #91

This longer reply was sent privately.  As before, since this is a private professional forum, I've removed identification.  If there is a desire on someone's part to ask questions of any of these responders, I will consider a request.

It appears that no one has jumped up to answer your question, so I’ll try to do so with this message.

Even with large dish reflectors and high microwave frequencies, the beam coming down from solar power satellites will have a wide footprint on the earth.  Recall the artist renderings of the “rectenna” arrays from years ago and how large of an area would be covered by them on the ground. 

The beam width, even though narrow, spreads a lot coming from 25,000 miles away.  The spreading will cause the power density per square foot of area in the beam to have a reduced level, decreasing the chance of damage to birds and aircraft flying through it.  I recall reading about these issues 40 years ago when they popped up in response to arguments against solar power satellites.

The beam field strength will be similar at the orbital altitude of the Starlink and other low earth orbit systems, and their exposure times will be quite limited due to the short time spent in the beams.  Since they orbit at such low altitudes to reduce latency, the high velocities of these satellites will help limit exposure as they zip through the beams.

All active satellites use radio transmitters and receivers, and signal levels in space can be very low.  Weak signals and multiple frequency use causes satellite design to be a real study in the radio art in an effort to avoid interference to and from receivers, transmitters and other electrical and electronic systems aboard satellites.  Since the Starlink satellites will use rather high power transmitters to get good signal strength over a wide hemisphere aimed towards the earth, these RF issues will be at the fore in their design.  The resulting filtering and shielding should keep interference to a minimum, and reduce overloading effects from strong signals like those from solar power satellites.

Today, low earth orbiting satellites must deal with strong signals from high power space tracking radar sets, TV transmitters and other ground based radar systems, so they are already designed with interference in mind. The RF shielding that is incorporated into active satellites will help reduce the effects of currents induced into their structures as they fly through the beams.  The best chance for interference will occur when the solar power satellites appear in or near the beams of the antennas on the Starlink or other satellites, but now that these low altitude internet systems are here, and solar power satellites are still a distant dream, if they are ever built, the frequencies they use to transmit power will have to be coordinated with radio authorities around the world.

I hope this helps!

Edit#1: This continuation arrived separately:

Another issue I did not bring up in my earlier message is static charge buildup on orbiting satellites.  Since they swim in a sea of charged particles, in a magnetic field, satellites can pick up a surface charge that is best to keep out of the electronics on the inside of the vehicle.  Solid metal sheets or composite panels incorporating conductors (metal particles or copper screening) is used to protect the interior of satellites from charge buildup and the damaging discharges that can occur once they charge up.  Antennas and wires coming in from devices and instrumentation outside of the screened interior are bypassed to allow RF and signals to pass, but keep the static charge out.

This shielding will act like the Faraday cage you mentioned with your question, so currents induced into the structure of the Starlink satellites will probably not interfere with circuitry inside.  The induced currents flowing on the outside structure of the satellite as it passes through beams from its solar power brethren may be beneficial by discharging some of the static buildup!

The ISS carries a large ion cannon that shoots charge off into space in an effort to keep the static buildup down on the structure.  You may recall a mission a few years ago where a Soyuz descent module flew a ballistic reentry trajectory because the crew could not get rid of the service module before entry interface.  Static discharge while attached to the ISS had damaged the control circuitry used to fire the explosive bolts holding the vehicle together, and the failure led to the high G, short landing that left the crew alone on the steppe for a while. Improved bonding to the ISS helped reduce the chances of that failure happening again.

You may recall that mission because the Soyuz that came in ballistically carried a Korean girl back from the ISS.  She got more G’s than she bargained for on that flight!

I think Starlink is supposed to use Ka band signals for up and down, and possibly S band for command and control.  If I recall, the solar power satellites of years gone by were to use the S band ISM (Industrial, Scientific, Medical) spectrum for transmission to earth.  This is the band used by microwave ovens at 2450 Mc, and it is close to the S band downlink spectrum, so some RF from the solar power satellites may cause trouble for command and control, but operators on that band are used to short term glitches, and a trip through the beams may just be tolerated as a nuisance.

It is possible that the high power RF could cause damage to the command receivers on Starlink satellites, but these are the issues that will have to be ironed out in the future by international regulatory bodies if and when solar power satellites approach practicality.

This gent spent most of his career working on gas engines of various kinds, for major vendors whose names would be familiar. However, his interests in electronics are extensive, including radio communication as should be evident from his posts.

(th)

Last edited by tahanson43206 (2020-02-19 14:04:03)

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#98 2020-02-19 17:01:51

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 26,806

Re: New Solar Power Technology

All one has to do is look at the sun and one would understand how the rf energy from the sun is and how all energy behaves whether the sun is the transmitter or the satelite is the one doing it. We know that the levels of solar at each planets orbit gets lower as we progress from the sun outward until its so small an amount that it isin the watts per meter levels.
https://solarsystem.nasa.gov/solar-system/sun/in-depth/
How to calculate the solar levels at each planet


image002.jpg

https://en.wikipedia.org/wiki/Electromagnetic_spectrum

Much like the radio waves that we listen to the transmissionis in 100's of kwatts and the recieving function is in micro watts of energy for signal and thats still on the earths surface.

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#99 2020-02-19 21:11:13

kbd512
Administrator
Registered: 2015-01-02
Posts: 6,252

Re: New Solar Power Technology

tahanson43206,

My takeaway from that was it's possible to do it, just as I thought it would be, but it requires special design considerations given to how it would affect the satellites' electronics.  The only real question remaining is, "Was StarLink designed with the intent to contend with the additional interference that would be caused by solar power satellites?"

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#100 2020-02-21 19:50:51

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 26,806

Re: New Solar Power Technology

post 79 update on Tesla and Germany factory...

Tesla resumes tree cutting in Germany to build Gigafactory

Germany on Wednesday hailed Tesla’s decision to build its first European factory in the country, days after the government said it would boost subsidies for buyers of electric cars. Tesla CEO Elon Musk said during an awards ceremony in the German capital Tuesday evening that “we’ve decided to put the Tesla Gigafactory Europe in the Berlin area.”

https://en.wikipedia.org/wiki/Giga_Berlin

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