Get ready for build of prototype SSP systems?

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Tim Cash

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Feb 24, 2023, 10:57:17 AM2/24/23
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All,

I am trying hard to get ready for design and build of prototype Space
Solar Systems, insofar as the component and sub system suppliers are
concerned.  I have a few opportunities to my knowledge, one of which is
to build large space structures as SSP platforms.  As we know, there are
a few demonstrations already on orbit for SSP, or more specifically,
power beaming.

The question is what do we do next as a group or as individuals to gain
traction?

I am ready to put forth every effort to make progress along these topics.

Tim Cash

cash...@gmail.com

Keith Henson

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Feb 24, 2023, 12:57:12 PM2/24/23
to Tim Cash, power-satell...@googlegroups.com
In some ways, this is relatively simple, it's been studied since the
late 70s. In other ways it is intractable.

Rectennas have not been studied much, I may be the only one who has
looked into their economics. I have made only one change in the last
15 years, using overhead high-voltage lines instead of underground
cables. The overhead lines cause little interference with the
microwave beam and they get the power out with far less heating
problems.

The microwave beam is based on 200-year-old optics. Non-continuous
(checkerboard) designs indicate a lack of understanding of
reciprocity, a fundamental antenna principle. (Or they have not
Googled "sparse array.")

The current major designs are older ones where the power generation is
separate from the transmitter and the integrated sandwich designs.
The former has better thermal control, the latter is probably lighter.
Sandwich transmitter power is limited by the PV capacity and the
thermal dissipation from the PV and the RF. Ian Cash's design is
closer to the sandwich in that the connections from PV to the
transmitter are short. One consideration in the trade studies is that
the lighter the power satellite, the more station keeping it needs due
to light pressure.

Despite the higher mass, I favor thermal designs. They are smaller
and more efficient than PV. They are not subject to PV radiation
damage, and would probably survive big CMEs and possibly a gamma-ray
burst. All power satellites have thermal excursion problems with
eclipses. There is a lot of data on the problems from experience with
communication satellites. How well this will apply to a km scale
object is a good question.

The big problems with power satellites are not technical, but economic
due to the massive scale they must be deployed to make a dent in the
energy humans use. (There is little point in power satellites that
replace 1% of what people use.) The scale and time to return a profit
are also problems. While power satellite economic models show immense
profits, they take a lot of money and a long time, far beyond the next
quarter horizon taught to MBAs. By analogy with Hoover Dam, power
satellites are likely to be a government project. (Sorry
libertarians.)

The major design choice is massive cargo up from the Earth or the
development of a space mining industry able to support large-scale
power satellite construction. StarShip and possibly Skylon are paths
to cope with the cargo.

A possible large-scale cargo proposal would use a multi-GW laser in
GEO to power a Skylon sort of vehicle. The first pass physics looks
ok, but it is not clear the technology can be developed. It takes
less cargo than power satellites, but it is a huge project, around the
same mass as 30 GW of power satellites. There are also political
problems.

Space mining dates back to O'Neill, but I am not aware of a project
that is spending serious money on it. Lunar dirt is hard to process
into useful materials. Metal asteroids might be better, but they are
far away. A first-pass analysis of a gold mining project indicated
that they need 30 GW of power for the front end. One providing power
satellite parts could be a lot smaller.

The current demos need to be done for PR reasons, but as far as I
know, there has never been a microwave power beam experiment that
produced unexpected results.

Wish I had better ideas.

Keith
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Jerome Glenn

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Feb 24, 2023, 1:07:29 PM2/24/23
to Keith Henson, Tim Cash, power-satell...@googlegroups.com
If space elevators become possible/reliable how would that effect the SSP economics?
To view this discussion on the web visit https://groups.google.com/d/msgid/power-satellite-economics/CAPiwVB6ZdLU4eBZKSQO8exrEfkapdOpxMKCMYUj_zXLmFU8EYQ%40mail.gmail.com.

Al Globus

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Feb 24, 2023, 2:18:35 PM2/24/23
to Keith Henson, Timothy Cash, power-satell...@googlegroups.com


On Feb 24, 2023, at 9:56 AM, Keith Henson <hkeith...@gmail.com> wrote:

One consideration in the trade studies is that
the lighter the power satellite, the more station keeping it needs due
to light pressure.

Depends on the definition of ‘station keeping’ (I think, correct if wrong).  For the same cross section changing the mass will cause the sat to move further from the desired orbit. Shrinking the cross section will cause a smaller perturbation.

Al Globus

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Feb 24, 2023, 2:22:12 PM2/24/23
to Keith Henson, Timothy Cash, power-satell...@googlegroups.com
On Feb 24, 2023, at 9:56 AM, Keith Henson <hkeith...@gmail.com> wrote:

While power satellite economic models show immense
profits, they take a lot of money and a long time, far beyond the next
quarter horizon taught to MBAs

There are a number of industries where the time horizon is much longer than three months.  The extraction industries, for example, look years or even decades to determine what path to take.  Mark Sonter would know this much better than I.

Keith Henson

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Feb 24, 2023, 2:23:29 PM2/24/23
to Jerome Glenn, Tim Cash, power-satell...@googlegroups.com
On Fri, Feb 24, 2023 at 10:07 AM Jerome Glenn <jgl...@igc.org> wrote:
>
> If space elevators become possible/reliable how would that effect the SSP economics?

The cable is the problem. Molecular bonds are just not strong enough,
though diamond with a no-load tapper ratio of 169 to one might be
possible. The other problem is cleaning up all the space junk. Even
diamond would not take a 7.5 km/s hit from a defunct satellite.

If we had the cable, climbers don't make sense, but moving cables do.
I made a model of a space elevator that tapered through pulleys a long
time ago.

The energy cost to lift cargo with a mechanical elevator to GEO is ~15
kWh/kg or an input of 1.5 GW will lift 100 tons to GEO every hour.
The energy payback time for a power satellite built this way is a few
days.

The only thing that came out of this work was a short story:
https://htyp.org/UpLift


Keith

Paul Werbos

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Feb 24, 2023, 8:34:40 PM2/24/23
to Keith Henson, Jerome Glenn, Tim Cash, Power Satellite Economics
As Keith says, the sheer launch costs (assuming more realistic numbers for SpaceX and sls) for space elevators to earth require the same dramatic reduction in launch costs which would make SSP as competitive as what Mankins' book presents.

That is the real key to the A team option for SSP serious enough for real large electricity markets. If we ever get that going, we have several other important B team options we should explore when we can, from DD laser fusion on space to deeper reductions in launch cost like the "space spruce goose" ideas discussed by some serious qualified aero designers in one past ISDV.


Keith Henson

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Feb 25, 2023, 12:15:07 AM2/25/23
to Paul Werbos, Jerome Glenn, Tim Cash, Power Satellite Economics
On Fri, Feb 24, 2023 at 5:34 PM Paul Werbos <paul....@gmail.com> wrote:
>
> As Keith says, the sheer launch costs (assuming more realistic numbers for SpaceX and sls)

If spacex can hit $100/kg to GEO, and the cost no more than doubles to
GEO the economic model works. SLS is just ridiculous, Mike thinks SLS
could be constructed at 5 per year, which would mean hauling up the
parts for one power satellite would take 100 years.

The bigger problem is the sheer number of flights for any reasonable
project. My estimate is 25,000 a year, about 70 per day. If they
last 100 flights, the construction rate would need to be 250 per year,
which seems possible.

> for space elevators to earth require the same dramatic reduction in launch costs

A moving cable type space elevator can self-construct from the ground
starting from one load of cable in GEO.

Keith

Narayanan Komerath

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Feb 25, 2023, 1:10:48 AM2/25/23
to Keith Henson, Paul Werbos, Jerome Glenn, Tim Cash, Power Satellite Economics
When this UKR war is over (soonest I hope!) there will be an energy glut with coal plants and fracking restarted - and they will FIGHT Green efforts to shut them down again this time.

Does it look likely that people will jump on the SSP bandwagon, when we are very very close to a Space War already and may be already in it? "High Frontier For All Humankind.. Peace and Prosperity For All" looks a bit far off. If anything, its Happy Days Again: frantic race to put killer lasers on the Moon and LEO. Attack helicopters with killer lasers. Spy balloons with lasers to kill fighter planes and SAMs.

Oh! I just realized. That IS the way forward. Will ensure more progress towards SSP than was achieved during Star Wars.



Keith Lofstrom

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Feb 25, 2023, 1:57:18 AM2/25/23
to Power Satellite Economics
Be aware that at the end of 2021, there were 8100 clean
energy projects in the United States waiting for permission
to connect to the US electric grids, an accelerating logjam.

https://www.nytimes.com/2023/02/23/climate/renewable-energy-us-electrical-grid.html

"... Many give up. Fewer than one-fifth of solar and
wind proposals actually make it through the so-called
interconnection queue, according to research from
Lawrence Berkeley National Laboratory. ..."

I ponder an alternative use for electrical power, rather
than grid connection, and may be allowed to talk about
that soon. Probably vaporware, but the brainfart might
inspire of you to utter my favorite phrase:

"THAT won't work, but THIS will."

Keith L.

--
Keith Lofstrom kei...@keithl.com

Tim Cash

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Feb 25, 2023, 7:32:15 PM2/25/23
to Jerome Glenn, Keith Henson, Power Satellite Economics
The IEC says we may have an Earth Elevator capability by 2035, which is quite ambitious in my opinion.  I have not seen the cost of lift for a powersat by an Elevator, except from the moon, about 10% the cost of rocket use.  At 10% it gets affordable.  I would not say it is impossible, just because we already live in an age where the impossible is routine, and who knows what the next age of geniuses will come up with.  We are quite lucky to be living in the present age with such incredible capabilities.

Tim Cash

John K. Strickland, Jr.

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Feb 25, 2023, 8:59:21 PM2/25/23
to Tim Cash, Jerome Glenn, Keith Henson, Power Satellite Economics

No one can say when or if we will get space elevators for Earth.

It depends on the tensile strength of the fiber used in the ribbon.

We do not know if or when we will develop fiber strong enough.

Opinions vary strongly on this issue.

 

John S

Keith Lofstrom

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Feb 25, 2023, 11:32:49 PM2/25/23
to Power Satellite Economics
On Sat, Feb 25, 2023 at 07:32:01PM -0500, Tim Cash wrote:
> The IEC says we may have an Earth Elevator capability by 2035, which is
> quite ambitious in my opinion.

Ambitous indeed, because you must first discover a
superstrong material that is NOT "superlubricious" like
*perfect* carbon nanotubes actually are. CNT stick
to nothing, not even each other.

A slight exaggeration; the sticking energy is 1/2 kT,
one third of the thermal energy of a single gas molecule.

Scientists have made pairs of PERFECT centimeter long
carbon nanotubes, a thinner tube inside a fatter tube.
Lift one end a wee bit, and the inside tube slides out,
pulled by gravity, no friction.

When I described this science a few years ago at the
International Space Elevator Conference, the smarter
ones went "oh hell" and the rest went "huh??" Guess
which group included the reporters and fiction writers?

-----

Another pathology (and there are MANY) is what happens
when a wheel locks up on a climber ... as would the
wheel bearings on your car, if they hadn't been lubed
during a 36,000 kilometer road trip, including 6000
vertical kilometers of hill climb.

RF engineer Tim Cash can imagine the consequences; it
is like launching a 10 volt step into a 1 ohm impedance
cable (fat inner conductor, thin insulation), propagating
through an impedance matching circuit into a 50 ohm
impedance cable, and connecting that to the unterminated
input of a circuit that breaks down at 30 volts. The
delivered signal is a 71 volt step after the impedance
transformation, which doubles to 142 volts when it
bounces off the unterminated cable end.

For those of you who aren't RF engineers like Tim, the
previous paragraph summarizes to "it's bad, it breaks."
Cables do the darndest things.

Very low throughput, space junk, lightning, undamped
mechanical oscillations, lunar gravity perturbations ...
a space elevator ain't Roy Roger's lariat. Ain't PERIOD.

-----

Real exploratory engineering is fail, fail, fail, fail,
fail, fail, demo, fail, fail, demo, fail, demo, demo,
alpha, fail, fail, beta, fail, beta, beta, ship, fail,
replace, ship, ship, ship, profit.

You want to do all those expensive fails at the smallest
scale possible. Near Earth space elevators don't scale.
They might scale on Phobos and Deimos.

Jerome Glenn

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Feb 26, 2023, 8:34:35 PM2/26/23
to Keith Lofstrom, Power Satellite Economics
Why not braded nano tubes, of braded nanotubes, etc.; and relay stations every 500 or 1000 miles so the cables don't have to be that long, and nano or micro robots running up and down the cables to check for problems, and redundant parallel cables to take over while repairs are made?

Jerry
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Tim Cash

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Mar 3, 2023, 7:53:38 AM3/3/23
to Keith Henson, power-satell...@googlegroups.com
Is there money in studying rectenna design in great detail?

If we form a non-profit organization for the specific task of improving
all aspects of space solar power system component designs, how exactly
would that be done?  By who, all organizations doing SSP design?  IEEE? 
AIAA?  Who?  How do you get the Chinese to pay you?  Good luck with that
idea!

I am not pooh-poohing the idea, I am stating it is absolutely required. 
I am just clueless how to fund it, that is all.  If every person on the
planet gave me $0.01, that would be a great deal of money, yes?

Who would I hire to study the problem?  The usual slave labor (graduate
students?), engineers just starting out?  All of us invested in the SSP
idea?

I recently went over the end-to-end efficiencies postulated by the
Caltech paper by Dr. Richard Madonna, and the computed nominal
end-to-end efficiency is 27% (Product of all efficiencies low ends, high
ends, mid point efficiency).  I have read that rectenna efficiency alone
is assumed to be 90%, as evidenced by the following rectenna efficiency
variable in one of my link budget model cases:

rfdc_rect_conv = 0.90000

pwr_mgmt_dist_loss = 0.99000

I have now reviewed most of Dr. William Brown's first book, the man was
a genius, a fantastic engineer who took great notes, I emulate his work,
trying to do my best these days.  That is why the 1975 JPL Power Beaming
record still stands.  If we strive to pick up that mantle and improve
upon it, I imagine we must improve all SSP component efficiencies,
likely using large scale integration of nanotech scale rectenna designs,
scaled upwards. This will not occur unless we stand up a research and
development organization to conduct such development.

At an AOC webinar last night, I heard a Johns Hopkins APL PhD postulate
the existence of a commercial version of DARPA, which he called CARPA. 
Funny name, but he hit the nail on the head, we need such an
organization for pushing R&D ahead for SSP. Greed defines how we move
ahead in this challenge.  Answer the question: Who wins from funding the
SSP R&D organization idea?  All of us!

Tim Cash

cash...@gmail.com

corne...@earthlink.net

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Mar 3, 2023, 9:53:52 AM3/3/23
to Tim Cash, Keith Henson, power-satell...@googlegroups.com
Hi Keith
There are a number of papers in IEEE Xplore from conferences and journals. The research is paid by a number of sources.

WRT Pioneer Brown, here is a youtube video, https://www.youtube.com/watch?v=tlv9WV7rjbM

Charlie
To view this discussion on the web visit https://groups.google.com/d/msgid/power-satellite-economics/9023da80-a46e-ea6d-2aa0-4ab3770aedcd%40gmail.com.

Keith Henson

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Mar 3, 2023, 4:38:05 PM3/3/23
to Tim Cash, power-satell...@googlegroups.com
On Fri, Mar 3, 2023 at 4:53 AM Tim Cash <cash...@gmail.com> wrote:
>
> Is there money in studying rectenna design in great detail?

Perhaps, but I am not aware of it.

> If we form a non-profit organization for the specific task of improving
> all aspects of space solar power system component designs, how exactly
> would that be done? By who, all organizations doing SSP design? IEEE?
> AIAA? Who? How do you get the Chinese to pay you? Good luck with that
> idea!

There is money being spent (or wasted) on power satellite design.
Perhaps as much as $200 million in military money and around $100
million in private money, most of it at CalTech. How you might tap
into this is something I don't know.

> I am not pooh-poohing the idea, I am stating it is absolutely required.
> I am just clueless how to fund it, that is all. If every person on the
> planet gave me $0.01, that would be a great deal of money, yes?
>
> Who would I hire to study the problem? The usual slave labor (graduate
> students?), engineers just starting out? All of us invested in the SSP
> idea?
>
> I recently went over the end-to-end efficiencies postulated by the
> Caltech paper by Dr. Richard Madonna, and the computed nominal
> end-to-end efficiency is 27%

Given the utterly stupid checkerboard design, it might be that low.
The standard loss budget gives 50% plus or minus a little for power to
the transmitter to power out to the grid. There is an analysis of
this problem on the NSS website. I think it has been cited here in
the last few years.

A URL to the Madonna paper would make this post much more valuable.

> (Product of all efficiencies low ends, high
> ends, mid point efficiency). I have read that rectenna efficiency alone
> is assumed to be 90%, as evidenced by the following rectenna efficiency
> variable in one of my link budget model cases:
>
> rfdc_rect_conv = 0.90000
>
> pwr_mgmt_dist_loss = 0.99000
>
> I have now reviewed most of Dr. William Brown's first book, the man was
> a genius, a fantastic engineer who took great notes, I emulate his work,
> trying to do my best these days. That is why the 1975 JPL Power Beaming
> record still stands. If we strive to pick up that mantle and improve
> upon it, I imagine we must improve all SSP component efficiencies,

The project is profitable at the current efficiencies. That's not the
problem, the massive scale is. Of the problems I consider dicey, the
worst is moving millions of tons from LEO to GEO or another high orbit
without using absurd amounts of expensive reaction mass hauled up from
the earth. The only way to reduce the reaction mass is a high
exhaust velocity, and the energy required is proportional to the
square of the velocity.

This is not a problem if you build the power satellites low and use
them to self-power out to GEO, but then you have to cope with the
space junk. A power satellite is so large that it gets hit about 40
times during transit.

> likely using large scale integration of nanotech scale rectenna designs,
> scaled upwards. This will not occur unless we stand up a research and
> development organization to conduct such development.

I can't think of any reason you need nanotech to build rectennas.

> At an AOC webinar last night, I heard a Johns Hopkins APL PhD postulate
> the existence of a commercial version of DARPA, which he called CARPA.
> Funny name, but he hit the nail on the head, we need such an
> organization for pushing R&D ahead for SSP. Greed defines how we move
> ahead in this challenge. Answer the question: Who wins from funding the
> SSP R&D organization idea? All of us!

One of the problems is that SSP is not recognized (after all these
years) as a potential replacement for fossil fuels. Far as I know,
it's not even on a comprehensive list. No idea of how to fix that.

Keith
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