The Space Review: Did a NASA study pull the plug on space solar power?

[k.a.c...@sympatico.ca]

https://www.thespacereview.com/article/4737/1

[vid.b...@fotonika-lv.eu]

I suspect numerous possibilities will emerge for SBSP for use in orbital manufacturing as well as possibilities for beam launch of spacecraft utilizing power beamed from SBSP to launching vehicles that are above the cloud layer. 

 

Another application could be to beam power to aerostats equipped with rectennas located above a disaster zone.  Power for disaster recovery is very expensive and could potentially justify an SBSP approach delivered from the aerostat to ground potentially even with cable.  SBSP – laser – aerostat – cable to ground or microwave to rectennas on the ground.

 

 

From: power-satell...@googlegroups.com <power-satell...@googlegroups.com> On Behalf Of k.a.c...@sympatico.ca
Sent: Tuesday, February 6, 2024 4:35 PM
To: power-satell...@googlegroups.com
Subject: The Space Review: Did a NASA study pull the plug on space solar power?

 

https://www.thespacereview.com/article/4737/1

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[Keith Henson]

On Sun, Feb 18, 2024 at 9:01 PM <vid.b...@fotonika-lv.eu> wrote:
>
> I suspect numerous possibilities will emerge for SBSP for use in orbital manufacturing

Generally wires are a lot more efficient and cost less.

> as well as possibilities for beam launch of spacecraft utilizing power beamed from SBSP to launching vehicles that are above the cloud layer.

That can be done from physics, but it's an expensive project. Takes at
least 4 GW of laser power.

https://htyp.org/design_to_cost#Space_laser

>
> Another application could be to beam power to aerostats equipped with rectennas located above a disaster zone. Power for disaster recovery is very expensive and could potentially justify an SBSP approach delivered from the aerostat to ground potentially even with cable. SBSP – laser – aerostat – cable to ground or microwave to rectennas on the ground.

Possibly, but I don't think disaster recoveries need GW scale power.
Plus the beam from GEO is around 10 km wide. Keeping a 5 GW ($12 B)
power satellite around just for emergency use seems seems excessive.

Keith

>
>
>
>
> From: power-satell...@googlegroups.com <power-satell...@googlegroups.com> On Behalf Of k.a.c...@sympatico.ca
> Sent: Tuesday, February 6, 2024 4:35 PM
> To: power-satell...@googlegroups.com
> Subject: The Space Review: Did a NASA study pull the plug on space solar power?
>
>
>
> https://www.thespacereview.com/article/4737/1
>
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[Bryan Zetlen]

Wire may be more efficient but it’s vastly more expensive over any significant distance. You’d think folks would have learned by now that by the kWh, transmission infrastructure structure is 2 or 3 times costlier than building conventional and nuclear power plants. Labor and materials are expensive enough without considering the cost of obtaining rights of way at $1M to $10M per mile. 

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[vid.b...@fotonika-lv.eu]

If you hang a cable from an aerostat  that is above the cloud layer where laser beamed power would have very modest atmospheric interference.  Consider aerostats above the Fukushima nuclear disaster zone delivering power beamed from a powersat to a rectenna mounted on the tethered aerostat.  Laser could be used to transmit the power reducing the size of the transmitting array as well as the rectenna.  If GW of power are required to substitute for the lost nuclear power a powersat to sustain operations in a region after a nuclear disaster could be a valuable option.

[Sherwin Gooch]

Keith, et al., 

I suspect it may have to do with the current global warming kerfuffle.  In a time when powerful people are discussing taking steps to increase the albedo of Earth to reduce its absorption of solar radiation, I can understand how an approach to a problem which would increase the effective surface area of the Earth WRT the sun might be unpopular among such true believers.  

S

On Sun, Feb 18, 2024 at 9:23 PM Keith Henson <hkeith...@gmail.com> wrote:

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[k.a.c...@sympatico.ca]

> > Another application could be to beam power to aerostats equipped with
>> rectennas located above a disaster zone. Power for disaster recovery is very
>> expensive and could potentially justify an SBSP approach delivered from the
>> aerostat to ground potentially even with cable. SBSP – laser – aerostat – cable
>> to ground or microwave to rectennas on the ground.
>
> Possibly, but I don't think disaster recoveries need GW scale power.
> Plus the beam from GEO is around 10 km wide. Keeping a 5 GW ($12 B) power

> satellite around just for emergency use seems excessive.

I think that Dick Dickinson was the first to come up with the idea of 2-stage power beaming: laser beaming from orbit to a high-altitude aerostat, then microwave beaming from the aerostat to the ground. Use an IR laser, hopefully the atmosphere will block it well enough that it won't be hazardous at ground level. The amount of power would obviously be way lower than GWs, which is OK because the satellites can be small (because the laser transmitter aperture is small). The size of the microwave transmit array and rectenna can similarly be small, because the range is only a few 10's of kms. (Dick also wrote and self-published an SF novel, set in a future in which this technology is in place, as an entertaining way of describing its details, as background to a pretty good story.)

(This may sound familiar to you --- I mentioned it in a 2019 post here.)

Stratosolar uses a similar idea, but I think that Dick's concept came first.

- Kieran

[Keith Henson]

On Mon, Feb 19, 2024 at 8:00 AM <k.a.c...@sympatico.ca> wrote:
>
> > > Another application could be to beam power to aerostats equipped with
> >> rectennas located above a disaster zone. Power for disaster recovery is very
> >> expensive and could potentially justify an SBSP approach delivered from the
> >> aerostat to ground potentially even with cable. SBSP – laser – aerostat – cable
> >> to ground or microwave to rectennas on the ground.
> >
> > Possibly, but I don't think disaster recoveries need GW scale power.
> > Plus the beam from GEO is around 10 km wide. Keeping a 5 GW ($12 B) power
> > satellite around just for emergency use seems excessive.
>
> I think that Dick Dickinson was the first to come up with the idea of 2-stage power beaming: laser beaming from orbit to a high-altitude aerostat, then microwave beaming from the aerostat to the ground.

Physics-wise, this would work, but at present efficiency, I think the
loss chain will kill you. High-power lasers are currently pumped by
laser diodes that are at most 50% efficient and the lasers themselves
are at best 50%. Tuned PV might get to 70%, but then you have the
microwave link.

> Use an IR laser, hopefully the atmosphere will block it well enough that it won't be hazardous at ground level. The amount of power would obviously be way lower than GWs, which is OK because the satellites can be small (because the laser transmitter aperture is small). The size of the microwave transmit array and rectenna can similarly be small, because the range is only a few 10's of kms. (Dick also wrote and self-published an SF novel, set in a future in which this technology is in place, as an entertaining way of describing its details, as background to a pretty good story.)
>
> (This may sound familiar to you --- I mentioned it in a 2019 post here.)
>
> Stratosolar uses a similar idea, but I think that Dick's concept came first.

The PV version of Stratosolar used wires to get the energy to the ground.

It had built-in storage by lifting weights on cables.

Keith

> - Kieran

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[k.a.c...@sympatico.ca]

Keith;

You wrote:

>> I think that Dick Dickinson was the first to come up with the idea of 2-stage
>> power beaming: laser beaming from orbit to a high-altitude aerostat, then
>> microwave beaming from the aerostat to the ground.
>
> Physics-wise, this would work, but at present efficiency, I think the loss chain
> will kill you. High-power lasers are currently pumped by laser diodes that are at
> most 50% efficient and the lasers themselves are at best 50%. Tuned PV might
> get to 70%, but then you have the microwave link.

There may be some niche applications for which the economics of this might make sense, even with lower end-to-end efficiency, given that the size of the satellite can be much smaller than for "SPS Classic". E.g., there are a number of communities in northern Canada for which power is supplied by diesel generators, with the diesel flown in --- because those communities aren't linked by road to the rest of the country. I believe the government subsidizes electrical power in those communities (among other subsidies up there); when last I looked, I think the cost of providing power was somewhere around $1/kW-hr.

- Kieran

[Keith Henson]

On Mon, Feb 19, 2024 at 6:50 AM Sherwin Gooch <sjg...@gmail.com> wrote:
>
> Keith, et al.,
>
> I suspect it may have to do with the current global warming kerfuffle. In a time when powerful people are discussing taking steps to increase the albedo of Earth to reduce its absorption of solar radiation, I can understand how an approach to a problem which would increase the effective surface area of the Earth WRT the sun might be unpopular among such true believers.

That might be the case, but it is at odds with reality. I think power
satellites produce the most power with the least warming, better even
than PV. (PV is black.) The worst might be nuclear reactors which
dump 2 GW of waste heat for every GW they put into the power lines.
(Relatively low temperature and poor Carnot efficiency.)

Power satellites are much better. The loss at the rectenna is around 15%.

Keith

[Bryan Zetlen]

forwarding - some good ideas 

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