Reflect Orbital

Michel Van

Michel Van

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On a large enough scale, orbital solar isn't a bad idea. Not sure if solar reflectors are the best way to go about it. The alternative I've heard mentioned is microwave emitters and receivers, as those wavelengths travel well through Earth's atmosphere, even clouds.

This idea of using mirrors is cheap and lightweight, but is still subject to weather issues. And it might be a few decades too early.
 
Well, Russia experimented with orbital mirror concept in early 90s. The "Znamya" project (rus. "Banner") was centered around collapsible metal film reflector, deployed from "Progress" cargo ship after it detach from "Mir" station:


Znamya-2.jpg
"Znamya-1" was deployed in February 1993. The 20-meter diameter reflector created a bright spot about 8 km in diameter on Earth, with luminosity of full moon.

The follow-up "Znamya-2.5" was planned to use larger (25 m diameter) concave reflector, stabilized by centrifugal force, and precisely controlled. The goal was to demonstrate the ability to hold a spot at selected point of Earth surface for prolonged time. Unfortunately, due to computer error, the mirror was not properly deployed and experiment failed.

"Znamya-3" was planned to use much larger, 60-70 m diameter reflector. Unfortunately, financial troubles led to it cancellation before launch.
 
Dilandu said:
Well, its obviously workable, and did not require any nonavailable technology, so... why not?
Click to expand...
Wen you think thorough on concept, problems show up:

How much light is reflected ? enough to power Solar farm on earth ?
if you take high reflected material solve that problem, but open new ones:

Light pollution, those reflectors will be very bright in night sky.
disrupting wildlife, astronomers and people try to sleep.

How better reflection more push the light the reflector out it orbit.
This also called Solar-sail, but you can use this to your advantage, preventing reentry of reflector.
Or moving reflector to new position for client.
Even make the reflector to a Starllite, Solar-sail a in fixed position held by equilibrium of Light and gravity.

What orbit ?
issue here take, low orbit, the reflector past too fast over Solar farm and it can not illuminate on dark side of earth.
medium orbit and the reflector is in cloud of Starlink or Kupier Satellites
You need higher orbit what make the reflector large very large, and its development more and more difficult.
(imagine a football-field size reflector squeeze in payload bay of Falcon 9 rocket)

There homepage graphic show a ring of reflectors in low Polar orbit,
i wonder if they try deflect light from one Reflector to another to target.
and i don't know if that even feasible...
 
Michel Van said:
How much light is reflected ? enough to power Solar farm on earth ?
if you take high reflected material solve that problem, but open new ones:
Click to expand...
Well, as I said above, 20-meters solar reflector was able to illuminate circular area of about 8 km in diameter with brightness about 0,25-0,3 lux.

The "Znamya-2.5" concave reflector was designed to illuminate the sane area with the brightness about 1.5-3 lux.

About 50 such reflectors would be able to illuminate the same area with 100 lux brightness of clear sunny day.


Michel Van said:
Light pollution, those reflectors will be very bright in night sky.
disrupting wildlife, astronomers and people try to sleep.
Click to expand...
The light is focused, and you could use it to illuminate solar panels in desert, or offshore. So no one would be disrupted.


Michel Van said:
imagine a football-field size reflector squeeze in payload bay of Falcon 9 rocket)
Click to expand...
Erm. The reflector is a very thin metal film structure, most likely inflatable. Falcon-9 rocket could easily handle several dozens of them.
 
Simpler than photovoltaics. Simple reflectors could also be useful to heat working fluids…less prone to solar events…
 

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