It always amazes me how the oldest ideas can become useful with a bit of modern technology. Along with bleeding edge tech like paint-on photovoltaics and breeder-reactors, we have sun-powered steam turbines.

I love science.

The Russians have already tried a very primitive version of this. They launched an unmanned Soyuz, with an inflatable mylar disk at the front. I don't recall how large it was (not very) but they wanted to test the idea of using orbital mirrors to reflect light onto Siberian cities, shrouded in darkness for large portions of the year. I don't believe it worked very well, it was probably way too small. Or the whole thing was just a creative cover story for an steerable orbital mirror for a ground based laser... Who knows.

@Illuminatus: Me too... Sometimes simple is better.

I love me some SteamPunk.

Well, if I had a solar death ray, I imagine I'd demand a good deal more than $500 million. =P

@tamoko: I actually read about that a long time ago and I'm pretty sure it actually did work. I remember pictures where it looked like daylight. Of course, pictures can be doctored, but hey.

They called it the Icarus and it was in one of the crappier Bond movies...

Look up the italian village of Viganella. For 80 days each year, their town stands in the shade of a neighboring mountain and gets no direct sunlight at all. So they built a mirror on the facing mountain and get a few hours of redirected sunlight onto the town square each day of their deep winter.

@MonkeyT: Cool!

@Huxleyhobbes: "one billion dollars!"

They could use it to clean up all the deadly space debris we've heard so much about. Or they could roast a chicken very fast. Mmmmmm roast chicken..................

I believe one of these was built in Arizona or California several years ago, but I don't know if it's still working.
I think "60 Minutes" did a piece on it.

@Greasy Thumb Guzik: That was the prototype. It had a small generating capacity, but actually exceeded their efficiency goals. It was decommissioned when the testing phase was complete.

Wasn't it one of the Command and Conquer games?

I believe the main issue with orbital platforms involving solar death rays is the fact that the energy quickly disperses once it hits the thicker parts of the atmosphere. It's the same reason ground-based telescopes have to be huge and use imaging software just to breach the pollution and light dispersing properties of Earth's protective blanket. The Hubble with a mirrored surface area of about 2 meters (I think) has significantly greater optical resolving power than the largest ground-based telescopes...even one as high up and huge as Mauna Kea. Anyone who knows better, please correct me if I'm wrong.

@Citizen Kang: I think the idea is that they play with the wavelength of the transmitting laser to minimize absorption when it passes through the atmosphere.

@Greasy Thumb Guzik: I think there is a working prototype in Spain, with another larger scale version being built nearby. I believe the same company has an agreement for one of the same style in Australia. I think there is a solar tower of a different design in Arizona (it collects hot air that is allowed to rise through the tower).

@tamoko: I saw a letter to the editor about this in the NYT. The writer said he observed the Russian test and that it was roughly as bright in the night sky as Jupiter, which isn't exactly a devastating amount of luminous power.

Did noone here see the movie Sahara with Matthew McConaughey? It's final climax happened at the top of a tower that looked exactly like that one in the picture above. In the film I believe it was something like a solar powered incinerator that diverted the solar energy down the center of the tower where it was used to destroy nuclear waste. In the movie there was a leak or something that was poisoning an underwater aquifer. But I swear they had to have filmed it at that facility in Spain. Looks exactly the same.

It's called a Stirling engine - and yes, there is one out in SoCal run for SoCal Edison. This is a much larger scale, if memory serves.

What would be interesting to see, of course, is if they replaced water (a relatively inefficient heat transfer substance) with something more efficient - such as sodium. I believe the Soviets had developed a tiny sodium-cooled nuclear reactor right before the collapse of the USSR; I wonder if anyone has tried to replace water with sodium to boost efficiency.

@varun: They are indeed moving to molten sodium as a heat collector/transfer medium. The main benefit is that it will stay hot long enough that they can continue to generate power through the night.

A timely summary: [ecoworldly.com]

@Ed Grabianowski

Would that be safe? Sodium tends to be extremely explosive when exposed to moisture.

Not molten sodium, molten *salt*.
[en.wikipedia.org]

@solar Thermal:

I just went to Nasa's Yuri's night and there were a few solar thermal companies there.

Now that free energy solar thermal is starting to break into the mainstream news, I find it interesting that a few articles I've seen about it have likened it to "a death ray"

It's basically just a bunch of mirrors that focus onto a point, then heat is stored in a salt tank, boiled or something.

Our government's Sandia laboratories built one of the first solar thermal plants back in the 90's.
Solar One

Here is a huge database of pictures and white papers of all the solar thermal plants being built around the world.