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Microwave Energy Transmitter

Posted by: skyhigh - Sun Jul 31, 2005 4:09 am
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Microwave Energy Transmitter 
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Post Microwave Energy Transmitter   Posted on: Sun Jul 31, 2005 4:09 am
This might sound like sci-fi, but I was wondering if something like this exists. I remember hearing a long time ago ideas for gathering solar energy in space (since you get much more given there is no atmosphere) converting this energy into microwaves, then beaming this energy down to earth, and reconverting the microwave energy into electricity.

First, does such a process exist?

Second, would it be possible to use this process for space travel. The idea being a shuttle wouldn't have to carry all the weight of its own fuel to get into space. Instead, you'd have a focused beam of microwave energy targeted at the space craft that would give it the energy to get close to space. The only thing I'm not sure of is can there even be such a thing as an electric rocket engine? I mean if its propeller driven that requires atmosphere, so it would only get you so high up.

So three questions. 1) Does this technology exist. 2) Are there electric propulsion systems and 3) Is it a feasible technology to get into space.

I mean, I'm always amazed seeing the space shuttle having to carry HUGE tanks of fuel with it just to get into space. If you could beam energy and save on the weight by I'd guess hundreds of tons, you'd lower your cost per pound.


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Post    Posted on: Sun Jul 31, 2005 5:37 am
Haven't got any links on me right now to back this up but:

1) Yes, but the microwave energy does not come down in a 'tight' beam. It is on the order of kilometers wide. Although it has been shown that they can do this with a low intensity beam that will not hurt plants and wildlife, we'll need to educate the public against the environmentalist dogma.

2) People have been talking about laser launch for some time, and experiments have been done at White Sands Missile Range with the big laser they have. They launched a craft that weighed less than a kilogram a few hundred feet in the air. That was ~ late '90s. Search Space.com for laser launch or the name "Myrabo" (The last name of the head researcher on that project.) Of course, you could power the laser with solar powered satellites, but you could also use a coal plant.

3.) As far as I know, research is ongoing in that field, so somebody thinks it can work.

I think that information is correct, but I wish I still remembered the links for you. I'm sure someone around here does.


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Post    Posted on: Sun Jul 31, 2005 10:22 am
Hello, Marshall,

I seem to remeber having read a printed article a few years ago which said that beaming energy from space down to Earth can be done without hurting animals or humans and that the receivers were like parabol-antennas. If I remember correct the antennas were placed in the deserts.

Regarding laser there is a NIAC-concept I intiated a thread about last year. The concept is to use lasers for improving the efficiency of hydrogen as propellant. The laser would heat up the hydrogen simply - perhaps this could be done by a microwave-laser beaming down to the vehciel from space. The increased efficiency should make it possible to reduce the amount of hydrogen required for the launch.

What about that? The thread about that NIAC-concept is listed in one of the stickies - "Drives, Engines amd Propellants" I suppose.



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Post    Posted on: Mon Aug 01, 2005 2:42 am
I went ahead and found some linkies for you to check out, Skyhigh.

Regarding laser launch:
http://www.space.com/businesstechnology/technology/laser_propulsion_000705.html
http://www.space.com/news/lasersail_000301.html

http://www.space.com/businesstechnology/technology/laser_craft_001103-1.html

On Solar Powered Satellites:

http://www.space.com/businesstechnology/technology/space_solar_000908.html

http://www.spacedaily.com/news/ssp-01b.html

Ekke:
The last article I linked to mentions that the receiving antennas or 'rectennas' (God, they have to come up with a better name for that!) can be small and remote as you say. However, they don't say how small. The information I gave about the necessity of a kilometers-wide beam and receiver may be an artifact of the original proposals from the 1970's, which envisioned using far less efficient photovoltaic cells. I'll have to look into that.


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Post    Posted on: Mon Aug 01, 2005 2:00 pm
How 'bout those MASER anti-manpads devices they're talking about putting up near major airports?

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Post    Posted on: Wed Aug 03, 2005 5:33 pm
I don't know if they have the power to push anything but protesters. Forward's Starwisp is an interesting concept.


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Post    Posted on: Sat Sep 13, 2008 2:54 pm
Obviously there is a bit of research and development on this according to the article "Experiment Boosts Hopes for Space Solar Power" ( www.space.com/businesstechnology/080912 ... -test.html ).

Quote:
A former NASA scientist has used radio waves to transmit solar power a distance of 92 miles (148 km) between two Hawaiian islands, an achievement that he says proves the technology exists to beam solar power from satellites back to Earth.
.

There seems to be the difference though that radio waves instead of microwaves have been used to do the transmission - but this may have been done for safety reasons.

Quote:
Mankins ... transmitted 20 watts of power between the two islands in May. The receivers, however, were so small that less than one one-thousandth of a percent of the power was received, Mankins said.


So the size and scale of the receivers seems to be the constraint in this experiment - they could be increased.

Quote:
Each of the nine solar panels used was built to transmit about 20 watts of power, but the transmission was scaled back to two watts per panel in order to obtain U.S. Federal Aviation Administration approval for the test.


Seems to mean that Mankins could have transmitted 200 Watts at the transmitter site which I suppose to mean the same factor at the receiver site.

Quote:
Despite the miniscule reception on the receiving end, Mankins said the ground-based test proved it is possible to transmit solar power through the atmosphere.

"The test was in no way fully successful," he said. "I think it showed it is possible to transmit solar power quickly and affordably."


Quote:
His vision is to transmit solar power collected by orbiting satellites as large as 1,102 pounds (500 kg) to lake-sized receiver stations on Earth.


What about it?



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Post    Posted on: Sun Sep 14, 2008 12:24 am
This is idiotic, the way they are going about this. Why would you want to make microwave powered rocket or even a laser propelled rocket when you can make a microwave powered SCRAMJET? That way you don't have to carry ANY fuel...

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