JAXA testing space solar power - Political Forum

Calvin-X · #1 (**permalink**) 02-24-2008, 11:43 AM

JAXA testing space solar power system ::: Pink Tentacle

Quote:

JAXA testing space solar power system
08 Feb 2008

For decades, scientists have explored the possibility of using space-based solar cells to power the Earth. Some see orbiting power stations as a clean and stable energy source that promises to slow global warming, while others dismiss the idea as an expensive and impractical solution to the world’s energy problems. While the discussion goes on, researchers at the Japan Aerospace Exploration Agency (JAXA) have begun to develop the hardware.

JAXA, which plans to have a Space Solar Power System (SSPS) up and running by 2030, envisions a system consisting of giant solar collectors in geostationary orbit 36,000 kilometers above the Earth’s surface. The satellites convert sunlight into powerful microwave (or laser) beams that are aimed at receiving stations on Earth, where they are converted into electricity.

On February 20, JAXA will take a step closer to the goal when they begin testing a microwave power transmission system designed to beam the power from the satellites to Earth. In a series of experiments to be conducted at the Taiki Multi-Purpose Aerospace Park in Hokkaido, the researchers will use a 2.4-meter-diameter transmission antenna to send a microwave beam over 50 meters to a rectenna (rectifying antenna) that converts the microwave energy into electricity and powers a household heater. The researchers expect these initial tests to provide valuable engineering data that will pave the way for JAXA to build larger, more powerful systems.

JAXA says the orbiting solar arrays, which have the advantage of being able to collect energy around the clock regardless of the weather on the ground, will need to transmit microwaves through the earth’s atmosphere at frequencies that are not affected by the weather. The researchers are now looking at using the 2.45GHz and 5.8GHz bands, which have been allocated for use with industrial, scientific and medical devices.

JAXA ultimately aims to build ground receiving stations that measure about 3 kilometers across and that can produce 1 gigawatt (1 million kilowatts) of electricity — enough to power approximately 500,000 homes.

[Source: Hokkaido Shimbun]

Go Japan!

This is the way to do it! Don't whine about the problem, find a freakin' solution!

I hope it proves workable. I wish it was us doing it. I wonder if we will copy them or just buy working satelites from them?

2030? Maybe we can beat them to it? Space race! Last one in is on the ash heap of history!

Pats&Sox · #2 (**permalink**) 02-24-2008, 08:10 PM

1. Solar is expensive enough without paying $90,000 per pound to launch it into orbit.

2. Are they going to use solar power to launch it? Or a massive carbon dioxide release with a fossil fuel powered rocket like usual?

3. What is the big benefit of having the panels in space? I dont see it. You wont even be able to service them if something goes wrong.

Shiva_TD · #3 (**permalink**) 02-24-2008, 08:45 PM

Based upon some simple calculations they will require about 125 million square feet of collectors to generate a gigawatt of power at 93 million miles from the sun. That's a pretty good size collector and it would take hundreds if not thousands of missions to transport that large of a collector into space. I would say that it is certainly testable but not practical at this time.

When it will be practical, and this might even be a motivating factor, is when we start space industries that could build the solar cells in space. So it is a positive sign of the times but it is still decades away from realization.

Please note I might have dropped a zero and that might actually be 1,250 million square feet.

Calvin-X · #4 (**permalink**) 02-26-2008, 07:43 AM

Quote:

Originally Posted by Pats&Sox

1. Solar is expensive enough without paying $90,000 per pound to launch it into orbit.

2. Are they going to use solar power to launch it? Or a massive carbon dioxide release with a fossil fuel powered rocket like usual?

3. What is the big benefit of having the panels in space? I dont see it. You wont even be able to service them if something goes wrong.

Any new energy production is going to be produced using current energy supplies.

In space there is no atmosphere, weather or night.

Calvin-X · #5 (**permalink**) 02-26-2008, 08:05 AM

Quote:

Originally Posted by Shiva_TD

Based upon some simple calculations they will require about 125 million square feet of collectors to generate a gigawatt of power at 93 million miles from the sun. That's a pretty good size collector and it would take hundreds if not thousands of missions to transport that large of a collector into space. I would say that it is certainly testable but not practical at this time.
When it will be practical, and this might even be a motivating factor, is when we start space industries that could build the solar cells in space. So it is a positive sign of the times but it is still decades away from realization.

Please note I might have dropped a zero and that might actually be 1,250 million square feet.

Likely so.

Quote:

Solar power satellite - Wikipedia, the free encyclopedia
A solar power satellite, or SPS or Powersat, as originally proposed would be a satellite built in high Earth orbit that uses microwave power transmission to beam solar power to a very large antenna on Earth. Advantages of placing the solar collectors in space include the unobstructed view of the Sun, unaffected by the day/night cycle, weather, or seasons[1]. It is a renewable energy source, zero emission, and only generates waste as a product of manufacture and maintenance. However, the costs of construction are very high, and SPS will not be able to compete with conventional sources (at current energy prices) unless at least one of the following conditions is met:[citation needed]

Low launch costs can be achieved[citation needed]
A space-based manufacturing industry develops that is capable of building solar power satellites in orbit, using off-Earth materials[citation needed]
In common with other types of renewable energy such a system could have advantages to the world in terms of energy security via reduction in levels of conflict, military spending, loss of life, and avoiding future conflict over dwindling energy sources.

Quote:

Extraterrestrial Materials
Gerard O'Neill, noting the problem of high launch costs in the early 1970s, proposed building the SPS's in orbit with materials from the Moon.[41] Launch costs from the Moon are about 100 times lower than from Earth, due to the lower gravity. This 1970s proposal assumed the then-advertised future launch costing of NASA's space shuttle. This approach would require substantial up front capital investment to establish mass drivers on the Moon.

Nevertheless, on 30 April 1979, the Final Report ("Lunar Resources Utilization for Space Construction") by General Dynamics' Convair Division, under NASA contract NAS9-15560, concluded that use of lunar resources would be cheaper than terrestrial materials for a system of as few as thirty Solar Power Satellites of 10GW capacity each.[42]

In 1980, when it became obvious NASA's launch cost estimates for the space shuttle were grossly optimistic, O'Neill et al published another route to manufacturing using lunar materials with much lower startup costs [43] This 1980s SPS concept relied less on human presence in space and more on partially self-replicating systems on the lunar surface under telepresence control of workers stationed on Earth. Again, this proposal suffers from the current lack of such automated systems, on Earth much less on the Moon.

Asteroid mining has also been seriously considered. A NASA design study[44]evaluated a 10,000 ton mining vehicle (to be assembled in orbit) that would return a 500,000 ton asteroid 'fragment' to geostationary orbit. Only about 3000 tons of the mining ship would be traditional aerospace-grade payload. The rest would be reaction mass for the mass-driver engine; which could be arranged to be the spent rocket stages used to launch the payload. Assuming, likely unrealistically, that 100% of the returned asteroid was useful, and that the asteroid miner itself couldn't be reused, that represents nearly a 95% reduction in launch costs. However, the true merits of such a method would depend on a thorough mineral survey of the candidate asteroids; thus far, we have only estimates of their composition. There has been no such survey. Once built, NASA's CEV should be capable of beginning such a survey, Congressional money and imagination permitting.

If the test is successful, then that might motivate grander schemes.

Of course if we happen to develope any space capablity for other reasons beforehand then the hurdles become less.

AzTeK · #6 (**permalink**) 02-26-2008, 08:26 AM

We really need to start establishing some permanent bases on the moon

I mean, it's been like 3 decades since we last landed on the moon, wtf's up with that?

atheistwoody · #7 (**permalink**) 02-26-2008, 08:48 AM

Agreed, what the fuck are they waiting for, what about Mars too? how about sorting out a manned mission to mars. I would gladly volunteer for it.

I think the idea by Japan is fantastic, its gonna take some doing but then again anything worth while is. People seem to moan about it taking to long and costing too much. These things cant be rushed otherwise it will go wrong.

Pats&Sox · #8 (**permalink**) 02-26-2008, 04:43 PM

Quote:

Originally Posted by Calvin-X

Any new energy production is going to be produced using current energy supplies.

In space there is no atmosphere, weather or night.

Well, technically, if a satellite goes in and out of the shadow of Earth, the temperature changes by about 500 degrees. Then there's radiation, coronal mass ejections, space junk, and meteors. Bottom line being, you cant fix it.

Ill take the rain instead.

Calvin-X · #9 (**permalink**) 02-27-2008, 07:32 AM

Quote:

Originally Posted by Pats&Sox

Well, technically, if a satellite goes in and out of the shadow of Earth, the temperature changes by about 500 degrees. Then there's radiation, coronal mass ejections, space junk, and meteors. Bottom line being, you cant fix it.

Ill take the rain instead.

Quote:

The SPS would be in Earth's shadow on only a few days at the spring and fall equinoxes; and even then for a maximum of 75 minutes late at night[38] when power demands are at their lowest[citation needed]. This allows the power generation system to avoid the expensive storage facilities (eg, lakes behind dams, oil storage tanks, etc) necessary in many Earth-based power generation systems. Additionally, an SPS will avoid entirely the polluting consequences of fossil fuel systems, the ecological problems resulting from many renewable or low impact power generation systems (eg, dams).

Politically, SPS would create new jobs and opportunities for companies. For nations on the equator, SPS provides an incentive to stabilise and a sustained opportunity to lease land for launch sites.

If the test is succesful than having someone or something (tele-present robot?) come over from where they are continually building new ones might not be much of a problem.

Pats&Sox · #10 (**permalink**) 02-27-2008, 07:48 AM

Quote:

Originally Posted by Calvin-X

If the test is successful than having someone or something (tele-present robot?) come over from where they are continually building new ones might not be much of a problem.

We're having a hard enough time getting people to switch to ground based solar. All I hear from the repub side is "it's too expensive!" and that's without paying $90,000 per pound to launch.

I understand Japan has a unique way of thinking, where they need to conserve space but that isnt as much of a problem for most other countries.

As for the new launch sites, what will they be made of? Where will the metals and plastics come from? Mining? Smelters? Oil? All Im saying is it seems excessive to the point where putting something like this in space will dramatically cut down the CO2 savings and increase the cost for a small benefit. Does not seem efficient to me at all.