December 24, 2007

Near term low earth orbit space based solar power

An interesting concept for solar power appears to be on track for testing in Palau by 2012. The Space Island Group is also proposing low earth orbit solar power beamed to multiple locations. Space Island Group hopes to have its first system up by 2010. Space Island group is targeting 10 cents per kilowatt hour (kWh). Space Island Group reports "very positive" discussions with a European utility and the Indian government about buying future power from satellite systems.

Low earth orbit (LEO) systems offer the advantage of reducing the scale of the solar power systems. Most solar power systems proposals have been for geosynchronous orbit (GEO). This means that the rectennas to receive the energy have to be huge (like the size of Manhattan.) and the systems have to generate gigawatts to justify the size of the system. The GEO solar space satellite systems end up having an initial start up cost of tens of billions of dollars.

Having reflector satellites (mirrors) in low earth orbit would also allow for the LEO solar power satellites to more easily direct solar power to different customers on the ground. With superior targeting of reflected power, it would be possible to direct more sunlight onto the solar panels of existing communication satellites and the space station. Those existing space resources could need and might pay a far higher price for increased power that could keep expensive resources functioning.

In September, 2007 American entrepreneur Kevin Reed proposed at the 58th International Astronautical Congress in Hyderabad, India, that Palau’s uninhabited Helen Island would be an ideal spot for a small demonstration project, a 260-foot-diameter “rectifying antenna,” or rectenna, to take in 1 megawatt of power transmitted earthward by a satellite orbiting 300 miles above Earth.

Reed said he expects his U.S.-Swiss-German consortium to begin manufacturing the necessary ultralight solar panels within two years, and to attract financial support from manufacturers wanting to show how their technology — launch vehicles, satellites, transmission technology — could make such a system work. He estimates project costs at $800 million and completion as early as 2012.

Reducing the size of the rectannas with low orbit solar satellite. Reduce the size of the cost effective solar satellites. Have several small satellites in orbit so that relatively constant power could be provided to multiple smaller rectennas.

California-based start-up Space Island Group, predicts it will supply space-generated electricity to the UK domestic market at competitive rates as early as 2012.

The Space Island Group has almost completed financing for a prototype system that it claims will be in orbit within 18 months, at a total cost of $200 million. "The satellite will deliver between 10 to 25 megawatts of power," says Meyers. "It will 'site-hop' across base stations in Europe, beaming 90 minutes of power to each one by microwave."


Here is where the Space Island Group will make a radical procedural change - a change that will shift the economics of space activity for decades.

Our vehicle’s large tank filled with fuel, its engines, its guidance hardware and the two rocket boosters can carry 100 tons of payload to orbit. If the return rocket were eliminated and the shorter tank was used to carry 10 ten-ton satellites to low Earth orbit about 400 miles up, it would cost about $400 million to launch. The satellite owners would be charged $40 million each for the launch, and two-or-three of these launches a year would handle all the commercial satellites placed in orbit annually.


The Space Island Group's proposed converted launch vehicle

The large tank, its engines, its guidance hardware and the shorter tank that held the satellites would all be left in orbit until gravity pulled them back to a fiery re-entry into the Earth’s atmosphere a year or a century later.

With the 30-ton return rocket filled with 30 people and the shorter tank carrying 65 tons of supplies, the $400 million launch cost would traditionally be recovered by charging the passengers $50 million each for the trip up, and charging the space station operator $2,000 per pound for the supplies. The station operator would recover their cost by charging the passengers many millions more to stay onboard this well-stocked station

During the last four years we have identified over 200 companies and over 300 university research groups eager to lease these facilities at these rates. And of course there’s a tremendous market for tourists spending a week in the comfortable, wheel-shaped stations for $200,000 each. By 2012 we expect to have one launch each week and by 2015 that will grow to two launches per week. These very high production rates will dramatically drop our cost per launch, but today none of these future tenants can individually finance the $5-$7 billion it will cost us to build and test our first two launch vehicles.

We’re asking the largest underwriters to discuss how they could back a five-year, $10 billion line of credit for us in exchange for several years of free, “as-needed” use of the solar satellites for storm control. That amount will get our first station components in orbit, and let us build our first solar satellite prototype.

Insurers now “own” some $15 billion worth of communications satellites they’ve bought through insurance payouts when they failed in orbit. Workers aboard Space Island stations could use “space tugs” to bring these dead satellites down from their 22,000 mile orbits to the 400-mile high stations, then repair or refuel them and tow them back to their operational orbits for $5-$10 million each. Insurers could sell them all for nearly $7 billion in clean profits.



Space island's space station in fuel tank

Advocates of the technology reckon recent advances in ion thrusters and thin-film solar cells have made such a prototype project viable today. Wireless energy transmission over distances of up to one mile has been successfully demonstrated since the 1970's, and some experts argue that subsequent improvements in transmission efficiency mean it would be perfectly feasible to beam power down from orbital solar power stations.


FURTHER READING
I had previous articles on creating affordable megawatt size solar power. My plans would be dependent upon using solar power converted to laser power for an effective scalable (down to smaller size) space power system.

In this article, I discuss the 40% efficient solar power to laser power conversion system from Japan.


Laser power beaming from space

Lorentz force propulsion could be developed that would enable propellantless movement in space. This would help the low earth orbit solar power satellites to loiter for longer periods over the smaller rectennas.

Here is the site for the writers and researchers of the lorentz actuated orbits.

Magnetic tethers can also provide propellantless orbit boosts.


The National Security Space Office's online study of Space-Based Solar Power development. I have made contributions to this study and corresponded with the leaders of this study.

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