Viable Alternative Energy: Solar Energy Production Satellite (SEPS) Republished from 28 December 2004, edited 03 August 2005
We need viable alternative energy sources. It is vital to our national security, to our economy, and to our day-to-day comfort that we have such energy sources at our disposal given the increasing precariousness of the oil supply.
The best proposal I have heard is for a Solar Energy Production Satellite (SEPS). As you may or may not be aware, a nuclear power plant is nothing more than a steam engine driven dynamo using nuclear fuel rods to heat water and create steam. In short, steam engines drive our most advanced naval vessels. Our standard coal burning plants generate electricity the same way. If we could somehow use solar energy to generate steam, we would basically have free, non-polluting, energy production. Well, it is possible to get enough solar energy to do this -- put it in orbit. We currently have the technology to put a standard-type power-plant satellite in geo-synchronous orbit. Such an energy production satellite would always be in the sun and thus could make use of solar energy to produce electricity 24/7. We have the technology to also transmit the energy a SEPS would produce to a receiver on the earth below in the form of microwaves.
SEPS would deploy a large concave mylar "sail" to focus solar rays onto a small area of the satellite. The solar energy would boil a contained liquid shunted by one-way valves through a generator and onto the cold side of the satellite. There the gas would be chilled back into liquid and shunted through a second generator as it returns to the boiler chamber.
Between the two generators a large amount of electricity could be produced, and translated into microwaves which would then be transmitted, via a broad-beam, down to the receiving station on the earth. The receiving station antenna would be about 100 meters square (to ameliorate the power of the microwave to anything flying through it, though the airspace would be restricted). The receiving station would then convert the microwaves back into electricity and send it out over the grid.
After the initial costs of implementing the plan (I think it is estimated to be in the low billions, as high as 40 billion), we would have very cheap and non-polluting energy -- energy that is produced by an advanced application of technology that we have used for a century. Once proven, the SEPS electrical system might be duplicated many times, and supply electrical power to much of the world.
Besides the initial cost, the major criticism of the SEPS is its use of mylar as a solar collector/focuser. Mylar is very thin and light. Several square kilometers of the material can be launched into orbit very cheaply (on the scale of materials we might transport into space). The argument is that it can easily be punctured by space debris. This is true, however, a sail of several square kilometers would have to suffer a great amount of damage before its solar-collection capacity is impaired (at least, that's what the experts say). At any point that the sail actually does require repair, the mylar has very low mass -- the cost would be minimal when compared to, say, a Hubble repair mission. Also, we are starting to see aircraft that can push into outer space. It is likely that by the time a SEPS would need repairing, space flight might be much more economical.
Subject Matter: Alternative Energy Science Space Exploration _____________________________________________