Greetings All, This list looks a little sleepy these days so here is my "short" version of the best approach to solving world's energy problems, space colonization, etc. I owe a debt to a great many of you for these ideas and hope that this shows that I have improved them over time. Please do criticise!!! 1) The goal I figure the earth needs on the order of 10-20 terawatts continuous solar power to deal with climate change, sea level rise, and general prosperity in the world (ie continuous economic growth). To me this means a moon sized solararrays locatedat both L4 and L5 and enough solar panels on the moon to deal with eclipses. Each solar panel in these structures is on the face of a triangular cylinder with verical armor panels that close in a snap like shutters. If a solar panel is damaged in any way it is simply rotated out of use and repaired offline. In this way the public is assured that nothing known in space can knock out one of these arrays be it a solar flare, dust storm, or sabotage. They can have the mass of trillions of tons and can stay where they are unattended for millenia. The power from these structures is beamed to GSO satellites from each of these three sources only when they are not in line with the earth and immune ifsome of the radiation spills over. From this point the GSO satellites beam to receivers located in the most hostile and remote places of the earth (Middle of the Pacific Ocean, Sahara Desert, Tibet Plateau, possibly the Mojave Desert or Brazil Jungle). These relay satellites are very low mass by comparison to the solar panels andhaveseveralreplacements nearby. Targeting is fool proof and the earth to satellite radiation may be in other frequencies than microwaves (subject to the voting public) like light or heat. In this way environmentalists are satisfied that promises of infallibility or protections from harm are backed up by the least risky and lowest maintenence approach. The cost of this is beyond anything we know now yet that is exactely what can change as a result of doing this. Once you have terawatts of power you can do anything in space including colonies. I'll leave that to you with better imaginations than I do on what to do with the spare power. After you give earth all it can handle, you have all this neat manufacturing to build other structures at the cost of the labor and maintenence of the equipment - ie not much. 2) The first lunar step My starting place is to go to the moon with robots and land on a nearly continuous sunlight peak at either the South or North pole. I'm not counting on space elevators or lower launch costs to help this. The robots are as simple as possible to heighten the chance of using one robot to repair another. The landing craft has some 10 kilowatts of premade solar panels that are extended straight up like a sail that rotates for continuous solar power.Earth based operators control every move like a video game with a 3 second delay. Total cost is under 5 billion and hopefully more like 1 billion. Look to the success of the Mars rovers or the Clementine mission and how these were done. If one mission is all you get funding for you still end up with a year's play time plus some infrastructure to go back to. After initial setup the next order of business is to produce fiberglass, ironstructural members and any kind of conductor material. Of these the Ca-Al conductor is the hardest to make so this is both a production environment and proving ground. Gradually you build up a circle and the mast and incorporate more premade solar panels that are landed nearby. My calculations show that the gain from being in 100% continuoussunlight outweigh the costs of building this structure for quite awhile over spreading the panels out and save an immense amount of weight by not bringing a reactor from earth. Without wind the safety factor of building this structure is greatly reduced over anything on earth. When the tower reaches about a megawatt continuous power production you are ready to start branching out and doing more complex things. 3) The second lunar step With a now pretty stable power supply, you try building solar panels on the moon. This is no easy feat and I don't expect to be either efficient nor that successfulon the first try. The facility is setup underground in what looks like a shipping container with dirt thrown on top for temperature & radiation stability. The aim here is to setup an environment that gradually produces lots of solar panels and can accomodate astronauts at a later time. If the solar panels don't pan out so well then you switch to making things ready for astronauts by bringing up a lot more premade solar panels. By premade I mean just the chips and the minimum of packaging. The robots do all the work of assembly including the manufacture of conducting cables, transformers, DC-AC converters, etc. These are simple yet key electrical devices that need to be perfected and leveraged. 4) Bring on the astronauts. By the time you have a couple of megawatts continuous power and about 10,000 square meters of underground facility space (like a lot of containers with airlocks welded between them) you are ready for astronauts. You shouldfind out how much water and other gasses rests in the perminently shaded craters. This is now easier since you have enough power to build a very small (10-20 cm wide) railway with track looking like alionel train set. Underneath two paralleltracks, a main conductor is buried towith taps at intervals to supply the track with power.A fairly elaborate robot receives dumb cars on one of two parallel tracks with new materials returns them on the other. With these materials and the supplied power the robot builds the trackout ever deeper into the shadows. The shaded areas are some 50 kelvin so everything working there has to be heated drawing considerable amounts of power. In the end water bearing material can be extracted in great quantities and brought back to a processing facility at the tower base. The track is not very expensive in terms of energy since most of the power is needed to create the Ca-Al conductor wrapped in fiberglass. It also solves the gritty problem of moon dust that is electrostatic and makes for a great grinding powder. Cars on the track are out of range of this (even if they have to besuspended meters above the surface) so they last virtually forever.This system can be extended for tens of kilometers in the coldest and darkest environments of the moon and to link to new nearly perminently sunlight peaks. On these additional peaks you send all the materials to setup new towers in bite sized chunks. With the water from the shade you have what you need to grow food under lights down in the underground base. You are all set to go for the big time being invulnerable to all sorts of problems due to mishaps and funding cuts even with people living on the surface. I envision the initialastronauts as really never leaving the base once they land as that puts them out in the open which is a really hostile place. They mainly focus on the production of solar panels which is doable if you oversee it in a factory environment. There is a lot of work tothe repair and maintain therobots which sharply increases their lifespan and lowers the cost overall. Simple food is grown on base with the rest of brought up from earth in monthly cargo supplies.Astronautsstay until they run into some medical problem that forces their return or several years unlike any current space mission. My favorite way to solve the bone loss problem due to low gravity is to build a large underground spinning cylinder that maintains an acceleration similar to earth. During off hours this is where the astronauts live and exercise. This is spartan living that is no more fun than being in a mineshaft on earth (where, except for the spinning, this can be easily replicated for trials). 5) Go for the big time (on the moon). At the point you can efficiently produce large amounts of solar panels, refine hydrogen and oxygen for refueling, and ship materials over long distances (via the minature railway), you are ready to go for the next step of a moon wide power network. Increasingly the focus is on small solar farms on the periphery of the lunar pole in the direction of earth. This is important to continue to increase very high bandwidth communications (ie control of the robots) by line of sight instead of by relay satellite. This cuts down on costs a bit and makes for easier maintenence and powering by tapping into the main conductor. At any point this system is autonomous from the earth for materials for an extended time allowing for all sorts of options. Eventually you end up remotely producing a lot of infrastructure like power lines, train tracks, moon bases and solar farms, always taking into account the highest need and best value at the time. The power grid serves to provide continuous power by shipping it from the day side to the night side and a small trickle during eclipse blackouts. I cannot predict how well things will go and only have a rough notion of the order of sequence at this point. In the end you build stadium sized factories that produce solar panels like newspaper and distribute these all over the place where they are assembed by robots into use. This does not have the virture of Criswells mobile manufacturing though if something breaks the resources to fix it are right there. If an astronaut gets sick (go figure) and you centralize your people, one of them can specialize in medicine. The robots are expendable and by now you have a staff of thousands on earth that have learned to use the video interface to get work done. Gradually everything you can make on the moon is made there at one of these bases. With this infrastructure in place everything gets very easy. Public support has a nucleus to rally around that is very tangible and the progress toward goals very measurable. Reliance on a stready stream of launches from earth is minimalized and no technologies are used that unproven to the degree that are they are fundamentally questionable. I in particular am concerned that the atmosphere of the earth is more sensitive than thought and want to minimize traversing it. At some point a 10-20 cm track system is inadequate for moving enough materials around so you build a regular sized one that also allows you to ship astronauts around easily without having to blast off and land. Here you mark the real boundary from being a science outpost to crossing the line of being a colony. You have a main space depot at the equator base and anything to do with astronomy at the poles where the view is always great and the temperature nice and cold. You can serve a pretty varied diet with some simple creatures like fish on the menu. The travel demand has created a monthly or bi-monthly schedule and people are used to the idea of living on the moon. The machine shop is beginning to fabricate televisions and luxuries are being planned like a swimming pool. 6) Reaching for the LaGrange points. Eventually you end up building mass drivers somewhere along the equator. After discussing the matter with Arthur I came to the realization that if anything went wrong with the launch of pellets into orbit, they would come down somewhere and confidence would not be very good. I don't know how precise things can be accelerated magnetically at the speeds needed. All sorts of things could cause loss of power.My safer approach is to launch really big packages with guidance systems, accelerated with a wide margin of error. This allows the shipment of premade solar panels, structural members, bottlesof gassesand all sorts of useful things. After launch, these packages find their way to L4 & L5powered byion engines and settle in to be welded together as a part of a very large infrastructure. This gives the orbiting L4 & L5 platforms a large mass right away making them hard to be moved undesireably. Within weeks you have astronauts living there supplied by hourlyshipments from the moon. Within months you have elaborate living quarters and the beginnings of the giant solar arrays. At some point the importance of the moon bases shiftto just preparing raw materials for shipment and the big actionmoves to the L4 & L5 platforms. Asteriods come into play as a source for carbon, platinum, nitrogen, and whatever else you need. They are more accessible since you havethe meanssupplied by the moon in the form of large space ships and lots of fuel. With enough carbon you have plastics and other key items. The need for these gasses depends on what you get out of the shaded moon craters and will drive the importance of this item. Either way science will never be the same with chunks of these things to examine. After a decade or so beyond thisyou have reached the terawatt milestone and have really large scale mining and shipment operations on the moon. The delay of developing a moon base is paid back by redundancy and lower cost of supplies such as food, premade conponentsand propellant. The experience of lunar manufacturing of even the simplest items is leveraged over the entire project and starts with landings on the moon of as little as a couple of tons and a few satellites. If the funding stays small you get there just the same at a slower rate. If the funding stays strong you advance some items quicker than you would otherwise. If the funding stops, you leave most if not all of you assets and infrastructure in place at every step. Nothing in orbit save L4 & L5 can offer this in such absolute terms. 7) Endgame The hardest of all sells will be on the earth to get people to use this wonderful asset you build in space. At some point the earth and political interests represented by its people will be receptive to this and it will become a complete reality. Until then there is a long incubation period while you keep costs extremely low, life very spartan, and very unassuming of anybody elses interests. If we go out right away and threaten the cell phone lobby they will crush us. If we go out and scare the Sierra Club they will crush us too. Make the price hundreds of billions to start with and you will be hunting for an army of like minded billionaires to fund this or under the competing agendas of NASA and every other governmental agency. Once it is in place in orbitand people have 20 years to warm up to this then you are in a great position to move forward. Prove ourselves worthy with a track record of small accomplishments first and we will have a great deal more credibility. Always we are as unassuming as a public utility that never goes on strike and cares about taking every precaution. Do this and I know we will succeed. Do something else and we might succeed yet my confidence is not as high. My gut feeling is that we will get funding at best a billion dollars at a time and we have to show something impressive for this to win the next one. Low orbit or GSO premade systems have a lot to show right away yet theyfail if you cannot convince a skeptical public to receive the power and cannot be leveraged to build infrastructure like moon development. The public will spend billions to send a person to Mars. Maybe we can leverage this to provide the seed money and have infrastructure left over to continue with. Sincerely, Thor

Thor,