Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!lll-crg!nike!ucbcad!ucbvax!H.CS.CMU.EDU!Dale.Amon From: Dale.Amon@H.CS.CMU.EDU Newsgroups: sci.space Subject: Re: Powersats, DOE study Message-ID: <531179395.amon@h.cs.cmu.edu> Date: Fri, 31-Oct-86 16:49:00 EST Article-I.D.: h.531179395.amon Posted: Fri Oct 31 16:49:00 1986 Date-Received: Sun, 2-Nov-86 23:58:06 EST Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 85 I find Gary Allen's attack on power sats rather interesting. I should pass it on to Dr. Glaser; I'm sure he'd get a kick out of it. A CMU professor was involved with the DOE study on powersats (I'm not sure he was with the university at that time) and has told me that he had a very strong dissenting opinion on the report findings. He felt that the study baselines chosen were chosen with the INTENT to kill official interest in powersats because DOE had a strong protective interest in fusion and MHD, and an even stronger bias towards 'soft-tech' wind power, solar cells, solar passive, cogeneration. They weren't interested in using any baseline scenarios that might make it look feasible. Remember, this was in the Carter era... Interestingly enough, powersats were panned by "Mother Jones" at about the same time in an article that used blantantly falsified information. I know of one person whose father was misquoted to a point which can only be called INTENTIONAL. >From the mumblings I pick up a conferences, it would appear that the soviets are quite interested in the powersat idea to supply cheap power for third world client states: a real diplomatic coup for them, regardless of the front end costs. And of course, once you've built #1, #2 is a breeze and a hell of a lot cheaper. There is also strong interest at Astrotech Corporation for building small powersats for orbital power augmentation. They have some agreements with Dr. Glaser (Arthur D. Little Corp), who holds US patents on the powersat idea. The idea is that you start small, make a buck supplying power for NASA, DOD or whoever, and gradually (over 30-50 years) bootstrap yourself to larger operations, culminating in GSO stations. I might add that laser transmission has also been considered as an alternative means of transmitting power to the surface. The laser technique is not as well known a quantity. Microwave energy transmission has been done experimentally over reasonably long distances with high efficiencies. Actually better than power transmission lines, and the cost effectiveness gap widens with distance. Even without GSO powersats, the beaming technology is useful. There have been proposals to transmit energy from sites where it is cheap (ie a solar power station in the Sahara) to places where cheap power is needed (Japan, Western Europe, US) by 'bouncing' it from passive reflectors in GSO. This might even beat superconducting power lines, because you don't have to build the infrastructure to get lots of power to where it is needed. You just tilt the reflector. This is particularly good for undeveloped countries. The Soletta is an interesting idea, but I have some misgivings about the environmental effects of it. Microwaves don't couple directly with the atmosphere, unless you transmit in the 'waterhole' like your home microwave ovens. High Power laser transmission could likewise largely avoid such coupling. But the Soletta will transmit a broad energy band into an extended region of the atmosphere. The lit oval would create a warm air mass. I would expect it to set up an elliptically symmetrical flow with strong updrafts in the center, cool surface winds sweeping from the surrounding dark areas and a warm high altitude outflow. If the effects are mild, it'll be great for hang gliders. I suspect the winds would be quite strong though. Desert areas would be preferred for such stations because of the dry air. But dry air also has less heat capacitance and high transmissibility. IE, as soon as it gets dark in the desert, the air gets cool and the ground radiates it's heat quickly. Thus we have a boundary temperature differential of perhaps 40 degrees or more across a boundary of only a few miles. That strikes me as enough to drive a damn good storm. At the very least, I would not be the first to fly a 172 anywhere CLOSE to it. Also due to the desert climate, one would expect such winds to pick up considerable dust, which as we know from Mars, improves the coupling if the heating occurs in the updraft rather than the down draft. (Science 10/24/86, "Interannual Variability of Global Dust Storms on Mars") By the way, I am NOT trying to say that this would cause global dust storms, only suggesting a possible positive feedback connection that would cause wider effects than one might at first suppose. It might continue after daylight, and in fact drift with prevailing weather systems since it would not be 'locked' in position by an external energy source. Needless to say, power generation would not be terribly efficient under such a scenario... My knowledge of weather dynamics is not that strong, but I wonder about the impact of coriolis affects. Would such a 60km cell spawn cylconic storms or other weather anomolies? Could the effects be used to rob energy from existing cylonic storms? Have we got any atmosphere modelers out there?