tag:blogger.com,1999:blog-17555522.post546549320237968591..comments2007-03-01T09:21:15.718-08:00bwhttp://www.blogger.com/profile/07541279438184352860noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-17555522.post-29358683477477724622007-03-01T09:21:00.000-08:002007-03-01T09:21:00.000-08:00<I>Since you work on the space elevator, would it make sense to adapt the mirror laser reflection system for the space elevator?</I><BR/><BR/>Up front let me point out that I am merely the bloke who takes care of the computers. That said "qualified maybe".<BR/><BR/>The important thing is to deliver energy to the lifter. How it gets done is immaterial except that the power delivery has to be reliable and cheap.<BR/><BR/>We've been going with the assumption that the laser only needs to have line of sight to the climber. Obviously the higher the lifter the wider the geographic spread for the laser gangs.<BR/><BR/>Mirrors imply the lasers could be anywhere. Hooray for flexibility.<BR/><BR/>But for at least the first space elevator getting anything into orbit is going to add enormously to the cost, which is always a huge deal killer. A mirror system based anywhere but GEO implies a constellation of mirror sats ..<BR/><BR/>On the other hand orbiting mirrors mean we can put the laser gangs where energy production is cheap. Would the cost of orbital mirrors be more than the cost of laser gangs in South, Central and North America?<BR/><BR/>Makes me want to go back to school for my Operational Research degree.Brian Dunbarhttp://www.blogger.com/profile/12952894032434503816noreply@blogger.comtag:blogger.com,1999:blog-17555522.post-2175147226484049352007-02-28T10:26:00.000-08:002007-02-28T10:26:00.000-08:00Brian Dunbar<BR/><BR/>Since you work on the space elevator, would it make sense to adapt the mirror laser reflection system for the space elevator?<BR/><BR/>If the climber was a donut around the ribbon and its base was mirrored. the donut could hold some number (6,8,12) of properly shaped mirrored targets as well. Then lasers would bounce between the mirrors and mirrors at the base. The efficiency could be quite good because it could be easier to keep maximum number of reflections. The system requirements would be reduced and the efficiency of the climber propulsion could be quite high. Also there would be less need to drive the climber at a very fast rate. The climber could also retract some of attachments to the ribbon if it was being driven very fast and would only need to stabilize and center itself. So the climb could be faster than a system that had beamed energy to drive a climbing mechanism. It would be like a controlled upward fall. <BR/><BR/>This would only be necessary if the ground launch with lasers and mirrors only had trouble with stability, performance and sufficient reflections without a space elevator.bwhttp://www.blogger.com/profile/07541279438184352860noreply@blogger.comtag:blogger.com,1999:blog-17555522.post-55481654344565436512007-02-27T21:30:00.000-08:002007-02-27T21:30:00.000-08:00So free electron lasers like the <BR/>http://www.physorg.com/news82217403.html<BR/><BR/>14 kw system U.S. Department of Energy's Thomas Jefferson National Accelerator Facility<BR/><BR/>http://en.wikipedia.org/wiki/Adaptive_optics<BR/><BR/>I think that could work for the ground launch system. Although once it gets 1-60 miles up the thousands of relections would be like going through many thousands of miles of atmosphere. Although even getting a a launch system that still had a 100 to a few hundred fold gain from the reflections would definitely be worth it.bwhttp://www.blogger.com/profile/07541279438184352860noreply@blogger.comtag:blogger.com,1999:blog-17555522.post-61244552999373536002007-02-27T21:01:00.000-08:002007-02-27T21:01:00.000-08:00<I>The wavelength would need to be one that is not absorbed by the atmosphere.</I><BR/><BR/>Adaptive optics.<BR/><BR/>My ears pricked up because I do some work for Liftport. One likely candidate for providing power to the lifters ascending the elevator ribbon are ground-based free-electron lasers using adaptive optics to beam power to receptors on the lifters.<BR/><BR/>It's always good to see that there might be other revenue streams for the laser gangs.Brian Dunbarhttp://www.blogger.com/profile/12952894032434503816noreply@blogger.comtag:blogger.com,1999:blog-17555522.post-67325254272606315322007-02-27T20:49:00.000-08:002007-02-27T20:49:00.000-08:00I think that both ground based arrays and space based arrays would be needed depending upon the mission.<BR/><BR/>The space based system for station keeping is the easiest, lowest power and simplest. Nasa looks like they are proceeding to develop it. <BR/><BR/>The mirrors bouncing lasers would also have less issues for energy losses and scattering if they were in or close to a vacuum. A lunar base with gas core nuclear reactors powering laser arrays would also work well. If one were launching a vehicle to Mars or a distant probe that seems like a good place to setup for launch.<BR/><BR/>An orbital system should have more mass than what it is launching and would also need engines to counter the thrust of launching a craft.<BR/><BR/>A ground based system would have challenges preventing the loss of laser energy. The wavelength would need to be one that is not absorbed by the atmosphere. There is also issues getting a properly designed vehicle that would have the right mirrored surface to reflect the lasers and be stable for launching through the atmosphere.bwhttp://www.blogger.com/profile/07541279438184352860noreply@blogger.comtag:blogger.com,1999:blog-17555522.post-73782341595479902142007-02-27T18:29:00.000-08:002007-02-27T18:29:00.000-08:00Question: The laser you want to power the craft with - ground based or in orbit?Brian Dunbarhttp://www.blogger.com/profile/12952894032434503816noreply@blogger.comtag:blogger.com,1999:blog-17555522.post-82336587161123835292007-02-26T22:58:00.000-08:002007-02-26T22:58:00.000-08:00Niven's Law "any sufficiently powerful propulsion system is also a very powerful weapon"?Anonymousnoreply@blogger.com