In reply to Stephen A. Lawrence's message of Mon, 30 May 2016 12:57:15 -0400: Hi, [snip] >Right, for sure, but seriously, anybody who watched Space Angel as a kid >knows you can't just let a solar mirror point anyplace it wants -- >you're just asking to have your headquarters burned to a crisp while the >bad guys escape. > >As I said to start with, you don't really need to point them all at the >ground. Just deflect them a degree or so off target, each mirror going >someplace random -- that shouldn't take much energy, and is probably >something you could do with distributed backup power.
Actually, this can be problematic too, as the reflected light can temporarily blind pilots, posing an air safety hazard. > >In any case, in the scenario which actually happened there wasn't any >lightning strike, power wasn't lost, and it was a lot more like the >meltdown at Chernobyl, where the technicians intentionally put the thing >into a bad state for testing and then bad stuff happened. If the thing >had a 'defocussed' mode one could even imagine spotting a few >temperature sensors around the towers to automatically shut it down in >the case of poor aim. Just because it's not radioactive doesn't mean >it's not dangerous. > >On 05/30/2016 12:02 AM, ChemE Stewart wrote: >> You guys are ignoring all of the mechanical and structural challenges >> of pointing 350,000, 30 foot mirrors at the ground using worm gears >> and stepper motors that have just lost power due to a storm and/or >> lightning strike. No motor power, no movement. The fuel source (the >> sun) keeps moving up and then down towards the west, so the focal >> point(s) of all of that incident power is constantly changing. >> >> It is not like a typical boiler where the flame safety system can cut >> the source of fuel. It is more like a cross between fukushima and the >> towering inferno :) >> >> On Sun, May 29, 2016 at 10:46 PM, <mix...@bigpond.com >> <mailto:mix...@bigpond.com>> wrote: >> >> >> In reply to Stephen A. Lawrence's message of Sat, 28 May 2016 >> 17:18:24 -0400: >> Hi, >> [snip] >> >It ought to be possible to build the things with a fail-safe mode >> >wherein loss of power results in the mirrors defocussing. >> Shouldn't be >> >hard; the /hard/ thing, presumably, is getting them all pointing >> at the >> >_same_ spot. Making them /not/ do that should be easy. >> > >> >> Just turn them all upside down so they point at the ground. >> >> Regards, >> >> Robin van Spaandonk >> >> http://rvanspaa.freehostia.com/project.html >> >> Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
