Fwd: Re: [extropy-chat] Worldwide SOS system

Mike Lorrey mlorrey at yahoo.com
Wed Oct 5 13:32:52 UTC 2005

Firs time this apparently didn't get through to the list.

> --- Emlyn <emlynoregan at gmail.com> wrote:
> > >
> > > How about we let people, who are so stupid as to go into the wild
> > > unprepared, win their Darwin awards as they deserve?
> > 
> > Even prepared people have problems sometimes.

Sure, just not for things they are prepared for.

> > 
> > btw Mike, do you think the microsats could be used to set up
> > "International Rescue" on a budget?
Well, if you are going to use the three meter SOS letters as your
trick, you need cameras that will have a one half meter or better
resolution from a 150-200 km altitude, automatically compensate for
satellite velocity to eliminate blurr, and contains the ability to
OCR six pixel tall letters from the noise of an image of natural

Lets say your CubeSpy is at 150 km and images 100 km-wide areas at a
time. You've installed a 5.5 megapixel camera on your sat, so you've
got approximately 2700 pixels by 2700 pixels to work with. A needed
one half meter or better surface resolution means you can only image
areas 1.35 km square at any given time to be able to spot your SOS
signal. You would also need a 60x optical zoom lense to image such an
area. A lense of that size is going to seriously eat into your mass
budget, and likely cannot fit into the 100cm x 100cm x 100cm volume of
a CubeSat using off-the-shelf components. You'll have to design a
special Dobsonian telescope for this application, with motion
compensating actuation features... Its also going to need some massive
memory capacity, maybe a few hundred gig of flash ram at a minimum,
with a shortwave transmission system to transmit repeatedly images that
turn up with the SOS pattern, along with location information.

Mike Lorrey
Vice-Chair, 2nd District, Libertarian Party of NH
Founder, Constitution Park Foundation:
Personal/political blog: http://intlib.blogspot.com

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