[extropy-chat] Worldwide SOS system

Emlyn emlynoregan at gmail.com
Thu Oct 6 01:04:02 UTC 2005

On 06/10/05, Dan Clemmensen <dgc at cox.net> wrote:
> Emlyn proposed a system with the following characteristics:
> "transmitter" fits in a one-gallon container and has a very long shelf life.
> Receivers are in orbit.
> Rugged, robust, dead simple.
> I think we need to add: satellites must be cheap and offer coverage in a
> short time,
> preferably less than two hours.
> Sorry, Emlyn, but radio can do all of this for a lot less money than
> satellite imagery.
> Use a highly simplified radio that is designed to broadcast at a low bit
> rate in
> a narrow bandwidth. This yields a high Eb/No (energy per bit) even with low
> power. The assumption is that there are only a few transmitters at any
> given time. in
> any particular part of the world,
> You can get arbitrarily long shelf life for a simple battery. For
> example. use a
> lead-acid battery, but keep the acid in a separate sealed container
> until you need to
> use the radio. You can get a lot of energy in a half-gallon container.
> The radio would
> be detectable from simple satellites for at least two days after you
> pull the tab. The
> satellite would notify the emergency response team, which would fly over
> the area
> to localize the transmitter. No need for GPS, cell phone, or even
> primitive AM radio,
> I think the emergency transmitter including container, battery, and
> acid, could cost
> less than $20.00,  Add GPS, FM receiver, AM receiver for less than an
> additional $30.00,
> and a transponder system (to speed up localization after the response
> team gets to the
> area) for an additional $10,
> Fifty satellites at $100,000 each would give great coverage and would be
> cheaper than
> a one satellite that is capable of the imagery your system requires.

I don't disagree with any of this, except for:
> "transmitter" fits in a one-gallon container and has a very long shelf life.

Going back to the original idea, it was that there are situations
where the transmitting entity has no equipment. The idea was that,
given we have orbits full of satellites, it seems a real shame that
people can be stuck in the wilderness and have no way of signalling
them. Radio doesn't count unless you have Gilligan Tech.

I reckon if I was castaway these days, I'd build the biggest SOS I
could possibly manage (if the time was dragging, it didn't seem like I
was going to be rescued, and I had some free time every day after
survival concerns). Eventually it'd find its way into Google Earth,
and some human would likely spot it :-)


http://emlynoregan.com   * blogs * music * software *

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