Of course, you can just use the existing satellite network to get
global coverage. Something like this:

http://www.daestra.com/overview.htm

Which uses the Satamatics SAT-201 terminal:

http://www.satamatics.com/

Sadly, you get to pay usage fees.

But notice you get to send messages. So you could have a 'panic' button
and a G switch.

--
Philip Plane _____
|
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Glider pilots have no visible means of support