[jjsalamon]

Amazing work! Where I lived in Australia tourists often would get lost and quickly dehydrate, be at risk of hypothermia overnight or immobilize themselves by breaking a leg. Phone coverage is not good in the country so you couldn't call for help. Depending on your location, vegetation is difficult to see through for search-and-rescue spotters in the air. Once you get off trail it's not as simple as backtracking and so have to wait for help to arrive (so long as you let someone know you were hiking ahead of time).

[prawn]

Makes me wonder if, when searching for someone lost in scrub, it'd be feasible to launch a temporary, roaming mobile phone tower/repeater that might give the hiker temporary phone access to get help?

[eru]

See https://www.google.com/loon/