Founded in Brooklyn to help people communicate all over the world, the goTenna:

“…enables you to communicate without any need for central connectivity whatsoever—no cell towers, no wifi, no satellites—so when you’re off-grid you can remain connected. In fact, goTenna will even work if your smartphone is in “Airplane Mode””

How useful will this be for school trips (between teachers), family outings, etc? Considering that it only needs a device running Bluetooth, your children could use it to tell you where they are when lost by using just their iPod Touch.
With two to three days worth of charge, and a price that probably beats most international roaming fees (and most certainly any sat phone alternatives), the goTenna looks like it’s going to be popular enough to inspire a few clones. And it has very noble beginnings:

The brainchild of Perdomo, a former journalist and startup product manager, and her brother and now-CTO, Jorge Perdomo, the company was born from the connectivity nightmare following 2012’s Hurricane Sandy. In the aftermath of the storm that devastated the tri-state area that fall, many residents were facing downed cell towers that left them out of contact with friends and family.

That’s precisely why GoTenna isn’t aimed solely at off-the-grid trips like hiking and camping. Its other use cases are traveling abroad without a dedicated SIM card, attending large-scale events like concerts and sports matches, and during natural disasters that leave cell service crippled and unreliable.

via CNET

If it were available outside the US, I’d be getting a pair now.