The world's largest commercial satellite has been launched into earth orbit with the goal of providing mobile phone service to "dead zones" all across North America.

Owned by Reston, Va.-based TerreStar, the satellite is designed to pick up and relay signals from mobile phones.

TerreStar has developed a smartphone with access to data and email. It needs a clear view of the southern sky to connect to the satellite. The phones can connect to regular AT&T ground-based towers as well.

The company could also pursue similar deals with other wireless carriers.

"Off the network grid, you can make calls via the satellite," said Jeffrey Epstein, President of TerreStar. "It's a terrestrial or cell tower in the sky."

The satellite is due be followed by two similar, even larger ones from a competitor, SkyTerra Communications within the next year.