Instant and easy connectivity for mobile devices is often taken for granted, but modern cellular networks are tied to cell towers. How do you make a call when cell towers are not available?

To answer this question, teams from the Air Force Research Laboratory's Information Directorate, the United States Navy and Lockheed Martin came together to design, build and test the Mobile User Objective System (MUOS), a satellite communications system designed to be a large cell tower in the sky which would improve and provide more communications capability for U.S. forces on the ground.

The basic design works like a typical cellphone system, except that the tower is not on the ground but instead is on a geosynchronous satellite 22,000 miles above the earth. There are four satellites to give global coverage. The original design of the 3G signal was modified so that it could connect to the satellite. The satellite beams the call signal down to a control station on the ground to connect to the network and complete the call.

User's need a MUOS "phone" to use the system. At this time, the "phone" looks like a typical tactical radio, but new MOUS radios will get smaller as the system matures.

One of the tests for the system took place in Antarctica.

Members of the team were able to catch a ride with the 62nd Airlift Wing which was responsible for Operation Deep Freeze, the annual resupply mission of the National Science Foundation (NSF), McMurdo and Amundsen-Scott Stations in Antarctica.

Within 20 minutes of arriving in Antarctica the team was able to send out the first ever voice and data communications from the Continent.

During the trip they were able to gather data that would be used to improve MUOS as it matures to full operation capability.

Michael Gudaitis, AFRL team lead said that tests demonstrated 3G- cellular quality voice, text, and data calls in a place where no cellphones exist.

"Think about how you feel when you don't have cellphone coverage, especially when you need it most," said Gudaitis. "In Antarctica, with the MUOS system we were able to demonstrate calls from places where no other radio or cellphone would work."

Gudaitis said there are commercial applications to the system.

"On an airline flight you can't use your cell phone except in 'airplane mode,'" he said. "But with MUOS you can stay connected at all times."