Satellite phones from Iridium Satellite have been increasingly popular tools for first responders working in the Gulf Coast areas where the effects of Hurricane Katrina have rendered other communications systems useless, an Iridium official said today.

During the first 72 hours of the disaster, Iridium traffic in the region increased more than 3000%, and the number of subscribers increased more than 500%. To meet the demand, Iridium adopted a round-the-clock manufacturing schedule. The FCC has granted use of additional spectrum to reduce the risk of network congestion, according to an Iridium press release.

“With all the water and no power immediately after the hurricane hit, it’s probably fair to say that satellite phones were the only form of communications in some areas,” said Ted O’Brien, Iridium’s vice president of market development. “And with Iridium, there’s no dependence on local infrastructure, which is unique to our particular satellite system.”

O’Brien said other satellite phone systems require a functional ground earth station within the same region, but Iridium’s 66 low-earth-orbit satellites are linked in a manner that provides worldwide coverage using just one earth station located in Arizona. The system design provides better signal strength, greater coverage and fault tolerance than other satellite phone systems, he said.

Iridium recently completed its first round of beta testing for its “group call push-to-talk” communications service, but the service is not available to Iridium users in the Katrina-affected areas, O’Brien said.