The system is being used extensively by the U.S. Department of Defense through the DoD gateway in Hawaii.[7] The DoD pays $36 million a year for unlimited access for up to 20,000 users[8] The commercial gateway in Tempe, Arizona, provides voice, data, and paging services for commercial customers on a global basis. Typical customers include maritime, aviation, government, the petroleum industry, scientists, and frequent world travelers. Iridium satellites are now an essential component of communications with remote science camps, especially the Amundsen-Scott South Pole Station. As of December 2006, an array of twelve Iridium modems was put online, providing 24/7 data services to the station for the first time. Total bandwidth is 28.8 kbit/s.[9]