Mobile Satellite Service Orbits
Satellites also provide mobile telephony services. Satellite mobile telephony enables regional to near-global coverage depending on the satellite or constellation, using handsets that communicate directly with a satellite. Mobile satellite telephone service is provided by satellite constellations in LEO, such as Iridium and Globalstar, and by satellites in GEO, such as Inmarsat, Thuraya, and ACeS. These services are provided by satellites primarily using the L-band. Satellites providing mobile phone and data services often are referred to as mobile satellite service (MSS) satellites.
One MSS industry leader, Iridium, is implementing a major network upgrade. In June 2010, Iridium selected France’s Thales Alenia Space as prime contractor for its second-generation satellite constellation, named Iridium NEXT. The upgraded network will consist of ## active and ## spare satellites, scheduled for launch between 2015 and 2017.[
Another MSS industry leader is Iridium, which operates a LEO constellation of ## active satellites to provide global coverage. The Iridium constellation uses intersatellite links to route network traffic directly between spacecraft, avoiding the need for multiple hops between space and ground to relay signals around the world. Like Inmarsat, Iridium is significantly upgrading its network to reach new customer bases with new technology.
The MSS sector was created to address a specific market that was underserved by FSS: maritime voice and data, enabling emergency communications for ships at sea. Subsequent MSS systems tried to create ubiquitous coverage for land and sea customers, especially in areas that were underserved by terrestrial mobile telephony. For years, MSS systems were designed using satellites in GEO or LEO that were able to transmit low-data rate information to mobile receiving systems, such as satellite telephones or receiving stations on ships.
Iridium’s LEO constellation of ## active and ## spare satellites relay signals to each other directly, unlike other systems that require multiple hops between space and the ground to send signals around the world. In June 2010, the company named France’s Thales Alenia Space as prime contractor to construct the communications payload for Iridium’s second-generation, ##-satellite constellation Iridium NEXT.
Mobile satellite services (MSS) providers enable users to connect phones and other handheld devices directly to a satellite to provide near-constant coverage, even in places underserved by terrestrial facilities, such as ships at sea, isolated rural villages, polar settlements, or other remote sites. Although they also provide a wide range of routing services to major users such as the U.S. Navy fleet, MSS is particularly useful in the aftermath of natural and man-made disasters when regular forms of communication are often unavailable.
Mobile satellite services (MSS) providers connect phones and other handheld devices directly to satellites to provide near-constant coverage, even in African villages, Antarctic bases, offshore oil rigs, and other remote places not served by terrestrial facilities. The services themselves can include telephone calls, internet access, or mobile television and radio. The satellite fleets can use different orbits ranging from LEO all the way up to GEO.
While FSS systems all operate in GEO, mobile satellite service (MSS) systems operate in a range of orbits. Some MSS operators have built their networks using a limited number of GEO satellites. In August 2008, the oldest and largest of these, Inmarsat, launched its ## Inmarsat-4 satellite, establishing global availability of its Broadband Global Area Network (BGAN) service, and bringing the fleet total to ## spacecraft. Another GEO MSS operator, ICO Global, launched its G-1 satellite in April 2008 to provide voice, data, video, and Internet service throughout the United States on mobile and portable devices.