WASHINGTON – After a two day delay caused by weather, the U.S. Navy launched the fourth satellite in its next-generation mobile communications system Sept. 2.
The multibillion-dollar Mobile User Objective System now consists of four geostationary-orbiting satellites. An on-orbit spare is expected to launch in 2016. Built by Lockheed Martin Space Systems of Sunnyvale, California, the MUOS constellation is designed to provide smartphone-like communications to mobile forces at rates 10 times faster than the legacy system.
The launch completes what the Navy describes as the initial constellation and now provides near global coverage. Industry and government officials have discussed adding more satellites to the constellation as part of future international partnerships .
The MUOS-4 satellite launched aboard a United Launch Alliance Atlas 5 rocket from Cape Canaveral Air Force Station, Florida, at 6:18 a.m. local time. The Atlas 5 configuration used in the launch featured a 5-meter payload fairing, five solid-fueled strap-on boosters and a Centaur upper stage powered by a single RL-10 engine.
In a press release issued Sept. 2 Lockheed Martin reported that the satellite had been safely delivered to geosynchronous transfer orbit and was responding to commands. The release said the satellite would take several days to reach geosynchronous orbit 36,000 kilometers above the equator, after which it will be undergo testing before being turned over to the Navy.
The first two MUOS satellites launched aboard Atlas 5 rockets in February 2012 and July 2013. The third launched in January.
Like the Navy’s legacy UHF Follow On satellites, the MUOS satellites are equipped with a UHF-band narrowband payload to provide links to ships at sea and to mobile ground forces operating in hard-to-reach areas such as beneath dense forest canopies. But MUOS is introducing a new capability akin to smartphones via a digital payload employing a technology standard known as wideband code division multiple access, or WCDMA.
To date, only the UHF payloads aboard the MUOS satellites have been utilized, a situation that is not expected to change until the end of the year.
The MUOS program is expected to cost about $7.4 billion, according to the Government Accountability Office. The initial constellation is expected to provide service through 2025.
credit: ULA
