A powerful new U. S. Navy communications satellite with huge antennas that will act as a giant military cell phone tower in space is poised to try again to launch from Cape Canaveral on Feb. 24 on board a 206 ft. tall 2.2 million lb. thrust Atlas V 551 rocket. Two previous launch attempts were scrubbed due to weather.
Launch of this first Navy/Lockheed Martin built MUOS “Mobile User Objective System” spacecraft will inaugurate a communications constellation 10 times more capable than the older spacecraft constellation that it is replacing.
The United Launch Alliance (ULA) Atlas V 551 vehicle with five solid rocket boosters is planned for liftoff from Space Launch Complex-41 (SLC-41) at 5:15 p.m. EST. The launch window extends until 5:59 p.m.
The nearly 7.5 ton mass of the satellite requires that the most powerful version of the Atlas V, previously flown just 3 times in 28 missions over the 10 year flight history of the rocket. The only other times were to fire NASA spacecraft to Pluto, Jupiter and Mars. The satellite’s dry weight is just over 8,400 lb. with more than 6,400 lb. of hydrazine fuel for maneuvering out of a transfer orbit to geosynchronous orbit.
The Pentagon’s new $6 billion satcom capability is being made possible specifically by adapting commercial 3G cell phone technology to military Ultra High Frequency (UHF) communications the Navy says. MUOS should provide communications at up to 40.21 Mbps compared with 3 Mbps for the old UHF system, according to Navy Capt. Paul Ghyzel, MUOS program manager.
The UHF spectrum is the military’s communications workhorse because it is the only radio frequency that can penetrate jungle foliage, inclement weather and “urban canyon” terrain like that under siege in Syrian cities.
The first MUOS spacecraft was to have been launched in 2009 but delayed by 3 years due to the technical challenges. By 2016 the new system is to grow to four spacecraft positioned around the planet in geosynchronous orbit. A fifth spacecraft is being built as a spare, the Navy said.
Among the most impressive features of each MUOS satellite are two large umbrella-like gold mesh antennas, one that will unfold to 46 ft. diameter and the other to nearly 18 ft. diameter.
The antennas are built by Harris Corp. based in Melbourne, Fla. – only about 20 mi. south of Cape Canaveral. Harris is one of the defense, intelligence and commercial satcom industries’ most important antenna suppliers. Harris acknowledges that it has built civilian satcom antennas up to 72 ft. in diameter. But the company is necessarily silent on the larger top secret antennas deployed on National Reconnaissance Office eavesdropping spacecraft also launched from Cape Canaveral.
MUOS will provide 3G data rate communications to highly mobile Navy, Marine, Air Force and Coast Guard forces that previously could not get such services, envisioned now to be a key enabler for the faster more nimble military operations anticipated in the 21st century.
To achieve this, the Navy, Lockheed Martin and its subcontractors adapted a commercial third generation Wideband Code Division Multiple Access cellular phone network architecture and combined it with geosynchronous satellite capabilities.
All U.S.military forces and many of their allies rely upon Navy satellites for narrow band communications. More than 60 percent of military satellite communication users are supported via the UHF band. Approximately 67,000 UHF terminals are currently in military use on more than 50 terminal configurations, many of them designed to be small and portable enough to be carried deep into theaters of operation by forces such as Navy Seals and Army Green Berets.
Although the Air Force oversees most Pentagon space systems, the Navy is responsible for all UHF narrowband satellite communications.
The Navy’s UHF Follow-On satcom constellation is the present narrowband military satellite communication system. It achieved Initial Operational Capability in November 1993 and Full Operational Capability in February 2000, says the Navy. This current UHF constellation consists of eight operational satellites, augmented by two “fleet” satellites and leased services on commercial satellites.
The four MUOS satellites are to replace all this with much higher capability, but a major Boeing “Legacy” system on the new spacecraft will ensure interoperability with the older UHF satcoms until the switchover is complete.
The big MUOS antennas, as well as the satellite’s fixed antennas, are to create spot beams, the largest with a footprint of about 2,000 mi. diameter. By splitting this continental coverage into several narrower beams, the Pentagon can reuse frequencies in different spots without interfering with each other. So in addition to boosting data rate, the Navy believes it can handle at least 15 times the communications volume with the new spacecraft.
The MUOS 1 satellite is so heavy that it will require the single engine Lockheed Martin Centaur upper stage to fire three times to boost the spacecraft into about a 22,230 x 2,150 mi. geosynchronous transfer orbit inclined 19 deg. to the equator. Normal Centaur transfer orbits require only two firings. The mission marks the 200th flight of a Centaur since the mid 1960s, the workhorse upper stage for NASA, the Pentagon and commercial users. After launch it will take about 3 months for the satellite to be positioned in geosynchronous orbit.
The spacecraft was placed into its launch shroud at the Astrotech commercial processing facility (pictured below) near Cape Canaveral.