The Mobile User Objective System (MUOS), a constellation of
four U.S. Navy spacecraft plus one on-orbit spare, is designed to supplement and
eventually replace the existing UHF satellites that provide narrowband capacity
for U.S.
military personnel operating in remote areas worldwide. Each MUOS satellite
will carry two payloads: a payload similar to the one currently flying on each
of the Navy’s aging UHF Follow-On satellites to provide links to currently
deployed user terminals and a second, digital payload designed to offer 10
times the capacity of the legacy satellites.
“The MUOS constellation will offer significantly improved
coverage, capacity and, for the first time, communications on the move for the
warfighter,” said Mark Pasquale, MUOS program manager for Lockheed Martin Space
Systems of Sunnyvale, Calif., prime contractor for the satellites and the MUOS
terrestrial network. MUOS satellites will function “basically like a cellphone
tower in the sky,” Pasquale said. “You can think of the handheld user terminals
as robust, rugged smartphones.”
That cellphone-like capability will not be available
immediately after launch, however, because General Dynamics C4 Systems, prime
contractor for the Joint Tactical Radio System (JTRS) Handheld, Manpack, Small
Form Fit program still is developing the waveform that will enable military
users to communicate with the MUOS satellites’ digital payload. That work is
scheduled to be completed next summer. In the meantime, the first MUOS
satellite will use its UHF Follow-On payload to augment the Navy’s narrowband
constellation and provide communications through existing user terminals.
Government and industry teams are evaluating the performance
of a preliminary version of the digital MUOS waveform. During tests in
December, U.S. Army Brig. Gen. Michael Williamson, the Defense Department’s
JTRS joint program executive officer, used a General Dynamics PRC-155 radio to
send and receive data using a MUOS satellite simulator and a MUOS ground
station, Chris Brady, vice president of assured communications for General
Dynamics C4 Systems of Scottsdale, Ariz., said in an email.
The Navy also plans to test the current version of the
waveform after the first MUOS spacecraft is launched on a United Launch
Alliance Atlas 5 rocket from Cape Canaveral Air Force Station, Fla., into geostationary orbit over the Pacific Ocean,
said Steven A. Davis, a spokesman for the Space and Naval Warfare Systems
Command in San Diego.
The spacecraft is scheduled to undergo approximately six months of on-orbit
checkout and testing before it becomes operational, Davis said.
MUOS user terminals are expected to feature the final
version of the waveform following the launch of the second MUOS satellite, he
added.
That satellite, which is undergoing thermal vacuum testing
at Lockheed Martin’s Sunnyvale
facility, is scheduled for launch in early 2013. Lockheed Martin has completed
construction of the third MUOS spacecraft and is building the fourth and fifth
satellites. Each MUOS satellite is scheduled to complete testing and
integration approximately one year behind the previous one, Pasquale said.
With the satellites in production, government and industry
officials are anxious to gain access to the digital MUOS waveform because
demand for UHF communications far outpaces available supply. The Navy launched
11 UHF Follow-On satellites between 1992 and 2003. The first satellite suffered
a launch failure and two additional satellites stopped working in 2005 and
2006. The eight remaining UHF Follow-On satellites are degrading due to age,
Navy officials told lawmakers May 11 during a U.S. Senate Armed Services
strategic forces subcommittee hearing.
“The delay in delivery of the MUOS system, coupled with the
age and fragility of the current UHF satellite constellation, has our full
attention and focus,” Rear Adm. David Titley, director of the Navy’s space and
maritime awareness domain, and John Zangardi, Navy deputy assistant secretary
for command, control, communications, computers, intelligence, information
operations and space, said in a joint statement.
To prevent gaps in UHF capacity, the Navy has leased
services on Intelsat General’s Leasat, the United Kingdom’s SkyNet satellites
and the Italian defense ministry’s Sicral satellite. In addition, the service
has repositioned and reprogrammed existing spacecraft to expand capacity.
“Currently, the military and commercially leased legacy UHF satellite communications
assets exceed warfighter requirements by approximately 111 channels worldwide,”
Davis said in
an email. “Although the unplanned loss of a [UHF Follow-On satellite] before
MUOS-1 [is operational] would result in the UFO constellation not meeting its
availability requirement, total UHF SATCOM capacity for the warfighter would
still be met.”
Former Pentagon officials note, however, that the Navy’s
published requirement for UHF satellite communications capacity falls far short
of actual demand. Demand continues to climb, due largely to the proliferation
of unmanned aircraft, while supply remains low, due largely to delays in the
MUOS program. The Navy originally planned to launch the first MUOS satellite in
late 2009.
In an attempt to meet high demand, the Senate Armed Services
Committee included language in a report accompanying the 2012 Defense
Authorization Act calling on the Navy to explore hosted payloads or other
options to expand UHF capacity and to deliver to the committee a report on that
review “no later than March.”
The Navy already plans to share UHF capacity in the Indian
Ocean region on a hosted payload the Australian Defense Force plans to send
into orbit in March on Intelsat General’s IS-22 commercial communications
satellite. In exchange, the Australian Defense Force will share MUOS capacity
in the Pacific Ocean region under an agreement signed in April 2010.
Intelsat plans to fly a copy of that UHF payload on IS-27, a
satellite scheduled to launch in December into a slot over the Atlantic Ocean,
said Richard DalBello, vice president for legal and government affairs for
Intelsat General of Bethesda, Md. While that satellite will be designed
primarily to offer television service to Latin America, it also will feature a
payload identical to the one on IS-22, so it can support the tens of thousands
of UHF terminals deployed around the world, he added.
“The Navy has not yet agreed to buy any capacity on Intelsat
27,” DalBello said in an email. “We hope the government will be supportive so
we can make this capability available to the war fighter and our closest
allies.”
Mobile satellite services operator Inmarsat also is eager to
help the U.S.
military augment tactical communications capacity with its Broadband Global
Area Network, which provides service to portable terminals. U.S. military
forces already use the Broadband Global Area Network, provided by London-based
Inmarsat’s fleet of L-band satellites, to supplement military tactical
communications networks, an Inmarsat official said.
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