Bandwidth Breakthrough

March 1, 2007

The Air Force—the world’s dominant space power—is on the threshold of a mighty upsurge in communications capabilities.

Top USAF officials report that the service some time this year will begin launching communications satellites of sufficient power and sophistication to generate an explosion of usable electronic bandwidth.

After years of problems, setbacks, and delays, the new spacecraft are ready to provide military users a data transmission “pipe” of unparalleled scope and magnitude.

In colloquial parlance, the term “bandwidth” is used to mean the capacity for data, while “data transfer rate” refers to the speed with which you can send the data.

In the new era, US troops previously lacking access to advanced satellite communication channels will be able to use the same links used by commanders to hold video teleconferences in the field, pass targeting data, and track friendly forces.

Troops that are already connected to such satellites will be able to communicate much faster. In addition, they can shift some messages from commercial to more-secure military systems.

The Air Force operates the primary Milsatcom systems that are used by all of the US armed services. Despite strains on the system, satellite communications play a key role supporting combat operations in Afghanistan and Iraq—and everywhere else, for that matter.

In the communications world, the relevant satellite systems are many—Milstar, Defense Satellite Communications System (DSCS), Advanced Extremely High Frequency Satellite Communications System (AEHF), Transformational Satellite Communications System (TSAT), Mobile User Objective System (MUOS), Polar Military Satellite Communications (Interim Polar), Wideband Global System, and so forth. (See “Space Almanac: Major Military Satellite Systems,” August 2006, p. 81.)

They are mostly obscure to anyone outside of the military space community. They are also expensive.

For all that, their significance is beyond dispute. Gen. Kevin P. Chilton, head of Air Force Space Command, Peterson AFB, Colo., observed in November, “We’re not on the Hill [Congress] arguing whether or not we need a new this or a new that. Everybody understands” that the military needs the capability.

High Priority

The Air Force recently designated the acquisition of new satellites for communications and early warning to be USAF’s No. 3 modernization need, trailing in priority only to next generation air tankers and combat search and rescue helicopters.

While the Air Force designs and pays for most of the military’s communications satellites, the heaviest users can be found in the Army and Navy. Richard W. McKinney, a retired colonel now serving as the civilian director of space acquisition in the Air Force undersecretary’s office, said that USAF accepts this responsibility, and the bill, as part of its mission.

Even with a dramatic influx of new and faster satellite connections, deployed troops probably will rely on commercial systems well into the future. While tremendously valuable to US forces, commercial services lack the same levels of security as the military’s own satellites, McKinney said. Military users can encrypt the data that they send over a commercial satellite, but those systems lack the protection against jamming and other types of interference typically found on an Air Force spacecraft.

The Pentagon conducted a variety of satellite communications experiments in the 1960s before designing the Initial Defense Communications Satellite Program, which was later renamed the Defense Satellite Communications System. DSCS is the Air Force satellite constellation most commonly used by deployed forces.

The Air Force began launching the first generation of DSCS satellites in 1966 and has upgraded them over time to include more bandwidth and faster data rates.

The Air Force launched the last of the DSCS III satellites in August 2003, and the final four of those satellites were upgraded to provide 200 percent more capacity than their predecessors—and up to 700 percent more capacity in certain situations. DSCS satellites are used by troops that range from those in ground vehicles to those in large aircraft like the airborne command post fleet.

The DSCS satellites have served as a workhorse for the US military, providing troops with a wide pipe for passing data, imagery, and video. Each DSCS satellite cost about $200 million.

While they retain some measure of protection against enemy attempts to jam or interfere with its signals, DSCS satellites lack the security needed for the most secure transmissions.

The most sensitive communications jobs are reserved for the Milstar constellation, which an Air Force fact sheet refers to as the “FedEx of communications systems—when it … has to be there, Milstar is the system.”

In addition to strategic messages, the Milstar satellites today carry air tasking orders, targeting data, imagery, and video teleconferences. The satellites have also been used outside of combat operations to support relief efforts for Hurricane Katrina.

Cold War Babies

The Milstar satellites, the first of which launched in early 1994, were designed during the Cold War and were built with the highest possible levels of signal protection to meet the needs of strategic forces. Unlike DSCS, Milstar reduces the chances of signal intercept or disruption by relying on links between satellites (rather than ground relay stations) to relay its signals over long distances.

With the end of the Cold War, the Milstar mission changed.

While Milstar still provides connectivity for the nuclear forces, the constellation has taken on an increased tactical role. For example, Air Force officials have credited the Milstar system with playing an important part in the command and control with the rescue of Army Pfc. Jessica Lynch from her Iraqi captors in 2003, though they have not publicized details.

While the Milstar satellites, which are built by Lockheed Martin, offer great protection against jamming, the satellites provide less bandwidth than DSCS birds, making them useful primarily for high priority messages such as nuclear command and control.

With changing priorities at the end of the Cold War, the satellites were redesigned with somewhat less—though still superior—signal protection as a trade-off to provide greater bandwidth for tactical users. Tactical users rely on Milstar for data and messages that simply must get through.

Each Milstar satellite costs about $800 million, and the last Milstar satellite was launched in April 2003. The Air Force plans to begin replacing the constellation in 2008 with Advanced Extremely High Frequency satellites.

Milstar is complemented today by a system known as Interim Polar, which features Milstar-compatible payloads hosted on classified satellites in orbits that can better reach the Earth’s extreme northern latitudes. The first of those payloads, which was built by Boeing, was launched in 1998, and a third satellite is slated to become operational this year.

The polar-orbiting communications system is of particular interest to submarines that operate in the Earth’s far northern regions. The Air Force is planning to begin launching a permanent polar replacement system, designed primarily to ensure continuity of service rather than a leap-ahead capability, around 2013. The program is still in the conceptual stage.

A dramatic expansion in available military bandwidth is expected to begin in June, according to Brig. Gen. Ellen M. Pawlikowski, commander of the Military Satellite Communications Systems Wing at USAF’s Space and Missile Systems Center, Los Angeles Air Force Base. That is when the first Wideband Global System satellite, built by Boeing Integrated Defense Systems, will launch. (The WGS satellites were known as Wideband Gap-filler System until November 2006, when the Air Force changed the name to better reflect their importance.)

Big Boost

A single Wideband Global System satellite will provide as much bandwidth as the entire DSCS constellation, according to Chilton. Each satellite will cost about $300 million.

Those satellites will play an important role in helping the Air Force take advantage of intelligence-surveillance-reconnaissance assets such as unmanned aerial vehicles. Fully exploiting UAVs requires a tremendous amount of bandwidth to transmit data such as high-resolution imagery.

The Air Force announced in November that it would modify the Wideband Global System satellites beginning with the fourth spacecraft in the constellation, which is expected to launch in 2011, to better accommodate ISR aircraft.

The Air Force conceived those satellites as a military-owned option that would provide service similar to that of commercial satellites, McKinney said. To build the satellites as quickly and inexpensively as possible, the Air Force elected to rely heavily on commercial technology.

While the wideband global satellites have some protection against jamming and interception, they do not have the same level of security as the predecessor DSCS satellites, McKinney said.

In addition to more bandwidth, WGS will offer military users greater flexibility, McKinney said. Troops today who have equipment designed to work with one frequency band cannot communicate directly with those with different types of terminals, he said.

Wideband global will feature both X-band and Ka-band links, so a user with an X-band terminal can send a message to the satellite that is transmitted back down to Earth on a Ka-band link, or vice versa, he said.

When the Air Force awarded the contract in 2001, the first Wideband Global System satellites were expected to be on orbit in 2004. Boeing hoped to take advantage of technology used on commercial satellite efforts that were well ahead of WGS in development, but ran into trouble when those programs fell behind.

Further difficulty was caused when, due to the downturn in the commercial satellite marketplace, Boeing was forced to lay off and reassign engineers who would have been working on related technology.

The wideband global program ran into other problems in 2005 due to the installation of substandard parts on the satellites, which delayed their anticipated launch into 2007.

However, Pawlikowski said that work on WGS has gone much better over the past year-and-a-half. While additional issues have cropped up with the antennas and other subsystems on the satellites, those problems have been resolved relatively quickly, she said.

The Air Force’s current contract with Boeing calls for the purchase of four wideband global satellites, with options for two more satellites. However, the Air Force could opt to order more and is working with US Strategic Command to determine whether doing so is necessary, Pawlikowski said.

Whatever Times Five

The increase in available communications bandwidth will continue in April 2008 with the launch of the first Milstar-replacement Advanced EHF satellite. The AEHF satellites, built by Lockheed Martin Space Systems, will enable users to pass the most secure communications at rates five times faster than the newest Milstar allows—and 3,400 times faster than the first Milstar spacecraft, McKinney said.

AEHF will also enable far more users to connect to the satellites simultaneously, an important capability for tactical forces. The number of users who can connect to Milstar at the same time is measured in the hundreds; Advanced EHF will allow several thousand connections at once, McKinney said.

The Air Force had hoped to have AEHF satellites on orbit by now. The service allowed Lockheed Martin and Boeing, which had been competing against each other to build the satellites, to join together as a team to accelerate the first launch by 18 months to late 2004.

However, the team fell apart, and technical difficulty on the program—most recently a delay in delivery of encryption equipment from the National Security Agency—contributed to moving the first launch into 2008.

The NSA has since delivered the needed encryption equipment, and the program’s schedule has been stable over the past two years, Pawlikowski said, during which time the Air Force has made “huge strides” in its cooperative work with the NSA.

Despite the promise of improved capabilities with Wideband Global System and Advanced EHF, the Air Force is already looking forward to a follow-on generation of satellites called the Transformational Satellite Communications System, or TSAT, which for the first time will offer highly protected communications to troops on the move.

Lockheed Martin and Boeing are currently leading teams competing to build the TSAT satellites, which are expected to launch beginning around the middle of the next decade. The Air Force expects to choose a winner from the two companies to build the satellites in late 2007.

TSAT is expected to provide highly secure communications with a tremendous increase in bandwidth over the Air Force systems in use today and planned to launch over the next several years. The TSAT satellites will carry roughly 10 times the bandwidth of the Advanced EHF satellites, Chilton said.

The Navy Contributes a UFO Satellite

The Air Force buys, maintains, and operates the vast majority of the military communications satellites, but the other services aren’t total freeloaders.

The Navy filled one key coverage gap with its constellation of the Ultra High Frequency Follow-On Satellite System.

UFO offers unique connections to troops on the move in aircraft, ships, and land vehicles, including those in locations shielded by wavelength-blocking tall buildings or jungle canopy. Troops often turn to these satellites, as well as commercial services, for their voice communications.

The UFO satellites are important to the Air Force. They carry payloads that connect users of the Global Broadcast System. GBS is a satellite-based system used to deliver maps, images, television news broadcasts, and other bandwidth-intensive products to deployed commanders.

The Navy’s UFO system is expected to be replaced beginning around 2010 by the Mobile User Objective System.

Laser Links

The satellites’ advanced capabilities are expected to be enabled in part by laser links that connect the satellites to each other as well as high-altitude aircraft. The system at times seems to have been portrayed as the Holy Grail in military communications capability, but the military has proved adept at rapidly expanding its bandwidth use to immediately soak up any additional capacity.

New technology such as the laser links for TSAT has raised concern on Capitol Hill that the Air Force was pushing immature components into space too quickly. (Congress trimmed $130 million from the Air Force’s $867 million request for TSAT in the 2007 budget, but the cut was far less than in previous years, when the Air Force had several hundred million dollars slashed from its request.)

Pawlikowski credited the Air Force’s new block acquisition approach to space systems with helping to improve Congressional confidence in TSAT. Beginning with its 2007 budget request, the Air Force revamped its approach to TSAT to field initial satellites with less capability. More advanced capabilities will be added in time as additional satellites in the constellation are launched.

Roughly 80 percent of the communications bandwidth used by forces in Iraq has been provided by commercial satellites, and it is not clear how that ratio may be affected by the launch of new military satellites.

McKinney acknowledged that commercial service is expensive, but noted that one of the prime benefits of commercial services is that it enables the military to buy just the additional bandwidth it needs to support surge requirements during a contingency.

Satellite communications is not the only area where the Air Force relies on the commercial sector for surge capability. Chilton said in a Dec. 18 interview that this model also works well in other areas for the military.

The Air Force operates and maintains military cargo aircraft such as the C-17 and C-130s for routine airlift, but also turns to the Civil Reserve Air Fleet during emergencies and when its own aircraft cannot handle all requirements, Chilton noted.

Despite the dramatic increase in bandwidth that is on the horizon with the advent of Wideband Global System, Advanced EHF, and TSAT, Air Force officials expect to continue their heavy reliance on commercial satellite communications services.

Jeremy Singer is a Boston-based staff writer with Space News in Washington, D.C. He covers the Pentagon and is the editor for special projects. His most recent article for Air Force Magazine, “Responsive Space,” appeared in the March 2006 issue.