Space: Never Enough Bandwidth


October 17, 2020: As the U.S. exported more of its large UAVs, like the Predator and now the Reaper, it found itself with a problem. The latest model Predator B (Reaper), the MQ-9B SkyGuardian makes heavy use of its satellite link. The problem is these new, larger (5.6 ton versus 4.6 ton) SkyGuardians have a lot more sensors and high-resolution vidcams. To send all this video back to the operators, especially the high-res video, requires a lot of bandwidth (data transmission demand), more than the American military satellite system can handle. A solution has been to find commercial communications satellites that can handle the high-bandwidth and low-latency (fast response) data transfer new surveillance satellites like SkyGuardian require for best performance. Over the last decade the United States has built a military communications network optimized to serve its UAVs and manned aircraft sending video and radar data to the ground or other aircraft or ships. Foreign customers for SkyGuardian and the maritime patrol variant SeaGuardian expect and requite high-bandwidth and low-latency sat links to perform as advertised. This has led to sales of these UAVs including the manufacturer finding suitable commercial communications. While the U.S. military does have surplus bandwidth, this is reserved for emergencies (military or civilian). In such cases the U.S. would share some of this bandwidth with allies. Even so, there will always be a shortage of high-performance bandwidth for larger UAVs, especially those doing maritime patrol. These UAVs, like SeaGuardian, have high-res cameras and radars to search coastal areas not matter how overcast it is at sea level. High-res cameras are vital to determine what is going on down there, especially of the maritime surveillance involves looking for small smuggler, pirate or terrorist boats. It’s not enough to build a UAV with all the needed maritime patrol sensors, you have to get that data back to operators in near real-time.

The U.S. military has, since the 1990s, been a major and increasing user of communications satellites. Not only military owned but also leased bandwidth from commercial satellites. Back in 2010 the military feared that there might not be enough commercial bandwidth available for lease to handle heavy wartime loads. That turned out to be less of a problem than predicted because of the rapidly growing number of commercial users for high bandwidth services (like streaming video). Now the military sees wartime shortages as less likely because, during a national emergency, commercial satellite owner can be compelled to lease bandwidth to the military and that commercial bandwidth is growing so fast that there was more than ten times more of it in 2020 than in 2016.

The U.S. Department of Defense is trying to get more money for its own communications satellites. In 2013 the Department of Defense launched its sixth WGS (Wideband Global SATCOM) communications satellite, and by 2019 the tenth one was put into service. The WGS is a six-ton satellite with a traffic handling capacity of 3.6 gigabits. The first WGS went up in 2007, but that was six years after that was supposed to happen. The WGS sat design is undergoing a major upgrade that takes effect in the 11th one, which will launch in 2023. To complement WGS there is the new ESS (Evolved Strategic SATCOM) and the first prototypes for these are supposed to be ready by 2025

WGS birds are optimized for military use and are more effective than equivalent civilian comm satellites. WGS originally stood for "Wideband Gapfiller Satellite" and they are actually modified versions of the Boeing 702 communications satellite. Boeing has built or has orders for over 36 of the commercial 702s, which are built on the earlier, and very successful, 600 series communications satellites. Using the 702 as a model for WGS seemed like a slam-dunk initially, basing needed military commo birds on a solid civilian model. A few tweaks and additions to deal with military security needs, and off we go. The Department of Defense wants to build six WGS birds, at a cost of some $220 million each. The WGS has ten times the throughput (3.6 gigabits) of the earlier DSCS III commo satellites. The first WGS bird in orbit more than doubled the transmission capacity of the Department of Defense satellite system.

This growing need for more comm birds has been a problem for decades. Between 2000 and 2002, Department of Defense satellite bandwidth doubled, and more than doubled every 18 months after that. Back in 2000, some 60 percent of Department of Defense satellite capacity had to be leased from commercial firms. While the Department of Defense had its own communications satellite network (MILSAT), it underestimated the growth of demand. Greater use of the internet and reconnaissance aircraft and UAVs using video cameras quickly used up MILSAT's capacity and forced the military to lease capacity on commercial satellites. This was done on the "spot market," meaning the Department of Defense had to pay whatever the market would bear at that moment. Since the military needed more capacity because of combat operations, the media was also in the market for more capacity to cover the war. The Department of Defense paid more than ten times as much as it would have if it had leased (for one to fifteen years) satellite capacity earlier. The situation was made worse by the fact that it was an emergency situation, so every heavy user of satellite communications was making their own deals. This resulted in some users, like the air force, or, say, the Atlantic Fleet, having some extra capacity when someone else, like Army Special Forces, was still short.

It was only in 1990 that the U.S. armed forces moved to satellite communications in a big way. This made sense, especially where troops often have to set up shop in out of the way places and need a reliable way to keep in touch with nearby forces on land and sea as well as bases and headquarters back in the United States. At the time of the 1991 Gulf War, there was enough satellite military communications capacity (commonly known as "bandwidth") in the Persian Gulf for about 1,300 simultaneous phone calls. Or, 12 megabits per second. By the end off the 1990s the military now had a lot more satellite capacity, but demand had increased even faster. UAV reconnaissance aircraft use enormous amounts of satellite capacity, especially after September 11, 2001. The Global Hawk needed 500 megabits per second, and Predators and Reapers about half as much. The major consumer of bandwidth is the live video. Data transmission capability had gone from 46 megabits (million bytes) per second in late 2001, just for troops in CENTCOM (the Middle East and Afghanistan), to nearly ten giga (billion) bits per in 2007. Demand increased even more in the next decade This explains the rush to get those WGS type birds up.

Attempts to get capacity from civilian satellites was complicated by the fact that there was a shortage there as well. This was created by the tremendous overbuilding of fiber optic cable networks on the ground (and under oceans) in the late 1990s. This provided cheaper bandwidth for civilian uses and has meant fewer communications satellites being put up. In fact, the fiber optic glut reduced planned satellite launches by some 60 percent for the first few years of the 21st century.

The solution was the WGS birds, with the first supposed to launch in 2004. But there were design problems, manufacturing problems, and scheduling problems getting an American launcher (having a Russian or Chinese rocket put these birds into orbit was not an option, for security reasons.) These problems have been solved and, while that provided more capacity, it was never enough.




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