August 22, 2007:
Military
satellites are getting priced out of the market by cheaper manned aircraft and
UAV alternatives. Even small, quickly launched micro-satellites, cost ten times
more, per hour over the battlefield, than do alternatives. These now include
things like weather balloons carrying satellite grade communications or
sensors.
The U.S. Department of Defense
has known for several years that it cannot afford sufficient satellites to meet
the growing demand for communications satellites. The commsats cost at least
$250 million each, and even the much touted micro-sats still cost about ten
percent of that. One of the more imaginative alternatives turned out to be
things like weather balloons equipped with satellite commo gear. The high
altitude "satellite replacement" balloons are based on existing
weather balloon designs, but carrying communications gear instead of weather
sensors. As long as you can pick up and broadcast the same kind of signals
commsats handle, you can put the equipment in a high altitude (up to 100,000
feet) balloon, or even a bomber or tanker that spends hours circling the
battlefield. Much of the satellite communications needed by combat troops is
with other people in the same general area. So the commsat replacement (a
balloon or B-52) can do the job, passing off the long distance stuff to the
real commsat.
A balloon can cover troops
needs for about a thousand kilometers in all directions. A B-52 or KC-135
tanker can deal with a smaller area, but is even cheaper than $25,000 balloon,
which is often only good for a few missions. Once launched, the balloon turns
on its battery powered transponder when it has reached the proper altitude,
maintaining its position like a hot air balloon, using computerized controls.
It acts like a very low flying satellite until the battery runs out after 8-12
hours. Then the balloon deflates, a parachute brings it to earth in one piece,
and a GPS beacon makes it possible for the equipment to be recovered for reuse.
One of the more useful aspects
of balloons is that they are easy to carry, and can be inflated and launched by
a Special Forces team out in the middle of nowhere. Special Forces recon teams
often want to send back live video of whoever they are keeping an eye on. These
balloon sats make that easier, because they can also carry satellite grade
sensors (various types of night and day cameras).
The major cause of more
commsat use is live video being generated by the increasing number of vidcams
on the battlefield. These vids are being exchanged by the units cooperating in
an operation. Since that's all local, a "satellite substitute" (a balloon, or
aircraft carrying the comm. Gear) will work. To that end, there are even plans
to put the comm gear in UAVs, including special UAVs that just fly circles high
in the sky, acting as satellite substitutes. These substitutes cost less than
ten percent, per hour in use, of what satellites cost.
The satcomm shortage problem
began during the 1990s, when 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 1300 simultaneous phone
calls. Or, as the geeks put it, 100 mega (million) bits per second. But while
the military has a lot more satellite capacity now (the exact amount is a
secret), demand has increased even faster. UAV reconnaissance aircraft use
enormous amounts of satellite capacity. The Global Hawk needed 500 megabits,
and Predators about half as much. The major consumer of bandwidth is the live
video.
UAVs have other sensors as
well, as do aircraft. A voice radio connection only takes about 2,000 bits per
second, and each of the multiple channels needed to control the UAVs use about
the same. But it adds up, especially since the military wants high resolution
video. At the moment, the U.S. has far more demand for satellite communications
than it can support. As a result, not all the Predator and Global Hawk UAVs in
combat zones have sufficient bandwidth to send their video back to the United
States. Data compression and using lower resolution is often necessary, or
using satellite substitutes (aircraft carrying transponders) to send the video
to local users. The substitutes are becoming more common, simply because there
is neither the money, nor the time, to get sufficient satellites into orbit.