Space: April 1, 2004



Delays in launching new American military communications satellites are causing severe shortages of bandwidth (the capacity to move data). The first of three Wideband Gapfiller 702 Satellites was supposed to have been launched this June, but is now delayed until some time in 2005. The Department of Defense is buying bandwidth on commercial satellites, but, for security reasons, prefers to operate on its own communications birds. 

The cause of the problem is the growing popularity, and usefulness, of real time video transmitted from UAVs, or troops on the ground. While a phone call takes up 2,000 bits a second (and email even less), full motion video takes up to 200 mega (million) bits a second. The new communications the Department of Defense is trying to get into orbit will handle eight giga (billion) bits per second each. But do the math, that capacity would be gobbled up by just 32 live video feeds. With dozens of UAVs in use in Iraq alone, you get a sense of how bad the problem is. 

New data compression techniques may be effective in reducing the amount of bandwidth needed for video, and UAV camera systems now allow for single pictures (files) to be sent periodically, rather than a constant video feed. The U.S. Air Force is also equipping some of it's tanker aircraft, which often circle combat zones for hours waiting to deliver fuel, with communications gear that, in effect, makes them "virtual satellites" and takes some of the load off the real birds much higher up. The army is also looking into using UAVs and blimps as virtual satellites for the same reason. But in the meantime, demands for bandwidth for operations in Iraq, Afghanistan and Korea means there is very little for anyone else.