Airships as Wireless Antennae
A company called Sanswire Networks is testing an airship called the "Stratellite," which is essentially a floating 802.11 wireless hub. Unmanned Stratellites can remain in a stationary position at 65,000 feet for up to 18 months, guided by GPS coordinates. The airships use a stable mixture of helium and nitrogen for lift, and are built from rugged Kevlar fabric.
Each Stratellite can hold several thousand pounds of communications equipment, and have a potential reach of 300,000 square miles -- approximately the area of Texas. Theoretically, two Stratellites, each deployed over Boston and Washington DC, could create a wireless network serving the entire northeastern US, reaching as far west as Ohio and as far south as the Carolinas. However, the first-generation airships will likely serve single metropolitan areas.
Sanswire is planning tests of the Stratellites in early 2005, and will proceed with development based on those results. One potential problem is that, by covering such a wide area, a Stratellite creates a massive single point of failure. Without some kind of redundancy (such as deploying Stratellites in pairs), the wireless network could be vulnerable to sabotage, natural calamities, or simple system failure.