A Stratellite is a rigid framed airship that hovers in a fixed position in the lower stratosphere and carries one or more repeaters to create wireless communication networks. Stratellites, classified as both unmanned aerial vehicles (UAVs) and high altitude airships (HAAs), are the brainchild of Bob Jones, a former NASA scientist. Other companies have proposed similar airships, including Advanced Technologies Group, SkyLINK and SkyTower.
A system of such balloons, held in position by six onboard GPS units connected to the ship's engines, was proposed by Sanswire Technologies in a joint venture with Globetel Wireless. Each Stratellite would be capable of providing cellular telephone and Internet communications from an altitude of 13 miles. The wireless network created by a single Stratellite will cover a roughly circular geographic area of 125,000 square miles. Sanswire believes that as few as fourteen Stratellites would create an overlapping radii of coverage around the continental United States.
The technological characteristics of Stratellites are similar to those of low-earth-orbit (LEO) satellite systems. In particular, the low altitude will result in low latency. Users of a Stratellite network would experience significantly reduced lag compared to low orbiting satellites and greatly improved latency for geostationary satellites.
The proposed radius of the commercial version of the airship is 100 feet. The rigid frame, made of advanced composite materials, will measure 245 feet in length and fill the nearly 1.3 million cubic feet of volume with a mix of helium and nitrogen. According Sanswire, at that scale a Stratellite would be able to carry up to a 5000-lb. payload at 8,000 feet for 10-16 hours of continuous operation.
Stratellites rely entirely upon solar photovoltaic (PV) thin film panels for propulsion, which makes them ideal for rapid deployment in areas with damaged or nonexistent energy infrastructures, such as battlefields or developing nations. Sanswire also uses a super-light insulation that it claims is 38 times more effective than the best fiberglass, based on advanced materials that are encapsulated in film.
In the US, HAA development is being jointly sponsored by the Department of Defense (DoD) and Department of Homeland Security (DHS) under multi-million dollar programs aimed at delivering a commercial prototype in 2008-2011 timeframe.
Sanswire believes that the Stratellite will have broad applications for the DHS and DoD, including the gathering of sigintel through surveillance, HAZMAT response, providing connectivity to first responders for disaster recovery and supplying bridge connectivity for post-war or conflict infrastructure replacement.
Tethered flights of a prototype Stratellite 125 feet in length are scheduled for late August of 2006 in the Mojave Desert north of Los Angeles. Here's a picture of that prototype.