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Environmental, Telecom Applications for Airships
March 6, 1998
(Image: Science and Technology Agency, Ministry of Posts and Telecommunications)
In 1998 a government project will get underway using an airship floating for long periods at an altitude of some 20 kilometers (12.5 miles). The joint operation involves an ecological project, run by the Science and Technology Agency to monitor ozone concentrations and other global-environment variables and to keep watch over disaster sites; and a project run by the Ministry of Posts and Telecommunications to lay the foundation for a next-generation communications technology using airships as radio-wave relay stations.
Eye in the Sky
The airship will be positioned in the stratosphere at a level twice as high as the flight paths of jet aircraft on international hauls. At this altitude, airships can be easily kept in one spot, since winds are light and unvarying. Floating only 20 kilometers above the earth--far lower than the 36,000 kilometers (22,000 miles) required for satellites in geosynchronous orbits or the minimum 700 kilometers (430 miles) for low-orbit satellites--airships should be able to take extremely high-resolution images of the planet and harness extremely high frequency (EHF; 30-300 gigahertz) radio waves known as "millimeter waves" that make possible high-volume data transmission.
The planned airship will be roughly 300 meters in length and feature propellers powered by solar batteries. It will be able to remain in a fixed location by using the U.S. Global Positioning System network of satellites to triangulate its position. It will be significantly cheaper to build than a satellite, which can cost from tens to hundreds of billions of yen, and will have a longer working life.
High-altitude airships are also being researched and developed in the
United States and Germany, with researchers working to achieve durability,
reliability, and lower weight. In Japan, trials began with a scaled-down
experimental model in fiscal 1997 (April 1997 to March 1998).
The Ministry of Posts and Telecommunications, meanwhile, hopes to use the airship as a relay station for EHF radio wave transmissions. EHF radio waves are unsuitable for ground-based transmissions, as they do not diffract well around buildings and other obstacles, anddo not diffuse widely, making them difficult to aim from high-altitude communications satellites; but they should prove ideal when beamed from the stratosphere. Furthermore, they have several thousand times the data-transmission capacity of the frequencies used currently for communications and broadcasting. An airship relaying EHF waves would enable large-volume, high-speed telecommunication and would have very high utility value. The advantages such airship communication technology offers could lead to the creation of new telecommunications services.
Edited by Japan Echo Inc. based on domestic Japanese news sources. Articles presented here are offered for reference purposes and do not necessarily represent the policy or views of the Japanese Government.