No abstract

No abstract

No abstract

Geostationary and geosynchronous satellites have a wide area of application in present day technology. The main drawback for the wider usage of such satellites is their high cost of launching into their orbit. As alternatives to conventional rocket launching, launching by high muzzle speed guns or by electric railguns have been proposed. However, it is hereby advocated that aerostats, stratospheric or mesospheric balloons tethered to a fixed point on the earth can also be used to fulfil the same tasks within a limited area of coverage. However, it is possible to widen the area of coverage by using a constellation of such balloons, presumably at a fraction of the cost of satellite launching. Presently, aerostats at about a few kilometers height are being used for a number of purposes, including border monitoring. The idea of tethered balloons reaching the lower parts of the stratosphere has been studied in 1960's for atmospheric research and successful results from prototype balloons have been obtained. The main problem related to high altitude aerostats has been found that extreme drifting loads are being induced by high altitude winds during the ascent (launching) and descent (recovery) phases. In the light of development of new high performance materials, as well as the development of superpressure balloons, it is now proposed to reconsider the same concept as a platform for high altitude devices used for communications, media broadcasting, environmental monitoring via optical or SAR imagery, monitoring for border security and illegal trafficking. Also, the possibility of two stage launching, ie, launching an aerostat from a high altitude airship shall be addressed. It is considered that the most convenient altitude for such aerostats is the stratopause region, with pressures at the order of 1 hPa pressure or 48 000-50 000 meters above the sea level.

No abstract