ISTS 2002-o-2-14v - 27-31 May 2002 - Matsue, Japan

Stratospheric Balloon Platform Experimentation Projects for Reunion Island

Guy Pignolet, Associate Researcher, University of La Réunion, France

1) Introduction : Stratospheric balloons -  2) Reunion Island in the European Union
3) Winds in the stratosphere -  4) Microwave power -  5) International cooperation

 

Abstract

Stratospheric platforms are coming of age for communication and observation. In the European Union, such platforms would be useful for places like Reunion Island, where high mountains and deep valleys make conventional communication and satellite observation difficult. Because stratospheric wind speeds over La Reunion are moderate compared to winds at higher latitudes, La Reunion would be a good place to test the operation of balloon sub-satellite platforms stationed at altitudes of 20 km. Furthermore, application of Wireless Power Transportation to power stratospheric balloons could be studied at the University of La Reunion where such systems are developed for Grand Bassin.

1. Introduction : Stratospheric balloons

Stratospheric platforms are coming of age for communication and observation, in Japan (fig. 1), in North America, also in Europe. After years of dreams, the technologies are now mature for operational development and within a decade, a combination of local stratospheric balloons and global geostationary relays could supersede the current satellite constellations. The development of such systems will require a whole series of testing, from the air worthiness of the balloon structures, to the control of stationary flight, to the development of associated ground systems and services.

Fig.1 : SPSW 2000 in Japan

2. Reunion Island in the European Union

Reunion Island (fig. 2), is one of the regions of France and of the European Union, located in the southern part of the Indian Ocean. Volcanic mountains, over 3 000 meter high, and deep canyon-like steep valleys make conventional communication and satellite observation difficult and make it necessary to use a large number of relays for television, FM radio and cellular phones. A stratospheric balloon platform would be a welcome and efficient replacement solution to the current complex system of communications within the island, and it would offer unheard possibilities in terms of observation for agriculture [1]. Because of it's unique environment in the European context, La Reunion would be a prime candidate for the use of stratospheric platforms, and this possibility has raised a lot of interest within the academic and the economic community of the island.

Fig. 2 : Réunion Island

3. Winds in the stratosphere

Even major meteorological perturbations (fig. 3) affect only the lower part of the atmosphere, below the 12 km level. Between 12 and 15 km, jet streams may flow steadily with velocities up to several hundred kilometre per hour. Then the wind speed decreases regularly with the altitude, wind is steady, with little variation around the seasons. Because the speed of stratospheric wind over La Reunion at the altitude of 20 km is rather moderate (30 to 50 km/h) compared to the speed at higher latitudes (80 to 100 km/h), La Reunion would be a good place for initial operational testing of balloon sub-satellite platforms, since it would be less requiring in terms of propulsion power.

Fig. 3 : Tropical Hurricane Dina (Jan. 2002)

4. Microwave power

The LGI/ACTES Laboratory of the University of La Reunion is developing operational WPT wireless power transport systems, by means of microwave energy beams (fig. 4), to provide electricity to the mountain village of Grand Bassin [2]. This technology could be applied in order to provide energy from the ground, rather than using a combination of solar cells and storage batteries.

Fig. 4 : WPT Prototype for Grand-Bassin

5. International cooperation

A potential for good international cooperation exists between France (La Reunion) and Japan, and possibly other countries, for the joint development of technologies for stratospheric platforms. Such synergy may bring many mutual benefits.

References

[1] Pignolet G., " The case of the high altitude platform ", SPS-IdR Conference, University of La Reunion, November 1996

[2] http://www.grandbassin.net

Project for a hybrid system

with local stratospheric platforms and global geostationary satellites

....for communication and observation

Altitude of balloons : 20 km
Ground coverage for communication : 200 km
Communication between balloons and satellites by high rate laser links