Balloons in space

A team of researchers from around Europe believe that high-tech airships could soon provide the perfect complement to satellite and terrestrial telecommunication and observation systems.

The European Space Agency, DaimlerChrysler, UK-based Lindstrand Balloons and the Technical University of Delft in the Netherlands, have completed a first assessment of a concept for High-Altitude Long-Endurance (HALE) aerostatic craft, positioned 20km above the earth, in a region of space where no aircraft or satellites fly – and with an operational lifetime ranging from months to years.

These large helium-filled powered airships with an aerodynamic ‘cigar’ shape about 220m in length and 55m in diameter will be able to carry payloads of up to 1000kg or so and, unlike Zeppelins, won’t need a rigid overall internal structure other than local reinforcements for the engine and payload attachments.

Indeed, the flexible, helium-tight and UV-resistant hull materials, mean that pressurisation alone will impart the necessary stiffness to the airship body.

With an engine providing mobility and stable positioning against stratospheric winds, the altitude of 20km will be high enough to give local or regional coverage of about 100km in diameter. Solar cells covering the upper, sun-oriented parts of the airship skin gather energy at daytime to power a high-efficiency electric engine, which drives a large propeller, and feeds energy into a storage and conversion system, from which it is drawn for night-time propulsion and operation of the vehicle.

It is thought that HALEs will be particularly useful in telecommunications. Located above a densely populated area, the airships will be able to support future mobile multimedia services without the need for a network of antennas and ground-based relay stations. Remote meter reading (gas, water and electricity) is another possibility.

ESA’s interest in HALEs is due to their relevance to a broad range of spacetechnologies such as thin-film solar cells, inflatable technology, telecommunication equipment, astronomical instruments and various subsystems such as power management and distribution, steerable antennas, Earth observation sensors and radar imagers. Lightweight design, another typical area of space expertise, is particularly important to the development of HALE airships.