Stratospheric Electrical Environments Applicable To Photovoltaic Arrays On HAA Platforms

The objective of this program is to characterize the upper atmosphere electrical environment so that the effects of this environment on high altitude airships (HAA) and other platforms intending to operate in this environment can be determined, and protection methods developed. This includes transient luminous events (TLEs), such as red sprites and blue jets and their associated electrical properties, in the region above active thunderstorms, as well as the fair-weather ambient. The induced and directly conducted currents that may be experienced by HAA PV arrays will also be defined. The approach is to fill gaps in present knowledge with a combination of high altitude electric field measurements, laboratory experiments to examine electrical streamer/leader and spark/arc characteristics at the reduced pressures equivalent to the 40,000 - 70,000 ft altitude range, and numerical modeling to compute the field enhancements and discharge currents at a high altitude airship operating in this range.