Design Considerations for High Altitude Platforms

Abstract

Solar powered high-altitude long endurance aircraft with the capability to perform persistent flight are an attractive alter-native to traditional low earth orbit satellite systems. The design of such platforms is a challenging task, due to the tight coupling of many design parameters. Since the sun is the only available power source, minimizing the power consump-tion of the aircraft, whilst maintaining the capability of carrying and operating the payload over the desired location, is a central design challenge. Further, the aircraft, including its systems, has to cope with the harsh environmental conditions in the stratosphere with extreme temperatures, low air density and cosmic radiation. To design an aircraft capable of flying persistently under the mentioned environmental conditions, the combination of sound theoretical knowledge and practical experience is necessary. To gain the required experience, the DLR develops a flight demonstrator for future high-altitude platforms. The main aim of this aircraft is to explore the environmental conditions of solar powered strato-spheric flight, to test and mature flight procedures and to demonstrate innovative payload systems. Initially, this aircraft shall conduct high altitude missions with mission durations of up to 24 hours. However, the design allows for persistent flight, if batteries with higher energy density become available.