The history of flight could be summed up as flying ever faster and higher than anyone before but, with a high-altitude platform, or pseudo satellite, (HAPS), the aeronautical goals are being turned on their heads. With velocities more likely to result in a stall warning and control surfaces that would not work on a conventional aircraft, nothing is typical about HAPS, not even the materials they are built from. Traditional aerospace materials are too heavy and not flexible enough for coping with the HAPS' environment, 60,000ft to 75,000ft; also known as the stratosphere. While temperatures of -90℃, harsh thermal cycling, exposure to ozone, cosmic radiation and the ultraviolet are not unknown to high altitude aircraft, being powered by sunlight and only having a fraction of the available energy an aircraft normally has, is unfamiliar, to say the least.
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