The tool to assess availability of solar powered HALE vehicles for any location at any time of year.
Persistent HALE operations require that the vehicle always stays above the high speed winds of the Troposphere but the power to fly higher is greater so the availability of the service is very dependent on the exact location and time of year of operation.
Whilst the variation in solar power and the change in length of night are determinable it is adding to these factors to the variation in wind speed and altitude based on years of real, measured data that makes PHAST essential to the development and assessment of high altitude, long endurance operations.