Riding the storm.-

Photo By Lori Losey.

NASA's Hurricane Severe Storm Sentinel Mission, or HS3, will be studying hurricanes at the end of the summer, and there will be two high-altitude, long-duration unmanned aircraft with different instruments flying over the storms.

The unmanned aircraft, dubbed "severe storm sentinels," are operated by pilots located in ground control stations at NASA's Wallops Flight Facility in Wallops Island, Va., and NASA's Dryden Flight Center on Edwards Air Base, Calif. The NASA Global Hawk is well-suited for hurricane investigations because it can over-fly hurricanes at altitudes greater than 60,000 feet with flight durations of up to 28 hours.

Using unmanned aircraft has many advantages. Hurricanes present an extreme environment that is difficult to sample. They cover thousands of square miles in area, and can also extend up to 50,000 feet in altitude. Second, they involve very high winds, turbulence and heavy precipitation. Third, ground conditions (high winds that create heavy seas or blowing material) make surface observations difficult.

Two NASA Global Hawks that will be flying during the HS3 mission. Each will have different payloads, or collections of instruments aboard. Necessary observations are winds, temperature, humidity (water), precipitation, and aerosol (particle) profiles from the surface to the lower stratosphere.

Both Global Hawks will be flying out of NASA Wallops Flight Facility in September, the peak month for the Atlantic Hurricane Season.