According to http://www.airforce-technology.com/projects/global/, the Northrop Grumman RQ-4 (or RQ-4B) Global Hawk is an unmanned aerial vehicle (UAV) utilized primarily as a surveillance aircraft by the United States Air Force and Navy. The RQ-4 has a gross takeoff weight of approximately 25,600 lbs and has the capability to remain in flight for about 42 hours with a maximum altitude of 65,000 ft. A typical range for the RQ-4 is approximately 11,000 nmi over a duration of 31 hours. This large UAV has a wingspan of 116.2 ft and a body length of 44.4 ft, and the Global Hawk has a 6.5 nmi turning radius. This aircraft also carries a full suite of sensors that enables it to utilize synthetic aperture radar (SAR) (which can provide spot resolution up to about 30 cm), detect moving targets traveling at speeds up to 4 knots, conduct wide area searches, and cover up to 1,900 spot targets in a 24 hour period.
With these capabilities, it is no wonder that the United States Air Force and Navy are using this aircraft for surveillance. However, the Global Hawk has recently been called upon for an interesting scientific research application – flying through hurricanes. The Global Hawk platform is certainly not new to scientific missions. According to an article by Frank Johnson, the National Oceanic and Atmospheric Administration (NOAA) has used the platform for missions over North Pole and it could be utilized to monitor ozone characteristics and pollutants. A project with NOAA and NASA called the Genesis and Rapid Intensification Processes (GRIP) experiment utilized three Global Hawks that have been instrumented with weather-monitoring sensors for flight over hurricanes. The first flight took place over Tropical Storm Frank and occurred on August 28, 2010 when a Global Hawk flew a mission over this storm in the Pacific Ocean. Due to the significant endurance and range of this aircraft, the Global Hawk has also been able to monitor hurricanes in the Atlantic Ocean. A flight over a storm in the Atlantic on September 2, Hurricane Earl, marked the first flight of an unmanned aircraft over a classified hurricane. With these capabilities, the people will be able to collect significant data regarding the formation and development of hurricanes without putting a human pilot in danger. The endurance of these aircraft will allow for prolonged data collection, possibly even with multiple unmanned aircraft monitoring these storm systems in the future.