This drone is as large as a B737 and used to spy on enemies from 60,000 feet, staying in the sky for more than a day. And more interestingly, it served as a hurricane hunter, flying into the eyewall of deadly tropical cyclones.
The RQ-4 Global Hawk is one of the most intimidating drones ever used by the US military. It was introduced in 1998 under a project of the Defense Advanced Research Project Agency as an advanced ISR (Intelligence, Surveillance, and Reconnaissance) platform. Here are some fascinating facts about this high-altitude, long-endurance drone.
The Global Hawk could reach altitudes exceeding 60,000 feet with an impressive loitering time of over 30 hours. The high altitude capability allows the drone to avoid usual air traffic and bad weather.
The drone has a high aspect ratio wing that stretches almost 40 meters, which is 4 meters greater than the wingspan of the B737. This high lift-low drag wing enhances the loiter time and range over 12,300 nautical miles. Currently, Global Hawk has the Guinness record for the farthest flight by an unmanned aircraft. It flew from California to Adelaide, covering a total distance of 13,219.86 km.
The sensor suite of the drone is its main weapon. The optical camera in the drone is of high power and able to capture objects as small as 12 inches from an altitude of 60,000 feet. The drone is capable of surveying an area of 53,000 square miles in 24 hours, which is approximately 25 million football fields.
The bulbous nose makes the drone standout and makes it look like a whale. This nose sports a 1.21-meter-wide Ku-band steerable antenna that is used for satellite communication.
The drone was developed under four block categories: Block 10, 20, 30, and 40. Block 30 is the multi-intelligence platform that carries EO/IR (Electro-Optical/Infrared) and SAR (Synthetic Aperture Radar) sensors with Signals Intelligence sensors. Signal intelligence plays a crucial role in modern warfare as it could identify electronic signal sources with extreme accuracy. Block 40 drones are extensively used for Ground Moving Target Identification (GMTI) missions, where the drone tracks moving targets on the ground.
The drone is powered by one Rolls Royce AE 3007 engine. It can carry 17,300 pounds of fuel in its fuselage tank. The engine is strategically positioned between the V-tails to reduce the radar cross section.
While it flies autonomously, the drone is always under the oversight of a remote pilot. Two ground segments control the drone. The LRE (Launch and Recovery Element) controls the drone during the launch and recovery phases, while the MCE (Mission Control Element) controls the drone throughout its mission. A single pilot flies the drone from LRE, and when handed over to MCE, an additional sensor operator is joined by the pilot. The LRE and the MCE can be geographically separated, allowing for more versatile operations.
While the Global Hawk is extensively used for military missions, NASA is using the Global Hawk as a hurricane hunter. They use the Global Hawk to fly above tropical cyclones to garner data on the cyclones and forecast their track and intensity. The method they use for this is interesting. A special probe named ‘dropsonde’ is launched from the aft belly of the drone when it reaches the right altitude (watch this video to see how the drone releases these probes inflight). Then these probes traverse through the cyclone, collecting data on pressure, temperature, humidity, and wind. The data is transmitted back to the drone and to a ground station via a satellite data link. In addition, NASA used two Global Hawk drones for the Hurricane and Severe Storm Sentinel, or the HS3 campaign, which focused on identifying the impact of physical environmental conditions on hurricane intensity change. They were able to cover most parts of the Atlantic Ocean thanks to the high endurance offered by the drone. Unlike other hurricane hunter aircraft, the Global Hawk played a unique role in data dissemination.