An Air Force Global Hawk deployed to the United Arab Emirates in 2010. Air Force photo

This All-Seeing Spy Drone Can Detect the Slightest Disturbance

As Maggie Ybarra explains, high-flying Global Hawk is incredibly powerful — and controversial

It can track ships at sea, sense the slightest change in the dirt and even take the temperatures of forests and crops. It’s the giant Global Hawk spy drone from U.S. manufacturer Northrop Grumman — and it’s making the world a very dangerous place for terrorists, insurgents and international criminals … and a better place for scientists.

But that doesn’t mean the Global Hawk is without its detractors. The U.S. Air Force, in particular, has mixed feelings about the drone — for reasons that are not entirely clear but could have something to do with an even more capable secret Unmanned Aerial Vehicle.

The Global Hawk, also known by its military designation RQ-4, is a high-flying, long-endurance remotely-piloted plane that can stay aloft for more than 30 hours straight, following GPS waypoints and responding to commands relayed via satellite by operators on the ground.

Northrop has created multiple variants of the 16-ton robot plane over the past 15 years, outfitting them with different sensor packages designed to meet specific mission plans.

Some of the giant robot planes, each with the wingspan of a 737 airliner, are tasked solely with collecting scientific data for NASA. Other Global Hawks are equipped with sophisticated radio relays for helping other airplanes communicate with each other.

But most are warrior-spies, meant for finding and tracking enemies of the state on land and at sea.

Since the mid-1990s, Northrop has built 42 Global Hawks at its Antelope Valley Manufacturing Center in Palmdale, California—and has orders for dozens more. The U.S. Air Force is the biggest user so far, with Northrop delivering 38 copies to the service to date, but the Navy could soon overtake the flying branch with its current four sea-surveillance demonstrator models plus plans for around 70 advanced maritime models called Tritons.

NASA possesses two Block 10 variants plus one demonstrator, Germany has a single Euro Hawk demonstrator and NATO is set to acquire five of the aircraft. Japan, Australia and South Korea are possible buyers.

A single Global Hawk sells for more than $200 million, counting sensors.

The giant drones are already able to find and track people and objects in a wide range of conditions. But the most interesting capability of all is the one that Northrop is poised to put on the Global Hawk in the near future, if the company can secure a buyer. The new “hyperspectral” sensor, made by Raytheon, has been described by some military officials as “a game changer.”

Earthquake damage in Haiti in 2010,as seen by an Air Force Global Hawk. Northrop Grumman photo

All-seeing sensors

Alfredo Ramirez, Northrop’s chief architect for Global Hawk, said his company could install the hyperspectral sensor on a Global Hawk via a “universal payload adapter,” which attaches to the bottom of the drone and would expand the number of sensors the aircraft can carry simultaneously. To date, Northrop has only pitched the possibility of fitting the adapter to the Air Force’s Global Hawk aircraft.

At certain wavelengths, the hyerspectral sensor can detect disturbances in the ground, Ramirez said. That means the Global Hawk could be able to tell if a criminal, terrorist or insurgent tries to hide his misdeed by digging and refilling a hole. The new sensor would be particularly useful for monitoring border regions where illegal activity frequently takes place, Ramirez said.

If a vehicle drives through sand or through dirt, the sensor can detect those areas, according to Ramirez.

For its own fleet of Triton drones, the Navy has invested in unique sensors for finding ships on the high seas, according to Ramirez. “It has a radar that scans, always, 360 degrees around it to detect ships at sea.” Plus the Triton can carry what Ramirez refers to as “other collection payloads” that can passively detect radar emissions from ships and planes.

The Tritons would probably first detect the target’s electronic emissions, narrow down its location with the radar then use a camera to focus on and identify the vessel.

Hurricane Earl, as seen by a Global Hawk in 2010. Northrop Grumman photo

Drone science

Global Hawks have been used in the Afghanistan and Iraq conflicts. But the drones aren’t just warriors. They have been used to survey earthquake damage in Haiti in 2010 and Japan’s unstable nuclear reactors in the aftermath of the 2011 tsunami. Also, NASA and Air Force Global Hawks have been used to take measurements of the ozone layer and of air pollutants and aerosols overseas.

Drone science could get even better as the Global Hawk improves. The new hyperspectral device could monitor the growth or decay of agricultural areas, sensing the health of the vegetation and of the environment surrounding the plants, Ramirez said.

“The humidity of plants, the temperature of plants in a certain area, you can monitor with a hyperspectral sensor at certain wavelengths to determine whether the crops that are growing are exactly in the environment that they need to be or if there are disturbances in that environment that are going to affect those crops,” he said.

NASA’s Global Hawks are equipped for scientific experiments focusing on Earth’s atmosphere, Ramirez said. NASA Global Hawks do air sampling and temperature monitoring as they fly over the ocean, and track hurricanes or embark on polar missions, he said. Scientists then take that data and compare it to data collected by weather satellites, Ramirez said.

“Whenever there’s a tropical storm of interest that’s forming, they’ll send the aircraft to overfly it and to drop instruments, basically, into it that are collecting information and relaying it back to the aircraft or to other systems,” he said.

“So from a scientific standpoint this mission for atmospherics, in promoting atmospheric science. it’s a great tool NASA can utilize. For Arctic monitoring, it is a great asset as well, because it flies so high it can record data even if communications are not present and relay that data back.”

A Triton drone. Northrop Grumman photo

Arm the spy?

None of Northrop’s Global Hawks carry weapons, but they could in theory, according to Ramirez. As originally designed, the giant robot has a reinforced titanium wing that’s tough enough to support the weight of guided bombs or the Hellfire missiles that equip smaller Predator and Reaper drones.

“You could mount a Hellfire on any aircraft, right? But you would have to modify the aircraft with wiring, with signals empowered through a pylon [and] you would have to install a pylon so you can carry,” Ramirez said.

Ramirez noted that Global Hawks, with their access to high altitudes, have the flexibility to deploy globally and perform missions at a better capacity than smaller, medium-altitude drones like the Predator and Reaper. The Air Force is in the process of adding extra fuel pods and heavyweight landing gear to some of the Reapers to allow them to conduct missions that require more than 30 hours.

Ramirez said that both types of robot have their own “particular sweet spot,” but for the most part the Global Hawk possesses the superior flight time — and definitely flies higher, up to 60,000 feet. If an unmanned plane is flying less than 180 knots at just 30,000 or 40,000 feet, the jet stream could be too strong, he said. Higher altitudes avoid those weather effects, he said.

Medium altitude assets are great for some things, but if the mission involves trying to scan “very large areas to find the needle in the haystack,” that is where the power of high altitude aircraft comes in, he said.

“There’s so many things that can be done to this kind of platform, and it’s so versatile so to … be able to mount different types of payloads, I mean, the possibilities are endless,” he said.

One of the earliest design sketches of the Global Hawk. Northrop Grumman art


Tell that to Germany and the Air Force. Both of these Global Hawk users have gotten cold feet in recent years. Germany has tried to back away from purchasing the Euro Hawk, with the country’s defense minister declaring that the Global Hawk system cannot meet the necessary flight certifications.

German Defense Minister Thomas De Maizière has leaned toward terminating the program, in part due to the fact that it would cost hundreds of millions of Euros to make the type of adjustments necessary for the Euro Hawk to gain flight certification.

The Air Force has also tried to reduce the number of Global Hawk drones it was on the hook to purchase. First the service shaved down the quantity of aircraft it intended to buy, reducing that number from about 60 drones to 45. Then the Air Force tried to get out of buying the final three Global Hawks from Northrop. Those three drones were not on contract at the time the Air Force began grappling with stiff congressional budget cuts.

There could be a good reason for the flying branch’s reticence. Flight Global reported in April that senior officials believe that Lockheed Martin’s U-2 spy plane and other “classified platforms” had the ability to take over the Global Hawk’s intelligence, reconnaissance, surveillance missions—and do it better.

Lt. Gen. Charles Davis, a top Air Force weapons-buyer, told Congress in April that there were aircraft capable of performing Global Hawk missions “in a variety of different ways.” Further discussions of those capabilities, however, would have to take place behind closed doors, he said. Because they’re secret.

Analyst Richard Aboulafia told Flight Global that of those classified platforms, one option could potentially consist of a long-range stealth reconnaissance aircraft, possibly also a Northrop product, that has long been rumored to be flying in the Nevada desert.

As amazing as the Global Hawk is, there could be a drone already flying around out there that’s even more incredible.

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