Imagine a surveillance aircraft that can fly at the edge of space, scan thousands of square miles below in stunning detail, and remain airborne for more than a day — without a pilot on board. That’s the RQ-4 Global Hawk, one of the most advanced unmanned aerial vehicles (UAVs) in the world.
Designed by Northrop Grumman for the US Air Force, the Global Hawk is the military’s ultimate “eye in the sky.”
Capable of cruising above 60,000 feet (18,000 meters) and watching over the battlefield for 30+ continuous hours, this high-altitude, long-endurance drone redefined what’s possible in modern intelligence gathering.
Since its debut in the early 2000s, the Global Hawk has quietly shaped key missions across the globe, from tracking insurgents in Afghanistan to surveying disaster zones in Japan.
It’s been a cornerstone of strategic decision-making, giving commanders the kind of real-time data that can turn the tide of conflict — or prevent it altogether.
This guide breaks down everything you need to know about the RQ-4 Global Hawk: how it works, what makes it unique, how it’s been used in the field, and what it costs to own and operate.
Northrop Grumman’s RQ-4 Global Hawk
The RQ-4 Global Hawk is a high-altitude, long-endurance unmanned ISR platform. It was developed by Northrop Grumman (originally Ryan Aeronautical) under a DARPA/US Air Force (USAF) ACTD program in the 1990s.
Global Hawk was engineered as an unmanned “near-space” aircraft: it climbs above commercial traffic and weather (60–65,000 feet) and loiters for 30+ hours, returning high-quality IMINT/SIGINT/GMTI data to ground stations.
The first prototype flew in February 1998, and production Global Hawks entered USAF service in 2001.
Global Hawk’s airframe is largely carbon-composite, with a very high-aspect-ratio wing and distinctive V-tail. It carries internal multi-sensor suites (such as electro-optical/IR, SAR, and communications intelligence) and datalinks, and its fuselage bulge houses a 48″ Ku-band SATCOM antenna.
From its Block-20 baseline the RQ-4B variants have an extended fuselage and wings.
A single Rolls-Royce AE 3007H turbofan (7,600 lbf thrust) is mounted on top of the rear fuselage.
Primary avionics include dual-launch/recovery and mission-control stations (each flown by a pilot and sensor operator) linked via satellite and line-of-sight datalinks.
Specifications
- Dimensions: Wingspan ~130.9 feet (39.9 meters), length ~47.6 feet (14.5 meters), height ~15.3 feet (4.7 meters)
- The wing area is ≈540 ft², giving a very high lift-to-drag ratio (≈33:1) at altitude
- Weight & Payload: Typical empty weight ~15,000 pounds (6,804 kilograms); maximum gross takeoff ~32,250 pounds (14,628 kilograms)
- Internal capacity ~3,000 pounds (1,360 kilograms) on RQ-4B, though early (Block 10) NASA/AAF versions carried about half
- There are hardpoints (up to ~1,000 pounds/453,5 kilograms each) under the wings for additional external payloads
- Performance: Cruise speed is about 310 knots (357 miles/570 kilometers per hour); max about 340 knots (391 miles/630 kilometers per hour). Service ceiling is about 60,000 feet (18,000 meters), with demonstrated loiter altitudes up to 65,000 feet (19,812 meters)
- Range/Endurance: Ferry range 12,300 to 14,200 nautical miles; typical missions 11,000+ nautical miles with 30–34+ hour endurance.
- In 2014 a Block-40 Global Hawk flew 34.3 hours, an unrefueled USAF record
- Powerplant: 1× Rolls-Royce AE 3007H turbofan (military designation F137) producing ~7,500–7,600 lbf thrust
- A secondary generator system doubles electrical power for avionics.
- Sensors: RQ-4 is an imaging and signals ISR platform. Block 30 carries a multi-int sensor suite (electro-optical/IR camera, Raytheon synthetic-aperture radar, and high/low-band SIGINT pods)
- A universal adapter even allows U-2 sensors (MS-117, SYERS II) to fly on early RQ-4Bs.
- Block 40 upgrades replace EO with the MP-RTIP AESA ground-surveillance radar for GMTI (moving-target indicator) and SAR
- (Earlier Block 20 aircraft had only electro-optical imagery.) Data links include wideband SATCOM (Ku-band 48″ antenna) and LOS links (X-band and UHF), enabling real-time imagery downlink to global ground stations.
Global Hawk Variants in Service
Northrop Grumman produced several RQ-4 versions, but only RQ-4B variants are currently active. The pre-production RQ-4A (Block 10) airframes (7 delivered) entered combat in 2001 but were retired by 2011.
The RQ-4B Block 20 (initial production, lengthened fuselage) was fielded around 2008 with enhanced sensors and payload capacity; five of these were later converted to EQ-4B Battlefield Airborne Communications Node (BACN) relay platforms.
The main operational versions are the RQ-4B Block 30 and Block 40. Block 30 (IOC Aug 2011) is a multi-intelligence variant carrying EO/IR cameras, SAR, and SIGINT.
USAF fielded 18 Block 30s by the mid-2010s, supporting every geographic combatant command and missions in Afghanistan (Enduring Freedom), Iraq (Iraqi Freedom), Libya (Odyssey Dawn), Japan (Operation Tomodachi).
Block 40 (EOC Sep 2013, IOC projected 2016) is dedicated to ground-surveillance; it carries the advanced MP-RTIP AESA/GMTI radar. Eleven Block 40s were operational by 2018, focused on GMTI and battlefield ISR. All current USAF GH inventory resides in three active models:
- EQ-4B (Block 20) – BACN communications relay (4 aircraft)
- RQ-4B Block 30 – multi-intelligence ISR (19 aircraft)
- RQ-4B Block 40 – radar/GMTI surveillance (10 aircraft)
In addition, a naval derivative RQ-4N/MQ-4C Triton was developed for the US Navy (see “Comparisons” below).
NATO’s Alliance Ground Surveillance program also contracted for five RQ-4B Block 40s (delivered 2019–21) with MP-RTIP radars. Germany’s canceled “EuroHawk” was a bespoke RQ-4B that never entered service.
Operational Use and Deployments
Global Hawks have flown thousands of combat and humanitarian missions worldwide.
By the late 2010s, USAF records showed 320,000+ flight hours supporting operations in Iraq, Afghanistan, North Africa, and elsewhere. For example, RQ-4s provided near-continuous surveillance over Afghanistan and Iraq in the 2000s (Operation Enduring Freedom/Iraqi Freedom).
Block 30 GHs also flew ISR over Libya during 2011’s Operation Odyssey Dawn, and assisted relief efforts after Japan’s 2011 earthquake (Operation Tomodachi).
USAF Global Hawks are based primarily at Beale Air Force Base, California, with forward detachments at overseas locations (such as Ali Al Salem AB, Kuwait; Andersen AFB, Guam; NAS Sigonella, Italy; Yokota AB, Japan).
Foreign partners have also acquired Global Hawks.
For example, in 2018 Japan ordered three RQ-4B UAVs (Block 30i) plus ground stations to enhance Indo-Pacific ISR. South Korea likewise contracted for four RQ-4Bs in 2014. These international GHs conduct strategic surveillance over coastal and border regions.
Comparison to Similar Drones
Global Hawk is the premier HALE (High-Altitude Long-Endurance) UAV. Comparable platforms include:
- Northrop Grumman MQ-4C Triton: A maritime-surveillance derivative of the RQ-4 (originally “RQ-4N”). The Triton has similar dimensions but strengthened for shipboard ops. It reaches 60,000 feet (18,000 meters) ceiling, 30 hours endurance, and 9,950 nautical mile range. Its payload is slightly less than RQ-4B; Triton carries an integrated AESA maritime radar plus EO/IR/SIGINT sensors. Triton entered US Navy service in the 2020s.
- IAI Heron TP (Israel): A medium-altitude MALE UAV (propeller-driven) with 36 hours endurance. It flies up to 45,000 feet (13,700 meters) and carries 2,205 pounds (1,000 kilograms) of payload. The Heron TP is smaller and slower, but has comparable mission duration. It is used for strategic ISR, targeting and even aerial refueling missions.
- Guizhou WZ-7 “Soaring Dragon” (China): A tandem-wing HALE drone with a powerful jet engine. The prototype cruises at about 466 miles (750 kilograms) per hour. Its range is 3,800 nautical miles, with about 10 hours endurance (production models may improve on this). Service ceiling is 59,000 feet (18,000 meters). Soaring Dragon is primarily for Chinese reconnaissance (over South China Sea/Indian Ocean).
By comparison, Global Hawk has by far the longest range and endurance of any operational UAV today (14,000+ nautical miles ferry range, 30 to 34 hours endurance). These capabilities distinguish it from shorter-endurance or lower-altitude systems.
Cost and Acquisition
Unit Cost: Early RQ-4s were relatively cheap on paper ($10 million each in 1994), but development overruns drove flyaway prices up.
By 2001 the unit cost was $60.9 million and later, the Government Accountability Office (GAO) reported $75 million per aircraft. By 2013 a new Block aircraft cost roughly $222.7 million each.
Foreign military sales (including ground control stations and support) imply even higher per-unit costs, for example, South Korea paid $657 million for four RQ-4s (including spares and engines) and Japan $490 million for three (each figure includes ground stations and services).
NATO’s Alliance Ground Surveillance program budgeted $1.7 billion to procure five RQ-4Bs ($340 million each fully outfitted).
Acquisition & Procurement: The program was originally slated for 63 aircraft, but cost growth led to a reduction to 45. To date, 42 have been delivered and 33 remain in USAF inventory. Congress and GAO repeatedly scrutinized GH costs under Nunn-McCurdy reviews.
The bulk of spending went into procurement and sustainment (development costs were relatively modest DARPA funding in the 1990s, followed by full-rate production contracts in the 2000s).
Life-Cycle Cost: Sustainment has been a major driver of cost.
In 2010 the RQ-4’s cost per flight hour was $40,600 (with $25,000 per hour of that in contractor logistics). By 2013 improvements and higher utilization had cut the cost to about $18,900 per flight hour (contractor support $11,000 per hour).
Global Hawk often showed higher flight-hour costs than legacy manned aircraft (like the U-2), influencing USAF decisions on retirement vs upgrades. Planned modernization aims to further reduce operations cost.
Foreign Sales: Several US allies have acquired Global Hawks.
South Korea’s FMS deal (announced 2014) was $657.4 million for 4 units and Japan’s 2018 contract was $489.9 million for three air vehicles plus two ground control elements. These packages included advanced Block 30i sensors, spares, and support.
NATO’s 2012 contract (5 UAVs + infrastructure) was $1.7 billion.
Overall, the RQ-4 Global Hawk remains an expensive but unique asset: its unmatched high-altitude, long-endurance surveillance provides ISR capabilities no other UAV can currently replicate.
