USAF Reaper Drones Can Finally Drop GPS Guided Joint Direct Attack Munitions

After nearly a decade of service, the U.S. Air Force’s MQ-9 Reapers now have the ability to drop the service’s most ubiquitous GPS-guided bombs. The upgrade significantly increases the drone’s capabilities and opens the door for its arsenal to expand further.

In May 2017, the Air Force’s 432nd Wing at Creech Air Force Base, the service’s main unmanned aircraft unit, reported that its Reapers had started training to employ the GBU-38/B Joint Direct Attack Munition (JDAM) in combat. According to the report, the wing had finished the testing phase of the upgrade in 2016.

“The GBU-38 is a weapon we’ve been trying to get on the MQ-9 for several years now and we had the opportunity to be the first to drop during training,” an Air Force instructor pilot from the 26th Weapons Squadron, identified only as “Captain Scott,” told the service’s reporters. “There’s definitely times when I could’ve used the GBU-38 in combat prior to this.”

Boeing’s JDAM is more or less a kit that converts basic dumb bombs into guided weapons. The new tail assembly has an inertial navigation unit, GPS-receiver and moving fins to direct it to the target. In addition, a set of wind wanes or strakes wrapped around the body of the bomb made it more stable as it glides toward the ground.

The Chicago-headquartered defense contractor offers these components for bombs in the 500, 1,000, and 2,000 pound weight classes. The GBU-38/B is the U.S. military nomenclature for the 500 pound configuration, of which there are different subvariants depending on the specific electronics and warhead. Armament specialists can assemble the weapons around the Mk 82 high-explosive bomb, the BLU-111/B PBXN-109 insensitive explosive filler, or the reduced-charge BLU-126/B. The Navy developed the BLU-126/B specifically for situations where there are increased concerns about hitting friendly forces or causing collateral damage, such as in dense, urban environments.

The GBU-38/B is in no way a new weapon. After the Persian Gulf War, both the U.S. Navy and Air Force had gone looking for a relatively cheap precision bomb. At that time, only laser-guided Paveway-series bombs were available to American pilots. The first members of the JDAM family made their combat debut during the NATO bombing of Serbia in 1999. 

A JDAM on an MQ-9 Reaper as seen through the drone’s camera., USAF

Still, the Pentagon didn’t see JDAM as a replacement for laser-guided weapons. While the GPS-guided weapons could reliably hit within 50 feet of static targets, laser-guided weapons could regularly manage to get within 10 feet of the aim point. Advanced laser-guidance systems – either inside the launching aircraft or the bomb itself – can also calculate the distance necessary to “lead” moving targets, too.  

But laser-directed weapons weren’t perfect, either. Most importantly, smoke, dust, and just bad weather could distort the laser beam or blind the seeker in the bomb, throwing it off target. This could potentially put troops or innocent civilians on the ground in danger and outright prevent pilots from providing badly needed support. And aviators had to get relatively close to either “lase” the specific point themselves or spot the beam another aircraft or troops on the ground were projecting on the target. JDAM offered a stand-off range up to 15 miles, depending on how high the aircraft was flying and where the enemy was situated down below.

GBU-49/B Paveways on an MQ-9 Reaper during a test in 2008., USAF

As the relative features of both systems became apparent, Boeing devised a new JDAM kit that included a laser seeker in the nose, the GBU-54 Laser JDAM, which entered service in the late 2000s. Paveway-makers Raytheon and Lockheed had similarly added GPS/INS-capability to some of their laser-guided bombs. A Reaper dropped one of these combination weapons, a GBU-49/B Paveway, for the first time in 2008.

Regardless, the JDAM was a ubiquitous feature of America’s aerial campaigns, including the fight against ISIS.  The U.S. military, as well as its coalition partners, had dropped so many of the weapons in Iraq and Syria that Boeing was having to ramp up production of the tail kits. In March 2017, the firm told DOD Buzz it was looking to build more than 36,500 units during 2017, which would mean making at least 150 every day. The GBU-38 is known for its affordability (everything is relative in the world of defense procurement) with each costing roughly $18,000.

A Reaper observers as its JDAM hits a training target., USAF

The addition of equipment necessary for the Reaper to employ the JDAM only opens a path for the service to add more GPS-guided weapons onto the drones, which are also in high demand. Before getting the GBU-38/B, the Air Force’s MQ-9s were limited largely to laser-guided AGM-114 Hellfire missiles and GBU-12/B Paveway II bombs. “The GBU-38, just like the Hellfire and GBU-12, is a very accurate weapon and the fact that it’s GPS-guided gives us another versatile way to guide the weapon, specifically, through inclement weather onto targets,” Scott added. The Air Force Special Operations Command’s aircraft have also employed the AGM-176 missile, which has a combination of GPS and laser-guidance. They may be dropping other small munitions we don’t yet know about, too.

However, a standard architecture for lobbing GPS-directed weapons on the Reaper would let the entire fleet employ a whole suite of existing weapons, as well as new munitions in development or already on the market. The most important of these would likely be the Boeing Small Diameter Bomb (SDB) and Raytheon’s up-coming SDB II. These 250-pound class glide bombs have proven ideal choices for attacking small targets in crowded environments. In addition to run low in JDAMs, the Pentagon had to divert stocks of SDBs to the Middle East to keep up with the needs of operations against ISIS.

A display of three Textron Fury bombs on a single launch rack at the 2017 Sea Air Space Exhibition., Joseph Trevithick

For drones like Reaper, the ability to carry multiple SDB’s on the same pylon would be a boon. As it stands now, the MQ-9 has four under-wing hard points, which can each carry a pair of Hellfires or a single GBU-12/B. Video and pictures the 432nd released shows single carriage of JDAMs, too. The unmanned attackers should be able to carry at least two SDBs in place of one of these larger bombs.

Lockheed, Orbital ATK, Raytheon, and Textron are all offering new, small GPS- or combination GPS/INS and laser-guided bombs and missiles, pushing particularly hard with racks that hold multiple weapons aimed small aircraft and drones.  Textron says three of its diminutive Fury glide bombs can fit in place of a single Hellfire and Orbital ATK is working on various options for its tiny Hatchet and Hammer weapons, which The War Zone previously reported on as a potential future option for the F-35 Joint Strike Fighter.

All in all, the GBU-38/B significantly increases the combat capabilities of the Reaper and we can reasonably expect to see evidence of that soon. On top of that, it is just the first step into further expanding the drone’s available arsenal with both old and new weapons.

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Joseph Trevithick

Deputy Editor

Joseph has been a member of The War Zone team since early 2017. Prior to that, he was an Associate Editor at War Is Boring, and his byline has appeared in other publications, including Small Arms Review, Small Arms Defense Journal, Reuters, We Are the Mighty, and Task & Purpose.