The Joint Direct Attack Munition (JDAM) is a guidance kit that converts unguided bombs, or “dumb bombs”, into all-weather precision-guided munitions. JDAM-equipped bombs are guided by an integrated inertial guidance system coupled to a Global Positioning System (GPS) receiver, giving them a published range of up to 15 nautical miles (28 km). JDAM-equipped bombs range from 500 pounds (227 kg) to 2,000 pounds (907 kg). The JDAM’s guidance system was jointly developed by the United States Air Force and United States Navy, hence the “joint” in JDAM. When installed on a bomb, the JDAM kit is given a GBU (Guided Bomb Unit) nomenclature, superseding the Mark 80 or BLU (Bomb, Live Unit) nomenclature of the bomb to which it is attached.
The JDAM is not a stand-alone weapon; rather it is a “bolt-on” guidance package that converts unguided gravity bombs into precision-guided munitions (PGMs). The key components of the system consist of a tail section with aerodynamic control surfaces, a (body) strake kit, and a combined inertial guidance system and GPS guidance control unit.
The JDAM was meant to improve upon laser-guided bomb and imaging infrared technology, which can be hindered by bad ground and weather conditions. Laser seekers are now being fitted to some JDAMs.
From 1998 to November 2016, Boeing completed more than 300,000 JDAM guidance kits. In 2017, it built more than 130 kits per day. As of February 2020, 430,000 kits had been produced.
The U.S. Air Force’s bombing campaign during the Persian Gulf War’s Operation Desert Storm was less effective than initially reported, in part because it had no precision bombs that were accurate in all weather. Laser guidance packages on bombs proved exceptionally accurate in clear conditions, but amid airborne dust, smoke, fog, or cloud cover, they had difficulty maintaining “lock” on the laser designation. Research, development, testing and evaluation (RDT&E) of an “adverse weather precision guided munition” began in 1992. Several proposals were considered, including a radical concept that used GPS. At the time, there were few GPS satellites and the idea of using satellite navigation for real-time weapon guidance was untested and controversial. To identify the technical risk associated with an INS/GPS guided weapon, the Air Force created in early 1992 a rapid-response High Gear program called the “JDAM Operational Concept Demonstration” (OCD) at Eglin Air Force Base. Honeywell, Interstate Electronics Corporation, Sverdrup Technology, and McDonnell Douglas were hired to help the USAF 46th Test Wing demonstrate the feasibility of a GPS weapon within one year. The OCD program fitted a GBU-15 guided bomb with an INS/GPS guidance kit and on 10 February 1993, dropped the first INS/GPS weapon from an F-16 on a target 88,000 feet (27 km) downrange. Five more tests were run in various weather conditions, altitudes, and ranges. The OCD program demonstrated an 11-meter Circular Error Probable (CEP).
The first JDAM kits were delivered in 1997, with operational testing conducted in 1998 and 1999. During testing, over 450 JDAMs were dropped achieving a system reliability in excess of 95% with a published accuracy under 10 metres (33 ft) CEP. In addition to controlled parameter drops, the testing and evaluation of the JDAM also included “operationally representative tests” consisting of drops through clouds, rain and snow with no decrease in accuracy from clear-weather tests. In addition, there have been tests involving multiple weapon drops with each weapon being individually targeted.
JDAM and the B-2 Spirit stealth bomber made their combat debuts during Operation Allied Force. The B-2s, flying 30-hour, nonstop, round-trip flights from Whiteman Air Force Base, Missouri, delivered more than 650 JDAMs during Allied Force. An article published in the Acquisition Review Journal in 2002 cites that “during Operation Allied Force … B-2s launched 651 JDAMs with 96% reliability and hit 87% of intended targets…” Due to the operational success of the original JDAM, the program expanded to the 500 pounds (227 kg) Mark 82 and 1,000 pounds (454 kg) Mark 83, beginning development in late 1999. As a result of lessons from Operation Enduring Freedom and Operation Iraqi Freedom, both the US Navy and US Air Force pursued improvements to the kits such as better GPS accuracy as well as a precision seeker for terminal guidance for use against moving targets.
JDAM bombs are inexpensive compared to alternatives such as cruise missiles. The original cost estimate was $40,000 each for the tail kits; however, after competitive bidding, contracts were signed with McDonnell Douglas (later Boeing) for delivery at $18,000 each. Unit costs, in current-year dollars, have since increased to $21,000 in 2004 and $27,000 by 2011. To the cost of the tail kit should be added the costs of the Mk80-series iron bomb, the fuze and proximity sensor which bring the overall weapon cost to about $30,000. For comparison, the newest Tomahawk cruise missile, dubbed the Tactical Tomahawk, costs nearly $730,000.
Experience during Operation Enduring Freedom and Operation Iraqi Freedom led US air power planners to seek additional capabilities in one package, resulting in ongoing program upgrades to place a precision terminal guidance seeker in the JDAM kit. The Laser JDAM (LJDAM), as this upgrade is known, adds a laser seeker to the nose of a JDAM-equipped bomb, giving the ability to engage moving targets to the JDAM. The Laser Seeker is a cooperative development between Boeing‘s Defense, Space and Security unit and Israel’s Elbit Systems. It is called Precision Laser Guidance Set (PLGS) by Boeing and consists of the Laser Seeker itself, now known as DSU-38/B, and a wire harness fixed under the bomb body to connect the DSU-38/B with the tail kit. During FY2004, Boeing and the U.S. Air Force began testing of the laser guidance capability for JDAM, with these tests demonstrating that the system is capable of targeting and destroying moving targets. This dual guidance system retains the ability to operate on GPS/INS alone, if laser guidance is unavailable, with the same accuracy of the earlier JDAM.
On June 11, 2007, Boeing announced that it had been awarded a $28 million contract by the U.S. Air Force to deliver 600 laser seekers (400 to the Air Force and 200 to the Navy) by June 2009. According to the Boeing Corporation, in tests at Nellis Air Force Base, Nevada, Air Force F-16 Fighting Falcons and F-15E Strike Eagles dropped twelve 500 pounds (227 kg) LJDAMs that successfully struck high-speed moving targets. Using onboard targeting equipment, the launch aircraft self-designated, and self-guided their bombs to impact on the targets. In addition to the LJDAM kits, Boeing is also testing under a Navy development contract, an anti-jamming system for the JDAM, with development expected to be completed during 2007, with deliveries to commence in 2008. The system is known as the Integrated GPS Anti-Jam System (IGAS).
Boeing announced on September 15, 2008 that it had conducted demonstration flights with the LJDAM loaded aboard a B-52H.
The GBU-54 LJDAM made its combat debut on August 12, 2008 in Iraq when an F-16 from the 77th Fighter Squadron engaged a moving vehicle in Diyala province. Furthermore, the GBU-54 LJDAM made its combat debut in the Afghan theater by the 510th Fighter Squadron in October 2010.
In September 2012, Boeing began full-rate production of Laser JDAM for US Navy and received a contract for more than 2,300 bomb kits.
On July 24, 2008 Germany signed a contract with Boeing to become the first international customer of LJDAM. Deliveries for the German Air Force began in mid-2009. The order also includes the option for further kits in 2009.
In November 2014, the U.S. Air Force began development of a version of the GBU-31 JDAM intended to track and attack sources of electronic warfare jamming directed to disrupt the munitions’ guidance. The Home-on-Jam seeker works similar to the AGM-88 HARM to follow the source of a radio-frequency jammer to destroy it.
JDAM Extended Range
In 2006, the Australian Defence Science and Technology Organisation in conjunction with Boeing Australia successfully tested extended range JDAM variants at Woomera Test Range.
In 2009, Boeing announced that it will jointly develop the Joint Direct Attack Munition Extended Range (JDAM-ER) with South Korea. The guidance kit will triple the range of JDAM to 80 km for the same accuracy, and will cost $10,000 per unit. The first prototypes are to be completed in 2010 or 2011.
The wing kits of Australia’s JDAM-ER weapons will be built by Ferra Engineering. First tests are to be conducted in 2013 with production orders in 2015.
In 2010 Boeing proposed adding a jet engine tailkit to the JDAM-ER for 10 times greater range. The U.S. Air Force initially didn’t show interest in the concept, but by 2020 Boeing believed the service had regained interest in acquiring low-cost cruise missiles. The Powered JDAM has the range of more sophisticated missiles through a low-cost engine while being cheaper through not have a stealthy shape or the ability to conduct low-altitude flights. Though less survivable, Powered JDAMs could be networked to provide a cheap standoff weapon to overwhelm air defense systems.
Precision aerial minelaying
On 23 September 2014, the U.S. Air Force performed the first-ever drop of a precision-guided aerial mine, consisting of a Quickstrike mine equipped with a JDAM kit. The Quickstrike is a Mark 80-series general-purpose bomb with the fuze replaced with a target detection device (TDD) to detonate it when a ship passes within lethal range, a safe/arm device in the nose, and a parachute-retarder tailkit in the back. Dropping of naval mines has historically been challenging, as the delivery aircraft has to fly low and slow, 500 ft (150 m) at 320 knots (370 mph; 590 km/h), making it vulnerable to hostile fire; the first aerial mining mission of Operation Desert Storm resulted in the loss of an aircraft, and the U.S. has not flown any combat aerial minings since. The Quickstrike-J is a JDAM-equipped 1,000 lb or 2,000 lb version, and the GBU-62B(V-1)/B Quickstrike-ER is a 500 lb or 2,000 lb gliding version based on the JDAM-ER, which has a range of 40 nmi (46 mi; 74 km) when launched from 35,000 ft (11,000 m). Precision airdropping of naval mines is the first advance in aerial mine delivery techniques since World War II and can increase the survivability of delivery aircraft, since instead of making multiple slow passes at low altitude directly over the area an aircraft can release all of their mines in a single pass from a standoff distance and altitude, and increase the mines’ effectiveness, since instead of laying a random pattern of mines in a loosely defined area they can be laid directly into harbor mouths, shipping channels, canals, rivers, and inland waterways, reducing the number of mines required and enhancing the possibility of blocking ship transit corridors. Enemy naval ports can also be blockaded, and a defensive minefield quickly planted to protect areas threatened by amphibious assault.
- 2,000 lb (900 kg) nominal weight
- GBU-31(V)1/B (USAF) Mk-84
- GBU-31(V)2/B (USN/USMC) Mk-84
- GBU-31(V)3/B (USAF) BLU-109
- GBU-31(V)4/B (USN/USMC) BLU-109
- GBU-31(V)5/B (USAF) BLU-119/B
- GBU-31v11: Guided BLU-136 cluster bomb replacement
- 1,000 lb (450 kg) nominal weight
- GBU-32(V)1/B (USAF) Mk-83
- GBU-32(V)2/B (USN/USMC) Mk-83
- GBU-35(V)1/B (USN/USMC) BLU-110
- 500 lb (225 kg) nominal weight
- GBU-38(V)1/B (USAF) Mk-82 and BLU-111
- GBU-38(V)2/B (USN/USMC) Mk-82 and BLU-111
- GBU-38(V)3/B (USAF) BLU-126/B
- GBU-38(V)4/B (USN/USMC) BLU-126/B
- GBU-38(V)5/B (USAF) BLU-129/B
- GBU-54/B Laser JDAM (Mk-82)
- Primary function: Guided air-to-surface weapon
- Contractor: Boeing
- Length: (JDAM and warhead) GBU-31 (v) 1/B: 152.7 inches (3,880 mm); GBU-31 (v) 3/B: 148.6 inches (3,770 mm); GBU-32 (v) 1/B: 119.5 inches (3,040 mm); GBU-38 (v) /B: 2.35 m (92.64 inches)
- Launch weight: (JDAM and warhead) GBU-31 (v) 1/B: 2,036 pounds (924 kg); GBU-31 (v) 3/B: 2,115 pounds (959 kg); GBU-32 (v) 1/B: 1,013 pounds (459 kg); GBU-38 (v) /B: 590 pounds (268 kg)
- Wingspan: GBU-31: 25 inches (640 mm); GBU-32: 19.6 inches (500 mm)
- Range: Up to 15 nautical miles (28 km)
- Ceiling: 45,000 feet (14,000 m)
- Guidance system: GPS/INS
- Unit cost: Approximately $22,000 per tailkit (FY 07 dollars)
- Date deployed: 1999
- Inventory: The tailkit is in full-rate production. Projected inventory is approximately 240,000 total, 158,000 for the US Air Force and 82,000 for the US Navy.