Drafted — not technically validated
Record revision 1 · The GPS/INS tail kit that made ordinary bombs accurate in any weather, and its laser-seeker version for moving targets.
Real-world weapon as described in public sources. Weights and dimensions change with the fins, fuzes and variant fitted; the data plate names the variants its figures describe, and differences are noted beside the number they affect. The record describes the weapon; it is not a guide to employing it.
Joint Direct Attack Munition (GBU-31, GBU-32, GBU-38, GBU-54) · GBU-31 / GBU-32 / GBU-38 / GBU-54
- Origin
- United States
- In service
- First kits delivered 1997; combat debut in Operation Allied Force, 1999 [1]
- Weight
- 500–2,000 lb class, depending on the bomb fitted [1]
- Dimensions
- Those of the bomb, with a tail section of control surfaces and a strake kit on the body [1] [2]
- Warhead or payload
- The bomb it is fitted to: GBU-31 Mk 84Mark 84 general-purpose bomb OrdnanceThe 2,000 lb heavyweight of the Mark 80 series, dropped by the thousand in Desert Storm and the warhead of the GBU-10 and GBU-31. or BLU-109; GBU-32 Mk 83Mark 83 general-purpose bomb OrdnanceThe 1,000 lb member of the Mark 80 family, used most by the US Navy and as the warhead of the GBU-16 and GBU-32.; GBU-38 Mk 82Mark 82 general-purpose bomb OrdnanceThe 500 lb low-drag bomb that is one of the most common air-dropped weapons in the world, with conical, Snakeye or ballute tails. [1] [2]
- Guidance
- Inertial navigation tightly coupled with GPS: 13 m CEP with GPS, 30 m on inertial only [2]; under 10 m in testing [1]
- Fuzing
- Not given in the cited sources
- Delivery
- Target coordinates loaded before flight or retargeted in flight; released inside the launch acceptable region from any altitude, level, in a dive, toss or loftLoft GlossaryWeapons: An attack in which the weapon is released by computer with the aircraft nose-up, so it is thrown at the target in a ballistic trajectory; it lets the attacker stay farther from the detonation and the target's defenses…, on or off axis [2]
- Range
- Up to 15 NM (28 km) [1]
- Carried by
- US Air Force: A-10A-10 Thunderbolt II AircraftThe Warthog: a straight-wing, armoured close air support jet built around the 30 mm GAU-8 cannon., F-15EF-15E Strike Eagle AircraftThe two-seat, long-range, all-weather strike derivative of the Eagle., F-16F-16 Fighting Falcon AircraftA single-engine multirole fighter: fly-by-wire, 9 g, and the US Air Force's main strike and SEAD aircraft., F-22, F-35, B-1B, B-2A, B-52H [1]
- US Navy and Marine Corps: F/A-18F/A-18 Hornet AircraftA carrier-capable fighter and attack aircraft that one pilot can switch between roles on the same sortie., F/A-18E/FF/A-18 Hornet AircraftA carrier-capable fighter and attack aircraft that one pilot can switch between roles on the same sortie., AV-8BAV-8B Harrier II AircraftA vectored-thrust jump jet: vertical or short take-off, flown by the US Marines for close air support. [1]
- Also listed for the MiG-29, Su-27, Tornado and Gripen [1]
A kit, not a bomb
The JDAM is not a weapon of its own but a bolt-on guidance package. A tail section with control surfaces, a strake kit on the bomb body and a combined inertial and GPS guidance unit turn an unguided bomb into an all-weather precision weapon, and the bomb then takes a GBU designation in place of its Mk 80 or BLU name. [1] The Air Force and Navy developed it together, hence “joint”. [1] The 2,000 lb version is the GBU-31, the 1,000 lb the GBU-32 [2], and the 500 lb the GBU-38. [1]
Why GPS
Desert Storm showed the gap it filled. Laser-guided bombsLGW GlossaryWeapons: Laser-guided weapon. A weapon that uses a seeker to detect laser energy reflected from a laser marked/designated target and through signal processing provides guidance commands to a control system, which guides the… were very accurate in clear air, but dust, smoke, fog or cloud could break their lock on the laser spot, and they could not be released from high altitude. [1] A JDAM needs no spot. The mission plan, with the release envelope, target coordinates and terminal parameters, is loaded before take-off; the weapon aligns its inertial system with the aircraft’s while carried, and once released inside the launch acceptable region it guides itself whatever the weather. [2] If GPS is jammed after release, the inertial system carries on alone with a wider error, 30 m CEP against 13 m. [2] It can be dropped from very low to very high altitude, in level flight, a dive, a toss or a loftLoft GlossaryWeapons: An attack in which the weapon is released by computer with the aircraft nose-up, so it is thrown at the target in a ballistic trajectory; it lets the attacker stay farther from the detonation and the target's defenses…, and several can be aimed at different targets in a single pass. [2]
In combat
JDAM and the B-2 made their combat debuts together over Kosovo in 1999, when B-2s flying 30-hour round trips from Missouri delivered more than 650 of them. [1] The Laser JDAM came out of Afghanistan and Iraq: it adds a laser seeker to the nose so the bomb can hit moving targets, while keeping its GPS accuracy if no laser is available. The GBU-54 made its combat debut in August 2008, when an F-16F-16 Fighting Falcon AircraftA single-engine multirole fighter: fly-by-wire, 9 g, and the US Air Force's main strike and SEAD aircraft. of the 77th Fighter Squadron hit a moving vehicle in Iraq. [1] By January 2024 some 550,000 JDAM kits had been built. [1]
Sources
- Joint Direct Attack Munition. Wikipedia (secondary source). https://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition (accessed 2026-10-27).
- Joint Direct Attack Munition (JDAM) GBU-29, GBU-30, GBU-31, GBU-32. Federation of American Scientists, Military Analysis Network. https://man.fas.org/dod-101/sys/smart/jdam.htm (accessed 2026-10-27).
Wikipedia articles are secondary sources and can change; they are cited with the date they were read. NAVEDTRA training manuals and budget justification exhibits are official US publications, but each describes the weapons in service when it was written.