The U.S. Air Force is exploring ways to achieve more lethality with air-launched weapons against sea-based targets.
The Air Force announced that three F-15E Strike Eagle combat jets from the 85th Test and Evaluation Squadron, part of the 53rd Wing based at Eglin Air Force Base in Florida, had taken part in an experiment to explore ways to employ modified 2,000-pound class GBU-31/B Joint Direct Attack Munitions (JDAM) against “both moving and static maritime targets.”
This particular test is part of a larger capabilities demonstration effort, dubbed Quicksink, that the Air Force Research Laboratory (AFRL) is managing.
“A Navy submarine has the ability to launch and destroy a ship with a single torpedo at any time, but by launching that weapon it gives away the location of the vessel,” an official Air Force news item said.
“The QUICKSINK JCTD [Joint Capability Technology Demonstration] aims to develop a low-cost method of achieving torpedo-like seaworthy kills from the air.”
The video montage below ends with a clip of a decommissioned Oliver Hazard Perry-class frigate having its back broken by a Mk 48 torpedo during a U.S. Navy-led exercise earlier this year, underscoring the anti-ship capabilities that those weapons offer. You can read more about that exercise here.
The Air Force did not say how the GBU-31/Bs had been modified to enable them to engage moving targets. Standard JDAMs have a GPS-assisted Interial Navigation System (INS) guidance system that can only be used to point them at specific coordinates.
JDAM is a guided air-to-surface weapon that can use several different warheads: the 2,000-pound BLU-109/MK 84, the 1,000-pound BLU-110/MK 83 or the 500-pound BLU-111/MK 82 warhead as the payload. Guidance is facilitated through a tail control system and a GPS-aided INS.
The navigation system is initialized by transfer alignment from the aircraft that provides position and velocity vectors from the aircraft systems.
The GBU-31s in the photographs released by the U.S. Air Force appears to be GBU-31(V)1/B, using the guidance kit on an MK-84. It would be interesting to learn a bit more about the “modification” mentioned in the public release and how the JDAMs were used to engage “moving maritime targets” as JDAMs are not Laser-Guided (unless they are Laser JDAMs – mentioned later) hence more suitable for use against fixed/stationary targets.
LGBs (Laser Guided Bombs) have long been used in maritime scenarios for moving targets but the seeker head of the LGB can be adversely affected by the elements (such as bad weather, fog, smoke, etc), potentially reducing its effectiveness.
These weapons use onboard seekers to track targets that are designated by laser, typically in the infrared spectrum, and adjust their glide path to accurately strike the target.