Directory of U.S. Military Rockets and Missiles
Appendix 5: Guided Bombs
Copyright © 2006 Andreas Parsch

Northrop Grumman BAT / GBU-44/B Viper Strike

The BAT (Brilliant Anti-Tank) guided anti-tank submunition was developed by the U.S. Army in the 1990s as a payload for the MGM-137B TSSAM and later the MGM-140 ATACMS missiles. BAT is an unpowered glide bomb with cruciform folding wings and four wrap-around tailfins. Once released, the BAT uses passive acoustic wingtip sensors for initial target acquisition, and an IIR (Imaging Infrared) sensor for terminal guidance. It is equipped with a tandem shaped-charge warhead. The IBAT (Improved BAT) version, also known as P3I BAT (Pre-Planned Product Improvement BAT), was equipped with a dual-mode (millimeter-wave active radar and IIR) seeker, but this variant was not procured in quantity.

While the MGM-137B was cancelled and the BAT-equipped MGM-140 Block II never procured for full operational service, the Army eventually found a use for the BAT as a weapon for its MQ-5 Hunter UAVs in 2003.

Photo: Raytheon

In early 2003, Northrop Grumman conducted a program to adapt the BAT for operations in urban terrain. The acoustic/IIR guidance package was replaced by a semi-active laser seeker, and the weapon renamed to Viper Strike. The first Viper Strike flight tests occurred in March 2003, and the whole test program was successfully completed within nine weeks. The laser guidance requires a "man in the loop" to designate a target and provides the necessary high precision for engagement in areas where avoidance of collateral damage is a high priority. Viper Strike rounds converted from existing BATs still have the wingtip extensions which housed the acoustic sensors. New-built examples come without these probes.

Photo: via Defense Update Website

The Viper Strike, designated GBU-44/B by the U.S. Air Force, will be primarily used from UAVs. The Army has fitted some of its MQ-5 Hunter UAVs with Viper Strike capability, and deployed the weapon to Iraq in 2005. Army plans then called for an immediate acquisition of 78 Viper Strike rounds (with a mix of new-built rounds and converted BATs). As of 2006, the USAF is evaluating the use of the GBU-44/B from MQ-1 Predator UAVs and AC-130U special operations aircraft. Several upgrades for further enhanced versatility are being developed for Viper Strike, including GPS guidance and a fragmentation belt around the shaped-charge warhead.


Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for GBU-44/B:

Length0.9 m (3 ft)
Diameter14 cm (5.5 in)
Wingspan0.9 m (3 ft)
Weight19 kg (42 lb)
WarheadShaped charge

Main Sources

[1] Defense Update Website
[2] Scott R. Gourley: "Viper Strike", Special Operations Technology, August 2004
[3] Frank Colucci: "Army Developing Tactics for Armed Robotic Aircraft", National Defense Magazine, April 2005

Back to Directory of U.S. Military Rockets and Missiles, Appendix 5

Last Updated: 19 September 2006