Directory of U.S. Military Rockets and Missiles
Appendix 4: Undesignated Vehicles
Copyright © 2003 Andreas Parsch


When the SDI (Strategic Defense Initiative) program was initiated in the early 1980s, a number of anti-ballistic missile programs were started. These included ERIS (Exoatmospheric Reentry Interceptor Subsystem), HEDI (High Endoatmospheric Defense Interceptor) and - as a lower-tier endoatmospheric complement to HEDI - LEDI (Low Endoatmospheric Defense Interceptor). LEDI was to be a ground-launched, radar-guided missile armed with a conventional HE warhead. To develop and test LEDI technologies, LTV received a contract to build and fly test missiles under the SRHIT (Small Radar-Homing Intercept Technology) program. At some point into the project, SRHIT was renamed FLAGE (Flexible Lightweight Agile Guided Experiment).

The SRHIT/FLAGE missile was a solid-propellant rocket powered vehicle with a maximum speed of around 1 km/s (3300 ft/s). It was guided by a millimeter-wave radar and was designed to intercept incoming ballistic warheads at altitudes of about 5 km (16400 ft) or less. The missile was spin-stabilized and could manoeuver with up to 100G by using 216 small solid rocket motors in the forward body.

Photo: via Scott Ferrin

During 1984, three SRHIT/FLAGE flights were conducted to test basic missile performance. The first intercept attempt, against a stationary balloon target, was attempted on the fifth flight test on 20 April 1986. The test was successful, and was followed by a successful intercept of a simulated missile target on 27 June that year. The seventh and final FLAGE test occurred on 21 May 1987, when an MGM-52 Lance short-range ballistic missile was successfully intercepted.

The LEDI program itself had already been terminated in 1986, but the FLAGE missile was further developed in the 1990s under the ERINT (Extended-Range Interceptor) program. The ERINT missile was eventually selected as the anti-ballistic missile for the Patriot system, and is now in operational service as the Patriot PAC-3.


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


Length3 m (10 ft)
Diameter25 cm (10 in)
Speed1000 m/s (3300 fps)
PropulsionSolid-fueled rocket

Main Sources

[1] George Lewis: "Chronology of hit-to-kill missile tests, 1997
[2] David Hobbs: "An Illustrated Guide To Space Warefare", 1986
[3] "Military Technology", Issue 05, 1985
[4] "Patriot Missile" at HAWK Site Denmark (originally at, now dead link (31 March 2004))

Back to Directory of U.S. Military Rockets and Missiles, Appendix 4

Last Updated: 13 October 2003