Historical Essay © Andreas Parsch

McDonnell-Douglas HEDI

The U.S. Army's HEDI (High Endoatmospheric Defense Interceptor) was an SDI (Strategic Defense Initiative) program for a lower-tier ballistic missile defense. As such it was to complement to ERIS (Exoatmospheric Reentry Interceptor Subsystem) upper-tier system.

No true HEDI missiles were built, but technology for an endoatmospheric hit-to-kill missile interceptor was tested by KITE (Kinetic Kill Vehicle Integrated Technology Experiment) test vehicles as part of the HEDI program. KITE was a rail-launched missile based on the older Sprint nuclear-armed ABM (Anti-Ballistic Missile). It was a two-stage solid-fueled rocket, powered by a Hercules X-265 and a Hercules X-271 motor. The KKV (Kinetic Kill Vehicle) was fitted with an infrared seeker, which was protected behind a shroud during the initial high-speed flight through the lower atmosphere. The KITE achieved an acceleration of over 200 G immediately after launch.

The first KITE test flight ("KITE-1") on 26 January 1990 was followed by a failed launch ("KITE-2") on 23 September 1991 and the second and last flight ("KITE-2A") on 26 August 1992. The operational HEDI program had been cancelled in 1992, but the KITE flights tested various system components like seeker, guidance and control systems. However, no actual intercepts were attempted.

I have no data about the exact physical characteristics of the KITE test vehicle or the planned HEDI operational missile.

[1] Army Strategic Defense Command memorandum about "KITE-2A" test, 26 August 1992
[2] Gunter Krebs: Gunter's Space Page

Manufacturer: Douglas. Launches: 3. Failures: 1. Success Rate: 66.67%. First Launch Date: 1990-01-26. Last Launch Date: 1992-08-26. Launch data is: complete. Apogee: 15 km (9 mi). Liftoff Thrust: 3,000.000 kN (674,400 lbf). Total Mass: 3,500 kg (7,700 lb). Core Diameter: 1.37 m (4.49 ft). Total Length: 8.20 m (26.90 ft).

• Stage1: 1 x Sprint ABM-1. Gross Mass: 4,000 kg (8,800 lb). Motor: 1 x X-265. Burn time: 1.20 sec. Length: 3.00 m (9.80 ft). Diameter: 1.37 m (4.49 ft). Propellants: Solid.

• Stage2: 1 x Sprint ABM-2. Motor: 1 x X-271. Length: 5.00 m (16.40 ft). Diameter: 0.82 m (2.69 ft). Propellants: Solid.

1990 January 26 - White Sands LC37. KITE-1 test Agency: SDIO. Apogee: 10 km (6 mi).

1991 September 23 - 15:40 GMT - White Sands LC37. FAILURE: Failure. KITE-2 test Agency: SDIO. Apogee: 0 km ( mi).

1992 August 26 - 14:31 GMT - White Sands LC37. KITE-2A test Agency: SDIO. Apogee: 12 km (7 mi).