High Endoatmospheric Defense Interceptor

{{Short description|US missile defense layer during the Cold War}}

File:White Sands Missile Range Museum-98 (8326903749).jpg

High Endoatmospheric Defense Interceptor (HEDI) was an atmospheric missile defense layer developed for the Strategic Defense Initiative, along with Exoatmospheric Reentry-vehicle Interceptor Subsystem. It consisted of a two-stage launch vehicle (booster) and an infrared homing kill vehicle with a conventional warhead.{{Cite web |date=31 May 1989 |title=High Endoatmospheric Defense Interceptor (HEDI) Technology Testing Program Environmental Assessment (ADA210006) |url=https://apps.dtic.mil/sti/pdfs/ADA210006.pdf |access-date=13 August 2024 |website=Defense Technical Information Center |publisher=Department of the Navy |pages=S-1-2, p.11}} Hughes Aircraft and Aerojet were contractors, and McDonnell Douglas was the system integrator.{{cite web|url=http://www.designation-systems.net/dusrm/app4/hedi.html|title=McDonnell Douglas HEDI|website=www.designation-systems.net|accessdate=17 February 2018}}

The HEDI aimed to employ ground-based missiles to intercept submarine-launched ballistic missiles and intercontinental ballistic missiles and operate in the high endoatmosphere region in order to destroy them.