Exoatmospheric Reentry-vehicle Interceptor Subsystem
The Exoatmospheric Reentry-vehicle Interceptor Subsystem, or ERIS, program, was a component of the United States' Strategic Defense Initiative during the Cold War. The ERIS system was named after Eris, Greek goddess of strife. ERIS was a kinetic kill system, launched from a ground-based system, and impacting directly to destroy an incoming Intercontinental ballistic missile (ICBM) before the targeted ICBM re-entered the Earth's atmosphere. Background The 1972 Anti-Ballistic Missile Treaty between the U.S. and the Soviet Union permitted each nation to have two ABM sites, each limited to 100 missiles, for a total of 200 ABMs per nation. A 1976 Protocol added to the ABM treaty further limited each nation to a single, 100 missile site. Development In 1985, Lockheed Corporation was awarded a contract to develop an ABM system - the ERIS - that was compliant with the ABM Treaty. ERIS was to be a high altitude component of SDI that would operate in outer space. It would intercept and destroy an incoming ICBM before the ICBM re-entered the atmosphere. ERIS was to be complemented by another ABM system, High Endoatmospheric Defense Interceptor (HEDI), which destroyed enemy missiles in the atmosphere. The ERIS delivery vehicle was composed of the second