In space and missile defense history, 1984 saw one of the first steps in a move from science fiction to reality. Although President Ronald Reagan announced his initial concept for the Strategic Defense Initiative in March 1983, it was not until December 1984 that the first elements were officially chartered.

On Dec. 20, 1984, the Secretary of the Army John O. Marshall, Jr. issued the first Project Manager Charters for the High Endoatmospheric Defense Interceptor, or HEDI, and the Exoatmospheric Reentry-vehicle Interceptor Subsystem, or ERIS.

Both project offices were to be located at 106 Wynn Drive, in Huntsville, Alabama, with functional and administrative support provided by the Ballistic Missile Defense Systems Command, or BMDSCOM. Both project managers reported through the BMDSCOM commander to the Ballistic Missile Defense program manager.

At this early stage the missions, as defined by the charters, were very similar. The managers were responsible for centralized management and direction of their projects in keeping with Army regulations, Department of Defense directive and instruction and related guidance. The two projects were to "support a BMDSCOM integrated technology demonstration."

To that end, they were to be interoperable with the various BMDSCOM technology development initiatives that included efforts in: the Airborne Optical Adjunct, AOA; the Terminal Imaging Radar, TIR; and the Battle Management/Command Control and Communications, BM/C3.

There was, however, a distinct difference in the two missions. While a nonnuclear intercept of the approaching reentry vehicle was the end goal for the two interceptors, they pursued a different approach. The HEDI mission statement described an interceptor that "[would] receive commit instructions and handover data from the BMD radar and battle manager; launch and flyout to the predicted intercept point; initiate onboard homing; home to the target reentry vehicle (RV); fuze and detonate a nonnuclear warhead, and achieve RV kill."

The ERIS interceptor meanwhile following the home to the target reentry vehicle was designed to intercept and achieve a nonnuclear kill of the RV.

In many respects, this divergence in the mission reflects the status of the missile defense technology in 1984. During the summer, the Homing Overlay Experiment, or HOE, demonstrated the feasibility of a kinetic energy intercept in the exo-atmosphere. Thus the ERIS was to physically intercept its targets. It would be two more years, however, before the Flexible Lightweight Agile Guided Experiment, or FLAGE, would prove that a kinetic intercept was possible within the atmosphere. As a result at this point the HEDI was to be equipped with a warhead.