The U.S. Missile Defense Agency (MDA) is planning another major flight trial involving multiple targets and multiple interceptors to increasingly challenge its young missile defense shield’s ability to handle “raids,” or multiple threats launched simultaneously.

The Pentagon’s interceptors downed four of five threats in the first such trial, which took place Oct. 25. MDA officials have not yet said what caused an Aegis-ship-based SM-3 Block IA to fail in intercepting its short-range ballistic missile target. However, a ship-launched SM-2 Block IIIA did intercept an anti-ship threat during the trial.

The Lockheed Martin Terminal High-Altitude Area Defense (Thaad) system destroyed a single medium-range ballistic missile target and the Patriot Advanced Capability (PAC)-3 destroyed two threats – a short-range ballistic missile as well as a cruise missile.

Pentagon officials are planning the next such test to take place by the end of June. A scenario has not yet been outlined, but officials say that Thaad will again be one of the elements.

This will be a linchpin for the MDA’s busy testing schedule in 2013.

The Ground-Based Midcourse Defense (GMD) is slated to return to flight early next year for a flight trial; an intercept test could come by the summer if the first flight is successful.

Mating of Ground-Based Interceptor (GBI, made by Orbital) with the Raytheon Exoatmopsheric Kill Vehicle Capability Enhancement 2 (an upgraded hit-to-kill mechanism) is still on hold pending a successful intercept. Boeing is the overall GMD integrator for the Pentagon.

Meanwhile, the agency is also planning two intercept tests for the Raytheon SM-3 Block 1B missile The first, slated between January and the end of March, will involve a separating short-range ballistic missile target, an Aegis Readiness Assessment Vehicle-C. Details of the second have not yet been planned.

MDA does not have any specific trials of Thaad on the schedule for next year other than the system’s participation in the big integrated operational exercise.