WASHINGTON — The U.S. Missile Defense Agency has narrowed the list of potential East Coast interceptor sites down to three locations, eliminating a base in Maine.

In a Jan. 15 press release, the agency said the Naval Air Station Portsmouth SERE Training Area in Maine “presented irreversible environmental impacts, significant constructability concerns, and extensive costs associated with developing infrastructure in a remote area.”

The current Ground-based Midcourse Defense system, which serves as the primary U.S. territorial missile shield, has interceptors at sites in California and Alaska that could shoot down North Korean missiles. The MDA, at the urging of House Republicans, is studying options for a third site in the eastern United States to counter a potential Iranian missile threat.

The price tag for an East Coast site is expected to be at least $3 billion. Defense Department officials have downplayed how quickly a potential site may be needed and have warned that the funding could detract from higher-priority programs.

Currently, the MDA is considering three sites:

  • Fort Drum, New York
  • Camp Ravenna Joint Training Center, Ohio
  • Fort Custer Training Center, Michigan[spacenews-ad]

The agency expects to complete environmental impact studies on those sites by the middle of 2016.

The MDA has said completing environmental impact studies would accelerate the timeline to build a new site.

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.