A new report by the U.S. Government Accountability Office (GAO) has raised questions about Defense Department plans to augment its U.S. territorial missile shield with interceptors placed in Romania and Poland.

The Feb. 11 report, citing reviews of internal Defense Department documents, casts new doubt on plans for a new interceptor dubbed the Standard Missile-3 Block 2B. The interceptor, currently the subject of a three-way competition between Boeing, Lockheed Martin and Raytheon, is slated for deployment in the late stages of U.S. President Barack Obama’s Phased Adaptive Approach to European defense.

In its initial phase, the president’s plan defends Europe from Iranian missiles using the existing sea-based Standard Missile-3 interceptor, which is built by Raytheon. The Block 2B would be a new variant that, when installed in Romania and Poland, also would be able to engage Iranian missiles launched toward the United States.

But the GAO said the U.S. Missile Defense Agency (MDA) did not conduct a full-fledged analysis of alternatives to the Block 2B before it began technology development. While the MDA was not required to do so, such analyses provide a basis for prudent acquisition decisions, the GAO said in its report, dubbed “Standard Missile-2 Block 2B: Analysis of Alternatives.”

Pentagon reviews conducted after Block 2B development work began suggest that additional investments will be required for the interceptor to augment the existing U.S. territorial shield, the GAO said. Specifically, according to the report:

  • Romania is not a good location “from a flight path” standpoint for defending the United States.

  • Standard Missile-3 Block 2B interceptors based in Poland would have to be launched earlier than originally assumed — while the attacking missiles are still in their boost phase — to be useful in defending the United States.

  • The North Sea offers the best vantage point for engaging offensive missiles using the Block 2B, but that would require additional investment to make the interceptor safe to launch from ships.

One leading critic of the Phased Adaptive Approach, which replaced former President George W. Bush’s plan to install a different type of interceptor in Poland, pounced at the GAO’s finding. “This report really confirms what I have said all along: that this was a hurried proposal by the president,” Rep. Michael R. Turner (R-Ohio), a member of the House Armed Services Committee, said in a prepared statement Feb. 11.

The GAO report bolsters the conclusion reached last year by a National Research Council panel that the Phased Adaptive Approach, though effective in protecting the Europeans, would not do much to shield U.S. territory.

MDA spokesman Richard Lehner declined to comment on the GAO report.

Mike Gruss is a senior staff writer for SpaceNews. He joined the publication in January 2013 to cover military space. Previously, he worked as a reporter and columnist for The Virginian-Pilot in Norfolk, Va. and The Journal Gazette in Fort Wayne, Ind. He...