WASHINGTON — Two key contractors on the primary U.S. missile shield say they have corrected software and other quality assurance issues with a critical system component that were identified in a September report by the Defense Department’s internal investigative arm.

The component in question is the kill vehicle that tops the interceptors on the Ground-based Midcourse Defense (GMD) system, which failed in three straight intercept tests before finding the bull’s-eye in a June demo. Two of those failures were attributed, in whole or in part, to the Raytheon-built Exoatmospheric Kill Vehicle (EKV), which thus became the subject of a yearlong investigation by the Pentagon’s inspector general.

In a Sept. 8 report, the inspector general said GMD prime contractor Boeing Defense, Space and Security of St. Louis and Raytheon Missile Systems of Tucson, Arizona, fell short of standard aerospace industry practices in a number of areas including software development and testing, quality assurance throughout the EKV supply chain, and managing configuration-change processes.

A second part of the report, which assessed the reliability of the EKVs on deployed GMD interceptors, is classified.

The report said that while the majority of EKV quality management systems were in compliance with AS9100C quality standards, there were 48 instances of nonconformance. “These nonconformances could result in the production of nonconforming hardware and software which could effect [sic] mission success,” the report said.  

AS9100C is an international aerospace standard that demonstrates a product’s ability to consistently meet requirements.

“Requirements were viewed as ‘goals’ with little focus on reliability, producibility, and maintainability requirements, which are integral to strategic systems with a life expectancy similar to GMD,” the report said.

The report recommended that the Missile Defense Agency document, implement and enforce software development processes throughout the EKV supply chain, the report said. Suppliers of critical items should be identified as such and “receive the necessary contractual requirements,” the report said.

The report also recommended that fielded GMD hardware be evaluated for risks.

The Missile Defense Agency concurred with all three major recommendations, the report said. The agency said it will address the weaknesses in software development by the first quarter of 2015, the report said. 

Dexter Henson, a Boeing spokesman, said in an Oct. 22 email that all of the issues identified in the report had been addressed. 

Heather Uberuaga, a Raytheon spokeswoman, echoed that assertion in an Oct. 21 email. “The successful June flight test demonstrates our commitment to improving the kill vehicle’s quality and reliability,” she said.

The EKV is a complex system designed to separate from its GMD booster rocket in space and destroy incoming missile warheads by force of impact. The GMD system, though already deployed and considered operational, has a spotty record in testing, recording nine intercepts in 17 attempts since 1999. 

Missile Defense Agency officials have stressed in recent months that the EKV was rushed through development and deployed as a prototype.

Currently there are 30 deployed GMD interceptors: 26 at Fort Greely, Alaska, and four at Vandenberg Air Force Base, California. 

The Pentagon in March 2013 announced plans to place an additional 14 interceptors at Fort Greely to counter a growing North Korean threat. At the behest of Congress, the Missile Defense Agency is evaluating possible GMD sites on or near the U.S. East Coast to counter what many see as a growing Iranian threat.

Twitter: @Gruss_SN

Email: mgruss@spacenews.com

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.