The U.S. Navy approved an Alliant Techsystems Inc. anti-radar missile for full production valued at as much as $1.1 billion, even though the Pentagon's chief tester says the weapon's performance flaws "largely negate" its "ability to accomplish its mission."

While the missile "has the potential to eventually provide some improved combat capability against enemy air defenses, the weapon as tested has multiple deficiencies," Michael Gilmore, the Pentagon's director of operational testing, said in an emailed statement.

Gilmore's position that earlier problems with the Advanced Anti-Radiation Guided Missile haven't been remedied wasn't known publicly when the Navy on Aug. 20 approved full-rate production, the most profitable phase for a defense contractor. Arlington, Va.-based Alliant Techsystems may see sales to the Navy and the Italian Air Force of almost 2,000 missiles through 2020.

The criticism raises the question of whether ineffective missiles may be deployed to the Navy's Boeing F/A-18 model aircraft and Italian jets, requiring costly improvement upgrades later. The missiles could be used to attack ground radar used by adversaries fielding sophisticated integrated air defenses, such as those of Syria, China and Iran.

The Navy said 600 hours of testing, including 12 live firings, showed the missile was ready for deployment.

Sean Stackley, the Navy's assistant secretary for research and acquisition, "made the call based on what the tests demonstrated and the fact that this weapon is a significant improvement on what's in the field," Capt. Cate Mueller, a Navy spokeswoman, said in an emailed statement.

Fixes for the issues that led to Gilmore's assessment are already in the works, with upgrades scheduled for delivery in 2015, Mueller said.

The Advanced Anti-Radiation Guided Missile was designed as an improvement on the HARM missile made by Raytheon Co. The Alliant Techsystems missile is equipped with a more modern homing receiver and navigation system to detect the radar signals of stationary and mobile air-defense systems.

The Navy has budgeted as much as $770 million through 2017 for the missile, with the remaining dollars after 2018.

Testing was halted in 2010 after six software and circuit- card failures in the first 12 trials. A new round of combat testing with upgraded missiles was completed this year.

While the missile's performance "has improved relative to that experience," it "is not operationally effective," Gilmore said. Details of its remaining deficiencies are classified, he said.

Gilmore said he presented his conclusions to the Navy, and its subsequent decision "is up to the discretion of the service."

The test office was established by Congress in 1984 to provide independent oversight of military service testing of weapons systems. Its director is the defense secretary's principal adviser on weapons evaluation issues.

Philip Coyle, who headed the testing office from October 1994 through January 2001, said "it would be astonishing" for the Navy to go ahead with production over Gilmore's objections.

How would a Navy official "justify going into full-rate production on something that was not operationally effective?" Coyle, who serves as a consultant after working in the White House Office of Science and Technology Policy, said in an emailed statement. "I would think it would be a career-limiting decision" to "spend the taxpayer's money on something that didn't work."

The Navy's Fleet Forces Command, Marine Corps and Chief of Naval Operations support immediate deployment, Mueller wrote.

Alliant Techsystems spokesman Steve Cortese said in an e- mail the company fully supports the Navy's decision and it stands behind the missile's "readiness for operational use and full-rate production."

Specific testing concerns "have either been remedied or are being addressed as part of a planned block software upgrade we are currently under contract to deliver," Cortese said.

The missile is produced at the company's facilities in Woodland Hills and Ridgecrest, Calif.

The company stands by past projections of $1.1 billion in revenue over a decade from full production, Cortese said, Revenue from the missile may increase to $100 million annually from $30 million in the current development phase, the company said on a March 13 conference call with analysts.

The Pentagon test office doesn't have an official role in deciding whether a weapon proceeds to full production. It can block a weapon from moving to that stage by disapproving of its combat testing plan.

In the case of the Alliant Techsystems missile, Gilmore had approved the test plan and subsequently rendered an assessment required by law for any major production decision as to whether the weapon was "operationally effective" and reliable.

The test office also provides input to the Pentagon's Defense Acquisition Board when a weapon is under review to move forward in development or production. The office publishes an annual report and interim assessments for congressional staff that could use the information to mandate a program delay or prompt a hearing.

Ben Freeman, a military analyst with the Project on Government Oversight in Washington said, "It might make sense to push ahead with full production even though testing results weren't stellar if our military desperately needed to field an improved anti-radar missile — but they don't."

"There's no area where this weapon will be immediately put to use," Freeman said. "So it makes little sense to go into full production of a weapon" the test office "says is not operationally effective.