Lockheed Martin's PAC-3 missile, part of the Patriot air defense capability. (Photo: Lockheed Martin)

A solid rocket motor (SRM) being developed by Northrop Grumman [NOC] was qualified in June as a second source to power Patriot air defense missiles and the company expects a production award later this year, the company’s top executive said on Tuesday. The pending award follows a $2 billion, seven-year framework agreement Northrop Grumman reached earlier this year with the Defense Department and Lockheed Martin [LMT], the manufacturer of the Patriot Advanced Capability (PAC)-3 Missile Segment Enhancement interceptor, Kathy Warden,…