Raytheon [RTN] and Boeing [BA], the two defense firms unsuccessful in their attempt to win the Navy’s recently completed competition to modernize the ship-based Aegis Combat System, say they do not intend to protest the award to incumbent Lockheed Martin [LMT].

The Navy announced March 4 that Lockheed Martin had won the lucrative competition and will continue as the prime contractor for Aegis, which is deployed on cruisers and destroyers and has been the cornerstone of the Navy’s sea-based air theater combat for decades.

Defense firms have 10 days to lodge protests with the Government Accountability Office after receiving debriefs on competitive contract awards. Raytheon and Boeing both said they opted not to protest.

“We recognize that the Navy faced a challenging decision and we appreciated their feedback as part of the post-award debrief,” Raytheon spokeswoman Carolyn Beaudry said in an emailed statement Tuesday, adding the company was briefed by Navy officials last week. “We don’t intend to protest their decision.” Boeing did not provide specifics on any debriefings.

As part of efforts to save money and avoid frowned-upon sole source contracting, the Navy reopened the Combat System Engineering Agent (CSEA) contract for Aegis to the competitive process and accepted bids from Lockheed Martin, Raytheon and Boeing in December 2011.

The initial award for Lockheed Martin was valued at $100.7 million and runs through 2018, when the Navy anticipates holding another competition.

The advanced combat command and control system harnesses radar tracking to guide weapons to airborne targets, and has also been modified for ballistic missile defense under a separate program overseen by the Missile Defense Agency.

Lockheed Martin inherited Aegis when it acquired Martin Marietta in 1995.