A U.S. Navy submarine floating beneath the surface of the Pacific Ocean fired an unarmed Trident D5 strategic missile, marking the 135th consecutive successful test flight of the Lockheed Martin-built weapon since 1989.

The Navy launched the missile as part of an operation to certify that the USS Nevada, recently returned to sea following a shipyard overhaul period, is ready for deployment.

The missile was converted into a test configuration using a test missile kit produced by Sunnyvale, Calif.-based Lockheed Martin Space Systems. The kit includes range safety devices and flight telemetry instrumentation.

“This test demonstrates the readiness and reliability not only of the missile, but also elements of the Trident II D5 Strategic Weapon System,” Melanie A. Sloane, Lockheed Martin vice president of Fleet Ballistic Missile programs, said in a statement.