Lockheed Martin Corp.’s Mitchel Field unit was awarded a $154.4 million contract to provide designs for navigation system hardware and software of Trident II D5 ballistic missiles, the Defense Department announced.

The contracts for systems used by U.S. and United Kingdom forces will include testing, delivery and installation.

Sixty percent of the work, worth about $92.6 million, will be done at Mitchel Field. The remainder will be divided among: Huntington Beach, California (26 percent); Clearwater, Florida (8 percent), and Cambridge, Massachusetts (6 percent).

The sole-source contract has a completion date of Dec. 31, 2020.

Trident II D5 missiles can be armed with nuclear warheads and travel more than 4,000 statute miles with a full payload.

Lockheed employs about 200 people at Mitchel Field out of a workforce of almost 10,000. Mitchel Field is a former U.S. Air Force base that was decommissioned in 1961.

In a separate announcement, the Defense Department said that Northrop Grumman Corp.’s Bethpage unit has won a $25 million modification to a previously awarded contract to develop software for mission planning involving precision-guided munitions for the U.S. Air Force.

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All the work will be performed in Bethpage and the contract is expected to be completed by Sept. 28, 2018.

Twenty-one percent of the contract will go toward the armed forces of Canada, South Korea, Norway, Singapore, Turkey and the United Arab Emirates.