On Friday, the U.S. Department of Defense announced it has awarded Lockheed Martin (LMT -0.20%) a trio of contracts related to the F-35 Lightning II fighter jet. The combined value of all three contracts amounts to $4.8 billion.

The largest contract of the three, valued at $3.7 billion, instructs Lockheed to build its sixth tranche of F-35s for the military, an order including 18 conventional takeoff and landing (CTOL) F-35As for the Air Force, six short take-off, vertical landing (STOVL) F-35Bs for the Marine Corps, and seven "carrier variant" F-35Cs for the Navy -- 31 fighter jets in all.

Additionally, the Pentagon awarded Lockheed a $753 million "undefinitized modification" to a previous award to fund "non-recurring sustainment and logistics support for delivered and projected air systems," as well as a $374 million undefinitized modification paying for the "manufacture and delivery of initial air vehicle spares in support of 60 low-rate initial production lot VI and VII air vehicles."

This latter contract refers to both the sixth tranche of F-35s now ordered and an anticipated seventh tranche yet to be ordered. Tranche seven is anticipated to contain 19 F-35As, six F-35Bs, and four F-35Cs.