The San Diego-based amphibious assault ship USS Boxer will undergo at least $150 million in repairs, maintenance and upgrades when it returns from the Middle East, where it is currently a key part of the U.S. involvement in Operation Epic Fury, the Defense Department says.

The new contract indicates that it could ultimately cost as much as $180 million to service the 31-year-old ship, which has experienced numerous mechanical problems in recent years that affected its ability to go on earlier deployments.

The 844-foot Boxer is the flagship of an amphibious ready group that has, at times, included two other San Diego-based amphibious ships, the USS Comstock and USS Portland. All three ships are carrying Marines from Camp Pendleton’s 11th Marine Expeditionary Unit.

The Boxer group deployed from San Diego in March. The Navy has not indicated when it will return home, nor has it said when the San Diego-based aircraft carrier USS Abraham Lincoln, a lead combatant in the war in Iran, will return to Naval Air Station North Island.

The carrier has been on deployment for about nine months, mostly in the Middle East. It has been the source of enormous attention in recent weeks due to concerns that the length of Lincoln’s deployment, as well as conditions aboard ship, have generated a lot of stress among members of its 5,000-person crew.

The Navy has not said whether Lincoln will briefly visit Guam or Hawaii on its way home.