America’s ballistic missile submarines can stay submerged and hidden from prying eyes for up to three full months at a time. But what happens when one of these vessels needs to be resupplied while out at sea? As a recent video released by the U.S. Navy shows, there are a number of resupply options available to these clandestine war machines, ranging from small drones to massive cargo aircraft.

“We don’t need to send them fuel, but sometimes we do need to send them [food], sometimes we do need to get them some parts to keep them at sea,” Commander of Submarine Force Pacific Rear Adm. Blake Converse said this week at the Naval Submarine League’s annual symposium.

“Our submarines are very reliable and can carry quite a bit of food, but [the resupply] further extends the range of those submarines. And that was hugely mission-enhancing for the BN force.”