The USS Illinois (SSN 786) was commissioned Oct. 29 in a ceremony at Groton, Connecticut.
The Virginia-class fast attack submarine can carry 12 Tomahawk cruise missiles to strike at targets on enemy shores, or it can switch some of its missiles out with other payloads to deliver special operators or mines to contested areas around the world.
The Illinois was originally scheduled for a commissioning in December, but the $2.5-billion boat was completed early and passed its sea trials with flying colors.
The PCU Illinois returns to base Oct. 6, 2016, after completing its sea trials. The Illinois was commissioned and became the USS Illinois on Oct. 29. (Photo: U.S. Navy Chief Petty Officer Steve Owsley)
Virginia-class submarines are designed to stealthily operate near other countries' coasts from where they can launch devastating attacks. They can attack facilities on shore with their Tomahawk land-attack cruise missiles, enemy ships with their Mk 48 torpedoes, or deploy mines and underwater drones.
The submarines can also support special operations by providing clandestine reconnaissance or by carrying teams of Navy SEALs and deploying them underwater through a special lockout chamber.
Conventional periscopes don't exist on the Illinois or other Virginia-class submarines. Instead, they feature photonic masts that send video and other image data to screens throughout the ship.
The Illinois is a Block III-version of the Virginia class, and features a horseshoe-shaped sonar instead of the older, spherical sonars. And, instead of packing 12 vertical missile tubes, Block III subs carry two sets of six missiles in Virginia Payload Tubes. If the Navy adopts a new missile in the future, the VPTs allow the Illinois to more easily switch to the new weapon.
The boat carries an S9G pressurized water reactor. The nuclear reactor powers the vessel for its entire lifecycle without ever needing refueling. The pump-jet propulsors push the boat forward are quieter than a traditional propeller.
Missions on the Illinois can go on for three months or longer, and the crew can spend nearly the entire time submerged.
To learn more about Virginia-class submarines, check out the Navy infographic below.
A cutaway look at Virginia-class fast attack submarines. Note that the USS Illinois features upgrades to its sonar, missile tubes, and other systems which cause it to slightly differ from this graphic. (Graphic: U.S. Navy All Hands Magazine)