"Carrier, battleships, cruisers, destroyers, frigates, and even cutters are equipped with the new SENTINEL Defense Networks, which consists of one or more MAC, VLS pods and cells, naval guns, railguns, and CIWS emplacements. This will increase the survivability of all human fleet vessels abroad."
Secretary of the Navy Erwin Rald on the SENTINEL Defense Network, c. September 7th, 2553.
Ever since the end of the Inner Colony Wars, UNSC Fleet Command has analyzed the naval battles against rebel fleets and have found deficiencies in its anti-fighter and -missile defenses used at the time. In order to better prepare for another war, the UNSC funded Project: SHIELD and from it the Ship Defense Network was born. So far the TITAN-, the HOPLITE-, and, most recently, the SENTINEL-class networks have been commissioned into service since 2463.
TITAN-class
Introduction: 2463
Retirement: 2501
Ships mounted on:
•Carriers
•Cruiser
•Destroyers
•Frigates
Weaponry:
*RSM-13 "Atlas-class" nuclear missile
*BSGM-06 "Zeus-class" ship-to-ship/ground nuclear missile
*BGM-04 "Hera-class" interstellar ballistic missile
*RSGM-23 "Ares-class" ship-to-ship/ground missile
*30mm M648 naval gun system/point defense network
*20mm M3 railgun network
*10mm M498 close-in-weapon-system
Armor: Titanium-A1 battle plate
HOPLITE-class
Introduction: 2501
Retirement: 2552
Ships mounted on:
•Earth-class dreadnought
•Epoch-, Calvary-, and Punic-class supercarriers
•Fleet carriers
•Light carriers
•Escort carriers
•Valiant-class battlecruiser
•Marathon-class cruiser
•Halcyon-class light cruiser
•Halberd-class destroyer
•Paris-class heavy frigate
•Charon- and Stalwart-class light frigates
•Corvettes
Weaponry:
*Magnetic Accelerator Cannon(s)
*RSM-42 "Shiva-class" tactical nuclear missile
*BSM-53 "Hyperion-class" interstellar ballistic missile
*BSGM-109 "Harpoon-class" ship-to-ship/ground nuclear missile
*RSGM-34 "Archer-class" multi-role ship-to-ship/ground missile
*RSGM-21 "Howler-class" multi-role ship-to-ship/ground missile
*RIM-130 "Medusa" long-range anti-air/anti-spacecraft missile
*M97 "Lance" long-range anti-air/anti-spacecraft missile battery
*150mm M2488 "Onager" mass driver cannon
*50mm M910 "Bofors" naval gun system/point defense network
*50mm M870 "Rampart" naval gun system/point defense network
*30mm M6 "Centurion" railgun network
*20mm M519 "Guardian" close-in-weapon-system
Armor: Titanium-A2 battle plate, later coated with tungsten; later Acheron Security-Cross Defense Ltd. Dynamic Energy Shielding Mk.I
SENTINEL-class
Introduction: 2553
Ships mounted on:
•Infinity-class battle carrier
•Sherman-class supercarrier
•Yorktown-class carrier
•Montana-class dreadnought
•Vindication-class battleship
•Everest-class battlecruiser
•Autumn-class cruiser
•Vulture-class stealth cruiser
•Midlothian-class destroyer
•Clairvoyant-class stealth destroyer
•Remembrance-class frigate
•Midsummer Night-class stealth frigate
•Strident-class littoral combat ship
•Type 1 cutter
Weaponry:
*Magnetic Accelerator Cannon(s)
*RSM-46 "Shiva-class" tactical nuclear missile
*BSM-53 "Hyperion-class" interstellar ballistic missile
*BSGM-109 "Harpoon-class" ship-to-ship/ground nuclear missile
*RSGM-26/Models 42 and 58 "Archer-class" multi-role ship-to-ship/ground missile
*RSGM-15/Models 64 and 75 "Rapier-class" multi-role ship-to-ship/ground missile
*RSGM-21/Models 82 and 96 "Howler-class" multi-role ship-to-ship/ground missile
*RIM-137 "Medusa" long-range anti-air/anti-spacecraft missile
*M97 "Lance" long-range anti-air/anti-spacecraft missile battery
*250mm M2551 "Onager" mass driver cannon
*70mm M965 "Fortress" naval gun system/point defense network
*50mm M910 "Bofors" naval gun system/point defense network
*30mm M12 "Paladin" railgun network
*20mm M647 "Oerlikon" close-in-weapon-system
Armor: Titanium-A3 battle plate coated with tungsten; Acheroan Security-Cross Defense Ltd. Dynamic Energy Shielding
Hope you like this!
This idea came from RiptideZ's Halo/Mass Effect story Beyond Contact, where in chapter 2: Deterrent, where a Marathon-class, the UNSC Mogadishu, was called a SENTINEL cruiser. That got me thinking, he is trying to tie some stuff from Halo to the real-world. So here's my thought: even if it's the future there would most likely be a Halo counterpart to the AEGIS combat system and that is the SENTINEL defense system.