|Manufacturer||Diplan 'Mechyards of Ozawa|
|Mech type||Inner Sphere BattleMech|
|Chassis||Kell/D Endo Steel|
|Armor||Mitchell GA3 Ferro-Fibrous|
|Targeting Tracking System||Beagle Active Probe|
The Mongoose BattleMech was introduced in 2660 as a deep recon 'Mech and a direct competitor (and hopeful replacement) for the Locust. As the 'Mech reached Star League Defense Force units though, it was found that the Beagle Active Probe on the Mongoose gave it extremely good command and control features that endeared it to light 'Mech command lances. Within eight years of its introduction the Mongoose was the standard command 'Mech for all light and recon lances. Due to its advanced electronics the Mongoose was capable of coordinating the maneuverings of an entire company of light 'Mechs and at the same time could engage medium 'Mechs with some success thanks to its weaponry and armoring.
Its popularity ensured that the Mongoose had a target on its back after the dissolution of the Star League. The start of the Succession Wars went poorly for the Mongoose when its factory on Ozawa was destroyed in 2837. The loss of the factory meant the 'Mech was already becoming a rarity by the Second Succession War and with many of its components now lostech surviving Mongooses were forced to make due with inferior spare parts. This was especially true for the Beagle Active Probe, and by the end of the Succession Wars not a single operational Mongoose serving the Great Houses had a functioning example. This trend was reversed with the recovery of the Helm Memory Core and many Mongooses were rebuilt to their former glory. ComStar was also revealed to have kept many Mongooses in their secret storage facilities which they used to outfit the Com Guards. Diplan 'MechYards eventually restarted Mongoose production from their factory on Aix-la-Chapelle and the design would continue to see use for years to come, including during the Jihad.
Weapons and Equipment
The weaponry of the Mongoose consists of three Sorenstein Medium Lasers split between the left arm, right arm and center torso, and one Starflash Plus Small Laser in the head. This light laser array, while not as deadly as most pilots would prefer, is typical of light 'Mechs and makes the Mongoose a highly independent unit that does not need to rely on a supply chain of ammunition for its survival when on recon duties. The centerline lasers in particular are extremely accurate thanks to special internal compensators, allowing precise fire even at a full run. Unfortunately the center torso laser rests right atop the Nissan 200 fusion engine, requiring replacement of the cooling jackets after a hundred firings. While not a difficult item to replace it can become an issue during extended campaigns. The extra heat from both laser and engine can also sometimes interfere with the sensor system and makes the cockpit uncomfortable.
The Kell/D Chassis around which the Mongoose is built uses Endo Steel construction techniques that, combined with an all energy weapon armament and standard engine, made the Mongoose very sturdy for its size. This also allows it to mount five tons of Ferro-Fibrous armor, much more than other light 'Mechs and gives the Mongoose the capability to survive a direct PPC hit to the chest without suffering internal damage. A top speed of 129 km/h and cruising speed of 86 km/h, one of the fastest of any 'Mech, makes up for the lack of jump jets on the design. Only ten heat sinks means the 'Mech is liable to run hot if the pilot is not careful, especially when the cooling jacket protecting the center torso laser fails.
- The MON-67 is the downgraded version of the MON-66 Mongoose introduced in 2830. The MON-67 removes the active probe and replaces the Endo Steel structure with a standard structure while the armor has been downgraded to standard plate armor. To keep the same level of protection as before, half a ton of armor has been added to the Mongoose. BV (1.0) = 612, BV (2.0) = 741 
- A variant of the MON-66 introduced in 2819, the MON-69 replaced the LosTech active probe with an SRM-2 and one ton of reloads since the advanced electronics were difficult to come by during the Succession Wars. In order to make this possible, a half ton of armor has also been removed. BV (2.0) = 737 
- The MON-76 is an upgrade of the Mongoose introduced in 3077. The original electronics, weapons, engine, and cooling system have been stripped from the chassis and a complete rebuild of the 'Mech has occurred. As far as the engine, the original Nissan 200 was replaced with an ExtraLight version and includes a MASC system allowing for incredible bursts of speed. Next, the standard heat sinks originally found on the 'Mech were replaced with double strength units. The original Beagle Active Probe was replaced with a Guardian ECM Suite to allow the Mongoose to interfere in enemy electronics and, finally, the original medium lasers have been replaced with Medium Pulse Lasers. BV (1.0) = 724, BV (2.0) = 894
- Upgraded to use a Light PPC and XL Engine, the MON-86 introduced in 3078 has a top speed close to 150 km/h. It also has a medium laser in each arm, while the right torso has an ER Small Laser. The MON-86 keeps the head-mounted small laser of the original Mongoose and the Beagle Probe for scout duty. BV (2.0) = 887
- MON-66GX Mongoose Gunslinger
- This Mongoose variant was developed for the SLDF Gunslinger Program, but never saw service. It kept the Mongoose ground speed, but stripped out the electronic equipment for more weaponry. Two medium lasers were in each arm, while a single torso mounted SRM-6 with a ton of ammunition was mounted in the chest. To offset the loss of the advanced electronics, this chassis was equipped with a Null Signature System and a Chameleon Light Polarization Shield. It also carried six tons of armor. BV (2.0) = 974
- Beowulf - After the Word of Blake captured Terra in 3058, Comstar decided to replace their lost Mongoose BattleMechs with new Beowulf 45-ton BattleMechs. It is equipped with an XL Engine and mounts far more armor, better weapons, and is jump capable.
- Mongoose II - A Jihad-era replacement for destroyed Com Guard war materials, the 40-ton Mongoose II was designed to incorporate sophisticated sensors, electronic countermeasures, and C3 Computers.
- Technical Readout: 2750, pp. 20-21
- Technical Readout: 3050 Upgrade, pp. 188-189
- Technical Readout: 3039, pp. 246-247
- Combat Operations, p. 107
- Record Sheets: 3050 Upgrade (Clan & Star League), p. ??
- Technical Readout: 3025 Revised, p. 12-13
- Objectives: Draconis Combine, p. 17
- Technical Readout: 3075, p. 169
- Record Sheets: 3075 Unabridged, p. 155
- Record Sheets: 3075 Unabridged - Age of War, p. 15
- Combat Operations, p. 125
- Record Sheets: 3039, p. 68
- Record Sheets: 3039 Unabridged, p. 404 "Mongoose MON-67"
- Record Sheets: 3039 Unabridged, p. 405 "Mongoose MON-68"
- Record Sheets: 3050 Unabridged - Clans & Star League, p. 228 "Mongoose MON-69"
- Record Sheets: 3050 Upgrade (Inner Sphere), p. 59
- Combat Operations, p. 134
- Record Sheets: Upgrades, p. 39
- Record Sheets: 3050 Upgrade (Inner Sphere), p. 60
- Technical Readout: 3085, p. 190
- Record Sheets: 3085 Unabridged — Old is the New New, p. 59
- Experimental Technical Readout: Gunslingers, p. 3
- Experimental Technical Readout: Gunslingers, p. 16
- Technical Readout: 3060, p. 88
- Technical Readout: 3075, p. 72
- Combat Operations
- Experimental Technical Readout: Gunslingers
- Record Sheets: 3025/3026
- Record Sheets: 3039
- Record Sheets: 3039 Unabridged
- Record Sheets: 3050
- Record Sheets: 3050 Upgrade (Clan & Star League)
- Record Sheets: 3050 Upgrades Unabridged (Clan & Star League)
- Record Sheets: Upgrades
- Record Sheets: 3075 Unabridged
- Record Sheets: 3075 Unabridged - Age of War
- Record Sheets: 3085 Unabridged — Old is the New New
- Technical Readout: 2750
- Technical Readout: 3025 Revised
- Technical Readout: 3039
- Technical Readout: 3050
- Technical Readout: 3050 Revised
- Technical Readout: 3050 Upgrade
- Technical Readout: 3075
- Technical Readout: 3085