Mercury (BattleMech)

This article is about the BattleMech. For other uses, see Mercury.
Mercury (BattleMech)
Production information
Manufacturer Mitchell Vehicles

Skobel MechWorks[1]

Production Year 2742[2]
Model MCY-99[1]
Class Light
Cost 1,808,440 C-bills
Technical specifications
'Mech type Inner Sphere BattleMech
Mass 20 tons
Chassis Bergan MX II
Armor Mitchell-091 Ferro-Fibrous
Engine LTV 160
Communications System DataTech 401
Targeting Tracking System Skyhunter IV
Heat Sinks 10 heat sinks
Speed 129 km/h (173 km/h with MASC)
BV (1.0) 471[3]
BV (2.0) 586[1][4][5]


The Mercury debuted for the first time in 2742, intended as a replacement for the aging Wasps and Stingers in use by the Star League Defense Force. Hailed as the beginning of a new age in 'Mech design, the Mercury was faster and better-armed than its competition without sacrificing armor protection. It also featured an advancement in weapons installation, making use of a modular replacement system to allow for easier repairs. The ideal scout and raider, sales of the Mercury were limited exclusively to the SLDF. After the Amaris Civil War and the dissolution of the Star League, those SLDF units which still fielded the Mercury were either stationed on Terra or at the Graham IV factory, all of whom left with General Kerensky in the Exodus.[2][6]

In the Succession Wars which followed, the Mercury factories were destroyed and the design teetered on the edge of the abyss. Of those SLDF units which stayed behind, the Third Regimental Combat Team had the highest concentration of the 'Mechs, with twelve Mercuries gathered together in the Eighth Recon Battalion; all of them were ultimately lost during fighting on Sendai in 2798.[2][6] As the years wore on those desperate few Mercuries still clinging to existence were increasingly rebuilt in haphazard fashion with less advanced and more shoddy parts until they ceased to look quite like the noble 'Mechs they once were. In the end nothing could be done to stop the decline of the Mercury and it eventually became extinct in the Inner Sphere.[7]

It was with some surprise that ComStar unveiled their Com Guards early in the thirty-first century, a brand-new military force fielding a number of extinct designs such as the Mercury. Precentor Martial Anastasius Focht even went so far as to restart three of the mothballed Mercury production lines on Terra to resume production of the original model. A new variant, the MCY-97, was unveiled in time to meet the Clan Invasion (the Clans had also preserved the Mercury, and indeed its revolutionary design was responsible for their development of the OmniMech). One of these lines was eventually turned over to making the Nexus (Star Python) in 3054 while the rest continued to produce so many Mercuries that the 'Mech's life was extended for several more years. This included the dark years of the Jihad, when the Word of Blake also used the Mercury to outfit their Militia.[8]

Weapons and Equipment[edit]

The Mercury carries an assortment of energy weapons which helps to extend its endurance on long campaigns. The primary weapons are two Martell medium lasers in the right arm and left torso. The right arm laser's power supply is spread across the length of the whole arm with multiple redundant systems, while the torso-mounted laser is clustered tightly in one area to decrease the chance of a penetrative hit damaging the system. These are supported by two Hessen IX small lasers in the center torso and head and feature the revolutionary modular replacement system. Using 'plug and fight' technology, the lasers are bolted down and connected by wiring to the power feeds and cooling system in three places. If any part of the weapon is damaged or destroyed technicians can replace the entire system in minutes, cutting back countless man-hours of repair and maintenance.[2][8]

The heart of the Mercury is its MASC system which, in combination with an LTV 160 fusion engine, allows for momentary bursts of speed up to 172 km/h. Though long-term use can damage the actuators, these bursts are often the difference between life and death in some cases. They also make up for the fact that the 'Mech lacks any jump jets, while three tons of ferro-fibrous armor gives it superior protection compared to other 20-ton 'Mechs.[2][8]


  • MCY-97 
    This variant of the Mercury was created by ComStar in 3049 for recon duties. The armor, engine, and MASC system are kept while one medium laser and one small laser have been dropped in favor of a Beagle active probe, giving the MCY-97 Mercury superior enemy detection capabilities at the cost of half of its firepower. Though an excellent scout, this variant was largely discarded after the Battle of Tukayyid on account of insufficient firepower.[1][8] BV (1.0) = 380,[9] BV (2.0) = 466[10]
  • MCY-98 
    This variant of the Mercury is the downgraded version introduced during the Succession Wars in 2810. While it retains the same armament and engine of the original, the primary changes in the 'Mech is its armor, using standard armor in place of ferro-fibrous, and the MASC system, which has been removed to allow for the armor to be one ton heavier. These changes lower its maximum speed to 129.6 km/h, but slightly increases the overall armor protection. It also features a Datacom communication system and Scarborough Track targeting system.[6] BV (1.0) = 484;[11] BV (2.0) = 553[12]
  • MCY-102 
    The MCY-102 is an upgrade to the Mercury introduced in 3067 by the Word of Blake. This variant retains the engine, MASC, and armor of the MCY-99, but carries two major modifications; the first is the rebuilding of the chassis using endo steel, which forced removal of one small laser and one medium laser to allow for the second modification: the installation of an improved C3 computer, making it capable of operating with five other units in a C3i unit. Both of the remaining lasers were also changed out for extended-range models.[1][8] BV (1.0) = 408;[9][13] BV (2.0) = 510[14]
  • MCY-104 
    An upgrade fielded by the Word of Blake during the Jihad in 3069, the 104 uses an XL engine for power. This allows the addition of an extra ER medium laser and TAG to the 102, with the remaining free ton going into improving the armor coverage. The heat sinks are not upgraded, however, so this Mercury could find itself in heat trouble while running with its C3i unit.[1][8] BV (2.0) = 683[15]
  • MCY-105 
    This Republic of the Sphere variant brings the ancient design back to the forefront using surprisingly little advanced technology. The traditional MASC has been removed and the large XL engine utilized instead to allow this Mercury to travel at speeds over 180 km/h. This design utilizes both endo steel and ferro-fibrous to save weight for its engine. For weaponry the -105 possesses two ER medium lasers, one in the right arm and in the left torso, and two ER small lasers, one in the center torso and the other in the head. 10 double heat sinks keep this variant cool in virtually all conditions.[8] BV (2.0) = 795[16]

Design Quirks[edit]

The Mercury is subject to the following Design Quirks:[17][18]

Related BattleMechs[edit]

  • Mercury II - The Mercury II was an enlarged and updated design of the Mercury produced by Clan Wolverine. This 'Mech lacks its predecessor's unique modular repair system, being a standard post-SLDF/early Clan era BattleMech.[19]
  • Coyotl - The Coyotl continued the original Mercury's legacy of technological advancement, developing its modular repair system into a fully modular hot-swapping system, leading to the OmniMech.[20]

Notable Pilots[edit]

See Category:Notable Mercury Pilots


  • In German products, the unit's proper name was translated to Merkurius. The model code was accordingly changed to MRS-97.



  1. 1.0 1.1 1.2 1.3 1.4 1.5 Technical Readout: Succession Wars, pp. 10–11: "MCY-99 Mercury"
  2. 2.0 2.1 2.2 2.3 2.4 Technical Readout: 2750, pp. 16-17: "Mercury 'Mech Profile"
  3. Combat Operations, p. 106
  4. Technical Readout: 3050 Upgrade, pp. 184–185: "MCY-99 Mercury"
  5. Record Sheets: 3050 Upgrades Unabridged (Clan & Star League), p. 221
  6. 6.0 6.1 6.2 Technical Readout: 3025 Revised, pp. 6–7
  7. Technical Readout: 3039, p. 238
  8. 8.0 8.1 8.2 8.3 8.4 8.5 8.6 Technical Readout: 3050 Upgrade, pp. 184–185
  9. 9.0 9.1 Combat Operations, p. 123
  10. Record Sheets: 3050 Upgrades Unabridged (Clan & Star League), p. 220
  11. Combat Operations, p. 121
  12. Mercury MCY-98 MUL entry
  13. Record Sheets: Upgrades, p. 34
  14. Record Sheets: 3050 Upgrades Unabridged (Clan & Star League), p. 222
  15. Record Sheets: 3050 Upgrades Unabridged (Clan & Star League), p. 223
  16. Recognition Guide: ilClan, vol. 19, p. 13
  17. BattleMech Manual, p. 93: "BattleMech Quirk Table"
  18. BattleMech Manual Errata (Version 6.01), p. 9
  19. Jihad Secrets: The Blake Documents, p. 148
  20. Field Manual: Warden Clans, pp. 40–42: "Birth of the Titans" & "Crusade of the Valiant"