GMCU Ground Mobile Command Unit C3I Aerospacecraft

GMCU Airborne Command and Control Early Warning Aerospacecraf 2

ROBOTECH Technical Files

by Pieter Thomassen, with Robert Morgenstern, Peter Walker, and Tim Wing


  • Surface/Orbital Command (SOC) mobile surface to orbit defense headquarters (2021-2030)
  • Ground Mobile Unit (GMU) mobile siege engine (2030-2033)
  • Ground Mobile Command Unit (GMCU) airborne command and control early warning aerospacecraft (2033-2046)


  • Design: Kraus Maffei Destroids GmbH
  • Builder: Kraus Maffei Destroids GmbH

Names and disposition:

  • Titan SOC-01: Destroyed 2044 over Earth with UES Saratoga (SDBC-69).
  • Colossus SOC-02: To reserve 2046, sold 2050 to the Terran War Museum, Oxford.
  • Leviathan SOC-03: Destroyed 2044 over Earth with UES Hood (SDBC-47).
  • Goliath SOC-04: To reserve 2045, Fantoma Orbital Storage, Vallivarre system.

Vehicle’s Complement:

  • Vehicle crew (40),
  • Combat Information Center (23),
  • Security detail (36),
  • Life support limits are for a full combat complement and about 230 supernumeraries.


  • Length: 102.4 meters (SOC), 123 meters (GMU, cannon extended).
  • Height: 34.7 meters (SOC), 96 meters (GMU, cannon elevated).
  • Width: 48 meters (SOC, GMU).
  • Mass: 5,175 metric tons (dry).
  • Cargo Mass: up to 1,100 metric tons.
  • Fuel Mass: 335 metric tons (typical).

Propulsion systems:

  • Main power system: Two RRG mk28 protoculture fueled reflex furnace clusters. This powerplant could deliver up to 450 MW for 30 minutes before thermal stresses force a SCRAM.
  • GMU 19Maneuvering Thrusters (24): Four triple thrusters on the forward and aft flank and edge of the upper superstructure, and four triple thrusters on the forward and aft flank and edge of the lower central body.
  • Reaction-mass Thrusters (5): Four SNECMA PF-45 fusion-plasma reaction engines with protoculture energizers in the aft superstructure and one more in the aftmost docking/engine sphere.
  • Secondary thrusters (8): Eight SNECMA PF-40 fusion-plasma reaction engines with protoculture energizers, two are mounted in each docking/engine sphere, facing (relative) downward.
  • Anti-gravity System (1): 3 RRG HL-1G anti-gravity pods.
  • Planetary Capabilities: The GMU/SOC had atmospheric capabilities through its reaction thrusters and anti-gravity system. Cold landings were no problem, effectively the vehicles were atmospheric bases with orbital descend and ascend capabilities, though orbital ascent required two SVC-30 Ox Aerospace Lift Tugs.

Endurance and mobility limits:

  • The dry stores endurance was limited to about 1 week with a full crew complement. After that, the vehicle needed to restock. Water could be extracted from atmospheric moisture, if present.
  • The Reflex furnace could function for about 15 years at normal usage levels before an energizer rebuild is necessary.
  • At full power, the main propulsion systems could nominally produce up to 30.8 Meganewtons of thrust.
  • The engines of the SOC/GMU were not optimized for long duration flight, and could achieve 2.0 gravities for three minutes, or 1.0 gravity for 40 minutes.
  • The maximum sustained atmospheric speed was limited to an airspeed of 475 kph. However, the engine power usually restricted the vehicle to a maximum speed of 380 kph. The maximum hover time on the anti-gravity systems was limited only by the protoculture supplies and maintenance requirements.

Weapon Systems:


  • 16 x Mk211 silo’s for Skylord missiles. The SOC mounted two octuple erectable silo launchers, two banks of four on top of each other; two of these clusters were mounted behind each other on the centerline of the SOC (OR each mounted in the side superstructure). Each silo could contain one Skylord missile, generally one with a nuclear warhead. The launchers would lay horizontal until the pre-firing sequence, when they were elevated to their launch position 45 degrees from the horizontal. From this position they were ejected from the tube by a gas generator until they had cleared the SOC and an undeterminate safe zone to avoid fouling the sensor arrays. Then, the engines of the missile would ignite, position the missile vertically, and begin its ascend to its target.


  • 1 x HRLC-500 High-Powered Heavy Laser Cannon mounted on the centerline. The cannon had an elevation of maximum 25 degrees and is optimized for shorting Invid protective force fields. The cannon could fire a continuous salvo of 400 MJ of energy to an effective range of 32 km.GMU 29
  • 2 x MM-6 Missile Launcher installations. Each installation contained 36 short range (8.2 km) Mach 3.0 combined infra-red imager and active radar homing Hughes Hammerhead point-defense missiles. The silos were located aft on the superstructure flanks.
  • GMU 221 x PBT-M2 double-barreled particle beam cannon. The cannon is mounted on top of the destabilizer cannon and has a yield of 30 MJ per full-power salvo. The weapon energizers could generate a full charge every 5 seconds.
  • 1 x MLWS-40 double barreled 40mm rapid-fire point defense laser turret. The cannon is mounted on top of the cockpit section and has a yield of 7.5 MJ per full-power salvo. The weapon energizers could generate a full charge every 2 seconds.

(GMCU refit after 2033)

  • 2 x Mk201 Hammerhead VLS installations. Each installation contains 40 short range (8.2 km) Mach 3.0 combined infra-red imager and active radar homing Hughes Hammerhead point-defense missiles. The silo’s are located aft on the superstructure flanks.
  • GMU 181 x MLWS-40 double barreled 40mm rapid-fire point defense laser turret. The cannon is mounted on top of the cockpit section and has a yield of 7.5 MJ per full-power salvo. The weapon energizers could generate a full charge every 2 seconds.

Air group and mecha complement:

  • 8 Standard drop pods fitted with remote orbital sensors and secure long distance communication links;
  • 12 VHT-1 Spartas Veritech Hover Tanks or Destroids
  • or 150 VR-series Cyclone equipped infantry troops. (Note: up to 16 additional VR-series Cyclone equipped infantry troops could be carried in each re-entry pod.)

GMU 11Design notes:

The SOC was without doubt the oddest re-entry capable vehicle ever to be designed by Terran engineers. Looking like nothing so much as a floating armored personnel carrier, the image only worsened when the eight drop-pods were mounted on the underside.

GMU 15Designed as a mobile headquarters and launcher for the United Earth Expeditionary Force (UEEF) ground-based orbital defenses, the SOC contained a raised center on top with two banks of eight silo’s for Skylord ground-to-orbit missiles. In addition, a large sensor tower was placed alongside the missile launchers, and numerous ESM flush arrays were mounted on the upper works. Two relatively small point-defense missile batteries in the back of the superstructure (after the 2033 refit) and one small particle gun turret on top of the cockpit forward of the superstructure provided the only close-in defensive armament. A small mecha hangar was located on the left side of the fuselage.

The SOC had a cockpit section forward of the superstructure, offset to the right. Offset to the left was the hangar. The center, raised, section of the superstructure was devoted to the electronics of the headquarters and the personnel that operated them. The two flanks housed the staff proper, including their quarters, meeting rooms, briefing rooms, and etcetera.

The upper frame housed the reflex furnaces and many of the flight support systems such as the life support; the engine and flight systems such as the anti-gravity units were mounted in four docking/engine spheres below the frame. These docking spheres could accommodate up to eight large standard docking pods. The drop-pods were fitted with remote radar and optical orbital sensors, and would be dispersed in a precise pattern for maximum over-the-horizon sensor coverage after re-entry.

During their refit in 2030 to GMU standard, the central and side superstructures were removed. In their place came two rotating side bodies, containing the gun control equipment and the nuclear missile battery. The large cannon was mounted on the centerline, and two large flare shields were fitted to the sides. The front cockpit and mecha bay remained in place; although both had to be evacuated for safety reasons when the cannon was firing. A secondary particle beam turret was mounted on top of the cannon barrel, although it too could not be operated in the main cannon fired.

After their re-conversion in 2033, the GMCU vehicles mounted the superstructures as they had when they were completed; these had been stored while they functioned as GMU’s. At this time the armament was expanded with two close-in defense missile batteries.


Before the departure of the UEEF, the SOC series were conceived as mobile orbital defense headquarters. Although the headquarters were intended to make use of remote missile launchers and ASAT-equipped aerospace fighters, the hull was given a large number of heavy anti-ship missiles as well, to form a reserve supply and to be used in massive saturation attacks.

The SOC came equipped with a comprehensive package of orbital sensors, both located on the vehicle as well as in dispersed pods that could be up to a thousand kilometers distant. Secure communications with the off-board sensors, diverse ASAT missile launchers, and with other major UEEF assets (such as headquarters and ships) were also provided for. The resulting system could coordinate the orbital defense, for an area of the size of continental Europe.

GMCU Airborne Command and Control Early Warning Aerospacecraf 1Originally, a number of Quell Quallie Zentraedi auxiliaries were to have been converted for this task, but it was decided instead to use a new design, as the Quell Quallie proved to be difficult to maintain previously by UN Spacy forces, and larger than required as well.

The SOC was designed to undock from its transport vessel, then slowly approach the planet it was to protect. Naturally, this could only been done when at the very least aerospace superiority had been achieved, and preferably after aerospace supremacy was won. While this may sound to be at odds with the SOC’s designed function, it must be remembered that the SOC was not designed to achieve superiority, but to maintain it until permanent defense centers could be constructed, typically deep under mountain ranges, such as the United Earth Defense Forces (UEDF) Khazadum complex in the Rocky Mountains. As the SOC approached its destination, the sensor drop-pods were released in a pattern that would offer maximum sensor coverage over the continent. Typically, the pods were landed high in mountain ranges several hundreds to thousands of kilometers from the SOC landing point. The drop-pods housing these unique relays and orbital sensors were built on the standard UEEF pod specifications, and as a consequence any UEEF drop-pod could be mounted. However, historically, the SOC always deployed its own sensor pods exclusively.

Due to its lack of aerodynamics, the SOC was to use its gravity system to reduce its relative speed to the planet to minimal values, then slowly descend into the atmosphere, thus avoiding the fiery re-entry of high-speed craft. When in the atmosphere, the SOC would use its thrusters and anti-gravity system to move in the operations area, never deploying without a security force or near enemy positions. The net result was a mobile air defense center that was both smaller and easier to maintain than the proposed Zentraedi Quell Quallie refits.

Initially, the Titan was deployed to Tirol, and formed the air defense headquarters for the invading UEEF army. As such, it performed as designed, coordinating the destruction of several Invid ships that tried to run the UEEF blockade and make it to Tirol’s atmosphere. However, also during the Tirol campaign, the UEEF encountered the Invid force fields for the first time, and found themselves without a weapon capable of breaking these protections down without levelling the surrounding area. Therefore, a new crash program was initiated. Eventually, this program would produce the Little Monster Destroid series and the Syncro cannon designs. In the meantime though a stopgap solution had to be found.

GMU 37This solution was to convert the SOC craft to GMU siege engines. The entire superstructure aft of the cockpit and mecha bay was torn down, and replaced with a large laser cannon, two rotating side bodies, and two erectable flare shields. The GMU could descend to a planet in the same manner as the SOC, touch down near an Invid Hive (assuming all external defensive forces had already been destroyed) and then let loose at the force field until it shorted out and troops could enter the hive.

This naturally left the UEEF without a major part of its orbital defense systems, and as a stopgap replacement, some salvaged Roil Tiluvo corvettes were fitted with the required command, control and communications equipment. To compensate for the lower number of missile launchers, a larger number of fighters were assigned to the UEEF Tactical Air Corps for service as ASAT launchers.

GMCU 2AThe GMU’s served with the UEEF and the Sentinels for four years, until the Little Monsters replaced them in the front lines. The four GMU’s were returned to Tirol, where they were re-converted into an improved SOC configuration, now called the GMCU. They served in the Opteran campaign, but thereafter were restricted to Tirol when the Invid war devolved into a large number of smaller actions. It was not until 2044 that the three of the SOC’s were shipped to the front lines again, for the liberation of Earth. However, the Titan was destroyed with the UES Saratoga and the Leviathan with the UES Hood which transported them, before they could reach the planet. The Colossus survived the assault in reserve with the rest of the ground forces on the moon, and was placed there in mothballs two years after the war, and sold to the Terran War Museum a few years after that. The Goliath became a part of the Tirolian Army after the war, although it was placed in reserve even before her sister.



Robotech (R) is the property of Harmony Gold. This document is in no way intended to infringe upon their rights.

Original artwork by: Tatsunoko Production Co., Ltd, Tim Wing and Charles Walton

Acknowledgement is extended to Peter Walker, Pieter Thomassen and Robert Morgenstern of the unofficial Robotech Reference Guide. Peter Walker, Pieter Thomassen and Robert Morgenstern are given credit for all quotes and paraphrasing of the unofficial Robotech Reference Guide that has been utilized in this publication. 

Content by Pieter Thomassen

Copyright © 2000 Robert Morgenstern, Pieter Thomassen, Peter Walker