Space Defense System

The Space Defense System (or SDS) was a series of defensive systems that were deployed on Terran Hegemony worlds during the time of the Star League. Based on multiple layers of defense, the Space Defense System relied on drone and robotic aerospace units (including WarShips) to interdict an invading flotilla in space. These systems were augmented by large capital grade energy weapons and LRM launchers located on a planet or moon.

SDS Components[edit]

Control Systems[edit]

The first SDS was built by the SLDF under the leadership of Jonathan Cameron in 2690. The command systems installed in the planetary bases and space elements were so advanced that a handful of people could control the SDS of an entire star system. The computers, designed by Ulsop Robotics and the Nirasaki Computers Collective, could route around damaged systems, and even launch more fighters and defenders on their own from Advanced Robotic Transport System specially built computer-run spaceports.[1] These computers were not without their flaws however. Shortly after the first M-2 Drone ships were deployed they accidentally destroyed three civilian vessels.[2] These problems were later solved, and the M-2 was replaced by the M-3 Drone.

The programmers worked with the Terran Hegemony's best admirals to enter a comprehensive set of naval tactics. The programmers did their jobs well, as the SLDF would later discover. The computer's desire to control the pace of an engagement and take the offensive was often a source of consternation to the officers that opposed them.[3] They also set their own target priorities and worked together to destroy enemy forces.[4]

The computers could not adapt to certain combat conditions, however. During Kerensky's assault on Terra, the captains of crippled SLDF WarShips piloted their ships on suicide runs to destroy battle stations and SDS WarShips. These tactics confused the computers, allowing SLDF forces to land.

Space Elements[edit]

The primary defensive element of the SDS was a series of automated space stations located at a solar system's primary jump points, the largest of which was known as the M-9 Pavise.[5] These stations mounted capital weapons and could easily destroy any attacker that came into range. Not content with that purely defensive stance however, the SLDF Navy created several mobile defenders, including the Caspar drone WarShip.

Technically named the M-5 "Caspar" Capital Drone, the Caspar series of drone WarShips used the frame of the Lola III-class destroyer as their chassis. With no need to stock food, supplies, or provide crew quarters, the ships were upgraded to include a weapons suite more common to a battlecruiser. As the ships were not hindered by human limitations, they could outmaneuver the manned vessels they were designed to attack.[6][7] Using the advanced computers provided by Nirasaki Computers Collective and control systems from Ulsop Robotics, the Caspars could outfight any manned ship in space.

To defend the Caspar from enemy aerospace fighters, they often carried robotic interceptors like the BlackWasp[8] or VoidSeeker.[9] Basically an aerospace fighter-sized drone, the BlackWasp was also used by worlds in the Star League that did not rate a full-fledged SDS. When deployed as part of the SDS however, the BlackWasps were far more effective in their duties.

Though the M-5 was the best known SDS unit, the design did not spring fully formed into existence. Engineers and technicians installed SDS control systems on several intermediate sized designs in order to validate them. These included the VoidSeeker and BlackWasp drones as well as the M-3 Drone, a drone based on the successful Pentagon-class DropShip. These smaller units were much easier to produce, and as a result many systems in the Terran Hegemony had at least a few of these ships.[10]

Planetary Elements[edit]

Realizing that the space elements wouldn't be able to destroy every incoming enemy, the SDS designers used ground-based systems to augment their firepower. By mounting Naval Lasers and Naval Particle Projection Cannons in fortified emplacements the engineers insured that any attacking DropShip or WarShip that reached the atmosphere of the planet would be engaged by heavy firepower. To engage smaller, faster targets like aerospace fighters the designers installed modified LRM batteries that would saturate the target area with munitions. These missile systems could also be used to attack incoming 'Mechs and supplement the firepower of the main anti-WarShip weapon. Each SDS ground base mounted at least one Capital Weapon and between three and ten missile batteries.[11]

SLDF records indicate that Terra had at least 30 of these bases located in Europe and Asia. Recent intelligence suggests that there were at least 500 SDS facilities on Terra.[12] How many of these were armed stations, rather than sensor or command stations, is unknown. There was at least one armed SDS station in the Andes Mountains however.[13]


The Space Defense Systems were a triumph of engineering and programming, which was unfortunate when the Usurper Stefan Amaris seized control of them during the Amaris Civil War. When the 34th Royal BattleMech Division attempted to retake Epsilon Indi from the Rim Worlds Republic forces garrisoning it, the unit and its escorting WarShips were utterly destroyed in the disastrous Battle of Epsilon Indi. This included a Black Lion-class, two Aegis-class, four Lola-class, and one Potemkin-class WarShip.[14] Until the SLDF forces gathered information from the ruins of the Nirasaki Computers Collective factories to develop an effective countermeasure, every star system defended by an SDS cost the SLDF Navy at least three WarShips.[15]

The only weakness in the system was the large number of communications links between the drones and the controlling computers. In 2775 the SLDF created a new ECM system that jammed the primary communications links with static, forcing the SDS system to use backup links. Though the Caspar drones nearest the SLDF fleet were still able to attack, ships farther away from the fleet and the planetary defenses couldn't get the communications they needed to target the fleet effectively. This allowed the SLDF fleet to defeat the SDS' component elements piecemeal without facing the ferocity of the entire system.[16]


Though the advanced control systems of the SDS were never duplicated by the Successor States, elements of the SDS concept were used as the basis for several weapons systems. The Draconis Combine Admiralty's BattleSat and Federated-Boeing's Capitol space station are two examples of the orbital battle platforms pioneered in the SDS system. It is known the Clans had the technological level to have SDS systems defending their planets. In fact, in 3060, it was confirmed than the Smoke Jaguar Clan homeworld, Huntress, had an operative SDS system, but a commando of DEST troops sabotaged their planetary control center, disabling it before Task Force Serpent fleet arrive on system to invade it.[17]

These systems would also be used as the inspiration for a new generation of SDS weapons developed by the Word of Blake after they took control of Terra. These were established at the start of the Jihad, as evidenced by the failures of Taskforce Vengeance and Case White. A similar system was encountered by Devlin Stone's Coalition forces when they attacked Rochelle.[18]

Word of Blake SDS (Caspar II Systems)[edit]

After the Word of Blake took control of Terra, they knew that ComStar would never allow them to keep the planet and would eventually retaliate. Given the size of ComStar's WarShip fleet, one of their first tasks was to rebuild the Reagan SDS weapons that surrounded the Terran system as a countermeasure. Though they were not able to recreate the advanced computer control systems used by the First Star League, the Word was able to combine their experience with advanced computer systems with drone control technology to create very capable fighting systems. These drone fighters, DropShips, and WarShips were able to inflict heavy damage on the Coalition forces that attacked Terra. The fact that these new systems were based on existing SDS technology that wasn't quite as advanced as the Star League systems they emulated led several designers to name them Caspar II class systems. This name stuck, and was later used to differentiate between the Word and Star League systems.

Like their Star League counterparts, the Word of Blake separated their defense systems into space-based and planetary systems. Unlike their Star League forebears, the Caspar II systems were designed to operate semi-autonomously in most cases. A drone unit would detect various enemy forces and follow basic decision trees, but would communicate back to a command center for strategic guidance. This command center could be either a modified WarShip, space station, or ground base.

The Caspar II systems were originally limited to the Terran system, but Precentor Martial Cameron St. Jamais later deployed several systems to other worlds in the Blakist Protectorate. The systems deployed at Halloran V,[19] Towne,[20] Hean,[21] Chara,[22] and Bryant[23] destroyed WarShips and inflicted heavy casualties on their supporting aerospace forces.

Unlike their Star League era inspiration, Terra's Caspar II planetary defense systems were controlled from a single location: The SDS Command Fortress at Governador Island in Rio de Janeiro. After this Castle Brian facility was captured by elements of the Iron Guard, 5th Crucis Lancers, and 20th Marik Militia, the Word's entire Terran SDS collapsed.[24]

Caspar II Space Elements[edit]

The space-based elements of the Caspar II network consisted of:[25]

  • Naga Caspar II Control Ship (Modified WarShip)
  • Dragau Assault Interceptor Caspar II drone (Drone Assault DropShip)
  • Tiamat Pocket WarShip Caspar II drone (Drone Pocket WarShip)
  • Drake SDS Control Station (Space Station, manned)
  • Cockatrice Monitor Platform drone (Drone DropShip)
  • Hive-class drone aerospace fighter
    • Tabanid-class drone aerospace fighter
    • Scarab-class drone aerospace fighter
    • Aeshna-class drone aerospace fighter
  • Dragon's Breath Multiple Capital Launch System (modified orbital ore processing station designed to fire ten Killer Whale or Peacemaker missiles at incoming WarShips).

Caspar II Planetary Elements[edit]

In addition to the stationary Star League era SDS systems that ComStar knew of, the Word of Blake also activated two additional Caspar II ground defense systems as part of their rebuilt SDS network:[26]

  • Rattler Mk II Anti-Aerospace Mobile Fortress: Served as air defense and artillery outposts for Castles Brian located on Terra's surface.
  • Wyrm-class SDS Submersible Fortress: Designed to bring the firepower of a light WarShip to planetary defense, the Wyrm submarines were massive fortresses that could hide beneath the waves of Terra's seas.

In addition to their direct defense role, both these systems carried facilities for additional units. Typically they carried at least one company's worth of jump infantry or battle armored infantry, and a company of VTOLs to transport them into combat. This is in addition to the 'Mech-scale weapons they carried for self-defense.[26]

Word of Blake Caspar III Command Automated Robotic System (CARS)[edit]

The Caspar III system was an experiment by the Word of Blake to make a jump-capable SDS drone. For many years, the Star League's unwillingness to deploy a jump-capable drone was thought to be a security measure. Though this is true to an extent, the Star League's every effort to create a jump-capable drone resulted in a drone that would jump and then immediately have a "paranoid psychotic break." The AI controlling the drone would become disoriented, revert to a self-defense mode, and lock out all attempts at communications. More importantly, it would register all ships - even friendly civilian vessels - as threats. As a result of these experiments, the Star League fitted the SDS drones with safeties that took the AI systems offline before they were moved from one system to another. Upon arrival, the AI systems were reactivated.

The Word of Blake created the Command Automated Robotic System (CARS) to address this problem. Nowhere near foolproof, the CARS instead reduced the possibility of artificial psychosis to a level deemed acceptable. This would allow the Word to deploy automated JumpShips and DropShips which carried drone fighters into enemy territory. Fortunately for the rest of the Inner Sphere, the Word was only able to complete one prototype, a Monolith-class JumpShip that was destroyed during the fighting at Titan.[27]

Planets protected by an SDS[edit]

The SDS, as it was created to protect Terran Hegemony worlds, was present on most of these during the Amaris Coup. After the Succession Wars, only some Clan Homeworlds had that class of defense. During the Word of Blake Jihad, the Blakists recreated the SDS to protect their key Protectorate worlds.

Inner Sphere[edit]

Clan Homeworlds[edit]


  1. The Star League, p. 61: "Military Renaissance"
  2. Historical: Liberation of Terra Volume 1, p. 153: "New Combat Equipment: Star League Space Defense System"
  3. The Star League, p. 88: "They took the initiative, which surprised me..."
  4. The Star League, p. 88: "After they passed my ship, they concentrated on the Rex, a destroyer. Her commander made a fatal error and tried to run away. Like sharks around a whale, the drones encircled the Rex and sliced her to pieces. They went after the transports next."
  5. Historical: Liberation of Terra Volume 1, pp. 172–173: "M-9 "Pavise" SDS Battle Station"
  6. The Star League, p. 88: "Our gunners found it difficult to aim at the drone ships because of their speed and maneuverability."
  7. The Star League, p. 91: "Each Caspar carried the firepower of a cruiser and had the maneuverability of a destroyer."
  8. Jihad Conspiracies: Interstellar Players 2, p. 130
  9. 1st Somerset Strikers, p. 35
  10. Historical: Liberation of Terra Volume 1, p. 169: "M3 Drone"
  11. BattleSpace Rulebook, p. 38: "Surface to Orbit Fire"
  12. Masters and Minions: The StarCorps Dossiers, p. 221
  13. The Fall of Terra, p. 16
  14. The Star League, p. 88: "Admiral Braso's Last Transmission"
  15. The Star League, p. 81
  16. The Star League, p. 90: General Kerensky's attack on New Home
  17. Sword and Fire, ch. 11
  18. Jihad Hot Spots: 3076, p. 82: "The New Earth Raid"
  19. Jihad Hot Spots: Terra, p. 178: "Fate was not so kind to the Confederation’s Franco Martell. It is now known that the Martell ran afoul of a fully functioning Caspar II orbital defense grid at Halloran V."
  20. Jihad Hot Spots: Terra, p. 37: "The Tale of Towne"
  21. Jihad Hot Spots: Terra, p. 37: "Situation Report: Naval Defenses"
  22. Jihad Hot Spots: Terra, p. 48: "Chara Operational Report"
  23. Jihad Hot Spots: Terra, p. 72: "Dire Straits"
  24. Jihad Hot Spots: Terra, p. 105: "Rio Goes Black"
  25. Jihad Hot Spots: Terra, pp. 178–187
  26. 26.0 26.1 Jihad Hot Spots: Terra, pp. 188–191
  27. Jihad: Final Reckoning, p. 134
  28. 28.0 28.1 The Wars of Reaving, p. 138
  29. The Wars of Reaving, p. 142