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Izumo Class Space Battleship (SBB)

Names and disposition:

(RFS=Robotech Factory Satellite)
(RNY=Robotech Defense Force Naval Yard)
(KNY=Kawasaki Naval Yard)

Ships' Complement:

• Ships' crew (3500 men)
• Space Naval air group (4700 men)
• Space Marine unit (10000 men)
• Life support limits are for a full combat complement and about 28,800 supernumeraries (3300,000 men total).

Note: The given numbers are approximations; the exact number varied somewhat due to operational realities and different ships.

Dimensions:

Propulsion Systems:

• Main power system(1): RRD Mk 7 anti-matter-fueled Reflex furnace. The powerplant of the Izumo-class vessel can deliver up to 156 Petawatts of power, and can operate for one hour minutes at maximum power before overheat initiates autoshutdown.
• Maneuvering thrusters (24): Overtechnology MRT-03 fusion-plasma reaction thruster clusters mounted on the side bodies (8), the central front body (6) and the central aft body (6).
• Reaction-mass thrusters (60): Shizuma Drive MRE-9 Fusion-Plasma Reaction Thrusters with anti-matter energizer. These engines are mounted in eleven clusters.
  Thrusting aft are 38 engines; one cluster of eight engines and two of six in the stern of the central and side bodies, augmented by one cluster of six engines in the upper aft body and one in the lower body, and two triple clusters in the lower side bodies.
  Thrusting forward for deceleration are 22 engines; two clusters of six, one in the lower central body and one in the lower body, and two clusters of five in the side bodies.
  Due to the large number of primary thrusters, no secondary thrusters are installed into these vessels.
• Anti-gravity system (1): 70 Shizuma Drive Behemoth anti-gravity pods.
• Gravitic displacement drive (6): Shizuma Drive GDD-5 local, monopolar-induced gravitic space-time distortion drive.
• Space fold (1): RRD Mk15d spacefold. This system is conformal to the vessels surface. The problem with the vast majority of the previous generation of fold systems was that the fold bubble weakened the state of the structure to the extent that they needed a refit after only five years of service. As such the RDF mandated the use of conformal systems similar to the old Zentraedi systems which also allows for much higher speeds.  The Mk15d was created placing six Mk15 drives in three sets of two so as to increase the mass that can be folded.
• Planetary capabilities: The Izumo-class has minimal atmospheric capabilities through its reaction thrusters and anti-gravity system. However, maximum speed and maneuverability are extremely low and extreme care must be taken not to overstress the hull structure.
  The ships' lower body has insufficient strength to let the ship land on it. Because of this, a 'cold' landing is not possible on open ground without crushing this section. While landed, the battlefortress must operate her antigravs at -99% local g at all times to prevent damage to the lower body. With the lower body detached, a 'cold' landing can be made, given a sufficiently hard underground (such as granite).
  As the ship will float, an oceanic landing is the preferred landing method, though the lower body will be inaccessible save through the central section of the ship.
  The lower body is detachable and capable of supporting its own weight, and this is the preferred method to land troops on a planetary surface.

  Note: The lower body engine clusters (forward and aft) are too far off-center to be used unless the main aft thruster clusters are also used in an off-centerline burn to retain stability.
  The other off-center engines aft (upper central and lower side body clusters) must be used in conjunction with one another or with off-centerline firing main clusters lest the ship destabilizes.
  The central upper aft engine cluster fires its exhaust along the control tower stem, which is armored specifically against the abuse. The central lower forward cluster fires against the forward part of the central hull, which is also specially treated against this. However, these thruster clusters must burn at lower temperatures and efficiency regardless to prevent burn damage to the ship.

Endurance and mobility limits:

• The dry stores endurance is limited to about six months with a full crew complement, assuming no mining and subsequent replenishment, which the Izumos are capable of doing. The on-board life support and recycling system ensure that only incidental biomass losses need to be replenished. Water stores are recycled almost completely. The hydroponics installations on board provide the crew with a steady supply of fresh foods, and much was exported to smaller ships in the fleet.
• The mecha consumables supplies (mainly missiles) are very extensive, and as long as the onboard factories remained supplied, the ship can sustain continuous combat operations for an unlimited period of time.
• The reflex furnace can function for about 40 years at normal usage levels before an energizer rebuild is necessary.
• At full power, the main propulsion systems can produce up to 1.9 Teranewtons of thrust at a minimal reaction mass efficiency profile, or as little as 60 Giganewtons of thrust at a maximum efficiency setting. At lower power levels, these thrusts are commensurately smaller.
• At full power, the Izumo-class can achieve a maximum delta-v of 311 kps at the cruising acceleration of 0.1 gees, a maximum delta-v of 62.2 kps at the battle acceleration of 1.2 gees, and a delta-v of at most 16.8 kps at the flank acceleration of 3.1 gees. At lower power levels, these ranges are commensurately smaller.
• Sublight drive acceleration is 800 g, but the vessel's maneuverability is reduced to such a degree that only minor course corrections are possible. Typical cruising speed is .05c.
• The fold systems are not navigationally guaranteed for any single jump beyond 1 kiloparsec. If longer voyages are required, the ships must conduct multiple fold jumps.
• The maximum sustained atmospheric speed is limited to subsonic values. During a re-entry, the Izumo-class must reduce its speed to subsonic velocities well in the stratosphere, or risk destabilization by its own supersonic shock wave in the lower atmosphere.
  The maximum hover time on the anti-gravity systems is limited only by the anti-matter supplies and maintenance requirements. However, large atmospheric environmental stresses may cause warping of inter-hull connections and should be avoided whenever possible.
  If the ship touches down in an oceanic environment with the lower body attached, care must be taken that the current differential between the lower and central bodies does not exceed 5 knots. Otherwise, stresses may cause warping of the hull connections. For this reason, hydronic landings in this condition are usually made in deep inland lakes. This does of course limit the number of possible touchdown sites, as the lower body has a very deep draft and few lakes on any world qualify.
  With the lower body detached, the central and side bodies can withstand current pressures of up to 10 knots in any direction. Should the environment exceed these limits, the ship must be laid stern-on to the current.

Weapon systems:

• RRD MRC-4 mini-reflex cannon(1): This miniaturized, less powerful version of the heaviest of ship-borne weapons has an effective range of 125,000 km; at full power it has the effective yield of a 75 MT fusion weapon. The weapon is located in an aperture in the center forward body. The mini-reflex cannon may fire once per minute. If utilized against starships, the largest vessels could be destroyed with the leakage of the beam. A direct hit would vaporize the target vessel. The weapon could also be set to a wider dispersal. In this setting, it was capable of clearing a wide area of fighters and other mecha, although starships in this area would only be blinded.
• Krupp PC-01 plasma cannon (3): The plasma cannon is a new cannon designed to replace the aging particle cannon and works by firing electrically charged hydrogen molecules that upon impact give off radiation and a tremendous amount of heat causing a large explosion. The cannon has a range of 175,000 km and can discharge up to 3.8 TJ five times per minute.  One is mounted in each of the side bodies and in the lower body. The cannons can fire separately at different targets or fire coaxially (by themselves, or with the Mini-Reflex Cannon) at a single target.
• Vickers HPC-15 heavy particle cannon turrets (20): These have a range of 175,000 km; designed to be used against spaceships, each turret is capable of delivering 8500 MJ of particle energy. The cannons fire once every five seconds at the maximum discharge rate.  These weapons are mounted on the upper central hull, aft (2) and forward (4), on top of the side bodies (2 each), under the side bodies (2), and under the central bodies aft (3) and forward (3). The cannons fire once every three seconds at maximum discharge rate.
• Bofors PL-5 point defense turrets (48): Mounted behind movable panels in the upper main hull (14) and the side bodies (17), these standard RDF weapons can fire 98 MJ of particle energy twice times per second at a range of up to 5 km.
• Mk.240 MLS missile systems (18): Each launcher has 10 individual launch silos. The silos each contain 6 ready missiles in a rotating mechanism, which can be reloaded while firing. The ready magazines store 300 missiles per launcher. These launchers typically fire Prophet missiles. Typical warheads are anti-mecha cluster munitions, nuclear reaction anti-warship and nuclear reaction re-entry capable weapons. Four launchers are located near the aft engines, two others near the bridge, four on each side body, and the remaining four are located forward.

Air group and mecha complement:

(circa 2055)

(Space Naval Air Group)

• 900 VF-11 Thunderbolt Veritech fighter
• 300 VF-17 Nightmare Veritech fighter
• 12 EC-12 Eagle Airborne early warning and control aircraft
• 11 SC-45 Hawk Personnel and cargo shuttle
• 10 VC-25 Samson Heavy VSTOL cargo transport
• 20 VC-27 Hercules Light VSTOL cargo transport

(Space Marine Unit)

• 60 VF-17 Nightmare Veritech fighter
• 120 MBR-25 Atma Heavy battle destroid
• 240 SDR-14 Tiger Missile destroid
• 240 ADR-14 Razor AAA destroid
• 5 RGM-78 Gundam Mobile suit
• 70 RGM-79 GM Mobile suit
• 10 HWR-04 Godzilla Heavy artillery destroid
• 2000 VR-071 Protector Veritech cyclone
• 2000 VR-077 Firefly Veritech cyclone
• 2000 VR-074 Gorilla Veritech cyclone

(circa 2063)

(Space Naval Air Group)

• 720 VF-11 Thunderbolt Veritech fighter
• 180 VF-17 Nightmare Veritech fighter
• 360 VA-14 Falcon Veritech bomber
• 12 EC-15 Lynx Airborne early warning and control aircraft
• 11 SC-52 Vulture Personnel and cargo shuttles
• 10 VC-37 Perseus Heavy VSTOL cargo transport
• 20 VC-39 Ajax Light VSTOL cargo transport

(Space Marine Unit)

• 30 VF-17 Nightmare Veritech fighter
• 30 VA-14 Falcon Veritech bomber
• 120 MBR-25 Atma Heavy battle destroid
• 240 SDR-14 Tiger Missile destroid
• 240 ADR-14 Razor AAA destroid
• 5 RGM-90 Double Zeta Gundam Mobile Suit
• 30 RGM-91 ReGZ Refined Gundam Zeta Mobile Suit
• 40 RGM-89 Jegan Mobile suit
• 10 HWR-04 Godzilla Heavy artillery destroid
• 2000 VR-071 Protector Veritech cyclone
• 2000 VR-077 Firefly Veritech cyclone
• 2000 VR-074 Gorilla Veritech cyclone

Note: The given numbers are approximations; the exact number and type of mecha varied somewhat due to operational realities and different ships.

Electronics:

• RRD DSO-5 omnidirectional barrier defense system(1): An advanced forcefield system which covers the full four pi steradians around the ship with a yellow-greenish forcefield (or if desired, only part of the ship). This field will stop all solids and directed energy weapons (except lasers through a narrow band). However, excess energy which cannot be shunted from the field will be stored in the virtual structure of the field itself. The storage wattage is high but not infinite, and when the barrier overloads the field will discharge the stored energy particles. This discharge will have the force of a high-yield (>45 MT) fusion bomb. However, as the discharged energetic particles' vectors will be away from the field and its generating vessel, the vessel will survive, though it will suffer severe damage to its internal electronics and power systems, and will not be battleworthy until repairs are made.
• Hughes DSP-5 pinpoint barrier defense system(2): Uses four movable disks of force field, conformal to the ship's surface, to repel light torpedo attacks, or particle beam fire.
• The Izumo-class carries several manufacturing centers modeled on those found on board the Macross-class. These are capable of producing almost all supply stores.

Design notes:

The origin of the Izumo class Battlefortress lies in 2034, after the Expeditionary Forces had send most of their active combat units to the Invid-occupied Earth. In order to bolster fleet strength with large capital ships, a new Battlefortress was designed, the very large SDF-4 Izumo class. Part of the reason for the enormous size is the Reflex cannon, which is a new design that does not require the ship to split like a tuning fork in order to fire. However, the weapon is also more bulky and requires far heavier shielding. In addition, the heavy secondary and tertiary armament as well as the large cargo requirements pushed up overall mass during the design phase. The result was the heaviest and largest ship yet built by Terran forces, rivaling the Zentraedi Thuverl Salan cruiser in mass.

The Izumo design is distantly inspired by the philosophy that yielded the Ikazuchi-class large cruisers. The main body of the vessel retains the 'brick on its side' shape for much of its length, though it can be divided into two sub-sections: A narrow, aft central section containing the central engines and anchoring the command tower, and an enlarged and heightened forward cannon section. In addition, three additional modules are attached; two connecting by a long plane to the two sides of the central body, directly to the central engine block, and one to the keel. At the front of the sub-bodies the heavy particle cannons are mounted, which, in concert with the main Reflex Cannon in the main body, can bring an enormous amount of fire to bear on the forward arc. In addition, the forward subsection of the main body shields much of the vessel from return fire, and the side bodies shield the aft main body from flanking maneuvers. At normal battle attitudes, the Izumo's vital aft central body is usually only exposed on its top and bottom sides, and only in a very limited way forward of the engine blocks. This all combines (because of the ships' attitude) to make the central section the least vulnerable section of the ship.

The lower body contains the Destroid hangars, as well as many ground forces supplies, to facilitate unloading. The troops are quartered in other sections of the vessel, and this section has an independent anti-gravity engine block to enable it to make planetary landings.

The command citadel is located on top of a tower that rises above the main hull, above the aft central engines. The Flag Bridge is located in this citadel.

Hangar decks and crew spaces are distributed through the central and side bodies, though most fighter mecha are launched from the side bodies. This includes no less than sixteen (in eight double housings) versions of the quick-launch bays first used on the Ikazuchi. There are two large Horizont bays located in the side bodies, just forward of the side aft engine sections. They are closed by a large trapezoidal shutter door in the roof, and capable of a high turn-around rate on the shuttles.

After the Third Robotech War ended in 2045, the RDF Navy was still lacking a viable battleship. It was decided that the Izumo-class would fill this gap and be used strictly as a fleet to fleet combat vessel with the capacity to carry out planetary strikes with veritechs and shipboard fire leaving other vessels to carry the troops. The drop ship bays were removed to clear space for more missiles and stores along with more veritech fighters. The first of the second generation of Izumo-class Battleships was launched in 2047 and dubbed SBB-5 Valhalla it became the first of an additional twenty-six more Izumo-class battleships to be built for the RDF Space Navy.  Among the largest changes in the vessel was the removal of the main reflex cannon.  While the ship now lacks the big punch of this powerful weapon, it was replaced by a much smaller mini-reflex cannon which, while not as powerful, can still destroy most smaller ships with a single salvo and still retains a faster rate of fire than its larger sibling.  The aging particle cannon design were replaced by extremely large plasma cannons.  These cannons have a much larger discharge than most plasma cannons in service.  However, these cannons are limited to a arc of fire directly in front of the ship.  The triple barrel particle cannon turrets were replaced by twin barrel heavy particle turrets.  These turrets, while fewer in number, offer considerably more firepower than its predecessor while taking up less space.  The missile launchers were upgraded to allow for newer missiles to be used,  The final change to armament increased the anti-mecha and anti-missile fire available by increasing the number of point defense turrets from eighteen to forty eight, a feature which the original ships sorely lacked.

History:

The design for the SDF-4 class dates back to 2032, when the Expeditionary Forces needed to rebuild their fleets and armies in order to attack the Invid entrenched on Earth. The class was seen as the follow-up to the SDF-3 Pioneer design, which had several known weak points, such as too little generating power for its main armament. Since the new class did not have to conform to a known Tirolian ship class, the designers were given a free hand, and after five years of design work, the final result bore little resemblance to the first three Terran battlefortresses. The vessels were named after the most holy cities and shrines of the major religions of Earth.

The construction of the first of the class, the Izumo, began in late 2038 in the Robotech Repair Factory, with the other vessels, the Jerusalem, Varanasi and Dunhuang, following at one year intervals. The SDF-4 Izumo completed in 2042, but the ship was too late to work up and join the ill-fated Mars Division attack of 2043. She did however participate (in fact, as Expeditionary Forces Flagship when the SDF-3 failed to defold) in the final battle of the Third Robotech War. The second ship of the class, the SDF-5 Jerusalem, was in service as well, but had not yet a fully trained crew, and remained behind to guard the various Expeditionary Forces supply and manufacturing centers. The third and fourth vessels of the class, SDF-6 Varanasi and SDF-7 Dunhuang, had not yet been completed.

As stated, the SDF-4 Izumo was present at the Battle of Reflex Point. During this battle, she was destroyed outright in the wake of the Invid departure fold. Jerusalem and Varanasi missed out on Reflex Point and continued to serve with the RDF Space Navy until it was destroyed in the 4^th Robotech War. Dunhuang was destroyed in the Transient War in 2057 victim of a Zentraedi Neld Flagship Reflex Cannon barrage.   The second generation of Izumo-class battleships fared much better than their predecessors surviving well into the next decade when production ended after a total of thirty, four old, twenty six new, class battleships were constructed ending with SBB-39 UES Olin. Several of these vessels became escorts for the Japan-class colonization fleets charting the galaxy. When SCO-7 UES Germany encountered the Varauta Empire in 2064, one of these vessels was lost. Almost all of the new type vessels were destroyed in the 4^th Robotech War 2063-2068.

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

Layout adapted from Robotech Reference Guide

Original content by Pieter Thomassen and Peter Walker

Content by Jeffrey R. Spillner
Copyright © 1998-2002 Jeffrey R. Spillner

Page Last Updated on January 21, 2002 @ 14:00 GMT