Technology & Combat Characteristics
A heavy mobile suit developed by Zimmad, the MS-09 Dom was a ground combat machine equipped with hovercraft technology. It was fitted with thermonuclear jets and rockets under its feet, allowing it to quickly move across the ground, greatly improving its mobility compared to previous ground-use mobile suits. Thanks to sensors located in front of its feet, it was able to traverse uneven terrain. While in cruising mode, it could hover across the ground using only its thermonuclear jets. The Dom can hover at a maximum speed of 381 km/hr for up to 5 hours.
Its primary thrusters adopted the Saturn Engine, a type of thermonuclear engine that used heavy elements such as zinc and lead as propellant, granting it higher thrust than thermonuclear engines that used lighter elements as propellant. The mobile suit's design was largely unchanged from the YMS-09 Prototype Dom aside from its appearance. It inherited the same cross-shaped monoeye rail from the MS-07C-5 Gouf Test Prototype, granting it an improved view of aerial targets. Lateral field of view was obtained by auxiliary sensors.
For defense, the Dom was heavily protected, adopting a unique "skirt armor" design to protect weak points in the back such as thrusters, and the suit was mockingly called by Federation pilots as a result. Its cockpit hatch armor, which was its greatest weakness in the front, was also greatly enhanced. However, since the cockpit was entered directly from the front of the Dom, pilots in desert and wetland areas complained that the console panel would become dirty from entering and exiting. Meanwhile, the Dom's head was merged into its chest, a design intended to deflect and ricochet enemy projectiles, as well as lowering the possibility of being hit.
The Dom's primary weapon, the 360mm Giant Bazooka, was developed in parallel with the mobile suit. It was capable of sinking a space cruiser with a single shot. It was also armed with a heat saber for close combat, as well as a scattering beam cannon in its chest, which was capable of blinding the enemy. It was said that the beam cannon was originally intended to be an energy port for beam weapons, but was repurposed after the development of beam weapons was delayed.
History
During the One Year War, the Principality of Zeon's ground-based mobile suits, including the MS-06J Zaku II Ground Type and the MS-07B Gouf, all suffered the problem of low deployment speed. It was determined that the maximum walking speed of a mobile suit could not exceed 200 km per hour. After several failed attempts to solve the problem, Zeon introduced the Dodai YS as a stopgap measure. Meanwhile, the development of a new mobile suit – the YMS-09 – was ordered to find a permanent solution.
Around six months after the start of the war, Zimmad technicians completed the basic design of the YMS-09. It was mostly produced at Granada and California Base. By late September, U.C. 0079, early mass production had begun at the Granada factory.
There were two accounts of the remaining members of the Black Tri-Stars' ultimate fate. In one account, the two surviving members went on to fight in Operation Odessa, during which they fought the Gundam once again and were killed in battle. In another, they were immediately defeated and killed by the Gundam and the FF-X7-Bst Core Booster after Mash's death. One unit was destroyed by anti-air fire while dropping, one unit was seen defending the base from Jet Core Boosters bombardment with a 120mm Zaku machine gun. Another unit attempted to destroy one of the RX-75 Guntank Mass Production Type, but was damaged by Karen Joshua's [[RX-79［G］ Gundam Ground Type|RX-79[G] Gundam Ground Type]] and destroyed by the Guntank from behind.