M145D Rhino

The M145D Mobile Artillery Assault Platform (MAAP), commonly known as the Rhino, is an artillery tank used by the United Nations Space Command. It is unique among UNSC vehicles in its armament, a plasma cannon that was reverse-engineered from Covenant technology.

Development
During the Harvest campaign the Office of Naval Intelligence procured large amounts of Covenant matériel in the hope of reverse-engineering it. These efforts yielded varied results, one of the most substantial being the Zeus 320mm cannon, which, like most Covenant weapons, is capable of focusing and directing plasma as a projectile. Chalybs Defense Solutions, the creators of the M808 Scorpion and M850 Grizzly main battle tanks, was contracted to manufacture the M145D Rhino as a platform for the weapon.

By February of 2531, the UNSC was field-testing the Rhinos. Several prototypes were kept on the, apparently for this purpose.

Operational history
The M145D's first known deployment was during the Battle for Arcadia on February 9, 2531. During their invasion of Arcadia, the Covenant established a large base at a complex of Forerunner ruins near an ONI base, over which they deployed an enormous energy shield dome. The crew of the, the only remaining combat-ready UNSC forces in the system, requested several Rhinos from the , which had been damaged in the initial stages of the attack. During a costly battle, Spirit of Fire ' s Marine complement, aided by a firebase built nearby, worked to escort the Rhinos into position. Professor Ellen Anders was able to determine that they needed five of them after an attempt to use three in conjunction with one another caused part of the dome to flicker but not fail. Finally, when five Rhinos were used simultaneously on the dome, they overloaded the shield's power supply and caused a section of it to disappear, allowing the Spirit of Fire to safely use its MAC guns to take out the shield generators and Covenant air defenses, destroying the dome.

Some of these Rhinos were then deployed to the ruins, where the Marines encountered a Scarab excavation platform that was still under construction. The remaining Rhinos then assisted in the destruction of the Scarab. The Rhino continued to see impressive use throughout the war, though it was rarely deployed. Some Rhinos still exist as of 2558, though they have been used sporadically due to insufficient resources and a lack of refinements to the prototype. However, the data gleaned from the Rhino's development and use was later used on other projects. The Rhino initiative has seen renewed interest in development due to the interest of Isaac Richardson, one of the UNSC's top procurement officers.

Design
The architecture of the M145D is similar to that of the M808B and M850, though it is longer and wider than the former vehicles. This larger chassis is designed to support the vehicle's six-bogey tread configuration, which in turn facilitates a lockdown mode - akin to that of the SP42 Cobra - when the cannon is fired. The tank's middle tread bogeys extend farther outward than the forward bogeys. The rear bogeys lie between the middle ones and jut from the back of the tank's chassis; stabilizer mechanisms are mounted to the rear tracks. The Zeus cannon is mounted to a large turret, akin to that of the Grizzly; the weapon is capable of traversing upward at a roughly forty-five degree angle. As with all plasma-based weapons, the Zeus is potent against energy shielding.

Gameplay
Although the Rhino's firepower is weaker than that of the Scorpion, it has superior armor. A group of these tanks is powerful enough to destroy heavy armor, but the vehicle is intended to play a fire support role alongside a large UNSC force. Its secondary ability deploys it into a 'lockdown' mode like that of the Cobra and the Elephant, giving the Rhino a more powerful attack with increased range.

The Rhino is exclusive to two campaign missions in Halo Wars: Dome of Light and Scarab. Besides its importance to the plot, the Rhino functions almost identically to the Cobra in terms of speed and firepower. The sound effect of its deployed artillery cannon is shared with the Cobra. Preventing all the Rhinos from being destroyed in the level grants the player the Rhino Hugger achievement.

Trivia

 * As with most UNSC vehicles, the Rhino is named after an animal.
 * The Rhino's turret and gun barrel resemble the turret from the Tiger II heavy tank used by the German Army during World War II. Both are designed based on long range bombardment, with a large caliber cannon to perform that role, and both have heavy armor. The turrets of both vehicles rotate slowly.
 * A lightning bolt is painted on the side of the Rhino's turret. This is likely a reference to Zeus, the chief deity of the Greek pantheon, who is the namesake of the Rhino's cannon. Zeus used lightning bolts as weapons and as symbols of his power.
 * Like its fellow artillery unit the Cobra, the Rhino's lockdown mode bears striking resemblance to the Terran siege tank from the StarCraft series.
 * On the Halo: Spartan Assault level The Mirror Mantle Counter-Assault, what appears to be plasma fire can be seen in the background originating from the UNSC lines and landing near Covenant vehicles. The plasma may be fired by off-screen Rhinos.

List of appearances

 * Halo Wars
 * Halo: The Fall of Reach - The Animated Series