The Battle of Mare Smythii (スミス海の戦い?) is a conflict featured in Mobile Suit Gundam: The Origin and its OVA adaptation. Taking place in the Mare Smythii in U.C. 0078, it was the first recorded mobile suit battle in history . It was also known as the Mare Smythii Massacre  and Mare Smythii tragedy .
Dr. Minovsky's Defection
A Lunar Line ship carrying Dr. Torenov Y. Minovsky landed in Granada. Also on the ship was Kycilia Zabi and her subordinate, Major Bergmann. Kycilia was disguised as a woman called "Catherine". On the dark side of the moon, Ramba Ral in his MS-04 Bugu led the Black Tri-Stars in their MS-05 Zaku Is, planning to reach the edge of Mare Smythii within 12 hours. When Ramba Ral mentioned that "their red friend" went up ahead, the Black Tri-Stars began to gossip about Char, whom they couldn't stand, much to Ramba Ral's annoyance. In a Zeonic buggy, Dr. Minovsky, left for the industrial zone, slightly ahead of the projected schedule. One of Catherine's agents relayed this to her at the Granada Plaza Hotel. The buggy exited into the lunar landscape and converted from hover mode, deploying its wheels. Three other defectors killed the unaware Zeonic staff in the buggy and head on Route 1 Westward instead of the Zeonic Granada Plant 5km away. The defectors communicated with Federation personnel in Von Braun, they were ten hours away from Abul wafa, a checkpoint between Granada and Mare Smythii .
Iron Cavalry Squadron Deployed
The Federation, who had been tracking the Dr. Minovsky, detected heat sources in Mare Smythii, which they presumed to be Zeon's humanoid weapons. As Zeon now had mobile suits on the moon, the commander ordered the deployment of the entire Iron Cavalry Squadron which outnumbered the 4 Zeon suits they detected. Tem Ray requested to come a long so he could see the Guncannons in action with his own two eyes . A nerve-wrecking alarm pierced through the hangar of the Earth Federation's Pizarro-class Mobile Transport Ship as it rushed to the Mare Smythii on the surface of the moon. Soldiers in pilot suits dashed into the bellies of the moon-gray squadron Guncannon First Types in a well-trained manner. The hangar was jacked up, and a sharp glint lit up in the head visors . Catherine was informed of the squadron's deployment .
Zeon Engages the Iron Cavalry Squadron
Private Char Aznable stood on the open cockpit of his MS-05 to witness the twilight on the moon. The Black Tri-Stars arrived. Warrant Officer Ortega was angered that Char was already at Mare Smythii rather than waiting at the rendezvous point and also asked why Char didn't send a beacon. Ortega didn't take kindly to the mere Private's tone of voice. Char responded that a beacon would've been seen by the enemy. Ramba Ral spotted the buggy ahead. They were not to shoot, just stop the vehicle. The buggy went off the road to escape the mobile suits, just in time for the Pizarro-class to approach. Ramba Ral asked Minovsky to come back as he chased the buggy. A Federation FF-1F Hog Lunar Attack Craft armed with a Gatling Gun spotted Char's Zaku I and was quickly destroyed by the Zaku I's main gun, the captain of the Pizarro-class now knew that there was 5 rather than 4. As Ortega saw Char destroy another Hog, he took Captain Ral's orders to not shoot to only be about the buggy, Ortega thus opened fire on a Hog shooting at him, too. The Pizarro-class deployed its twelve RCX-76-02 Guncannon First Types led by Erdush, with the objective to protect the buggy. Erdush's Guncannon and Guncannons VB102 through to VB107 fired their cannons at the Bugu and the Black Tri-Stars. Unfortunately, the four targets leap out of the explosions undamaged. The Bugu dealt heavy damage to Erdush's Guncannon's chest with his main gun and then kicked it over. Gaia laughed as he destroyed Guncannon VB107. Mash then destroyed Guncannon VB105 with only a single shot from his Zaku I's Bazooka and then Ortega destroyed Guncannon VB106. Captain Ral commended the Black Tri-Stars for showing the "Federation Scumbags" what "real mobile suits" could do but failed to notice the buggy approaching Guncannons VB111 and VB112. He fired shots from his machine gun at the buggy while the two Guncannons returned fire from their Missle Launchers, Captain Ral dodged every missile and the buggy lost its wheels .
Iron Cavalry Squadron Destroyed
Tem Ray was determined to collect data even though his spacecraft's pilot thought it was too dangerous to get closer. Seeing the destroyed Guncannons, he was in awe at how far Zeonic have advanced. To the soldiers of the Earth Federation Forces aboard the Pizarro-class mobile transport ship, the sight unfolding below them was a nightmare. Seeing this devastation, the captain of the transport ship ordered a recall of the Guncannons but lost his voice when a red shadow loomed into view in front of the ship. It was a mobility that far surpassed his imagination. The red machine fired the machine gun it held at the ship's bridge. The ship's triple-mounted anti-aircraft gun reacted and bombarded the red suit, but the red suit effortlessly dodged the attack, and fired a round at the rear engine. Engulfed in explosive flames, the ship sank into the Mare Smythii . Ortega bludgeoned Guncannon VB102's head with his Zaku I's heat hawk, declaring the Guncannons to not be mobile suits but playthings. Ortega saw the fallen Pizarro-class, and was pissed off that Char hogged all the fun. Gaia brushed off a shot from Guncannon VB104 like nothing and bended his Zaku I over for Mash stand upon and deal the final blow with a bazooka. The injured Erdush climbed out of his cockpit with a cracked helmet to see Ortega bludgeoning a Guncannon and collapsed. Tem Ray's spacecraft's infrared sensors were no longer functioning. Tem Ray saw Dr. Minovsky and a defector on the lunar surface. Captain Ral turned his Bugu around to see Gaia's Zaku I chasing an armless Guncannon VB103 and ordered him to let the Guncannon go, Gaia ignored the order and sliced the Guncannon's backpack reactor, causing it to fall on Dr. Minovsky, to the horror Tem Ray. Captain Ral was irritated but Gaia laughed. Char's Zaku I stood beside the Pizarro-class wreckage .
Tem Ray took advantage of the Mare Smythii tragedy to urge the management of Anaheim Electronics to advance the development of the RX-78. Perhaps this was a form of atonement to Dr. Minovsky, who had died with his objective only partially achieved .
- Mobile Suit Gundam: The Origin Episode 4, Eve of Destiny
- Mobile Suit Gundam: The Origin Chapter 50
- WORLD｜MOBILE SUIT GUNDAM THE ORIGIN. Retrieved on 2021-01-18. “Introduction to the Universal Century IV Part 2 Development of the RX-78”
- Mobile Suit Gundam: The Origin Chapter 49
- (November 2016) HG 1/144 RCX-76-02 Guncannon First Type (Iron Cavalry Squadron) Manual. Bandai, 3.
- (March 2017) HG 1/144 MS-05 Zaku I (Char Aznable) Manual. Bandai, 1.