The Federation Forces were shocked by the blitzkrieg of the Principality of Zeon whose forces were composed primarily of mobile suits during the One Week War and Battle of Loum at the start of the One Year War. They delayed their mobile suit development and operation project called “Operation V”. Among the group of prototype mobile suits that were apart of the first stage, the revered RX-78 for anti-mobile suit battle became the Federation’s first candidate for a mass produced mobile suit. This would be the Gundam type Mass-production model or GM for short.

Although the Federation Forces practical introduction of mobile suits was significantly delayed compared to the Principality of Zeon forces, the performance of the GM implemented sufficient trial production and came to surpass the Zeon with technology such as portable beam weaponry and a learning computer. However, the GM was an expensive weapon and even with the national resources of something as mighty as the Federation, it was impossible to amass a suitable amount against the Zeon forces who had deployed mobile suits as their main weapons at the start of the war. Therefore, by utilizing GMs only for missions that are difficult to carry out without mobile suits (for example close combat), inexpensive weapons for supporting attacks and the like were substituted and an idea came up to make up the number of weapons with a smaller budget. The Federation Forces foresaw a battle at Solomon and in the lunar orbit early on so substitute weaponry for mobile suits in space was planned under the same idea.

First, for mass production, it was required to simplify the manufacturing process slightly and to increase production efficiency. Areas that stuck out were: getting rid of the core block system, simplifying the head and beam rifle. Even after being transferred to mass production, countless improvements were made based on operational reports in combat. Among the reports was valuable data acquired from the RX-78-2 as it overcame countless battles on board the White Base. The first battle between mobile suits in history that took place inside a colony at Side 7 and the airspace outside it was first confirmed in data left behind at Luna II followed by a larger portion of data again at Jaburo following descent to Earth. The data that was first left at Luna II was utilized for the basic design of the GM and it was pointed out with the data gathered at Jaburo that there were some ways to configure it for various space combat roles. Based on this data, major improvements to mobile suit operations in space which would be the focus of the later half of the war, thus giving birth to the GM late production type.

The biggest feature of the late production type is its backpack. The thruster configuration was drastically changed from the RX-78 and the early production type GM giving it a total of six thrusters. In the RX-78 and the early production type, it had to fire the main thrusters while changing the direction of the suit via AMBAC and attitude control verniers to adopt high mobility including deceleration. This was because the thrusters on the backpack were all facing downward. Both methods had their strengths and weaknesses but operability in space was drastically improved and this backpack plan was going to be fed back to the RX-78-2 as an option.

The backpack is a refined version of the GM Space Command from 0080. It is able to carry a set of beam sabers and it also has a bazooka mount.