A Mass Driver or electromagnetic catapult is a proposed method of non-rocket spacelaunch that would use a linear motor to accelerate and catapult payloads up to high speeds. In the Gundam series, it used mostly to send people and materials from a planet into space. They appear in numerous timelines.
Mass Drivers are located both on Earth and on the Moon to propel spacecrafts containing both people and materials into space.
There were several points in the story of the Universal Century where Mass Drivers served a significant role. In the battle for Ayers City, a mass driver concealed within the city was the primary means for the forces of New Desides to escape. Judau Ashta and the crew of the Argama also used one such mass driver to return to space during the First Neo Zeon War. One mass drive is seen in Palau during Third Neo Zeon War. Riddhe Marcenas and Mineva Lao Zabi use it to launch their MSN-001A1 Delta Plus in order to reach Earth. Many years later during the Zanscare Empire War, the Shrike Team suffered heavy losses in order to maintain a mass driver to launch shuttles of the League Militaire into space.
There are two Mass Drivers that are known to exist in the After War Gundam X universe. The first Mass Driver to appear is located at the Eighth Base of the New United Nations Earth, a base set up to supply the NUNE space forces when they start operations in space once more. The base was occupied by spies from the Space Revolutionary Army, who after making a deal with the crew of the Freeden for protection, were able to escape into space with a captured Bartolk.
A second Mass Driver is located at the New Orleans Base, a military base that belonged to the United Nations Earth before the end of the 7th Space War. The base became one of the headquarters of an opposition group against the New United Nations Earth's movement to unify North America. A space ship left in an underground hanger after the 7th Space War was refurbished by the resistance force and christened the "Freeden II". Using the Mass Driver, the Freeden II was able to launch into space to take part in the 8th Space War.
In this timeline, all mass drivers are built around the equator and often protected by large armies. Facilities containing mass drivers include the Victoria Base in Africa, the Panama Spaceport in South America, Kaohsiung in Taiwan and the Orb Union's Kaguya mass driver. During the first war, these mass drivers were major attack targets of ZAFT, to prevent the Earth Alliance from sending weaponry and people to space. Several mass drivers are destroyed during the war, but eventually rebuilt afterwards. There is another mass driver known as the Giga Float, built by the Junk Guild. A constantly-on-the-move mass driver, it was designed for usage by civilians. However, it came under attack by the MBF-P01-ReAMATU Gundam Astray Gold Frame Amatsu and had to be rescued by Lowe Guele and his MBF-P02 Gundam Astray Red Frame.