The GX-9900 Gundam X (aka Gundam X, GX) is a limited production mobile suit built by the United Nations Earth, and the titular mobile suit of After War Gundam X. Its pilot include Jamil Neate and Garrod Ran. Another slightly different unit appeared in the manga sequel, After War Gundam X: Under the Moonlight, and is piloted by Rick Aller.
Built at the height of MS advancement by the UNE, the GX-9900 Gundam X is one of the most advanced MS of its time. It was produced in limited numbers and deployed near the end of the 7th Space War. After the environmental devastation at the end of the war, MS development on Earth became stagnant as humanity recovered; Gundam X and its brethren Gundam series thus remain top-of-the-line after 15 years. Because the UNE no longer existed, there was no regulation over the Gundams and they found new life in the hands of the Vultures.
The Gundam X carries a powerful beam cannon known as the Satellite Cannon. The cannon requires power beyond what Gundam X is capable of on its own, so UNE engineers created the D.O.M.E. lunar microwave facility to power it. When the Satellite Cannon is activated, solar power collected at the facility is sent to the Gundam X via a microwave beam and stored in the large reflector panels mounted on the suit's back, enabling the cannon to fire a particle beam powerful enough to destroy a space colony with a single shot. While the Satellite Cannon is indeed powerful, it requires a lengthy time to charge and fire. Enemy units can take this opportunity to attack Gundam X and disrupt its ability to absorb the microwave beam. During the war, several relay satellites were positioned in Earth's orbit that allowed the microwave beam from D.O.M.E. to be transmitted to any location. However, they were all destroyed or damaged in the war, so this resulted in the Satellite Cannon being usable only when there is a clear line-of-sight to the lunar facility.
Other weapons on the Gundam X include a large beam sword, four chest mounted vulcan guns, and a shield buster rifle. This allows Gundam X to be adaptable and versatile in most combat situations. Both the large beam sword and the shield buster rifle can utilize the stored microwave energy. The Vultures who have salvaged Gundam X units also gave these machines new weaponry such as shoulder vulcan, torpedo launcher, holster shield, buster sheath rifle, etc. The Gundam X was also designed to exploit the capabilities of its Newtype pilot, but was usable by regular humans as well. A Newtype pilot at the helm can use the Flash System to mentally command remote controlled drone versions of Gundam X, the FX-9900 GX-Bits. These GX-Bits are very similar in design to the Gundam X, and in combat, they are used for coordinated attacks. For regular human pilot, the bits are useless as UNE engineers never created an alternative control system for them to exploit the full potential of Gundam X.
The UNE's Gundam series, including Gundam X, has a simple security measure: a G-Controller, a detachable control stick that also serves as the activation key for the mobile suits. However, this is not a strong security measure, as any G-Controller can be used to activate the Gundam. A skilled MS engineer can also hot-wire the system, bypassing the need for a G-Controller to activate the Gundam, and install a new control stick to control the machine.
Garrod's unit was defeated by a Newtype pilot utilizing RMSN-008 Bertigo and then upgraded into the GX-9900-DV Gundam X Divider. The New UNE later created the GX-9901-DX Gundam Double X as Gundam X's successor.
