XM-X1 Crossbone Gundam X-1 is a testbed mobile suit developed by the Earth Federation's Strategic Naval Research Institute (SNRI). It was featured in the Mobile Suit Crossbone Gundam manga series.
The F97 is specifically designed by the SNRI to be used near Jupiter, where the strong gravitational field creates serious propulsion problems. Units operating on Earth and near Earth's orbit usually achieve high mobility using thrusters distributed across the mobile suit's body. However, under Jupiter's gravitational influence, this would require enlargement of the thrusters, leading to an increase in the mobile suit's size and mass. Larger thrusters would require more powerful reactors, which in turn adds more mass.
To resolve this, the F97 is equipped with a set of four movable thrusters in an X-shaped array. Used in tandem with the unit's AMBAC system, these thrusters allow high mobility around Jupiter's orbit without increasing the size and mass of the mobile suit – and when combined into one huge thruster column, they are capable of dramatically increasing the unit's top speed. Of course, there are tradeoffs; a unit designed for these unique conditions like the F97 is difficult to control on or near Earth.
Though technically the F97 are general purpose mobile suits, they were designed with extra emphasis on their close range combat abilities. With their high mobility, they easily outmaneuver most enemy mobile suits, allowing them to slip into close range and past the beam shield. Additionally, the Crossbone Vanguard leader, Berah Ronah, sought to fight the war against the Jupiter Empire with as little loss of life as possible. With blades it is easier to take out a mobile suit without destroying the cockpit than it is with a beam rifle.
Another notable equipment is the Anti-Beam Coating cloak, which can be stored on the F97's back and unfolded when needed. When unfolded, it covers the mobile suit's entire body, and disperses beam energy over the cloak. It can usually withstand five standard beam shots without spending any energy, with the additional advantage of stealth. Like its predecessor F91 Gundam F91, its "mouth" can be opened as a vent. The F97 is also equipped with a plug-in type core fighter, which mounts the movable thrusters and two standard beam sabers.
Four units were made in total and given by SNRI to the Crossbone Vanguard. In order to cover this secret dealing, they were assigned the codes X-0, XM-X1, XM-X2, and XM-X3 and given the name Crossbone Gundam.
