The origins of what would become the IR-22 began when the UEPC put out a contract for a fixed-purpose Space-marine combat Axel, as at the time (and still the case today) the UEPC lacked a definitive unit that could combat equally in ground and space (The KR-14 had been filling this role ever since the moon seceded from Earth control). Eventually the contract proposals became inadequate to fill the task, and the competition ended.
As a side-effect of the research into 'acclimatizing' an Axel to joint space-land warfare, Skeleton 97A was conceived in the German Branch of the Mobile Armor Division at the Munich base. Largely constructed as an alloy and frame study model (in miniature), after the Space-Marine project fell through the design team reconsidered the frame and developed a full axel around this miniaturized prototype. The resultant design was designated "Trial-98" and put through a prototype stage, simultaneously proposed to the UEPC's Defense Board.
At the time the UEPC was still operating VT-8s, which were showing almost eight decades of continuous use and were being outclassed by newer Axels in the lighter categories. Trial-98 not only was a newer design at the higher end of Axel weight, but it also incorporated newer features with standard materials and at adequate costs. The fact that Trial-98 was a little more expensive than the VT-8s was inconsequential, since it was felt the new design was worth it in terms of performance. Trial-98 completed its prototype phase and was adopted for production.
As a side-effect of space adaptability research the Axel does have some improved characteristics in space handling. The movement of its mass in the limbs and legs not only save fuel costs when in space, but also make the unit an agile fighter on land. While not the lightest Axel in UEPC service, it can hold its own during a scouting mission and in packs can prove quite deadly.