For years, I have had a theory that Hideo Kojima’s two video game franchises, Metal Gear Solid and Zone of the Enders, were part of the same universe, but were set at different times in the Kojima universe.
It is highly possible that the design specifications for Metal Gear Ray (http://metalgear.wikia.com/wiki/Metal_Gear_RAY_(manned)) were used after the events of METAL GEAR SOLID 4: THE GUNS OF THE PATRIOTS (http://metalgear.wikia.com/wiki/Metal_Gear_Solid_4:_Guns_of_the_Patriots).
The Orbital Frame program (http://zoneoftheenders.wikia.com/wiki/Orbital_Frame), in conjunction with the Metatron Ore program (http://zoneoftheenders.wikia.com/wiki/Metatron) later gave rise to the creation of powerful Orbital Frame units.
and Neith (http://zoneoftheenders.wikia.com/wiki/Neith).
Furthermore, there might exist a familial link between the former child soldier known as Jack/Raiden (http://metalgear.wikia.com/wiki/Raiden) and Dingo Egret (http://zoneoftheenders.wikia.com/wiki/Dingo_Egret).
Perhaps Dingo Egret is a direct descendant of Jack/Raiden through his son, Jack.