So, I've seen a few references to an Orbital Ring.
I already know Gundam 00's involved, but..... Tekkaman Blade, perhaps?
A space ship named Argos went missing. Of course its Tekkaman.
Lets see if I can't guess what other series are being used here... Obviously, there's Geass, Evangelion, Tekkaman Blade, Gundam Wing, Gundam 00, and Fafner. Currently, things are extremely real-heavy, so I'm wondering what supers are lurking behind the scenes.
This being Super Robot Wars, some version of Mazinger is almost certain. There's no mention of Photon Power or any of the Mazinger villains, its so probably Mazinkaiser SKL with Death Caprice being used as elite special forces by one of the three powers (Britannia?), or by Mithril if FMP's in. Getter Robo may or may not be around somewhere, probably in its New or Manga incarnations. There was mention of two unknown robots fighting in the Rule Britannia route, so that might be something not on the list? It can't be Eva-01, Britannia would know about it if that was the case since Emperormoto's definitely a member of SEELE, and Blade isn't big enough to be classed as a mech.
Unfortunately since a lot of super robots are built by secret organizations we're probably not going to get any hints about them until they decide to reveal themselves. I just really, really hope that one of them isn't Zambot 3. That would be bad, for many reasons.