How far-fetched would it be to find small Combined Army forces in Sol system, within Earth itself even? I was wondering about some narrative ideas I have had and it occurred to me that while it might be astronomically unlikely for the CA to have made it there, it could possibly happen. They would have to go first through Acheron and then either the Daybreak, Sheyk or Abyss blockades, and finally make it through the next jump to Sol, but considering we already have seen them in Dawn and the Human Edge it does not seem like a complete impossibility, especially as I doubt the wormholes out of Bourak, Dawn and the Edge are anywhere near as well guarded. Am I crazy?
Frankly speaking, Sol is just a sentimentality. "Space United Nations" is in Concilium, and what the CA looks for is the Tzechi Digestor, currently in the Toybox installation which location is not known by anyone but those running supply runs there... And if I were in charge, the supply runs (and personnel transportation) would be made using Aleph Aspects that can have the location removed after the end of the run, while the only way to get out would be in those supply runs (aboard an opaque cargo pod), or in case of destruction of the installation via resurrection. Then each faction has its own capital planet/city. So no, the CA would have no interest into reaching Sol unless the Toybox were to be there, and considering how much empty space there is in the Human Sphere, it would be more logical to locate it somewhere else, since humanity knows the CA wants that thing.
Sol and the other "capital" worlds should be fine unless something were to happen like one of the most capable and reputable smugglers in the Human Sphere being replaced by a Shasvaasti Naish. Oh no...
I'm not as concerned with whether they would want to as with whether they are able. I'm not about to write a campaign about the Penny Arcade, which is the current mainline narrative, to later have it invalidated by official materials. Let's just say if there were a mcguffin on Earth, could the EI send people to nab it? I think it's not too crazy That makes perfect sense!
It's possible, and would potentially be good to scare the hell out of the civilians. But for anything more militarily significant, unless the Toy Box is in Sol, there's not much point in the Combined Army reaching for Sol. IIRC, Sol is also several jumps from Paradiso, so there's multiple sets of 'customs inspections' to have to pass, as well.
Wouldn't they need to get smuggled into a Circular, and then get past Sol's inspections? Certainly, to have control of one of the most succesfull and extended smuggling rings is a great success for the CA. However, I think it was mentioned that "Aïda Swanson" had trouble separating the shasvastii from the human, being more of a messed up merge than a clean mask (I think it might be akin to Spock mind-melding with Bones in Star Treck)
Is it necessary that the CA forces be alien forces? We have two examples of humans joining the CA (either willingly or not). How difficult would it be to turn some Paradiso citizens that could then travel the human sphere as displaced refugees? They could smuggle software, setting up an attack on Human Sphere infosystems. With human assets, you may need some alien handlers, but a small number of aliens could probably make it through at an acceptable casualty rate.
The blockades protecting the Sphere from the Combined Army are at least a little porous... you have Swanson, the Nomad ship carrying Shasvastii in Wotan (and a Combined Army carrier making it all the way through the Paradiso system and whatever defenses are on the OTHER side of the Wotan gate), the existence of Shasvastii ships with significant stealth capabilities, and the movement of lots of materiel and agents from Paradiso to Novyy Bangkok in Human Edge. Earth has a number of vulnerabilities for low-level infiltration... being home to several Sphere powers, and a whole slew of minor nations, the sort of customs inspection regimes that might catch an infiltration will have weaknesses rare elsewhere: ability to exploit jurisdictional disputes as cover, ability to pick the weakest of several choices in order to get planetside or set up front companies, lack of full cooperation among local authorities which could see the pattern revealed by the operation's inevitable slip-ups. I don't think it is a big military target, there are other planets and targets whose destruction helps the CA's invasion effort more, even something like what was hinted as being done on Novyy Bangkok might be too large. But for small operations, intel gathering, sowing discord within humanity, sabotaging or stealing technologies the EI sees as important, etc, having Combined Army agents active seems very conceivable.
Sounds like a good plot for an alternate future fan-fiction. I've been thinking of writing something based off a similar idea to this. A future where the E.I. pushes far deep into the Human Sphere effecting all the planets with warfare but is stop miraculously before it is able to reach the Sol system. Then Humanity must begin a recolonizing effort to drive the Combined remnants and reclaim their lost planets in the Human Sphere and reach Paradiso once again.
Those are really good points. Earth would be an infiltrator's dream. "Oh, I'm from [ planet/system/Nomad weirdness ]" is a really good excuse for not quite grokking the dominant culture. It's even applicable inside the US (claim to be from someplace like Cali, or somewhere in the middle of the country, totally different cultures)
Dropfleet is probably one of the most interesting concepts, as you are fighting in very low orbits, as opposed to most other game's deep space.