New Solari Empire Update:
First sign of this new species is a small ship in Ross 47, behaving like a geo survey ship. (Ross 47 is three jumps and maybe 8bn km from Sol.) Interviews and autopsies of the crew and analysis of the wreckage tell us little: They're a high-gravity species who call themselves the Regulus.
A pretty talented diplomatic team very quickly threw in the towel, announcing that no communication was possible.
We spent the better part of a year tuning up our ships and preparing ammunition for the invasion, and deployed several survey ships to the area to search for the Regulus homeworld. Nothing within 1 jump of Ross 47. Nothing within 2 jumps. Eventually we find it 3 jumps from Ross 47 and six jumps from Sol. (Sol->Proxima Centauri->The Expanse->Ross 47->Crossroads->Okinawa->Regulus). They've got about three dozen ships sitting directly on their JG which poses a problem since we employ only missile boats that, despite their heavy armor, won't do well in a fight at close range owing to their launch reload times (600 seconds on the current generation of battlecruisers.)
Fortunately, despite the impossibility of communication and our destruction of their surveyor, relations remained calm and then warmed a bit when they offered trade access. This was a surprise. We'd imagined that since communication was impossible, implacable hostility must necessarily follow, but it was a welcome surprise since it offered a solution to our breaking-through-the-JG problem.
We prepared listening posts in Crossroads and Ross 47, and a fuel depot in Ross 47. We rolled all our warships up into one big fleet and sent it in. Three command cruisers, nine missile-defense cruisers, twelve missile cruisers, and three colliers. All ships are 16,000 tons and travel at 8,750 kps on Internal Confinement Fusion drives, and the fleet totals 480 size-5 launchers (reload 600s) and 420 size-1 antimissile launchers (reload 5s.) Total ammo load is around 3000 "Harpoon Mk3" anti-ship missiles (warhead 16, range ~190mkm) and about 9,000 "Nike Mk2" antimissiles (speed 57,600, MR 49).
We jumped in to Regulus to find their fleet still sitting on the Okinawa JG just as we'd first seen them a year earlier. Despite the sudden arrival of 384,000 tons of fast-moving warship with actives on, they didn't react. We moved to a position about 160m km away and then opened fire.
The Regulus ships turned out to be made of tissue paper. Slow-moving tissue paper. Nothing bigger than a FAC was observed moving at speeds greater than 1,500kps, and their FACs didn't reach 3,000. We destroyed everything at the gate--about a dozen 15,000-tonners and then maybe two dozen 7500-tonners, then a handful of stragglers as we advanced on the homeworld. There we demolished what was most likely a bunch of civilian ships, though it's hard to say for sure since they weren't noticeably slower or thinner-skinned than the ships we'd met at the Okinawa gate.
It took about a quarter of our available ammunition to destroy their entire fleet. Later analysis suggests that we used 2-3 times as much ammo as the job required. Near as we can tell, they didn't get a shot off.
Fearing nothing that might emerge from it, we've left their (extremely large: ~1.3 million tons) shipyard complex intact. First infantry and third armored divisions are on en route.
During these preparations we made first contact with another bizarre species we're calling the Tyranids, mostly in a cluster of systems near Tau Ceti (about four jumps from Ross 47.) Like the Necrons, their ships leave no lifepods. Unlike the Necrons they leave no wreckage. We've encountered two 60,000-ton supercarriers toting 800-ton FACs, and a 20,000-tonner that we don't know what it does because we killed it from long range before it did whatever it was going to do.
Our Harpoon missiles can kill these, but they're poorly shaped for the task. It takes several hundred to kill the supercarriers, and they manage only 50% hits against the FACs. We've created two new missiles for dealing with Tyranids: The slow, long-range "Tomahawk" missile with a 25-strength warhead for killing slow-moving heavies like those carriers, and short-range fast-moving "Sparrow" missile for killing FACs. (warhead 18, range 54mkm, maneuver 21, speed 40,000.)
Nids don't move around much. Once spotted, they wait patiently where we found them while we go home and get a rock to drop on them.
