A few game years ago, I encountered my first (5.42) alien ship just drifting between two jump points. It was completely stationary, and largely remained so for the following years. I had a scout on station to keep an eye on it, but nothing ever happened. Here's the observation data I ultimately gathered:
Cross section: 274
Estimated tonnage: 13700
Thermal signature: 2250
Observed speed: 8211 km/s
Estimated speed: 8211 km/s
Armour: 3
ECM: 30
Given it's puzzling nature, I eventually managed to build a couple of dropship-equipped assault carriers to try and capture it. Despite its tonnage and impressive speed, the vessel didn't appear to be armed, as it tried to flee whenever one of my ships tried to get closer than 30 million km or so. My first attempt speed failed largely due to the insufficient speed ratio between the target and my dropships (25k+ km/s). On my second try, a year or so later, I employed a squadron of HPM-armed corvettes: the ship came to a stop presumably when it couldn't see my units, so to infinitely boost the ratio for boarding, I would have the corvettes blind it.
That part of the operation went well, if a bit bizarrely. As far as I understood, microwaves weren't supposed to damage anything but electronics. However, somehow, they gradually slowed the target down through sustained fire and even caused a secondary explosion, meaning they were possibly damaging engines and/or potential reactors.
So once I had the alien vessel down to 455 km/s, I sent in the dropships. The 10 companies of marines landed perfectly, yet they ended up fighting a slow, losing battle. My ground unit strength technology was 25, and I had thought it was enough. But it wasn't, and eventually all my marines perished. I had the aliens vaporized with missiles in anger, despite surprisingly capable CIWS.
But now I'll never know (at least by conventional means) why the ship remained there all those years. Given the advanced technology and crew fighting strength, I assume it was a Precursor vessel that either ran out of ammunition, broke its jump drive and/or was damaged in a battle against an unknown NPR. But as far as I know, all Precursor ships are armed, and either this one got heavy damage exclusively to its armament (my corvettes went in as close as 10,000 km to fire on it, and the target never shot back) or wasn't a Precursor at all.
Thoughts? Opinions?
Facts?