With no resistance evident and no way to demand surrender, Bellerophon's captain, Commander Valentine Lamarliere, ordered his tactical officer to turn all available weapons on the alien, obliterating it in a hail of fire.
Have you thought at all about surrender mechanisms? I've run into this situation a lot - I ambush an unarmed survey vessel (silly aliens - always trying to survey the same survey point...), knock out all its engines, then have to destroy the hulk because there's no way to demand or recognize surrender. I like the idea of boarding shuttles and boarding parties/marines, but realize that's a bit much on the coding side....
The aliens were humanoid in shape, although taller than humans, and had a knobbly, chitinous exoskeleton covering their entire body.
How did your race figure this out? The "Races" (ctrl-F2) screen doesn't show any computer-controlled NPR for me, even if they've been contacted/captured. (BTW, I'm expecting an answer of "I used my deity-like powers as the author of the game :-)" )
BTW, I've also not yet seen any intel come out of prisoner interrogations, even though I've probably captured prisoners from 20-30 ships from this race (although I forgot to attempt communications for a long time, so only 10 pickups might have happened since I had comm established).
Guessing it was too small to be a warship, Rear Admiral Gilles assumed it was some type of scout or survey ship and ordered the launch of a single volley of ten SS-N-2 Sunburns. Forty-two minutes later, with no sign of defensive fire, the missiles reached the alien vessel. Despite almost a fifty percent chance to hit, only two missiles struck their target, both of which resulted in atmosphere loss.
I noticed a similar effect (few hits from big salvo) when ambushing survey ships. To counter-act it, I've started using ripple-fire volleys, where I fire one missile every 5 seconds for a fleeing or stationary target (for a closing target, I would probably use a 10 second spacing). The advantage of this is that the first hit slows down the target, raising the hit probability of follow-on missiles. The ripple fire is a bit of a micro-management pain to control, though, since you have to advance in 5-second increments and change launcher assignments every timestep. I suspect you wouldn't want to ripple-fire at a target that had anti-missile defenses, though :-)
John