Okay, this keeps popping up in my feed due to the up-votes, so I was finally motivated to research this one myself. Here's what I've found:
The F.S.S Beagle, exploratory vessel of the Galactic Federation - Captain Bork Riesling, commanding - was the crashed starship in Blackmoor... aka: the City of the Gods (Module DA3).
The marooned F.S.S Beagle was also revealed in DA3 as the origin of another famous Blackmoor character: St. Stephan (of the Temple of the Frog), whose previous mention (in Supplement II) listed only the following:
This fellow is not from the world of Blackmoor at all, but rather he is an intelligent humanoid from another world/dimension.
Dave Arneson, creator of the Blackmoor setting and campaign was quoted as saying:
John [Snider], the author (of the Star Probe and Star Empires games, the basis of an ongoing concurrent campaign), was another of the original [Blackmoor] group. He had outlined a whole series of books and maps.
Greg Svenson is quoted with:
My recollection is that it was a crossover from our parallel "Star Empires" campaign that John Snider was running (from early 1973 to late 1974 or so, when John went into the Army). There was an RPG component to "Star Empires" which we were also playing, but TSR never published it. We had several encounters with scout ships from the neighboring galactic empires before the world Blackmoor is on was quarantined by the local galactic government, I can't remember which empire controlled it.
Greg Svenson also recollects the following useful information:
There were eight major empires. Three were humanoid empires with one each of ursoid (bears), feline (cats), avian(birds), amoboid (amoebas) and icthioid (fish). There were also a variety of minor empires with just a couple of worlds inhabited by exotic races (along with the normal ones above) [...] We had encounters in Blackmoor with both human and avian scouts (Scott Belfry ran the avian empire). I remember someone getting a 'magic cape' that allowed the wearer to fly (the avians wings were no longer functional, so they created alternate ways to fly). The Blue Rider's armor was a suit of powered Battledress. I was running a galactic empire controlled by a race of ursoids
[The Star System]was almost immediately quarantined due to the loss of several scout ships from two empires, one human and one avian...
This then, is the extent of the information that I can find, to this date. Please note the link to the official Star Empires website... if you want to get involved, that is the spot for you.
Star Probe game
Star Empires game
The official Star Empires web site (Note that the last activity seems to be quite a while ago.)