Note: I am still somewhere around the early parts of the game, having befriended several of the alien species. I am unsure about any details of the victory condition (and in fact don't even know if there is one), and have only vague ideas about the overarching mysteries of the game. I would greatly appreciate hiding any spoilers from myself or others who are interested.
I am curious about whether it is possible to beat the game without visiting the human outpost altogether? AFAIK, it would be possible to get enough fuel from the Melnorme traders to last a long while if the player knew what they were doing.
If that is not possible, is it possible to avoid getting the radioactives from the Sol system? Let's say that the player's lander is destroyed on Mercury while having all the radioactives onboard, and they accidentally shoot any others they come across in the system. Is continuing from this point possible? What if the player has only a single unit of fuel?
These questions assume that the player will win all fights with the accompanying Earthling Cruiser, without any losses. However, not with the flagship (without great improvements).
Best Answer
Disclaimer: I did not test this with the original game but with the open source clone The Ur-Quan Masters. While it is based on the original sourcecode and known to be extremely faithful to the original, there is no guarantee that it is mechanically identical to it in every regard.
No, but you can get pretty far... theoretically. You problem number one is that you will likely get ripped apart by Slylandro probes. For unexplained reasons they will be far more numerous before allying with the outpost. Also, without the outpost you won't be able to get any replacement crewmembers, new flagship modules or new landers.
But when you somehow manage to survive under these conditions, you can theoretically get most things done in the game. If you want to give it a try: A source of bio-matter nearby to pay the Melnorme for fuel is the nearby Alpha Wolf system.
Unfortunately you can't finish the game. In order to do so you will need a special module on your flagship which needs to be installed at the outpost.
It doesn't matter where you get the material. An alternative source nearby is Gamma Centauri I which you can just about reach with the 10 units of fuel you start out with... if you get past the Slylandro probes.
Until then, the base is a source of free landers (if you have none) and free fuel (if you are barely out).
Return to the starbase and they will give you a new one.