I am presently running a little side campaign using Stars Without Number. "Voyage of the Albatross" isn't actually the campaign's name, but it's not a bad point of reference.
I have only two players. Their characters are:
-Eaverin Raideen (5th level Psychic), a noble who belongs to one of the Hydrin Clans.
-Vrinn Hollow (5th level Qotah Expert), a former intelligence agent/hacker who joined the Clans.
Their NPC henchmen:
-Gustav Volkovic (3rd level Warrior), a mercenary rescued from captivity and hired on by the PCs.
-Dane Kestra Pedrana (3rd level Warrior), a Dane, or House Guard, of the Raideen Clan. She is the sworn protector of Eaverin and has been ordered to accompany him on his wanderings.
NPC Crew Hirelings:
-Sofia Lucullo, skilled pilot/navigator, rescued from the same pirates who held Gustav.
-Adler Spiel, an engineer/mechanic who served on the same ship as Sofia. He was rescued from being turned into a zombie by a bizarre alien mold he accidentally unleashed while exploring some ruins.
The game is sandbox style. We're on the second "leg" of the campaign right now. Having completed an expedition into an alien culture that gained the attention of Houses Raideen and Sashara, the party has been granted a small vessel, the Albatross. The party is currently docked at the starport of Guangxi. They've run a job on the planet and discovered how morally...flexible...operatives are expected to be. The party was hired to reclaim an asteroid belt mining/processing facility for a corporation, only to find out that the opposition were slave miners who had risen up against their captors and a group of unusually altruistic warriors sworn to help them. Thanks to clever party, they managed to complete the job, save the miners, and befriend the warriors... (frankly, I expected them just to blast everyone, take the money, and run.) We'll see if they're able to navigate their next job as adroitly.
I was skeptical about running with such a small group at first, but it's growing on me. At any rate, being a GM is in my blood; I'm just not truly satisfied unless I'm running something.