My thought with the vague outline I gave above was to have things less clearly demarcated than that – but if you are playing the Space Captain of an Imperial Space Battleship then you have... Well, a Space Battleship, you are also probably the cousin of somebody who is more traditionally a Space Countess, but you are at least allegedly trying to further the goals of the Space Emperor.
Actual physical contact rather than minimal communication with the Space Empire is 20 years away though and Space Battleships need Space Fuel and Space Ammunition to keep going, you also probably need Space Conscripts to keep the thing crewed or to invade planets. A Space Count cannot just conscript you though – you have contacts, you have some kind of authority from the nominal superior power, you have a Space Battleship.
The same for the person who is the Space Governor, no doubt separated from the Space Battleships quite deliberately. Nominally, people have to do what you say, you can send nastigrams about them back to the Space Emperor as well, but your direct power would be rather limited. On the other hand if you send messages to the Space Emperor about how great somebody is then that is a huge boon to them and their family and you no doubt have your own personal resources as well as the right to say, tax all interstellar trade by 15%. Maybe you also have terrifying auditors.
So, now added, some thoughts on resources and economy to try to keep it simple and encourage people to do stuff.
Basic resources would be:
Manpower – Retainers, conscripts or volunteers, access to people for projects like manning factories, staffing Moon Palaces or forming military units. NOT transferable.
Slaves– Manpower can be converted into slaves but not back again, can also be used for manning factories, staffing moon palaces or forming Janissary type military units but in a more limited manner, can also be transferred or traded freely.
Wealth – Money, mundane manufactured goods, used for construction projects, building low tech space craft, equipping armies, hosting lavish parties.
Rare Elements – Used to make high tech items in a starship's nano factory. A Space Noble's panoply, small spacecraft, the high tier stuff used by Space Nobles personally.
Social resources would be:
Prestige – How socially important you are and are expected to be in future, can be gained through extravagant spending and decadence, hosting, demonstrating Imperial Favour and holding important offices. Can be used to influence NPCs or destroy other people's social resources (either Glory or Prestige)
Glory – How badass you are and how much you are seen to embody the ideal Space Noble, gained by fighting Space Elves, crushing revolts, winning duels or showing people up in other contests or demonstrations of skill and ability. Win the Grand Dance Off at the big party? Glory. The more Glory you have the easier it is to gain Prestige and the harder it is for people to make you lose either Glory or Prestige, it applies as a modifier to gains/losses of the previous.
You would gain Manpower by having authority over substantial human populations, this is extremely large scale. 1 point of Manpower is enough to start raising a battalion (say 400 ish) of Space Soldiers, man a Space Frigate or convert into say a thousand random semi skilled slaves. Big military formations will have a Manpower upkeep. You are also likely to need Manpower components to big projects like establishing Space Stations or staffing Moon Palaces.
To get a point of Manpower an interval (say a month) you need to control a decent sized city or a populated space station. You can also convert Manpower into Wealth or Prestige on a 1:1 basis to represent having people do productive things such as work on your plantations or stand around wearing uniforms at your fancy ball.
Slaves are transferable manpower! So you might well find other PCs who need manpower but have something else and are willing to trade, they make worse military units than normal manpower (though this can certainly be offset by stuff like shipping them to alien worlds and using them to brutally suppress the natives they feel no connection to). Turning your Manpower income into slaves might make native populations resent you more though.
Wealth comes from trade, industry, tariffs and taxes, most Space Nobles who control stuff are going to have an income of Wealth points. This is biased toward control of off world resources and trade stations, somebody who rules a prosperous orbital city might only have a Manpower income of 1 but have a Wealth income of 10, the ruler of a continent with a population of a hundred million might have a Manpower income of 10 but a Wealth of 3. A single unit of Wealth is required every interval for a Space Noble to live in minimum suitable social style and extravagance, with no real upper limit to the scaling, perhaps every time you double this you get an extra point of Prestige that interval.
Two points might be required to outfit a battalion of Space Soldiers, three for a really nicely armed battalion of Space Soldiers. Five for a small warship (Not a Space Noble warship, a more expendable one). A Moon Palace might need a hundred, plus Manpower and Rare Elements.
Rare Elements would come from mining and only in limited locations, so certain (otherwise horrible) star systems would have Space Mines for people to control, possibly ones which consume Manpower at a steady rate (Hello slaves!). Maintaining Space Noble nanoships would need a trickle of Rare Elements, repairing them substantially more. A single point of Rare Elements would allow a nanoship to manufacture a full panoply of Space Noble grade gear (Space Armour, Space Shield, Space Sword, Space Smart Dress, Space Cufflinks, etc) for one person. More to allow outfitting of Moon Palace suites for supreme luxury or to build in special security or entertainment arrangements beyond the regular level of advanced technology, significant quantities to make smaller spacecraft (Say, 5 man corvettes for going off on personal level Space Adventures)
Incomes of these points would be reverse exponential thanks to inefficiencies in administration and abstracted stuff – the person who rules a good sized city might get 1 Manpower a month, the person who rules an entire world with a billion people might get 20, so at a certain point just grabbing MORE would be inefficient compared to handing out good sized chunks of your stuff to people in return for their support.