What are the ongoing costs of ships?

[Jumpp (OP)]

I'm trying to wrap my head around the ongoing costs of ships.  I think I've got a handle on their fuel and ammo use, and probably their use of maintenance supplies while in the field.  I'm wondering what other costs there might be.  I see an item for "Maintenance Facility Operation" on the Wealth/Trade tab of the Population and Production Tab, but I haven't been able to find any information about exactly what that number represents and how it's computed.

Can anyone shed some light on that, and any other hidden ongoing costs of ownership that I might be overlooking?

[Nathan_]

Its probably the amount of minerals(1 wealth for 1 mineral) you spent to maintain your fleet.

[Conscript Gary]

Yeah, maintenance facilities consume minerals to freeze the maintenance clock of ships in orbit at or below their size rating

[Prince of Space]

The estimated annual mineral requirements for maintenance facilities in the mining/maintenance tab is equal to 0.5% of the mineral cost of the ships supported by the maintenance facilities. The yearly wealth expenditure for maintenance facility operation on the wealth/trade tab is equal to the total mineral cost back in the maintenance table, at least in my save. There may be corner case rules that don't apply in my case.

So ships have an ongoing cost in minerals and wealth. You could avoid this by parking the ships in hangar PDCs instead, but they'll cost minerals up front.

[Jumpp (OP)]

That's exactly the kind of answer I was hoping for.  That's very helpful.  Thank you.