Mining capabilities

If a ship has mining capabilities, it can utilize onboard systems to synthesize fuel and/or raw materials which are contained within nebulas, asteroids and other spacial objects which flying.

Nebulas
Nebulas are a great source of fuel containing vast amounts of hydrogen and helium.

Black Holes
Dangerous, but extremely profitable, extracting anti-matter and matter from black holes can be incredibly valuable. Such materials are hard to store, but allow unparralelled amount of power so much so that only a few units can run an entire fleet for weeks. Ships able to extract from black holes are few and far between, and many which go in to attempt such extraction fail, or worse, are sucked into the blackholes depth to their untimely demise.

General Asteroids
Asteroids come in many different forms but many contain the 3 basic raw materials: These materials are used (after and before refining) as building materials, possible fuels and construction metals for starships.