Resources are gathered on planets you encounter and then turned into usable materials and tools in processing modules. Elements such as Iron, Copper, Uranium and Plutonium must be mined from planets and then refined on-board your ship. These will be utilized to build new modules, weapons, clones and tools.
However, with each trip the harvester can bring back hitchhikers.
Resources can be divided into four main categories, ship resources, weapon resources, travel resources, and plants.