A major concept in ES2 are "resources" - special substances of great commercial, industrial, and scientific import. These can be acquired and stockpiled, and can be used for a variety of benefits. They're tracked as numerical quantities measuring the size of your current stockpile (a stark contrast to some famous games like Civilization 5 and 6, which track some resources by the number of 'sources' you have available), and can be bought, found, traded, or harvested (in an infinitely renewable manner) from deposits on planets you have access to.
Resources are broadly divided into two categories, "Strategic" and "Luxury", based on how they're used, but outside of usage, the mechanics behind them are largely identical.
