Unidentified signal sources (USS)When Super-cruising around, you may notice some unidentified signal sources. These are basically random events which you can choose to ignore or not. To enter a USS event, do the same you would when reaching - get within 1.0km, and disengage super-cruise. Sometimes you can find cargo, hostile ships, etc. its random. If you are trying to farm USS, reduce your speed in super-cruise and wait them to spawn (they will spawn very close-by).
There are also various strengths such as weak signal sources and strong signal sources. These offer different levels of challenges.
Although to be honest I havnt really found much at USS events.