All stations can be seen on 'Map', after you dock. Map is divided on 16 "sectors" and each of 200 stations can be found within those sectors.
Based on location, every station has it's own marine life (and therefore, different trade prices for certain products). Also, every station has different technology level (with maximum 10). Stations with higher technology level are more likely to have better equipment in hangar and for better price.
Stations can be found on different depths between radiation and pressure, some not reachable until later in progress. At the very beginning of game, your first ship will be able to reach between 2000 and 2500 units, which is first and safe diving zone. Between 20k and 15k is first zone of radiation, while everything after 15k must be played carefully. Pressure zone starts between 25k and 30k (first zone) and 30k- (second zone). The only stations known to be in those high limits are Contact One and Loyalty Two, know for their super high tech levels. All ships and other equipment can be found on those two stations.Some of the stations play key role in story, while others are free to visit by will.