Exploration Stations are stations that are designed to cruise the solar system. They typically have enough resources to last on their own without being resupplied for a long period of time. New stations can also have Airlocks, as the crew would likely have to perform spacewalks to repair the ship from time to time. Some stations would also have landers and capsules for exploring planets.
With the new standalone station parts, exploration stations can now be much more compact as they do not need room for separate large solar panels and engines.For those who have purchased them, Transponders may be useful too, considering that the station will be moved about frequently.