WIthin Influence a single crewmate allows you to play, however, each account can have any number of crews. Having uniqure compositions of various crewmates within your crew will allow you to take different types of actions with increased or decreased effciency.
Having at least one of a crewmate class within your crew will allow you to take that crewmate class's actions at 100% effciency. If you lack a crewmate class that class's actions will be reduced to 50% efficency.
Example: You have a crew with no miners. This would mean that all extraction and core sampling actions would have their time increased per cycle and the abundance of deposits reduced. This would make it extrmeely difficult to be competitive at mining actions.
The impact on the efficiency of each action, based on the number of class-aligned Crewmates present on a crew: