Clans - it is an association of players without their own galaxy. Only the owner and his authorized Clan leaders can accept new members, as well as exclude existing ones. A Clan can have from 1 to 10 members. Clan creation is paid. Clan members cannot attack each other. To join a Clan, you must select it in Clan list and apply for membership.
Corporation - it is an association of players with their own corporate galaxy. Only the owner and his authorized managers of the Corporation can accept new members, as well as exclude existing ones. The Corporation can have from 1 to 100 members. The creation of the Corporation is paid. Corporation members cannot attack each other. To join the Corporation, you must select it in list of Corporations and apply for membership.
The main advantage of Clans and Corporations is the ability to build Space Stations in the orbit of stars and mine the Solarium on them, build trade Spaceports for processing minerals brought by other players into Energy.
Any player in the open world who has already graduated from a Clan or a Corporation can apply to join Academies.
Alliance - it is an association of Corporations and / or Clans. Only owners of Corporations and Clans can create Alliances (enter and leave them). The Alliance can have from 2 to 10 Corporations and Clans. Alliance members cannot attack each other.
Below is the difference between Clans and Corporations and their characteristics.