Space studies, which started in the Cold War environment, moved to a new stage with the participation of private sector in the 21st century. Space companies established in the US and in other countries began their studies with measures to reduce the cost of space-related research on space agencies. One of the important benefits of this study was the success of companies such as Space X and Blue Origin for re-usable rockets. Private space and aerospace companies, which started commercial flights, developed rocket and related vehicles of space agencies carrying low orbit and orbiting satellites and other vehicles. These companies also head for the projects in the fields of space mining and space tourism.