In September 2016, Elon Musk's SpaceX presented an Interplanetary Transport System consisting of a spaceship and rockets to be used to colonize Mars. Space development by private organizations may commence in the near future. This paper summarizes an overview of simulation studies for space habitation and life support systems conducted by public and private organizations in facilities around the world, such as BIOS3, Biosphere 2, and Closed Ecology Experiment Facilities (CEEF). In addition, this paper describes the author's own simulation study and analog study regarding space habitation and life support systems. The computer simulation study was conducted to analyze mass flow inside CEEF. The analog simulation study was conducted at Mars Desert Research Station (MDRS) to know space habitation problems. The analog simulation study includes research on human metabolism, food science, and food production as well as an analog Extravehicular Activity (EVA) study similar to the MIT Haughton Mars Project conducted at Haughton Island. Finally, issues regarding design of a habitation system, a life support system, biomedical measurement system for keeping a crew healthy, EVA equipment, and an EVA navigation system on a planetary surface are compared with previous research conducted by other crews at the MDRS in the past.