The payload capacity of launch vehicles must be increased in order to allow the exploration and development of space to be extended from low-Earth orbit into the solar system. A propellant system using a cryogenic fluid such as liquid oxygen or liquid hydrogen must reduce the amount of unusable propellant due to evaporation and boiling. However, in the space exploration and development where safety and reliability of missions are critical, predictions of the boiling heat transfer of the present technology are not sufficiently reliable for thermal management design due to a lack of knowledge and relevant research. Therefore, the objective of this research is to understand and accurately predict boiling heat transfer by developing numerical simulation tool for two-phase flows that consider phase change. In this paper, some recent research activities toward the development of chill-down process simulation technology are presented.