"귀환기체" (Gwi-hwan-gi-che) refers to a type of spacecraft designed for re-entry into a planetary atmosphere. This technology is crucial for missions returning from space, as it ensures the safe descent and landing of vehicles like the Space Shuttle or Mars rovers. The design of 귀환기체 typically includes heat shields to protect against extreme temperatures during re-entry. These spacecraft must also be aerodynamically shaped to manage the forces encountered when entering an atmosphere at high speeds, making them essential for successful space exploration and return missions.