Spacecraft reentry is the process of a spacecraft returning to Earth's atmosphere from space. During reentry, the spacecraft encounters intense heat and pressure due to friction with the atmosphere. To protect against this, spacecraft are equipped with heat shields that absorb and dissipate the heat generated. The reentry trajectory is carefully calculated to ensure a safe landing. If the angle is too steep, the spacecraft may burn up; if too shallow, it could skip off the atmosphere. Successful reentry is crucial for missions involving astronauts, such as those conducted by NASA or SpaceX.