1. Reentry vehicles are objects containing nuclear warheads. They are released from the last stage of a booster rocket or from a post-boost vehicle early in the ballistic trajectory. They are thermally insulated to survive rapid heating during the high velocities of reentry into the atmosphere, and are designed to protect their contents until detonation at their targets. 2. That part of a space vehicle designed to re-enter the Earth’s atmosphere n the terminal portion of its trajectory.