reentrada

Reentrada, or reentry, is the phase in which a spacecraft returns from space to a planet’s atmosphere. It follows the departure from orbit or interplanetary travel and ends with landing or splashdown. The term also describes natural entries of meteoroids into planetary atmospheres, which produce visible meteors when they heat up and disintegrate.

During reentry, the vehicle travels at hypersonic speeds through the upper atmosphere, creating a strong shock layer and a hot, ionized plasma around the craft. Aerothermal heating is a central challenge, requiring effective thermal protection. Spacecraft use a thermal protection system (TPS) consisting of heat shields, insulating materials, and sometimes ablative layers that carry away heat and protect structural components. The design of the TPS and the vehicle’s shape aims to minimize heat transfer while keeping mass and aerodynamic requirements manageable.

Entry dynamics are governed by the entry angle and velocity. A shallow angle can cause a long, shallow deceleration or even skip out of the atmosphere, while an overly steep angle increases heat load and mechanical stress. Deceleration typically spans tens of seconds to a few minutes and can impose several g’s of force on occupants or equipment, depending on the vehicle and trajectory.

Controlled reentries are planned with precise trajectories and guidance to ensure a safe landing or recovery area. Uncontrolled reentries, though relatively rare for crewed missions, can scatter debris; most large fragments burn up, with only a small portion reaching the surface.

Reentry remains a critical phase in mission design, balancing thermal protection, structural integrity, and survivable deceleration to achieve a safe conclusion of the mission.