Deorbit and re-entry Orbital spaceflight

returning spacecraft (including potentially manned craft) have find way of slowing down as possible while still in higher atmospheric layers , avoid hitting ground (lithobraking) or burning up. many orbital space flights, initial deceleration provided retrofiring of craft s rocket engines, perturbing orbit (by lowering perigee down atmosphere) onto suborbital trajectory. many spacecraft in low-earth orbit (e.g., nanosatellites or spacecraft have run out of station keeping fuel or otherwise non-functional) solve problem of deceleration orbital speeds through using atmospheric drag (aerobraking) provide initial deceleration. in cases, once initial deceleration has lowered orbital perigee mesosphere, spacecraft lose of remaining speed, , therefore kinetic energy, through atmospheric drag effect of aerobraking.

intentional aerobraking achieved orienting returning space craft present heat shields forward toward atmosphere protect against high temperatures generated atmospheric compression , friction caused passing through atmosphere @ hypersonic speeds. thermal energy dissipated compression heating air in shockwave ahead of vehicle using blunt heat shield shape, aim of minimising heat entering vehicle.

sub-orbital space flights, being @ lower speed, not generate anywhere near heat upon re-entry.

even if orbiting objects expendable, space authorities pushing toward controlled re-entries minimize hazard lives , property on planet.