Coming back is harder than leaving. A spacecraft in orbit moves at roughly 7.8 kilometres per second. Slowing down means converting that kinetic energy into heat, and the atmosphere is the only brake available.

The vehicle enters at a shallow angle, compressing air ahead of it into plasma. Temperatures reach thousands of degrees. Heat shields absorb or shed that energy while the structure underneath stays cool enough to survive.

Reentry profiles

• Ballistic reentry, steep and fast
• Lifting reentry, using vehicle shape for control
• Skip reentry, bouncing off the atmosphere once
• Aerobraking, repeated shallow passes to slow gradually

Communications black out during the hottest phase because plasma blocks radio signals. Controllers wait through the silence, watching radar and hoping the vehicle emerges on the other side.