Getting to orbit takes nine minutes of violence. Getting back means shedding all of that speed with no engine to spare — so spacecraft do something audacious: they use the air itself as the brake.
The energy has to go somewhere
A returning spacecraft carries the full speed of orbit — 7.8 kilometers per second, about 25 times the speed of sound. Carrying enough fuel to burn all that speed away would take a rocket nearly as big as the one that launched it, so capsules fire their engines only briefly, just enough to dip into the upper atmosphere. From there the air does the braking — and the price is that all that energy of motion becomes heat, concentrated around one small falling object.
The blunt-body surprise
Intuition says a returning craft should be needle-nosed and sleek. The opposite is true, and the discovery — made in the 1950s — saved every astronaut since: a blunt, rounded shape pushes a shock wave out ahead of itself, and that cushion of compressed air keeps the hottest gas standing off the surface rather than touching it. It's why every crew capsule from Apollo to Dragon to Orion is shaped like a gumdrop falling bottom-first. The air just ahead of the shield is heated into glowing plasma at thousands of degrees — hotter than the surface of the Sun in places — while inches away the crew ride in shirtsleeves.
Minutes of fire, then silence
The plasma sheath has a famous side effect: it blocks radio. For several minutes, mission control simply waits — through the era of ocean splashdowns, those blackout minutes were the longest of every flight. Lunar returns raise the stakes further: a capsule coming back from the Moon hits the air at nearly 11 km/s, so Orion flies a skip entry, dipping into the atmosphere and porpoising back out once to bleed off speed, like a stone skipped across a pond. Only after the fire comes the laundry: drogue chutes, then mains, slowing a capsule from twice the speed of sound to a splashdown gentler than a carnival ride.
Why reentry is the frontier again
Reentry is also where reusability faces its hardest exam. The Shuttle protected itself with thousands of fragile ceramic tiles; Starship is attempting the same idea at far larger scale, with steel structure and rapid-turnaround ambitions — and its test flights have shown, in public, exactly how unforgiving the regime is: flaps burning through, tiles shedding, each flight ending with better data. Watch any booster or capsule return on the Live page and you're watching the oldest unsolved trade in spaceflight: speed for heat, heat for home.