First orbital-rocket landing

On 21 December 2015, after delivering 11 satellites toward orbit, a Falcon 9 first stage flipped around, reignited its engines, and flew back to a landing pad at Cape Canaveral, touching down upright in a column of fire. It was the first time an orbital-class rocket booster had ever been recovered intact after a launch.

For decades, reusing orbital rockets had been dismissed as impractical; two earlier SpaceX attempts on a drone ship had ended in crashes. The 2015 landing changed the economics of spaceflight permanently. The first stage is the single most expensive part of the rocket — recovering and reflying it is the difference between throwing away an airliner after one flight and operating it for years.

This is the foundation on which the entire modern launch market rests, and the reason SpaceX can launch more often, and more cheaply, than any nation on Earth.