Friction normally slows things down. But atmospheric drag makes a satellite lose orbital energy and fall into a lower orbit — and lower orbits are faster. So although drag initially slows the spacecraft, the resulting orbital decay can leave it moving faster around Earth. Scientists were analysing this effect as early as 1958.

Atmospheric drag always removes orbital energy, but gravity can leave a decaying satellite moving faster after it falls into a lower orbit. The post Friction normally slows things down. But atmospheric drag makes a satellite lose orbital energy and fall into a lower orbit — and lower orbits are faster. So although drag initially slows the spacecraft, the resulting orbital decay can leave it moving…