Geocentric orbit

[1] More than 16,291 objects previously launched have undergone orbital decay and entered Earth's atmosphere.

For a low Earth orbit, this velocity is about 7.8 km/s (28,100 km/h; 17,400 mph);[2] by contrast, the fastest crewed airplane speed ever achieved (excluding speeds achieved by deorbiting spacecraft) was 2.2 km/s (7,900 km/h; 4,900 mph) in 1967 by the North American X-15.

[4] Spacecraft with a perigee below about 2,000 km (1,200 mi) are subject to drag from the Earth's atmosphere,[5] which decreases the orbital altitude.

The rate of orbital decay depends on the satellite's cross-sectional area and mass, as well as variations in the air density of the upper atmosphere.

[6] The escape velocity required to pull free of Earth's gravitational field altogether and move into interplanetary space is about 11.2 km/s (40,300 km/h; 25,100 mph).

Low (cyan) and Medium (yellow) Earth orbit regions to scale. The black dashed line is the geosynchronous orbit. The green dashed line is the 20,230 km orbit used for GPS satellites.
The lower axis gives orbital speeds of some orbits.