Airspeed is the speed of the spacecraft relative to the launch site, it does not include the rotation boost. For a spacecraft launching to orbit from the ground at the equator, airspeed starts at zero then increases to about four hundred meters per second less than the low drag orbital velocity. Ideally the spacecraft should be at least twenty kilometers high before breaking having an airspeed greater than Mach 1. The easiest way to achieve that is to launch the spacecraft froma ballon or an airplane. Airspeed along with the deceleration; which is derived from the density and frontal area of the spacecraft, is used to calculate the air resistance.

air resistance = deceleration * airspeed^2
 

This is used in atmospheric spacecraft, multi stage spacecraft, and spacecraft cost.
 
 

Feedback   Free Electronic Nation Home    Spacecraft   GNU Free Documentation License   Resume