Delta-V

The delta-v capacity of a rocket is the theoretical total change in velocity that a rocket can achieve without any external interference (without air drag or gravity or other forces).

When detlta-v is constant, the delta-v that a rocket vehicle can provide can be calculated from the Tsiolkovsky rocket equation:[63]

{\displaystyle \Delta v\ =v_{e}\ln {\frac {m_{0}}{m_{1}}}}\Delta v\ =v_{e}\ln {\frac {m_{0}}{m_{1}}}}

The required delta-v can also be calculated for a particular manoeuvre; for example the delta-v to launch from the surface of the Earth to Low earth orbit is about 9.7 km/s, which leaves the vehicle with a sideways speed of about 7.8 km/s at an altitude of around 200 km. In this manoeuvre about 1.9 km/s is lost in air drag, gravity drag and gaining altitude.