Noun
(physics) A vector change in velocity, especially a small change as a result of a corresponding change in some other parameter
(astronautics) the maximum change in the scalar speed of a rocket if the rocket were operated in a vacuum away from external forces
(astronautics) a minimum scalar requirement for rocket delta-v to be able to achieve a particular manoeuvre
Source: en.wiktionary.orgAtmospheric and gravity drag associated with launch typically adds 1.3–1.8 km/s to the launch vehicle delta-v required to reach normal LEO orbital velocity of around convert. citation Equatorial low Earth orbits (ELEO) are a subset of LEO. Source: Internet
As an example of the velocity changes involved, a spacecraft travelling from low Earth orbit to Mars using a simple trajectory must first undergo a change in speed (also known as a delta-v ), in this case an increase, of about 3.8 km/s. Source: Internet
For low exhaust velocity with respect to the mission delta-v, enormous amounts of reaction mass is needed. Source: Internet
For a high delta-v mission, the majority of the spacecraft's mass needs to be reaction mass. Source: Internet
Calculated for circular orbit of 200 km it is 7.79 km/s and for 1500 km it is 7.12 km/s. citation The delta-v needed to achieve low Earth orbit starts around 9.4 km/s. Source: Internet
Comparisons Lifetime Ion thrusters' low thrust requires continuous thrust for a long time to achieve the necessary change in velocity ( delta-v ) for a particular mission. Source: Internet