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Anapogee kick motor (AKM) is arocket motor that is regularly employed onartificial satellites to provide the final impulse to change the trajectory from thetransfer orbit into its final orbit (most commonlycircular). For a satellite launched from the Earth, the rocket firing is done at the highest point of the transfer orbit, known as theapogee.
An apogee kick motor is used, for example, for satellites launched into ageostationary orbit. As the vast majority of geostationary satellite launches are carried out fromspaceports at a significant distance away from Earth'sequator, the carrier rocket often only launches the satellite into an orbit with a non-zero inclination approximately equal to thelatitude of the launch site. This orbit is commonly known as a "geostationary transfer orbit" or a "geosynchronous transfer orbit". The satellite must then provide thrust to bring forth the neededdelta v to reach a geostationary orbit. This is typically done with a fixed onboard apogee kick motor.[1] When the satellite reaches its orbit's apogee position, the AKM is ignited, transforming the elliptical orbit into a circular orbit, while at the same time bringing the inclination to around zero degrees, thereby accomplishing the insertion into a geostationary orbit. This process is called an "apogee kick".[1]
More generally, firing a rocket engine to place a vehicle into the desired final orbit from a transfer orbit is labelled an "orbital insertion burn" or, if the desired orbit is circular, acircularization burn. For orbits around bodies other than Earth, it may be referred to as anapoapsis burn.
The amount of fuel carried on board a satellite directly affects its lifetime, therefore it is desirable to make the apogee kick maneuver as efficient as possible. The mass of most geostationary satellites at the beginning of their operational life in geostationary orbit is typically about half that when they separated from their vehicle in geostationary transfer orbit, with the other half having been fuel expended in the apogee kick maneuver.[2]
AStar 48kick motor was used to launch theNew Horizons spacecraft towards Pluto.[3]