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An apogee kick motor (AKM) is a
Kick In the Apogee: 40 years of upper stage applications for solid rocket motors, 1957–1997
, 33rd AIAA Joint Propulsion Conference, July 4, 1997
abstract
Retrieved 18 July 2017. 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". 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, a ''circularization burn.'' For orbits around bodies other than Earth, it may be referred to as an ''apoapsis'' 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.
An apogee kick motor (AKM) is a rocket motor
A rocket engine is a reaction engine, producing thrust in accordance with Newton's third law by ejecting reaction mass rearward, usually a high-speed jet of high-temperature gas produced by the combustion of rocket propellants stored inside t ...
that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit
Orbits
Astrodynamics
In orbital mechanics, a transfer orbit is an intermediate elliptical orbit that is used to move a spacecraft in an orbital maneuver from one circular, or largely circular, orbit to another.
There are several types of tran ...
into its final orbit (most commonly circular
Circular may refer to:
* The shape of a circle
* ''Circular'' (album), a 2006 album by Spanish singer Vega
* Circular letter (disambiguation), a document addressed to many destinations
** Government circular, a written statement of government pol ...
). For a satellite launched from the Earth, the rocket firing is done at the highest point of the transfer orbit, known as the apogee
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values.
Apsides perta ...
.
An apogee kick motor is used, for example, for satellites launched into a geostationary orbit
A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular orbit, circular geosynchronous or ...
. As the vast majority of geostationary satellite launches are carried out from spaceport
A spaceport or cosmodrome is a site for launching or receiving spacecraft, by analogy to a seaport for ships or an airport for aircraft. The word ''spaceport''—and even more so ''cosmodrome''—has traditionally referred to sites capable of ...
s at a significant distance away from Earth's equator
The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...
, the carrier rocket often only launches the satellite into an orbit with a non-zero inclination approximately equal to the latitude
In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...
of the launch site. This orbit is commonly known as a "geostationary transfer orbit
In space mission design, a geostationary transfer orbit (GTO) or geosynchronous transfer orbit is a highly elliptical type of geocentric orbit, usually with a perigee as low as low Earth orbit (LEO) and an apogee as high as geostationary orbit ...
" or a "geosynchronous transfer orbit". The satellite must then provide thrust to bring forth the needed delta v to reach a geostationary orbit. This is typically done with a fixed onboard apogee kick motor.Jonathan McDowell,Kick In the Apogee: 40 years of upper stage applications for solid rocket motors, 1957–1997
, 33rd AIAA Joint Propulsion Conference, July 4, 1997
abstract
Retrieved 18 July 2017. 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". 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, a ''circularization burn.'' For orbits around bodies other than Earth, it may be referred to as an ''apoapsis'' 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.
Use on interplanetary missions
AStar 48
The Star 48 is the largest of a family of solid rocket motors used by many space propulsion and launch vehicle stages, almost exclusively as an upper stage. It was developed primarily by Thiokol Propulsion and after several mergers, is manufact ...
kick motor was used to launch the New Horizons
''New Horizons'' is an Interplanetary spaceflight, interplanetary space probe launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institut ...
spacecraft towards Pluto.
See also
* Advanced Cryogenic Evolved Stage *Centaur
A centaur ( ; ; ), occasionally hippocentaur, also called Ixionidae (), is a creature from Greek mythology with the upper body of a human and the lower body and legs of a horse that was said to live in the mountains of Thessaly. In one version o ...
*Hohmann transfer orbit
In astronautics, the Hohmann transfer orbit () is an orbital maneuver used to transfer a spacecraft between two orbits of different altitudes around a central body. For example, a Hohmann transfer could be used to raise a satellite's orbit fro ...
* Liquid apogee engine
* List of upper stages
*Multistage rocket
A multistage rocket or step rocket is a launch vehicle that uses two or more rocket ''stages'', each of which contains its own engines and propellant. A ''tandem'' or ''serial'' stage is mounted on top of another stage; a ''parallel'' stage is ...
*Space tug
''Space Tug'' is a young adult fiction, young adult science fiction novel by author Murray Leinster. It was published in 1953 in literature, 1953 by Shasta Publishers in an edition of 5,000 copies. It is the second novel in the author's Joe K ...
References
{{DEFAULTSORT:Apogee Kick Motor Rocketry Rocket engines