Apogee kick motor

The apogee motor (also kick stage, English Apogee Boost Motor, Apogee Kick Motor ) is a rocket engine of a satellite to reach the final orbit.

Launchers bring satellites do not directly into a high circular orbit. Instead, they put the payload into a highly elliptical orbit whose apogee ( erdferner point) is close to the diameter of the desired path. The transfer orbit is called geostationary satellites Geostationary transfer orbit ( dec engl. GTO ) when the satellite to geostationary orbit. The name for the apogee motor is derived from the ignition point. By starting the engine at apogee he raises the perigee ( near-Earth point) and reduces the eccentricity of the satellite orbit.

Different technologies are used in Apogäumstriebwerken used:

  • Solid engine: in smaller satellites often comes a small solid rocket motor used. This raises during the combustion phase lasting about a minute at apogee to the perigee. Because it can be fired only once, a correction (e.g., with a misalignment of the satellite) is not possible. In most cases the engine is coupled to the satellite, but especially in the case many weather satellite, it is rejected.
  • Liquid-propellant engine: This is a small engine, the (mostly nitrogen tetroxide or Mixed Oxides of Nitrogen and monomethyl hydrazine ) is supplied via a pressure gas production with storable propellants. A characteristic feature of the engine is a relatively small boost in the S400 family of engines of EADS are depending on the version about 400-425 N. At the same time a long burning time typical, often five to ten minutes. Raising of perigee occurs by repeated firing of the engine at a plurality of passages of the apogee. Most apogee motors are today (2013 ) liquid-propellant engines.
  • Ion thruster: A special feature are the new ion drives here that have lower thrust but extremely long burn times distinguished: the thrust is much lower at about 70 mN, the burning time is extended to many days at intervals. To use the ion engines a special GTO is required.

There is now a satellite model, which has only ion engines that emit xenon. By using the ion drive as apogee, these satellites are only 33 % to 50% by weight have the same power as a satellite with liquid propellant apogee motor. But raising the perigee to geostationary orbits of achievement will take a few months.

72358
de