Introduction And Brief History Of Satellites
A satellite is any object that orbits a different object (that is referred to as its primary). All masses that are part of the solar system, like the Earth, are satellites either of the Sun or satellites of these objects, like the Moon. It truly is not constantly a simple matter to decide which can be the ‘satellite’ inside a pair of bodies. For the reason that all objects exert gravity, the motion of the major object can also be impacted by the satellite. If two objects are sufficiently comparable in mass, they are typically referred to as a binary system as an alternative to a principal object and satellite. The general criterion for an object to be a satellite is that the center of mass on the two objects is inside the principal object. In common usage, the term ‘satellite’ commonly refers to an artificial satellite (a man-made object that orbits the Earth or yet another body).
Sorts Of Satellites
- Astronomical satellites: They are satellites utilized for observation of distant planets, galaxies, and also other outer space objects.
- Communications satellites: They are artificial satellites stationed in space for telecommunications using radio at microwave frequencies. Most communications satellites use geosynchronous orbits or near-geostationary orbits, though some recent systems use low Earth-orbiting satellites.
- Earth observation satellites are satellites specifically designed to observe Earth from orbit, comparable to reconnaissance satellites but intended for non-military uses for instance environmental monitoring, meteorology, map producing, and so forth. (See particularly Earth Observing System.)
On lots of occasions, satellites are characterized by their orbit. Though a satellite may orbit at pretty much any height, satellites are usually categorized by their altitude:
- Low Earth Orbit (LEO: 200 – 1200km above the Earth’s surface)
- Medium Earth Orbit (ICO or MEO: 1200 – 35286 km)
- Geosynchronous Orbit (GEO: 35786 km above Earth’s surface) and Geostationary Orbit ( zero inclination geosynchronous orbit). These orbits are of certain interest for communication satellites and will be discussed in detail later.
- Higher Earth Orbit (HEO: above 35786 km)
The following orbits are particular orbits that can be also applied to categorize satellites:
- Molniya Orbits: This is a class of a hugely elliptic orbit. A satellite placed in this orbit spends the majority of its time over a designated location of the earth, a phenomenon referred to as apogee dwell. Molniya orbits are named immediately after a series of Soviet/Russian Molniya communications satellites that have been applying this class of orbits because of the mid-1960s.
- Heliosynchronous Or Sun-Synchronous Orbit: A heliosynchronous orbit, or extra generally a sun-synchronous orbit is an orbit in which an object usually passes more than any given point of your Earth’s surface at the same nearby solar time. This can be a helpful characteristic for satellites that image the Earth’s surface in visible or infrared wavelengths (e.g. weather, spy, and remote sensing satellites).
- Polar Orbit: A satellite in a polar orbit passes above or almost above each pole of your planet (or other celestial body) on every single revolution.
- Hohmann Transfer Orbit: For this specific orbit form, it can be more typical to recognize the satellite as a spacecraft. In astronautics and aerospace engineering, the Hohmann transfer orbit is an orbital maneuver that moves a spacecraft from 1 orbit to one more.
- Supersynchronous Orbit Or Drift Orbit: orbit above GEO. Satellites will drift within a westerly path.
- Subsynchronous Orbit Or Drift Orbit: orbits close to but beneath GEO. Applied for satellites undergoing station modifications in an eastern direction.