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Rotational Behaviour Saturn

There are various types of satellites. They are Astronomical satellites, Communication Satellites, Earth Observation Satellites, Navigation Satellites, Reconnaisance satellite, Solar Power satellites, Weather satellites and Miniaturized satellites.

w Astronomical Satellites

Astronomical satellites are those which are used for observation of distant planets, galaxies, and other outer space objects. Astronomical performance from the Earth’s surface is limited by Earth’s atmospheric conditions. It makes it even more worse by the filtering and distortion of electromagnetic radiation. This makes it desirable to place astrononomical observation devices into space.

But space-based astronomy is even more important for frequency ranges which are outside the optic and radio window. For example, X-ray astronomy is nearly impossible when done from the Earth, and has reached its current important stand within astronomy only due to orbiting satellites with X-ray telescopes.Infrared and ultraviolet are also greatly blocked.

w Communication Satellites

Communication satellites are satellites stationed in space for the purposes of telecommunications. Most communications satellites use geosynchronous orbits or near-geostationary orbits. Some recent systems also use low Earth-orbiting satellites for this purpose.

These satellites are useful for fixed services as well as mobile applications. For fixed services, they provide a technology complementary to fiber optic sub marine communication cables. It is useful for communications to ships and planes for which other technologies are impractical.

w Earth Observation Satellites

These are satellites specifically designed to observe Earth from orbit, intended for non-military uses such as environmental monitoring, meteorology, map making etc. Geostationary Operational Environmental Satellites, Himawari, Misc ets are some of the earth observation satellites.

w Navigation Satellites

The satellites which use radio time signals transmitted to enable mobile receivers on the groung are called navigation satellites. These satellite navigation systems are enabled to measure the location to accuracies on the order of a few metres in real time.

The first satellite navigation system was Transit of which the operation was based on the Doppler effect. Here, the satellites traveled on well-known paths and broadcast on a well known frequency were the received frequency will differ slightly from the broadcast frequency because of the movement of the satellite with respect to the receiver. By monitoring this frequency shift over a short period, the receiver can determine its location to one side or the other of the satellite.Several such measurements combined with accurate knowledge of the satellite's orbit can fix a definite position.

Satellite navigation is widely used for military applications. Thus it can be regarded as a force multiplier. In particular, the ability to reduce unintended casualties has particular advantages for wars and hence is an essential asset for any aspiring military power.

w Solar Power Satellites

The proposed satellites built in high earth orbit that use micro power transmission to beam solar power is called solar power satellites. These solar power is beamed to a large antenna on earth where it can be used in place of conventional power sources.

w Weather Satellites

A type of artificial satellite, weather staellite is mainly used to monitor weather and climate of the earth. City lights, fires, pollution, auroras, sand and dust storms, snow cover, ice mapping, ocean currents, energy waste, etc., are other environmental information collected from weather satellites.

The first weather satellite was Vanguard 2 which was designed to measure cloud cover. But TIROS 1 was considered to be a successsful weather satellite.

w Miniaturized Satellites

Miniaturised satellites are recent artificial satellites of low weights and samll sizes. One reason for this miniaturisation of satellite is reduction in cost and constellations for low rate communications. Hey also allow for cheaper designs as well as feasibility of mass production.

There are many counties that are capable of placing satellites in orbits including the production of launch vehicles. Some are Russia, US, France, Japan, UK, India, and Israel.