These satellites revolve round the planets and provide all the information about the planet through satellite imagery. The primary purpose of launching artificial satellites is to study the planet and communicate relevant information back to the scientists studying it. These satellites can retrieve and process images from topographies which are difficult to photograph and map large areas of terrain. Petropedia explains Artificial Satellite Artificial satellite imagery and remote sensing techniques can be applied in many industries.
The Columbia Encyclopedia, 6th ed. Copyright The Columbia University Press artificial satelliteobject constructed by humans and placed in orbit around the earth or other celestial body see also space probe. The satellite is lifted from the earth's surface by a rocket and, once placed in orbit, maintains its motion without further rocket propulsion.
The first artificial satelliteSputnik I, was launched on Oct.
During the first decade of space explorationall of the satellites were launched from either the United States or USSR. Today, there are more than three dozen launch sites in use or under construction in more than a dozen countries. Satellite Orbits If placed in an orbit high enough to escape the frictional effects of the earth's atmosphere, the motion of the satellite is controlled by the same laws of celestial mechanics that govern the motions of natural satellites, and it will remain in orbit indefinitely.
At heights less than mi km the drag produced by the atmosphere will slow the satellite down, causing it to descend into the denser portion of the atmosphere where it will burn up like a meteor.
To attain orbital altitude and velocity, multistage rockets are used, with each stage falling away as its fuel is exhausted; the effect of reducing the total mass of the rocket while maintaining its thrust is to increase its speed, thus allowing it to achieve the required velocity of 5 mi per sec 8 km per sec.
At this speed the rocket's forward momentum exactly balances its downward gravitational acceleration, resulting in orbit.
Once above the lower atmosphere, the rocket bends to a nearly horizontal flight path, until it reaches the orbital height desired for the satellite.
Unless corrections are made, orbits are usually elliptical; perigee is the point on the orbit closest to the earth, and apogee is the point farthest from the earth.
Besides this eccentricity an orbit of a satellite about the earth is characterized by its plane with respect to the earth. An equatorial orbit lies in the plane of the earth's orbit. A polar orbit lies in the plane passing through both the north and south poles.
A satellite's period the time to complete one revolution around the earth is determined by its height above the earth; the higher the satellite, the longer the period.
At a height of mi kmthe period of a circular orbit is 90 min; at mi kmit increases to min. At a height of 22, mi 36, kma satellite has a period of exactly 24 hr, the time it takes the earth to rotate once on its axis; such an orbit is called geosynchronous.
If the orbit is also equatorial, the satellite will remain stationary over one point on the earth's surface. Tracking and Telemetry Since more than 1, satellites are presently in orbit, identifying and maintaining contact requires precise tracking methods. Optical and radar tracking are most valuable during the launch; radio tracking is used once the satellite has achieved a stable orbit.
Optical tracking uses special cameras to follow satellites illuminated either by the sun or laser beams. Radar tracking directs a pulse of microwaves at the satellite, and the reflected echo identifies both its direction and distance.
Nearly all satellites carry radio transmitters that broadcast their positions to tracking antennas on the earth. In addition, the transmitters are used for telemetry, the relaying of information from the scientific instruments aboard the satellite.
Types of Satellites Satellites can be divided into five principal types: Research satellites measure fundamental properties of outer space, e. Early research satellites included a series of orbiting observatories designed to study radiation from the sun, light and radio emissions from distant stars, and the earth's atmosphere.
Also contributing to scientific research were the experiments conducted by the astronauts and cosmonauts aboard the space stations launched by the United States Skylab and the Soviet Union Salyut and Mir ; in these stations researchers worked for months at a time on scientific or technical projects.Collection of information about natural resources of earth Artificial satellites are also used for collecting information about natural resources of earth like oil wells, underground water, minerals, natural gas and coal deposits etc.
Artificial satellites are used for many purposes, including communications, navigation, gathering weather information, creating maps and even spying. Artificial satellites come in several forms, including telescopes and probes. Sputnik 1 was the first artificial satellite to be successfully launched into space, by the USSR (Soviet Union) on 4 October Satellites are launched into space by rockets, and orbit up to and beyond 35, kilometres (22, miles) in altitude.
An Artificial Satellite is an artificial object that is manufactured by humans and launched into the Earth’s orbit or in another planet’s orbit. These satellites revolve round the planets and provide all the information about the planet through satellite imagery.
Satellites. This is a list of all Indian (wholly or partially owned, wholly or partially designed and/or manufactured) satellites, both operated by the Indian government (ISRO, Indian defence forces, other government agencies) or private (educational and research) entities.
Artificial satellites are human-built objects orbiting the Earth and other planets in the Solar System. This is different from the natural satellites, or moons, that orbit planets, dwarf planets.