Earth's Satellites


Introduction

A satellite is an object that revolves around a planet in a curved path. When it comes to satellites, there are two major types of classification. The first is a natural satellite, and the second is an artificial satellite.

A natural satellite is one of the celestial bodies that orbit a larger body in space. Other than planets and their moons, natural satellites such as comets and asteroids exist. Artificial satellites are satellites that are built by humans and launched into orbit using rockets. Artificial satellites include navigation satellites, weather satellites, communication satellites, and so on. This article will provide a brief overview of satellites.

Natural Satellites

A natural satellite is one of the celestial bodies that revolve around a planet. We are currently aware of 91 natural satellites. The moon is the Earth's only natural satellite. In 27.3 days, the moon completes its revolution around the earth. In addition, one rotation around its axis takes 27.3 days. Mercury and Venus have no natural satellites, whereas Jupiter, Saturn, and Uranus each have 28, 30, and 21 satellites. Other than planets and their moons, there are some natural satellites.

  • Comets − Comets are objects that travel in an elliptical or oval orbit around the sun. Comets are also referred to as hairy stars.

  • Asteroids − Asteroids are rock-like objects that can be found mostly between Mars and Jupiter. They are composed of rocks, metals, and minerals.

  • Meteors − Due to the Earth's gravity, some small stray pieces of rock entered the Earth's atmosphere from the asteroid belt. These stray asteroids are referred to as meteors. These rocks burn up in the Earth's atmosphere before reaching the surface.

Natural Satellite of Earth

Artificial Satellites

Artificial satellites are satellites that are built by humans and launched into orbit using rockets.

Types of artificial satellites

Navigation Satellites

A satellite navigation system that determines an object's ground position. It determines the geographical location of ships, planes, and other objects.

Weather Satellite

The primary purpose of a weather satellite is −

  • To monitor the Earth's weather and climate.

  • To forecast daily weather conditions such as temperature and precipitation.

  • To track the development and evolution of weather conditions such as storms, hurricanes, cyclones, and tropical storms over time.

Communication Satellite

A communication satellite is a satellite that transmits signals such as phone calls, television broadcasts, radio broadcasts, and internet signals over long distances.

Types of Satellite Orbits

There are three types of satellite orbits based on inclination.

Equatorial Orbit

An equatorial orbit occurs when a satellite rotates in a circular path directly above the equator. It has a 0$\mathrm{^{\circ}}$ inclination.

Inclined Orbit

Except for those that travel directly above the equator or directly above the North and South Poles, all orbits are inclined. The angle of inclination ranges from 0 to 180$\mathrm{^{\circ}}$.

Polar Orbit

A polar orbit occurs when a satellite rotates in an orbital pattern perpendicular to the equatorial plane, passing over the North and South Poles. Polar-orbiting satellites travel at a low altitude close to the Earth's surface, passing over and very close to the North and South Poles. A satellite in polar orbit has an inclination angle of nearly 90$\mathrm{^{\circ}}$.

The function of Earth Satellites

The process of launching a satellite into orbit consists of two steps −

The satellite has to be first lifted to the required altitude. Then it has to be launched at the proper velocity to begin and maintain its orbit. A rocket or a space shuttle is used as a launch vehicle to place a satellite in a specific orbit about the Earth. Only for the first few seconds of its flight does a launch vehicle fly straight up. A multistage rocket serves as a satellite launch vehicle. It also has some smaller booster rockets. During the launch, the boosters provide the rocket with initial thrust and carry the vehicle through the early stages of flight.

As the fuel in the boosters runs out, the rocket disintegrates and the other boosters take over. When a booster is removed, the vehicle becomes lighter, allowing it to travel faster. When it reaches the required altitude and speed, it launches the satellite into orbit. Satellite communication is made up of three major components −

Uplink

The desired signal is transmitted to the satellite by an UPLINK earth station or other ground equipment.

Satellite Transponder

The satellite TRANSPONDER amplifies and changes the frequency of the incoming signal.

Downlink

The signal is transmitted back to the DOWNLINK earth station by the satellite transponder, and it is received by the ground equipment.

Ground stations are used in satellite communication to send and receive microwave signals between artificial satellites in orbit around the Earth.

Importance of Earth Satellites

  • Climate change − Satellites can help us better understand climate change and its consequences, allowing us to focus on our action plans and response activities.

  • Ecosystem Protection − Using satellites, we can monitor changes and promote responsible land and natural resource use to protect our ecosystems and biodiversity.

  • Daily activities − Satellites assist us in watching TV, making phone calls or other forms of communication, accessing the Internet, and so on.

Conclusion

We have briefly discussed satellites, types of satellites-natural satellites and artificial satellites, the importance of Earth satellites, and the function of Earth satellites in this article. A satellite is any object that revolves around a planet in a curved path. When it comes to satellites, there are two major types of classification. The first is a natural satellite, and the second is an artificial satellite. A natural satellite is any celestial body that orbits a larger body in space. Artificial satellites are satellites that are built by humans and launched into orbit using rockets.

FAQs

Q1. Who invented Satellites?

Ans. Sputnik, the first man-made satellite, was launched on October 4, 1957, shocking the American public and ushering in the Space Age. Before Sputnik was launched, people had been fantasizing about space travel.

Q2. Which country has the most space satellites?

Ans. In terms of satellites, the United States leads with the maximum number of 2,944 satellites, followed by China which also has a huge number of 499 satellites. Russia stands in third place with 169 satellites. The International Space Station and several other large space stations have been sent to space in pieces and then they are assembled over there.

Q3. How do satellites easily travel?

Ans. A satellite can orbit a planet when its speed is balanced by the gravitational pull of the earth. If this balance is not obtained, then it would cause the satellite to either fly off into space or crash back to the surface of the Earth. The satellites orbit around the Earth at various altitudes, at individual speeds, and on non-identical paths.

Q4. What is the range of satellites?

Ans. When the distance of the satellite from the earth 36, 000 km, it takes an orbiting time of 24 hours, which corresponds to the time taken for the rotation of the Earth about its axis. So when the satellite is at this specific distance from the earth above its equator, it will seem stationary from the surface of the earth.

Q5. How many satellites does India have?

Ans. It was stated by Singh in the form of a written reply to the Rajya Sabha that India currently has as many as 53 operational satellites in space and these satellites provide numerous identified and important services to this nation. There are 3 science satellites, 21 communication satellites, 21 Earth observation satellites, and eight navigation satellites.

Q6. Do satellites require fuel?

Ans. Satellites do have their fuel supply, but unlike a car, it is not required to maintain speed in orbit. It is only used to change orbits or avoid collisions with debris.

Updated on: 24-Jan-2023

220 Views

Kickstart Your Career

Get certified by completing the course

Get Started
Advertisements