How Satellites work
In this post, you will get info about How Satellites work? So let’s Start – We go about our daily lives knowing that several satellites circle our planet every day and assist us in a variety of ways. You might be astonished to learn that the Earth is orbited by about 4900 satellites. The following are the most obvious questions that come to mind:
Why are these satellites in totally different orbits?
How does the satellite carry out all of its functions?
What are the components inside them?
This aids them in completing all of their assigned chores. Let’s take a closer look at the answers to all of these questions.
It is well knowing that a satellite maintains its orbit due to a balance of gravitational pull and centrifugal force.
The force balancing equation, which balances gravitational and centrifugal forces, determines the satellite’s angular velocity. When the satellite is launched, it is given enough speed to counteract these opposing pressures. To withstand the gravitational pull, a satellite that is close to Earth must travel faster than one that is farther away.
Satellites never lose speed in space due to their low resistance. This means that satellites will continue to orbit the Earth in a circular motion without requiring any external energy.
Low Earth Orbit, Medium Earth Orbit, and Geosynchronous Earth Orbit are the three types of satellite orbits. These three orbits are depicted in this diagram. We’ll go over them in further depth later.
The Van Allen belt is a fascinating location in outer space. An area is dense with highly energetic charged particles that could badly harm a satellite’s electronics. In general, satellites should not be parked in the Van Allen belt. The application and purpose of the satellite influence the selection of which orbit to choose for its placement.
If the satellite is built for:
- Earth observation
- weather forecasts
- geographic area surveying
- satellite phone calls, etc…
After that, orbits that are closer to the Earth are picked. At an altitude of 160 to 2000 kilometers, LEO is the closest to the earth, with an orbital period of around 1.5 hours. However, because these satellites cover a smaller area of the earth, a large number of them are required to provide global coverage. As a result, a high orbit like GEO is chosen for broadcasting.
Satellites in geosynchronous orbit are 35,786 kilometers above the earth’s surface and revolve at the same angular speed. It indicates that one rotation of the satellite takes exactly 23 hours 56 minutes and four seconds. There is a particular sort of orbit known as a geostationary orbit that exists within the geosynchronous orbit.
which is concentric to the earth’s equator In relation to the earth, these satellites remain stationary. As a result, geostationary satellites are an excellent choice for television broadcasting because they eliminate the need to constantly modify the angle of your satellite dish. This is why the geostationary belt, which is administered by the International Telecommunication Union, is so densely packed with satellites.
A few navigation satellites also occupy geosynchronous orbits. Three GEO satellites are enough to cover the entire Earth because they can cover one-third of its surface. MEO is the best choice for navigation applications like GPS. Despite the fact that the LEO orbit is the closest to the planet, satellites in this orbit rotate at a very fast rate.
As a result, receivers on Earth are unable to perform precise navigation computations. Furthermore, because LEO requires a large number of satellites to cover the entire Earth, GPS satellites employ MEO. 24 satellites may cover the entire world in a standard GPS system, with an orbital period of 12 hours.
Let’s have a look at the major components and operations of a communication satellite now. The transponders are the brains of communication satellites. A transponder’s primary function is to adjust the frequency of a received signal, reduce signal noise, and boost signal power.
The transponder in KU band satellites transforms from 14 to 12 gigahertz, and the satellite can have 20 or more transponders. Transponders, of course, demand a significant amount of electrical power to perform all of these activities.
A satellite’s power source choices include batteries and solar panels. The electronic equipment is powered by the solar panel, but during an eclipse, batteries are used. On the satellite, you can see a sun sensor. This sun sensor aids in angling the solar panels in the proper direction to extract the most power from the sun.
Let’s look at how the transponder receives the antenna’s input signal. Reflector antennas are the most frequent antennas used on spacecraft. A satellite’s designed smooth orbit is meant to be followed. Due to the asymmetrical mass distribution of the earth and the existence of the moon and the sun, the gravitational field around the satellite is not uniform. As a result, the satellite is occasionally pushed from its intended orbital position.
This is a risky condition since it will result in a full signal loss. Satellites utilize thrusters to prevent this type of predicament. The thrusters are activated, maintaining the satellite’s position. These also assist satellites in avoiding space debris. The thruster fuel is stored in tanks within the satellite body. A ground station continuously monitors the satellite’s position and control of the thrusters.
The earth station not only manages the satellite’s position, but it also monitors its health and speed. Tracking, telemetry, and control systems are used to accomplish this. The systems provide the signal to the earth station on a constant basis and maintain contact between the Earth and the satellite. To distinguish themselves from other communication signals, these signals are typically exchanged at various frequencies.
Have you ever thought about what happens to a satellite when it is no longer functional, or its lifespan is nearing the end?
Other operating satellites or spacecraft could be harmed by these satellites. Inactive satellites are transported to the graveyard orbit by igniting the thrusters to deal with this problem. We may relocate the satellite to a larger radius orbit simply by increasing its rotating speed. In That Image, the surgery is explained in detail.
A few hundred kilometers above the geostationary orbit is the graveyard orbit. The thrusters use the same amount of fuel that a satellite would for three months of station holding for this activity. The spacecraft we’ve talked about thus far have all been communication satellites. The antenna and an atomic clock are the most significant components of GPS satellites. The L band navigation antennas that are employed in these satellites are also depicted. The Earth observation satellites, which are largely in low earth orbit (LEO), carry a variety of data.
- Various types of sensors,
- Imagers, etc…
Depending on their mission.
Now for some fascinating details. You may have noticed that the satellites in this post were covered in gold-colored foil in the images. What exactly is the function of this foil? It is not, in reality, foiled as it appears at first glance. It has a multi-layered structure, as you can see from a cross-section. Satellites are subjected to extreme temperature changes in orbit, with temperatures ranging from -40°C to +60°C ( minus 150 to 200 degrees Celsius)
Satellites also have to contend with the sun’s intense solar radiation. This material serves as a shield, shielding the satellite’s components from extreme temperature changes and solar radiation. We hope that this post has given you a solid understanding of different types of satellites and how they work?