You must have wondered how the earth might look from space and have questions in mind like how big is the earth, what are those bodies that appear in the sky, how do we talk on phones, connect with people through the internet, or predict weather conditions, and what are satellites, how big are these as compared to our earth, right?
All of these things that we talked about in the questions above have a simple answer to it, that is, with the existence of a SATELLITE.
So, let us move ahead in detail and learn about satellites, their type, size, and their functions.
- SATELLITE is a term that is used for a body, machine, or planet that orbits around another body in the solar system.
- For example, Earth is a satellite that revolves around the sun in an elliptical path or orbit. This makes Earth a satellite of the Sun.
- Similarly, the moon is a natural satellite of Earth, as the moon orbits around the earth.
The Moon is a natural satellite of the Earth, similarly, there are man-made or artificial satellites that are launched to the Earth’s surface or orbit using launch vehicles like rockets and space crafts for various purposes. Let us look into the details ahead.
What Are Artificial Satellites?
- Artificial Satellites are man-made or human-built satellites that are made on the earth and launched from the earth to space through launch vehicles, rockets, space crafts, and space flights.
- These Satellites are made for several purposes and each one of them differs in its size and type based on its roles and functions. The first artificial satellite – Sputnik 1 was sent into space in 1957, on the 4th of October by the Soviet Union.
- The Artificial satellites have the bird’s eye, or the vision to have a large area of the earth covered. These satellites are placed at such a height (height could vary) that they can look at a large portion of the earth and send those data on the earth’s surface.
Applications of Satellite:
- An Artificial Satellite is sent into space intentionally for the following purpose:
- Satellites are used for communication purposes. For example telephone communication on planes.
- It is used for navigation purposes as well. We use google maps, calculate the distance, and enable you to navigate through places and regions on the maps. All this is made possible due to the navigation process that is the Global Positioning Systems.
- Satellites provide a wide range of data about various places while orbiting around earth from space. This enables video calling or conferencing for people to connect. Satellite provides information for business and finance.
- The satellite has made possible the early prediction of weather conditions and climatic change as well as environmental conditions. Some meteorologists gain this information through satellites and help save the lives of people during natural disasters occurring through weather conditions.
- The above point also provides safety. The cities, countries, or continents’ weather conditions can be well informed beforehand, through the data, pictures sent by satellite.
- Satellites can detect mineral sources and underground water. They are capable of monitoring large-scale infrastructure for military purposes.
- Satellites have helped the astrophysicist and astrologists to provide an overview of space. Unlike in earlier times, space enthusiasts used telescopes from the earth’s surface to view the elements of the universe, now these satellites provide a large amount of data and information including pictures of other celestial bodies in space.
There are more applications of satellites in addition to the above points. These were the basic and some essential uses of satellites that have enhanced our way of life on earth.
How big are satellites?
As the satellites are built by humans so they are termed artificial satellites. They vary in their size based on their uses and types. They occupy different parts of space and are placed at different altitudes based on their roles and functions.
There are no particular or universally accepted sizes of the satellites. Let us discuss ahead their variations in their sizes and the factors it is based on.
- LARGE SATELLITES
Large satellites have large structures and they weigh over 2000 kg.
Large satellites are found to orbit space in the geosynchronous orbit (GEO). The majority of large satellites are placed at higher latitudes (35,786 km) above the earth’s surface.
ViaSat-1 and ViaSat-2 are one such example of a large satellite and they weigh approximately 6500 kg. ViaSat is an essential satellite that is very powerful and is placed at the highest altitude in space that a satellite can orbit the earth.
The International Space Station is an example of the largest satellite.
- MEDIUM SATELLITE
Medium Satellites weigh around 500 to 1000 kilograms. There are a vast number of medium-sized satellites in space orbiting the earth. An example of a medium-sized satellite is the American-European earth observatory satellite named Jason-3. It was a collaboration of American and European scientists to launch a satellite for observation purposes in space. It weighed around 550 kg.
Another example of a medium-sized satellite is a Canadian space satellite SCISAT-1. The purpose of this satellite was for atmospheric science and studies.
A medium-sized satellite can orbit from low earth orbit (LEO) to medium earth orbit (MEO), and up to geosynchronous earth orbit (GEO) as well.
- MINI SATELLITES
Mini satellites weigh around 100 – 500 kilograms. The satellites orbiting in the low earth orbit (LEO) are vastly categorized as mini-satellites. They are launched at an altitude of 180 to 2000 kilometers.
Microsatellites are smaller in size than mini-satellites. They weigh approximately ranging from 10 kg to 100 kg. These satellites can easily obtain their position in the low earth orbit (LEO) and perform their functions. They are also placed at an altitude of 180 to 2000 kilometers.
Nanosatellites are very small in size as compared to other satellites. They do not require expensive parts. These satellites are used in the areas for communication, global positioning, monitoring, and signal detection purposes.
Nanosatellites weigh around 1 kg to 10 kg. Some nanosatellites require a “mother satellite” to send the data back to the earth or the ground station. These satellites have limited technical abilities and that is why they are launched at low altitudes in the low earth orbit (LEO).
Picosatellites are the lightest and smallest satellites and they weigh approximately 1 kilogram. These satellites are also launched in low earth orbit.
These were the sizes of the satellites that orbit the earth according to their size, function, and stability. There are more than 6500 satellites in space that were built and launched by different countries over the decades.
Now that we are talking about different sizes of satellites, let us also learn about the launch vehicles needed to launch these sizes of satellites at their respective altitude or earth orbits.
A launch vehicle is a rocket engine that uses rocket propulsion to carry a rocket. It is a vehicle that carries a payload (a body that is to be carried by the launch vehicle or an aircraft). The payload is launched from the earth’s surface to the earth’s orbit and sometimes even beyond the orbit with the help of a launch vehicle.
A launch vehicle is capable of launching the following payloads:
- A spacecraft – (crewed or un-crewed)
- Satellites of various sized
- Robotic spacecraft
- Some scientific probes
- Landers, etc.
There is a whole launching system that includes a launchpad, a launch vehicle, and assembly of the launching vehicle, fueling system, range safety, and many other essential parts.
These launch vehicles are categorized based on the masses of the payload they are carrying and other notable factors. The launch vehicles that launch a minimum at low earth orbit are termed Orbital launch vehicles.
The National Aeronautics and Space Administration (NASA) has classified the launch vehicles based on capabilities of the payload at low earth orbit (LEO), which are:
- Small-lift launch vehicles
- These orbital launch vehicles that are categorized as small, can carry/lift the payloads from the earth’s surface to the low earth orbit.
- These small lift launch vehicles can carry up to 2000 kilograms or can also lift up to 5000 kilograms.
- These are inexpensive, more reliable, and widely used by various space agencies.
- Some examples of small-lift launch vehicles are Vanguard, Juno I, Atlas LV-3B, Vector-R, etc.
- Medium-lift launch vehicles
- Medium lift launch vehicles are also a category of orbital launch vehicles based on their size and the weight it is capable of lifting from the surface of the earth to low earth orbit (LEO).
- Medium lift launch vehicles can carry payloads that weigh between 2000 kilograms and 20,000 kilograms. (As specified by NASA)
- Sometimes they can also lift up from 50,000 kilograms to 50,000 kilograms according to Russian Space agencies.
- A few examples of medium launch vehicles are:
- Heavy-lift launch vehicles
- A heavy-lift vehicle (HLV) is a type of orbital launch vehicle. It carries heavy payloads like spacecraft, satellites of various sizes, and other parts.
- An HLV is capable of carrying payloads of weight from 20,000 kilograms to 50,000 kilograms.
- Although, the heavy-lift vehicles have not been able to carry a 20-tonne weight of a payload into low earth orbit yet.
- A few examples of heavy-lift vehicles are Falcon 9 Full Thrust, the long march 5, etc.
- Super heavy-lift launch vehicles
- Super heavy launch vehicles (SHLV) have the capability of lifting payloads with a weight of up to 50 tonnes.
- As of the year 2021, there is 1 functional super heavy-lift launch vehicle that is Falcon heavy. It has not been able to lift more than 50 tonnes yet.
- Examples of the 2 super heavy-lift vehicles that are currently under development are SpaceX Starship and The Space Launch System of NASA.
- Saturn V is another example of an SHLV.
NASA uses small-lift launch vehicles to launch satellites into the low earth orbit, that is, small-lift launch vehicles are also called satellite launch vehicles. Other satellites that are bigger are launched using medium and high-lift launch vehicles for medium earth orbit and beyond.
Space is a fascinating and one of the most exciting subjects for the world in the coming decades. Several space exploration programs, research, and development of satellites, robotic spacecraft, and other technologies are being studied and experimented with to explore the future of space.
So, these were the information on different sizes of satellites, along with their functions. The launch vehicles and their sizes have also been discussed.
**Thank you for your interest in the article