My title is: Science and Technology | Awareness in the field of IT and Space
2020-01-10 | 6 minutes
An American company, SpaceX aims to send a large number of satellites and provide good quality Internet access at low-cost to the whole world. It has recently launched sixty satellites into space under the Starlink network.
- Space X aims to send 12,000 satellites by the mid-2020s under its project known as Starlink network.
- It has also informed International Telecommunication Union (ITU) by means of the Federal Communications Commission (FCC) of United States its plans to position additional 30,000 Starlink satellites in Low Earth Orbit (LEO) in the future.
- All Starlink network satellites (12,000 permitted and 30,000 proposed) will be located at the height of 350 km-1,200 km.
- The project to establish a group of artificial satellites that will work with each other as a system termed satellite constellation was announced by SpaceX in January 2015, and two test satellites were launched in February 2018.
- As of now, Space X has sent 122 satellites. Out of these, the first 60 satellites were sent on May 24 and 60 were sent on November 11, 2019. The satellites launched on November 11 will not be part of the Starlink network.
- The aim of Starlink is to begin Internet services in the Northern United States and Canada by 2020 and to cover the whole world by 2021.
- The Starlink will start providing Internet services after 400 satellites reach the space. From November 2019, 60 satellites will be launched every week.
- Other private companies like Amazon, OneWeb, and O3B (Other Three Billion) also have plans for providing space-based Internet services through projects that are small in comparison with Starlink.
Need for satellite Internet services or space-based Internet networks:
- Out of the total population of the world, more than half (nearly 4 billion people) do not have the opportunity to access Internet networks with good quality and performance.
- Uninterrupted Internet services with good quality and performance are not only fundamental facilities required for the progress and functioning of modern society but also being increasingly used worldwide for the delivery of public services.
- Fiber-optic cables and cellular networks are conventional means of providing the Internet. These traditional ways cannot provide Internet services everywhere Fiber-optic cables and mobile towers cannot be established in remote regions and regions having difficult terrain.
- Internet access through signals from satellites placed in space can succeed in handling the difficulties posed by traditional ways of providing the Internet. This will make sure that uninterrupted Internet services with good quality and performance are accessible in every part of the world.
Current space-based Internet systems:
Space-based Internet systems are currently available to the small number of users only. They are based on satellites placed in geostationary orbit.
Advantage of transmitting signals from geostationary orbit:
- Lower number of satellites are sufficient for entire Earth: Signals from a single satellite located in geostationary orbit can extend overnearly a third part of the Earth. Therefore, signals from three to four satellites in geostationary orbit can cover the entire Earth.
- Satellites in geostationary orbit can be easily connected: Although the satellites in geostationary orbit travel at a speed of 11,000 km / h, they appear stationary to the observer on the Earth’s surface as time taken by them in achieving one revolution of the Earth is equal to time taken by the Earth in completing one rotation on its axis. This makes it easier to link the satellites in geostationary orbit.
Disadvantage of transmitting signals from satellites located in geostationary orbit:
- Latency of data transmission: Latency refers to the delay at the beginning of data transfer between a user and a server. As the geostationary orbit is located at a distance of 35,786 km from the surface of the Earth and data transmission cannot take place at speed higher than the speed of light, the transmission of data using satellites in geostationary orbit gets delayed. The transmission of data using satellites in geostationary orbit has a latency of nearly 600 milliseconds.
Advantage of placing satellites in the Low Earth Orbit (LEO) for providing space-based Internet:
- The satellites located in the Low Earth Orbit (LEO), which exists at the height of 200-2,000 km from the Earth's surface, will minimize the delay in data transfer to 20-30 milliseconds. This will be approximately equal to the time taken by the Earth-based Internet systems in transferring data from the server to the user.
The rationale for deploying large number (42,000) of Low Earth Orbit (LEO) satellites under Starlink network:
- As satellites in the Low Earth Orbit (LEO) are located at lower heights, their signals extend over a comparatively lower area and a large number of satellites are required for sending signals to every part of the Earth.
- To counter the effects of the earth’s gravitational force, the satellites in the Low Earth Orbit (LEO) move at an approximate speed of 27,000 km / h. This speed is more than twice the speed of satellites located in geostationary orbit. As a result, it is not possible to see them from the surface of the Earth for more than a few minutes and a large number of such satellites are needed for uninterrupted transmission of data.
Concerns over deploying large number (42,000) of Low Earth Orbit (LEO) satellites under Starlink network:
- Increase in space debris or space junk: Most of the 2,000 working satellites are currently positioned in the lower orbits. Since the starting of the Space Age with the launch of Sputnik 1 in 1957, nearly 9,000 satellites have been sent into space.
- More risk of collisions: European Space Agency (ESA) has recently prevented collision of one of its functional satellites with a mega constellation on 2nd September 2019 by changing the orbit of a spacecraft.
- Light-pollution: The astronomers have expressed concerns that constellations of a large number of artificial satellites in space will cause difficulties in observing natural objects in space and in identifying signals from these objects. A large number of artificial satellites will reflect light that may interfere with the light of other celestial bodies. The reflected light may be misunderstood as belonging to natural objects in space
Internet access through Space-based Internet networks has the potential to transform technologies such as automated car driving and make the introduction of the Internet of Things possible even in houses located in rural areas.