Starlink: Constellation of satellites that revolutionized broadband internet by reducing latency

 

The constellation of satellites of Starlink, owned by SpaceX, is already revolutionizing the broadband internet in terms of speed of data transmission, low latency and of course, the possibility of accessing it from anywhere in the world - even in the remotest parts of the world.

Since Arthur C Clark, the science fiction writer, first envisioned the possibility of using satellites in communication, the use of geostationary satellites grew by leaps and bounds. 

Since those who deploy them want them to be 'stationary' above a specific position of the Earth, they are compelled to make them revolve around the planet at the same speed of the Earth's rotation around its own axis - 24 hours in rotational time..

Newton's Law of Gravitation and Kepler's Laws of Motion help us calculate the specific altitude of a geostationary satellite as follows:

F = GMm/r²,  the force between the Earth and a satellite of mass m

The centripetal force of the satellite = mrω², where w is the angular speed of the satellite.

To calculate the height of a geostationary satellite using its period, you can use the formula for the orbital radius of a geostationary satellite. The orbital radius is the distance between the center of the Earth and the satellite. The calculation is as follows:

Since the centripetal force in this case comes from the gravitational attraction,

mrω² = GMm/r² | m = mass of satellite | M = mass of Earth | r = distance between the centre of Earth and satellite | G = gravitational constant |ω = angular speed of satellite

ω² = GM/r³ → 1)

If the Time period is T,

T = 2π/ω

ω = 2π/T

From 1)

4π²/T² = GM/r³

r³ = T²GM/4π²

r = (T²GM/4π²)^1/3

T = 24 hours G = 6.67x10^-12 M = 5.9x10²⁴

r ≈ 42,164 km

Since the radius of the Earth is close to 6371km, 

The altitude = 42164 - 6371 = 35,793 km

Geostationary Satellite: simulation by Vivax Solutions

In order to make the geostationary satellites 'stationary', they have to be placed in an orbit at an altitude of over 35,700 km. The relatively large distance involved, inevitably, results in a latency - time taken for a round trip by an electromagnetic wave between the Earth and the satellite -  that ranges from 250ms to 600ms.

The latency has been an issue to be dealt with in light of the explosive growth of streaming services and bandwidth-heavy games.

Since the satellites of Starlink constellation are in an orbit that is at an altitude of 550km, the latency has been brought down to a figure around mere 20ms.- a marvelous technological feat. 

Starlink Constellation of Satellites

In addition, thousands of satellites that have been already deployed give a greater bandwidth for users when steady streams of fast data are in need. 

Thanks to Falcon 9 rockets, owned by the very company, SpaceX, the number of satellites in Starlink satellites is growing exponentially, covering the entire globe. 

The reusable rockets in question can deploy thousands of relatively-light, highly-efficient satellites at a time that in turn has left the would-be competitors lagging far behind SpaceX.

In addition to making broadband internet widely available across the world, SpaceX has come up with a state-of-the-art dish that can receive broadband in a very efficient way. 

The dish, 51cm X 34cm X 54cm,  that can be placed on the ground anywhere in the world. Each consists of 1280 antennae, a combination, which is claimed to be 3500 times as powerful as a single antenna despite its compact size, when it comes to transmission of data.

All in all, Starlink has taken a revolutionary step in enabling the faster internet access, defying the challenges posed by the difficulties that arise from geographical factors.