SpaceX also has several other ambitious projects underway. One of the most talked-about ventures of SpaceX is its Starlink project. It promises a no-lag, low latency internet that is accessible and affordable by all. Whilst also claiming to provide superior quality broadband to the most remote areas of the world where internet facilities are presently non-existent.
The launch of the prototype satellites was intended to be in 2016 with the project fully functioning by the end of 2020. However, in the search for a more user-friendly and affordable receiver, the launch was delayed until February 2018. The first two prototypes, Tintin A and B, were launched aboard a Falcon 9 rocket and mainly gathered information to get closer to the Starlink goal. In November 2018, SpaceX received the approval from the Federal Communications Commission to deploy 7500 more satellites in addition to the previously approved 4,400. Recently, it has been observed that the orbit of the Tintin Starlink satellites have reduced from 500km to 490 km which might lead us to believe that Spacex must be preparing to de-orbit the prototypes.
The biggest question that arises is how Project Starlink could achieve something as humongous as global connectivity?
In comparison to geostationary satellites, the satellites in this project would be much closer to the earth. Since the amount of space debris ranging from paint flecks of rockets to dead or failed satellites, is increasing, it poses a risk of collision. The Starlink satellites will have a small orbital radius, and thus, it would cut space junk considerably. Latency is the time delay while sending information from one point to another and Starlink aims to decrease this time lag as much as they can. Each satellite will have an 81 degree coverage of the earth and so covers an area with a radius of 500 km. This differs from SpaceX’s original plan: a coverage area with a radius of 1060km. One might think that decreasing the altitude will lead to a decrease in the coverage area, which shouldn’t be favourable to a project with the intent to cover the entire world. However, it is important to note whilst a lower altitude may lead to lower surface area coverage, it also leads to a significant decrease in latency. To achieve latency as little as 3.6 milliseconds, SpaceX has to deploy as many as 42,000 satellites around the earth.
SpaceX is the first to launch spacecraft that use only krypton in its ion thrusters instead of xenon which is worth taking a look at. Ion thrusters use Newton’s third law of motion which states every action has an equal and opposite reaction. A difference in potential is used to fire ions out of the spacecraft, which in turn causes upward propulsion. Xenon is the most ideal for this purpose due to its high atomic mass, inert nature, and high storage density, all of which are essential for this purpose. However, Xenon is very rare which makes it an expensive fuel. Since Starlink aims to provide affordable access to its facilities, it uses Krypton propellers instead. Krypton is 10 times less expensive than Xenon. It is also lighter and hence smaller acceleration voltages could be used to generate the same velocity. These ion propellers would be used to propel the satellites from their initial height of 440km to their final orbit of height 550km.
SpaceX claims that 95% of the satellites would burn on re-entering the atmosphere. The remaining 5% would include the silicon carbide components that have very high melting points as they are used to operate lasers.
Transmission of information in space is very profitable. One knows that the speed of light depends on the refractive index of the medium it passes through. The refractive index of space i.e. vacuum is very minute compared to that of glass fibre cables used on land. This means that light will travel 47% faster in a vacuum than in such glass fibre cables. Thus resulting in a significant decrease in latency even during information transmission over long distances. Additionally, it is very tedious and expensive to lay fibre optic cables across long distances.
Every satellite has 5 individual lasers. When information reaches a satellite, it is transmitted to 4 other satellites through laser beams. Although there is a slight delay during the conversion of the laser beams to electric signals and then once more to lasers for re-transmission, the delay is negligible. The satellites give directional laser beams as undirected radio waves interfere with other means of communication.
The concept of having a high-speed broadband connection all over the world is indeed captivating. But astronomers have their concerns. The Starlink satellites reflect and shine in the night sky. Since astronomy is based wholly on the observation of the dark sky, the presence of artificial light would be a hindrance in their research. It would mostly affect the branches of astronomy that deal with wide-field observation of the sky with large telescopes. Another one of the major concerns raised by astronomers is that the light pollution from the satellites could conceal meteors heading our way. Thus, resulting in a delay in possible protective measures due to the late spotting of the meteor. It would also be difficult to study far away planets like the mysterious Planet Nine.
Elon Musk addressed the concerns in the 2020 Satellite Conference at Washington DC and said that there’s a “zero” chance of the Starlink project becoming an interferer in astronomical studies. However, he also adds that they’ll take “corrective action if it’s above zero.” The project has already started modifying the satellites to make them reflect less light in space. SpaceX plans on changing the orientation such that it\’s knife-edged to the sun which leads to a decrease in the amount of surface area exposed to sun rays and in turn, reduces the brightness of its satellites in the night sky. However, this is still in a phase of testing. It is also deploying visors (or shields) that would block sunlight from falling on the brightest parts of the satellites.
This project would exceedingly benefit the financial sector. When billions of dollars are transferred in fractions of a second, lower latency forms one of the most important pillars. Companies often lose a lot of money because their competitor probably had a faster internet with lesser lag. With the help of Starlink, these losses could be minimized and that would mean a lot of revenue for both the financial market as well as SpaceX.
3 thoughts on “Starlink”
A very good read. Just wondering 42000 satellites……
It was very useful
Thank you for the time and energy that you spend for your audience