Insights into Editorial: Understanding space Internet
The SpaceX, the world’s leading private company in space technology, fired a spray of 60 satellites into orbit.
This is the first operational batch of what is intended to eventually evolve into a constellation of nearly 12,000 satellites aimed at providing low-cost and reliable space-based Internet services to the world.
About Starlink network project:
- The Starlink network, as the project is called, is one of several ongoing efforts to start beaming data signals from space, and also the most ambitious.
- SpaceX announced the satellite Internet constellation in January 2015, and launched two test satellites in February 2018. The company has now deployed 122 satellites in orbit.
- SpaceX appeared ready to scale up its ambition, telling the International Telecommunication Union (ITU) in filings through the United States Federal Communications Commission (FCC) that it intends to deploy another 30,000 Starlink satellites in Low Earth Orbit (LEO) in coming years.
- The ITU is the United Nations specialised agency for information and communication technologies, with a membership of 193 member states, some 900 companies, universities, and international and regional organisations. The FCC is the statutory communications regulator of the US.
Why is it necessary to launch satellites in order to provide Internet services?
- This is mainly to ensure that reliable and uninterrupted Internet services now part of humanity’s basic infrastructure.
- An important means of delivering a wide variety of public services to the world’s peoples are universally available in every part of the globe.
- Currently, about 4 billion people, more than half the world’s population, do not have access to reliable Internet networks.
- And that is because the traditional ways to deliver the Internet fibre-optic cables or wireless networks cannot take it everywhere on Earth.
- In many remote areas, or places with difficult terrain, it is not feasible or viable to set up cables or mobile towers.
Present usage of Internet from the Geo-Stationary Satellites:
Space-based Internet systems have, in fact, been in use for several years now but only for a small number of users.
Most of the existing systems use satellites in geostationary orbit. This orbit is located at a height of 35,786 km over the Earth’s surface, directly above the Equator.
Satellites in this orbit move at speeds of about 11,000 km per hour, and complete one revolution of the Earth in the same time that the earth rotates once on its axis.
To the observer on the ground, therefore, a Satellite in Geo-Stationary orbit appears stationary.
But, How will placing satellites in lower orbits help?
- One big advantage of beaming signals from geostationary orbit is that the satellite can cover a very large part of the Earth.
- Signals from one satellite can cover roughly a third of the planet and three to four satellites would be enough to cover the entire Earth.
- Also, because they appear to be stationary, it is easier to link to them. But satellites in geostationary orbit also have a major disadvantage.
- The Internet is all about transmission of data in (nearly) real time. However, there is a time lag called latency between a user seeking data, and the server sending that data.
- And because data transfers cannot happen faster than the speed of light (in reality, they take place at significantly lower speeds), the longer the distance that needs to be covered the greater is the time lag, or latency.
- In space-based networks, data requests travel from the user to the satellite, and are then directed to data centres on the ground. The results then make the same journey in the reverse direction.
Bringing down the Latency from 600 milliseconds to 20-30 milliseconds:
A transmission like this from a satellite in geostationary orbit has a latency of about 600 milliseconds.
A satellite in the lower orbit, 200-2,000 km from the Earth’s surface, can bring the lag down to 20-30 milliseconds, roughly the time it takes for terrestrial systems to transfer data.
The LEO extends up to 2,000 km above the Earth’s surface.
The Starlink satellites the 12,000 for which SpaceX has permission, as well as the other 30,000 that it wants to launch will be deployed in the altitude band of 350 km to 1,200 km.
However, Lower Orbits have their own problem:
Owing to their lower height, their signals cover a relatively small area. As a result, many more satellites are needed in order to reach signals to every part of the planet.
Additionally, satellites in these orbits travel at more than double the speed of satellites in geostationary orbit about 27,000 km per hour to balance the effects of gravity.
Many more satellites are needed in the networks, so that there are no breaks in the transmission of data.
That is the reason why the Starlink network is talking about 42,000 satellites.
When will Starlink be able to provide its space-based Internet service?
- Starlink aims to start service in the northern United States and Canada in 2020, and expand to cover the whole world by 2021.
- The current plan is to deploy satellites in two constellations of around 4,400 and 7,500.
- Launches 60 satellites at a time will take place at frequent intervals now onward.
- SpaceX says it can start services on a small scale once 400 satellites join the network.
- Once operational, space-based Internet networks are expected to change the face of the Internet.
- Services such as autonomous car driving are expected to be revolutionised, and the Internet of Things (IoT) can be integrated into virtually every household, whether urban or rural.
Is there a downside to this projection?
Three issues have been flagged increased space debris, increased risk of collisions, and the concern of astronomers that these constellations of space Internet satellites will make it difficult to observe other space objects, and to detect their signals.
To put things in perspective, there are fewer than 2,000 operational satellites at present, and fewer than 9,000 satellites have been launched into space since the beginning of the Space Age in 1957. Most of the operational satellites are located in the lower orbits.
Too many satellites could lead to a space-junk catastrophe:
- Over 100 million bits of junk surround Earth, from abandoned satellites, spacecraft that broke apart, and other space missions.
- Each piece of debris, no matter how small, travels at speeds high enough to inflict catastrophic damage to vital equipment. A single hit could be deadly to astronauts on a spacecraft.
- The more stuff we put into orbit, the higher the risk of collisions becomes.
- Any potential collision would fragment satellites or other orbiting objects into smaller pieces, making additional collisions more likely.
- If such a situation were to spiral out of control, that could spur a catastrophic chain crashes known as a Kessler event.
Recently, the European Space Agency (ESA) had to perform, for the first time ever, a “collision avoidance manoeuvre” to protect one of its live satellites from colliding with a “mega constellation”.
Astronomers and scientists have also complained about increased “light-pollution”, a reference to light reflected from the man-made satellites that can interfere with and be mistaken for light coming from other heavenly bodies.
One collision could create and spread bits of junk that then cause another collision, which in turn begets more debris and leads to a chain of crashes.
Eventually, Earth would wind up surrounded by a field of debris so impassible that any spacecraft passing through would be unable to avoid catastrophic collisions.