Satellites: Unlocking New Boundaries
By: Pujan Yadav
Tags: Science, NASA, Space, Technology, World Space Week

The role and impact of satellite technology in everyday life!

Space agencies and services companies spend millions each year to send new satellites into our orbit. But is it actually necessary? And what could be the reason behind this amount of expenditure? Are we wasting time and effort?

The space race began when the Russians took a leap of faith with the Sputnik 1. These new satellites were meant for military purposes; predominantly to establish radio communications. Unfortunately, the Sputnik 1 burned up after completing 1440 orbits around the Earth — a huge achievement, and marking the beginning of “The Monitoring Era.”

The word satellite means ‘companion’ from the Latin word ‘satellium’. Obviously, since the moons were planetary companions, we started calling them the natural satellites. And ones we launched, we called them artificial satellites. A fun fact: the word Sputnik also stands for ‘companion’ in Russian. So if the Sun is accompanied by Earth, must not Earth be a satellite as well?

Satellites are classified into a boatload of varieties factoring on size, type of orbit, altitude, inclination and eccentricity. But, just by focusing on the type of orbit, we can analyse the various functions a satellite performs in a typical day.

Following Sputnik, many attempts were made to establish communications over the radio, by both the USSR and the US. However, the first non-probationary satellite, called the TIROS, was sent into orbit by the Radio Corporation of America (RCA). It was meant to test the Television (TV) capabilities and the worldwide meteorological satellite information system, or in short, the weather monitoring.

By the 1980s, the North Americans and many European countries had successfully installed TV and communications satellites. These are what we call Geostationary satellites. Geostationary satellites are very far from the ground and are stationary relative to the Earth’s rotation. They basically hover directly over a specific spot on the Earth. This is also the reason why all the TV antennas or receiver dish in a locality focus in the same direction. They’re all aiming for the same satellite. Another important application of a satellite is, of course, weather monitoring. There are multiple types of orbits that these can follow. However, the geostationary orbit is optimal because the weather is reported continuously for a given region.

Working of a GPS system. Credits: Mocomi

Global Positioning System or GPS is one of the highly used and important functionalities of satellites. However, the way they work is a bit complex. It would make sense that a GPS satellite is geostationary since one can always connect their GPS device at any time of the day. But the fact is that GPS does not use a geostationary orbit. A GPS satellite uses, what is called, a medium Earth orbit (MEO). This is a great article from NASA explaining the MEO. In short, a GPS satellite can only stay reachable from a given spot on Earth for a configured time (generally 12 hours), after which another such satellite replaces it. Similar to MEO, we have the LEO or the low Earth orbit. It is much closer to the Earth (a factor of 20 to 40 times) than the previously discussed orbits. This is where the International Space Station orbits the Earth.

Satellites also find use when one needs to communicate from areas with no reception. Special devices have been made which are used in expeditions, scientific exploration sites, and even by the military where information can be remotely accessed or a mayday call can be made. A very important application of satellites that comes into the picture here is a relay. A relay satellite is one that communicates with different satellites in orbit and acts as a medium of transfer. This way, we can even access the satellites which are on the other side of the Earth!

Image of a shark trying to eat away your ability to read this article. Credits: WIRED

Believe it or not, the Internet wouldn’t cease to function if there weren’t any satellites. The Internet actually works by cabling the connections and not wireless transfer. Yes, these cables go over the Pacific and the Atlantic Oceans too!

As human endeavours expanded, so did the technology. As we further explored the various possible applications of satellites, we discovered its true potential. New types of orbits were used to satisfy different needs. An interesting concept was that of the Sun-synchronous orbit (SSO). A satellite using this type of an orbit would be stationary with respect to the movement of the Sun on the Earth. This means that the satellite would pass over the same place, at the same time, every day. This is useful in certain weather monitoring applications as well as ‘spying’ applications.

We have explored all kinds of applications, but one remains — telescopes and imaging satellites. These satellites may have varied orbits, depending upon the application. The Hubble telescope is fairly close to the Earth (at ~570 kilometres and has a circular orbit. However, newer telescopes are aiming at the Lagrange-point orbits, which are more than a million kilometres away! These will help the telescopes avoid the distortions created by the Earth’s atmosphere and possibly help us detect the objects that have never been detected before.

So many companions in the sky. Credits: Graphique

Whatever the case, the exploration of satellite technologies has led to the creation of various other technologies. These have formed an integral part of our lives and will continue to play even bigger roles. Satellites have been one of the major factors in advancing technology. Not only this, but they have also created various new industries. This only goes to show; satellites are pushing new boundaries and will only continue to do so.