On 4 October 1957, the Soviet Union launched Sputnik, the first-ever artificial satellite in space. It was as big as a basketball and weighed around 85 kg. Carried on a giant rocket, Sputnik was put in a low Earth orbit about 577 km high. That is a little shorter than the distance between Belfast and London.
Once separated from the carrier rocket, Sputnik 1 started orbiting the Earth, just like the Moon, but it was much faster. At a speed of 29,000 km per hour, Sputnik could complete one circulation around the Earth in just 90 minutes. And while doing so, it sent small beeps from space as tiny little hellos from the other side. Anyone with a radio receiver from anywhere around the world could hear these hello beeps.
By 5 October 1958, that basketball-sized metal satellite had already changed the world forever as it opened the door for all the space technologies we now have.
So how could Sputnik do that? Why was it sent to space? And what is a satellite in the first place?
Well, this is precisely what we are discussing in today’s lesson.
So let’s hop into it.
What is a satellite?
In astronomy, a satellite is a celestial object that orbits another bigger object. In this context, Earth is a satellite because it revolves around the Sun. Likewise, the Moon and the Galilean moons are satellites because they orbit the Earth and Jupiter, respectively. Such objects are known as natural satellites.
Then, humans mimicked the universe by making large devices and sending them to space to orbit the Earth and other planets. These man-made objects are called artificial satellites.
To simplify the terminology, the word Moon, capitalised, is used to refer to the Earth’s natural satellite. Natural satellites themselves are also referred to as moons, lower-cased. In addition, the word satellite is now most commonly used to mean an artificial satellite.
Why are satellites important?
Satellites are not just devices hanging up in the sky and watching Earth from above. But because they watch Earth from above, they can efficiently study our planet and provide us with valuable information about it.
Specifically speaking, satellites are launched to perform different functions. Here are some of the most important ones.
Take, for example, satellite TVs.
TV stations usually send the signals from their tower antennas, through the air, to the receiver antenna at our homes. But these signals cannot travel to distant places. Tall buildings and high mountains can easily block them too.
But when using satellites, TV signals are sent more efficiently, providing better signal quality, and clear pictures on the screen. Instead of travelling in the air, TV signals are projected toward a satellite which then reflects them to different areas on Earth.
The same thing happens with phone signals.
Satellites can also be used to monitor the weather. Since they already hang above the air and clouds, they can provide pictures of the Earth and detect the movement of the wind, clouds, and storms. We can prepare for and protect ourselves from nasty weather with such information.
Similarly, satellites can provide data about wildfire spread, volcano eruptions, and sand storms. Such data comes in handy when dealing with such natural disasters.
Are you familiar with GPS? Well, it is a satellite work too.
This acronym stands for Global Positioning System. With the help of a GPS satellite, we can use this facility to determine our position relative to our surroundings.
All mobile phones are now equipped with a GPS tracking system. When turned on, the GPS on your phone sends a signal to a GPS satellite that says something like ‘tell me where I am. So the satellite, which can quickly locate you based on the signal it receives from your phone, replies with a map of the area and a dot that shows precisely where you are standing.
What are the types of satellites?
As mentioned, satellites are used to perform different functions. So their types vary accordingly. For instance, there are:
- Communications satellites
- Weather satellites
- GPS satellites
- Research satellites
In the same way, telescopes are satellites. They are man-made objects launched to observe space objects and take pictures of the universe. The Hubble Space Telescope and the James Webb Space Telescope are two of the most significant observatory satellites.
Likewise, the International Space Station (ISS) is a satellite. Well, it is the largest satellite currently residing in an Earth orbit. The first part of the station was launched in 1998, and the construction continued until 2011. For over a decade, astronauts travelled back and forth between Earth and space to assemble the pieces and build up the station.
What are the parts of a satellite?
The design, structure, shape, and weight of each satellite vary based on what function the satellite is doing.
For instance, the International Space Station is 108 metres long and weighs about 453.6 metric tons. On the other hand, the James Webb Space Telescope, which is NASA’s largest observatory satellite, is only 22 metres long and 12 metres wide and weighs around 6.2 metric tons.
But apart from the size and structure, each satellite must have three main parts: a power source, an antenna, and a propulsion system.
The power source is necessary to keep the satellite alive and functioning. It can be batteries or solar panels. Solar panels turn sunlight into electricity which keeps the satellite running. They are much more efficient than batteries and help the satellite perform better and stay longer in space.
Antennas are essential so satellites can send and receive signals to and from Earth.
Every satellite must also have a propulsion system. This machine is used to push the satellite forward and helps it stay in its specified position in orbit. If the satellite deviates because of the gravity of the Moon or the Sun, the propulsion system allows it to relocate itself.
Where did the idea of satellites come from?
Well, that goes back to the 17th century.
It is believed that the English scientist Isaac Newton was the one who opened the door to the idea of satellites. He used mathematics to understand how moons revolve around planets using the force of gravity.
Then, it was literature that dived more into the idea. Writers imagined sending objects to space which could orbit the Earth the same way the Moon orbits it. The first known story introducing a satellite was The Brick Moon, published in 1869.
The Brick Moon
The Brick Moon follows the story of a group of friends who thought of building a device and sending it to space to watch Earth from above and help sailors with navigation, much like the North Star.
They made a spherical design and built their ‘moon’ from bricks. They chose bricks to help the moon bear the extreme fraction with the atmosphere and not burn. Yet, they made it hollow to allow the lowest weight possible and ease the launch process.
Accidently, the brick moon was launched with people aboard. But according to the author, they could find a way to survive inside the moon while floating in space.
That 19th-century story was considered fictional back then and up until the 1950s. But it was also quite inspiring, and some might even consider it predictive. For some reason, the author imagined, or maybe believed, that humans could send satellites to space and even travel and survive up there, which they did in less than 100 years.
It was not only that story that featured launching objects to space, but other space-related fantasies continued to appear, whether in literature or the scientific field.
But it was not until 1957 that the first actual satellite came into existence.
What was the first satellite?
It was Sputnik 1. It was Russian. And it was born in one of the most critical periods of the history of humanity.
After World War II, the United States and the Soviet Union started competing with one another. Every country wanted to prove it was more powerful and scientifically advanced than the other. That period lasted until the 1990s and is historically known as the Cold War.
Power meant that one of the two countries had a much more robust military and more powerful weapons than the other. Meanwhile, being more scientifically advanced meant that one country had more science, technology, and a better life than the other. And these two things, power and science, were serving one another.
To be more powerful, each country needed to develop more destructive weapons. While the Americans made the first atomic bomb and later the first hydrogen bomb, the Soviets were superior in rocket technology at the time. They developed rockets that could travel way faster and farther than planes, for instance, from Russia to the United States.
But then they, the Soviets, wondered, if their rockets could travel such a long distance horizontally, why would they not send them vertically to space?
Interestingly, the Soviets were even encouraged by the Americans themselves to send a satellite to space. On 29 July 1955, America announced it would launch satellites in the Spring of 1958. Two days after, on 31 July, the Soviet Union announced it would send a satellite before the Americans, precisely by the autumn of 1957.
And they kept their word.
On 4 October 1957, the Soviets launched Sputnik, the world’s first satellite. As mentioned, it was carried on a Soviet rocket and put in orbit 577 km above. When it arrived in orbit, Sputnik separated, and the rocket fell back to Earth.
Sputnik 1 was as heavy as 85 kg. Its power source was three batteries that were expected to operate for three weeks before they died. Surprisingly, they operated for longer than that, allowing the satellite to send radio signals, the beeps, for a more extended period.
The Soviets used these radio signals to track Sputnik in order, with the help of
Interestingly, the Soviets did not launch Sputnik 1 only to show off their scientific advancement. But the first satellite was also meant to do another job. It studied the higher layers of the atmosphere as it was already residing in the fourth layer, the thermosphere. The Soviets could learn a lot about these upper layers through their effects on the satellite itself and the radio signals it transmitted.
Sputnik 1 revolved around our planet for three months. On 4 January 1958, when it was time to return home, the satellite burned up completely while reentering the atmosphere. By that time, it had already completed 1,440 revolutions around the Earth.
What was the second satellite?
It was Sputnik 2.
A month later, the Soviets sent the second artificial satellite, Sputnik 2, after significantly modifying the first design. For instance, it was larger than Sputnik 1. Instead of a sphere, it was a cone-shaped capsule, four metres high with a base of two metres wide. It weighed 500 kg, almost six times as heavy as Sputnik 1.
Another difference is about the rocket. Sputnik 2 did not separate from the rocket that took it to orbit. In other words, they remained connected and revolved around the Earth together.
Additionally, Sputnik 2 was relatively more complicated than Sputnik 1. It had several radio transmitters instead of only one and multiple other scientific instruments and systems, including one for temperature control.
While Sputnik 1 will always be remembered as the first satellite in space, Sputnik 2 is recognised for carrying the first living passenger, a Muscovite dog named Laika. And because it was carrying a living thing aboard, Sputnik 2 was called a biological spacecraft.
Laika was primarily sent to space to study the effect of being in space on organisms. She was kept in an independent capsule in the satellite, with a television screen transmitting pictures of her back to Earth.
The cabin where Laika was kept provided enough food for the dog to survive for 10 days. But after that, she would run out of oxygen and die. Unfortunately, Laika died much earlier, only after a day or two of launch, because of overheating.
By sending Laika to space, humans slowly and steadily made everything in the 19-century story, The Brick Moon, come true. Soon after, the Soviets would send the first man into space, astronaut Yuri Gagarin. A decade later, the Americans would send the first men to the Moon, astronauts Neil Armstrong and Edwin Aldrin.
Sputnik 2 was sent much higher in space than Sputnik 1. Its orbit was 982 km above. Additionally, it stayed in space much longer, about five and a half months, and revolved around the Earth 2,570 times. Sputnik 2 met the same fate as Sputnik 1 and burned while reentering the atmosphere on 14 April 1958.
The Soviets kept developing their satellites and sent more of them with animal passengers aboard. Luckily for those animals, the Soviets brought them safely back to Earth. That means the mission of Sputnik 2 had already provided them with valuable information about how to survive in space.
What was the world’s reaction to Sputnik 1 and 2?
While both satellites were outstanding achievements for the Soviets, the launch of Sputnik 1 and Sputnik 2 was not well received at all in America. In fact, it was even known as the Sputnik Crisis, as it sparked intense public fear.
The Americans were already viewing the Soviets as their enemies. So, the launch of the two satellites unveiled the giant technological gap between America and the Soviet Union. Such a gap meant the Soviets were more powerful and, therefore, could attack them.
Everyone was panicking and feverishly talked about that gap everywhere on TV and in the newspapers. They believed that the American military was officially behind its Soviet counterpart, and, therefore, they felt threatened.
The launch of Sputnik 1 and 2 also sparked what was known as the Space Race between the United States and the Soviet Union. The two nations publicly competed to explore space, which was why NASA was established.
From then on, satellite technology was taken to a brand new level.
What was America’s first satellite?
While Sputnik 1 and 2 were circulating our planet in different orbits in 1958, the United States tried to launch its first satellite, Vanguard 1A, but it failed. Unexpected engine problems caused the satellite to explode during launch. Vanguard 1A was so small and only weighed 1.36 kg.
Two months later and after major modifications, the US tried to launch another satellite, which was a success this time. The satellite was Explorer 1, and the launch took place on 31 January 1958.
Explorer 1 was only 16.5% the weight of Sputnik 1, almost 14 kg. Unlike the rounded Sputnik 1 and the cone-shaped Sputnik 2, Explorer 1 looked more like a giant pencil or a small rocket. It was only two metres long and 15.2 cm in diameter.
Explorer 1 also ran on non-rechargeable batteries called Mercury batteries. They were expected to keep the satellite alive for three years, but they did not live up to the expectations.
Mercury batteries could only feed the satellite for around four months. During this period, Explorer 1 was sending data back to Earth. But then, the batteries died on 23 May 1958, and the data transmission stopped.
Interestingly, Explorer 1 stayed in orbit for 12 more years and made 58,000 orbits. Then, it reentered the atmosphere on 31 March 1970 and fell into the Pacific Ocean.
While Explorer 1 was still sending data from space, the US tried to send another satellite, Vanguard 1B, but failed. A month later, it tried again with the launch of Explorer 2 but failed too. Meanwhile, the Soviets successfully sent their third satellite on 15 May 1958.
Despite the remarkable achievements it made later, the US was quite unlucky at the beginning of the Space Race and was still falling behind the Soviet Union in space technology. This can be seen from the many times the Americans failed to launch satellites while the Soviets never really failed to send any of theirs.
What about other countries?
Starting 1962, many other countries began launching their satellites. Some of them developed their own using the technology that became widely available. Others bought satellites constructed by either the US or the Soviet Union.
However, most of these satellites were carried to space on American rockets. For instance, the UK successfully sent its first satellite on 26 April 1962, followed by Canada, which constructed its own satellite, and launched it in September of the same year.
In the following years, many other countries launched their satellites into space. These include Italy, France, Australia, Germany, Japan, China, and India.
As of April 2022, there were 5,500 active satellites revolving around our planet. Like our city streets, it is pretty crowded up there. It is expected to get even more crowded since 58,000 active satellites are estimated to be circulating Earth only by 2030!
And here we come to the end of today’s astronomical journey, in which we discussed satellites.
In this article, we learned what satellites mean, their types, and their purposes. We discussed where the idea of satellites came from and how the writers’ imagination somehow inspired the birth of that technology.
Then we moved on to the first satellites ever manufactured and launched into space. We looked into their development and how pioneering they were as they sparked the Space Race between the Soviet Union and the US.
Finally, we discussed America’s first unlucky attempts to send satellites, compared to the Soviets’ successful trials. Soon after, the Americans could get the hang of it and successfully sent people to the Moon.
We hope you enjoyed today’s lesson as much as we loved writing it for you.
And until another one, keep learning.