Sputnik 1: The First Machine in Orbit
Listen to the radio transmissions from Sputnik 1
In 1952, a group of international scientists came to the consensus that, based on historical data, 1957 would be the start of a high solar activity period. To capitalize on the potential scientific gain, countries around the world sought to place equipment in orbit that would allow them to make measurements during that crucial window.
In 1955, the United States announced their intention to place a satellite into orbit, and a number of research organizations began development on various designs to compete for the project. However, in 1957, the Soviet Union beat the US to a successful orbital satellite by launching Sputnik I.
As the world's first artificial satellite, Sputnik I did not feature very advanced technology, and nothing that could be considered a "computer". However, what it may have lacked in onboard scientific equipment was more than made up for in what it captured in the public's imagination. Sputnik was instantly revolutionary, in part because it was visible with binoculars in the night sky and the radio signals it transmitted could be picked up by amateur radio equipment operators listening on the ground. In the United States, Sputnik I sparked fears of Russian dominance in military superiority.
Sputnik I burned up only a few weeks after its launch, but during those weeks it still managed to spark an entirely new era of scientific advance and revealed the possibility of using satellites for military and commercial applications.
The Rise of Contemporary Satellites
After several decades of exploratory satellite launches, access to satellite technology began to become more widespread during the 90's and multiple countries were able to start launching satellites that remain in orbit today.
The following chart shows the frequency of still-orbiting satellite launches since 1974. As can be seen from the chart, satellite launches have undergone exponential growth in the last decade:
To understand the trends involved with rising satellite use, the following chart breaks down the contributions to global satellite launches by the top 10 countries or entities that sponsored them. All other countries or entities are grouped in the "Other" category:
It's interesting to note that while the USSR was the first to put a satellite in orbit, the data show that modern-day Russia did not start launching significant numbers of satellites until the most recent decade. The United States has historically been the most prolific launcher of satellites, but in the most recent decade China has begun to launch its own satellites at an increasing pace, matching those launched from the US. However, a recent spike in 2017 saw the United States launching 259 satellites, soaring back to being the world's foremost launcher of artificial satellites.
What Satellites Accomplish For The World
Another interesting way to examine satellite launches is to compare the uses they have been put to since they first started becoming prevalent in the 1990's. The following chart breaks down the reported use categories for each satellite that is still orbiting the Earth today:
The first satellites were designed for military use, and when satellite launches first started becoming common in the 1990's they were primarily used for communications, likely for military purposes. However, throughout the early 2000's a clear trend emerged that saw Earth Observation satellites becoming more popular, both for the purpose of military reconnaissance and for commercial mapping of the Earth. In 2017, there was a massive spike in Earth Observation satellites launched by the United States.
Kessler Syndrome: A Worst-Case Future
Although the amount of space possible for satellites to orbit is tremendous, we can't continue to put satellites in orbit forever. As NASA scientist Donald J. Kessler identified in 1978, because most satellites can be destroyed with the impact of only a tiny piece of debris, the total number of debris particles poses a much greater risk to satellites in orbit than their total mass.
The threat posed to satellites, now known as "Kessler syndrome", is that each collision happening in Earth orbit creates an exponentially greater risk to the other objects in Earth orbit. If two satellites, traveling at extremely high speeds through space, were to collide, they would create a high number of additional objects also traveling at high speed. This serves to exponentially increase the number of objects that may collide, ultimately leading to a cascading effect where the chance of satellites experiencing collisions continues to rise.
There are ways we can mitigate the threat posed by Kessler syndrome, such as by moving defunct satellites out of orbit once they have reached the end of their carefully-calculated operation lifespans. However, the threat posed by Kessler syndrome cannot be ignored as the human race continues to increase its reliance on satellite communications. If anything, Kessler's observation makes it clear that we have to consider a possible future in which satellite launches are impossible.
Works Consulted
UCS Satellite Database. Union of Concerned Scientists, 9 Jan. 2019, www.ucsusa.org/nuclear-weapons/space-weapons/satellite-database.
This source provided a database with information about the origin and purpose of the satellites currently in orbit around Earth. It was used to create the data visualizations and informed the conclusions made about them.
“Sputnik and The Dawn of the Space Age.” NASA, NASA, 10 Oct. 2007, history.nasa.gov/sputnik/.
This source provided background information about the beginning of the space race and the launch of Sputnik I.
“Sputnik Launched.” History.com, A&E Television Networks, 24 Nov. 2009, www.history.com/this-day-in-history/sputnik-launched.
This source had additional background about Sputnik I.
“The Kessler Syndrome Explained.” Space Safety Magazine, www.spacesafetymagazine.com/space-debris/kessler-syndrome/.
This source gave information about the theoretical idea of Kessler syndrome and the dangers it poses.