It was April 21, 1961, and the place was Baikonur Cosmodrome in the erstwhile Soviet Union. Vostok 3KA, a space capsule had launched with cosmonaut Yuri Gagarin, making him the first human to cross into outer space. Though the flight lasted just an hour and forty eight minutes, it changed the history of mankind, spanning some thousands of years at the time. Humans had now successfully leaped into the space age.
The space age began when the Soviet Union sent the first artificial satellite, Sputnik, into outer space. But the Vostok flight was different. Through the eyes of Yuri Gagarin, human beings got the first glimpse of the blue planet and our only home in the entire universe.
This flight had a political implication as well. The sixties were the time when the cold war between the Soviet Union and the US was at its peak and the Vostok flight immediately triggered the space race. The race to send satellites into outer space, eventually led to mission Moon and Mars. Like the great powers of Spain, Dutch and Portugal who once fought each other to control the high seas five centuries ago, this was the battle to ‘occupy’ outer space by the then world's powers- the US and the erstwhile Soviet Union.
Soon satellites became a symbol of power and status rather than a necessity among nations. In such times, it was only natural to forget that like any other machine, satellites do not last forever. Eventually, all satellites grow old, wear out, and die. The lifetime of a satellite depends on its orbit. For example, on average, a satellite in an initial 300 km high orbit will have a lifetime of only a few months. A satellite in a 500 km orbit has a lifetime of around 10 years, and one at 1,000 km will stay in orbit for many years.
According to an estimate by the National Aeronautics and Space Administration, US, there are more than 10 crore objects in space, ranging from less than 1 cm to 10 cm. These numbers continue to rise every day as the number of satellites in space continues to grow.
But what happens when a satellite’s time has come? At first look, the tiny debris may seem harmless. Satellite fragments are revolving around the earth at a speed of ten kilometres per second and because of its high speed, it has high kinetic energy. A typical impact occurs at a speed of 10 km/sec or 36,000 km/hour. For example, at this speed, a fragment of just 2 mm will hit like a cricket ball at 100 km/hour and a 10 mm fragment at the same speed will hit like a large motorbike at 100 km/hour.
Now the question is what to do with the ever-increasing space debris? The heat from friction in the atmosphere burns up the satellite as it falls towards earth at thousands of miles per hour. For larger spacecraft, there is a final destination far away from human civilisation. Called the Spacecraft Cemetery, it’s located in the Pacific Ocean.
The cloud of debris has now created a new problem for astronomers who relied solely on the light coming from far away galaxies and stars to study them. Because of the debris, the light gets distracted and scattered making the vision blurry. Space debris or human-made junk in space is the best example of the paradox of progress. The technology which once enabled us to see our planet from outer space and to get an insight into our origins is now blurring our vision.