Sputnik 1: the first artificial satellite

Satellites are fantastically useful tools, and there are thousands of them in orbit around the Earth right now. We’ve already talked about satellite orbit types and what satellites are used for. Before the current age of satellites could come into being, though, someone had to take the first step.

In today’s post, we’re taking a look at the early history of satellites, and in particular at Sputnik 1: the first artificial satellite in space.

What was Sputnik 1?

On 4 October 1957, the Soviet Union launched the world’s first manmade satellite, Sputnik 1, into low Earth orbit. Sputnik 1’s orbit was elliptical; it was approximately 230 km from Earth at its closest point (perigee) and 940 km away at its furthest point (apogee). It took just under an hour and a half to circle the entire planet.

Sputnik 1 was an extremely simple satellite. It was a metal sphere with four long antennas protruding from it. It contained a thermometer, a fan, a radio transmitter, batteries and little else.

The sphere was only 58 cm in diameter and weighed 83 kg, making it very small and light in comparison to many of today’s satellites. Modern-day geostationary communications satellites can weigh as much as 7,000 kg: over eighty times as much as Sputnik 1. The largest artificial satellite currently in orbit, the International Space Station, weighs more than 5,000 times as much as Sputnik 1 at 440,000 kg.

Why was the first satellite called Sputnik?

‘Sputnik’, or спутник, literally meaning ‘fellow traveller’, is simply the Russian word for a satellite. Although Sputnik 1 was the first artificial satellite, the word ‘sputnik’ was already in use to describe natural satellites such as moons.

‘Sputnik 1’ was therefore more a description than a name. It would be similar to an English-speaking country launching a satellite called ‘Satellite 1’.

What was the international response to Sputnik?

Sputnik 1’s successful launch created huge international interest.

The launch took place in the midst of the Cold War, and it was seen as a display of great technological ability from the Soviet Union. This created a sense of anxiety and competition in the USA, which considered the Soviet Union a rival.

The USA hurried to catch up and, on 6 December 1957, just two months after Sputnik 1’s launch, attempted to launch the satellite Vanguard TV-3. Unfortunately, the launch was unsuccessful. The unmanned rocket carrying the satellite lost thrust almost immediately, fell back to the landing pad and exploded in a fireball. Although there was no live broadcast, the failed launch was filmed, rushed to broadcasters and shown on television within two hours: a discouraging experience for the American public. (For details of the broadcast, see the 16 December 1957 edition of Broadcasting magazine, p.76.)

Vanguard TV-3 was thrown clear of the explosion and recovered, damaged but still transmitting a signal. It can be seen at the National Air and Space Museum in Washington, DC.

On 31 January 1958, the USA successfully launched its first satellite, Explorer 1, making the USA the second country to launch a satellite into space. However, Explorer 1 was not the second artificial Earth satellite; the Soviet Union had already launched another, Sputnik 2, on 3 November 1957.

What was Sputnik 1 used for?

Sputnik 1 didn’t remain in orbit for very long. Its batteries ran out after three weeks, so it could no longer transmit radio signals. Its orbit decayed over time, and on 4 January 1958, three months after launch, it burned up from air friction after re-entering Earth’s atmosphere. Despite this, it was still an incredible achievement.

Sputnik 1’s short life in space gave scientists basic but essential information about how satellites could operate. By observing how quickly the satellite’s orbit decayed, scientists could draw conclusions about atmospheric drag and density at high altitudes. Sputnik 1’s radio transmissions also showed how radio waves could travel through Earth’s atmosphere from orbit.

The signal Sputnik sent out was a simple one; it transmitted a steady beeping. However, it had a very simple, very clever way of communicating major changes in pressure or temperature. If the pressure inside the satellite dropped dramatically due to a puncture (Sputnik was filled with nitrogen gas), or if the temperature went above or below a certain threshold, a switch would be triggered and the beeping would become slightly different. Because of this, Sputnik could convey specific information without needing to transmit anything more complicated than a beep.

These beeps weren’t solely received by researchers. Any interested member of the public with a shortwave radio could tune in and hear Sputnik beeping as it travelled overhead.

Sputnik 1’s most significant function was simply being the first artificial Earth satellite. It told the world that artificial satellites weren’t simply theoretical; it was possible to put an object into orbit around the Earth. With this knowledge, researchers were able to build on Sputnik’s success and launch more ambitious satellites.

In the present day, we make use of satellites on a daily basis. We use them for navigation, communications, weather forecasting and much more. None of that would have been possible without somebody taking that first step. In that sense, both modern society and Darwin owe a lot to Sputnik.

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