Artist's rendering of Sputnik

On October 4, 1957 a small object had people around the globe looking excitedly – or anxiously – up at the sky. Satellites are now such a fact of life, people today would find it hard to imagine the effect of the very first one. In sending up Sputnik, the USSR had thrown down the gauntlet for the Cold War's space race.

International Geophysical Year
Some individuals had already realized that rockets didn't have to be weapons. They could take satellites – and perhaps even humans – into space. But in the 1950s the immediate stimulus for launching an artificial satellite came from an international scientific project, the International Geophysical Year (IGY).

IGY was longer than a year, lasting from mid-1957 to the end of the following year. Sixty-seven countries took part, and they agreed all data would be be received by a number of data centers and made available to everyone.

As part of this effort, satellites could provide valuable geophysical data, but the development costs would be high. Yet in July 1955 the USA announced it would be launching a satellite for IGY. Not to be outdone, the Soviet Union also decided to launch one.

Sputnik
Although the USA had more resources than the Soviet Union, the Soviets nonetheless set to work on an ambitious program that included a launch vehicle, scientific satellite, and ground stations for tracking. When they found that their plan was too ambitious for the time available, they abandoned it. But they didn't give up. They wanted to be first, and their strategy was to design and build a very simple satellite and launch it with a military ballistic missile. Sputnik – it meant fellow traveler – was born, and the word later became a generic term.

Sputnik was spherical. It was about the size of a beach ball, and made of a shiny metal alloy. There were two pairs of radio antennae sticking out and famously, Sputnik continuously beeped out its radio signal as it orbited. The satellite was in a low Earth orbit, taking 96 minutes to complete one orbit. Batteries that lasted just over three weeks provided the power.

Although Sputnik didn't have sensors, scientists used its radio signals to calculate temperature and pressure, as well as the density of the upper atmosphere. There wasn't much data, but Sputnik fulfilled its main purpose: a giant propaganda coup against the USA.

The Americans had assumed that they would be first in space, so Sputnik was a shock. It got worse when a month after Sputnik 1, the Soviets launched Sputnik 2 with the dog Laika on board. The heavy payload was impressive, though it didn't impress animal lovers.

The space race was on
The Cold War had begun not long after World War II ended. The space race was a new competitive aspect of it, and Round 1 went to the Soviet Union.

Meanwhile in the USA, as James Woudhuysen writes,

Sputnik 1 transmitted its signal for 22 days, then continued to orbit. It finally dropped out of orbit in early January 1958 and burned up as it re-entered Earth's atmosphere.

But at the end of January, at last, the first American satellite – Explorer 1 – was launched. It was the first to carry scientific instruments, including a cosmic ray detector that measured radiation in Earth orbit. This instrument, designed and built by James A. Van Allen, discovered the radiation belts encircling the Earth. They now bear his name.

In March 1958 the USA launched Vanguard 1. It reached the highest altitude of any of the four satellites, and was the first to be solar-powered. Interestingly, it's the oldest artificial satellite still in orbit, but it hasn't transmitted since 1964.

Reactions to Sputnik
Radio amateurs around the world were tuning in to Sputnik. And people went outside to try to spot it coming overhead. The satellite was visible with binoculars. However the upper stage of the rocket that shared the satellite's orbit was larger than Sputnik itself, very bright, and visible to the unaided eye. Some people were excited by the dawn of the Space Age, but others were fearful.

The Soviets were happy to inform the world of their superior technology. However US President Eisenhower had known about much of it from U-2 surveillance flight photos, and wasn't fazed when Sputnik appeared in the sky. Other politicians weren't so calm and exploited it for their own purposes. Much of the American public was unsettled by the perceived gap between the two countries, and wondered what this Soviet space technology meant for their possession of guided missiles?

The founding of the National Aeronautics and Space Administration (NASA) was a direct result of Sputnik. And the US government decided they needed a greater emphasis on science and technology in schools. If only that were still a priority!

Reference:
James Woudhuysen, “Sputnik: when American fears went into orbit” https://www.spiked-online.com/newsite/article/3926#.V_YxQrVc_sk