What was the name of the first artificial satellite, launched on 4 October 1957, a polished metal sphere that broadcast a simple radio beep?

• A Explorer 1
• B Luna 1
• C Sputnik 1 ✓
• D Vostok 1

Sputnik 1 weighed 83.6 kg and orbited for three weeks; its launch triggered the space race and spurred the creation of NASA the following year.