Space Race — 3 museum-grade prints from the period. Sputnik 1 was the first artificial satellite to orbit Earth, launched 4 October 1957 from Baikonur on the R-7 rocket. Its radio beacon — heard worldwide on 20 MHz and 40 MHz — announced the Space Age and triggered the Space Race that reshaped Cold War science funding, education policy, and military space programmes. Sputnik 2 launched Laika — the first dog in orbit — on 3 November 1957, barely four weeks after Sputnik 1. The mission demonstrated that a living organism could survive launch and early orbital conditions, paving engineering assumptions for Vostok human flights. Explorer 1 was the first successful US orbital launch on 31 January 1958, responding to Sputnik 1 with a science payload rather than a hollow sphere. James Van Allen's Geiger counter aboard the spacecraft discovered the radiation belts that now bear his name — a finding that shaped radiation shielding for every crewed mission that followed.