How long was the space race?

The opening date is uncontested. On 4 October 1957 the Soviet Union placed Sputnik 1 in orbit, a polished 83.6 kg sphere whose radio beeps were audible to amateur receivers worldwide and whose political effect in Washington was immediate. The United States answered with Explorer 1 on 31 January 1958 and created NASA that October.

The closing date is where historians diverge. One reading ends the race on 20 July 1969, when Apollo 11 landed and the goal President Kennedy had set in May 1961 was met — a span of just under twelve years. The other continues to 17 July 1975, when an Apollo command module docked with a Soyuz in orbit and the two crews shook hands, the first joint American-Soviet flight and a deliberate symbol of détente. That reading gives close to eighteen years.

The pace was extraordinary. Laika flew in November 1957; Luna 2 struck the Moon in September 1959; Yuri Gagarin became the first human in orbit on 12 April 1961, followed by Alan Shepard's suborbital flight three weeks later. Valentina Tereshkova flew in June 1963, Alexei Leonov performed the first spacewalk in March 1965, and Gemini matured rendezvous and docking. The Soviets led almost every early first; the United States led the one that closed the contest.

The race ended because its logic did. The Soviet N1 heavy launcher failed on all four test flights and its lunar programme was abandoned. Apollo funding, which had absorbed an enormous share of the federal budget, was cut, and the final three landings were cancelled. What followed was cooperation in orbit, not competition.