October 4·Every year

World Space Week

World Space Week runs October 4–10, the dates bookended by two milestones: Sputnik's launch on October 4th, 1957, and the Outer Space Treaty's signing on October 10th, 1967. The UN proclaimed the week in 1999. Over 90 countries now participate with educational events, telescope nights, and screenings. The cosmos is the one domain where national borders genuinely do not apply.