Timeline

20th century

1. October 4, 1957★★★★★

   Launch of Sputnik 1

   The Soviet Union launches Sputnik 1, Earth's first artificial satellite, opening the Space Age.

   TechnologyExploration· Russia, Kazakhstan
2. April 12, 1961★★★★★

   Gagarin becomes the first human in space

   Soviet cosmonaut Yuri Gagarin orbits the Earth aboard Vostok 1, becoming the first human in space.

   ExplorationTechnology· Russia, Kazakhstan
3. April 26, 1986★★★★★

   Chernobyl disaster

   Reactor No. 4 of the Chernobyl nuclear power plant in Soviet Ukraine explodes, spreading radioactive material across Europe in the worst nuclear accident in history.

   DisasterTechnology· Ukraine, Belarus, Russia
4. November 20, 1998★★★★★

   First module of the International Space Station launched

   The Zarya module is launched from Baikonur, beginning assembly of the multinational International Space Station.

   TechnologyScienceExploration· Russia, Kazakhstan, United States