The Soviet Union's robotic probe Luna 24 successfully lands on the Moon.

The Union of Soviet Socialist Republics (USSR), commonly known as the Soviet Union, was a transcontinental country that spanned much of Eurasia from 1922 until it dissolved in 1991. During its existence, it was the largest country by area, extending across eleven time zones and sharing borders with twelve countries, and the third-most populous country. An overall successor to the Russian Empire, it was nominally organized as a federal union of national republics, the largest and most populous of which was the Russian SFSR. In practice, its government and economy were highly centralized. As a one-party state governed by the Communist Party of the Soviet Union (CPSU), it was the flagship communist state. Its capital and largest city was Moscow.

Luna 24 was a robotic probe of the Soviet Union's Luna programme. The 24th mission of the Luna series of spacecraft, the mission of the Luna 24 probe was the third Soviet mission to return lunar soil samples from the Moon. The probe landed in Mare Crisium. The mission returned 170.1 g (6.00 oz) of lunar samples to the Earth on 22 August 1976.

The Moon is Earth's only natural satellite. It orbits around Earth at an average distance of 384,399 kilometres (238,854 mi); about 30 times Earth's diameter. Its orbital period and its rotation period are synchronized at 29.5 days by Earth's gravity pulling on the Moon. This makes the Moon tidally locked to Earth, always facing it with the same side. The Moon's gravitational pull produces tidal forces on Earth, which are the main driver of Earth's tides.

August 18 is the 230th day of the year in the Gregorian calendar; 135 days remain until the end of the year.