Any of a series of unmanned Soviet lunar probes. Luna 2 (launched Sept. 12, 1959) was the first spacecraft to strike the Moon, and Luna 3 (Oct. 4, 1959) made the first circumnavigation of the Moon and returned the first photographs of its far side. Luna 9 (Jan. 31, 1966) made the first successful lunar soft landing. Luna 16 (Sept. 12, 1970) was the first unmanned spacecraft to carry lunar soil samples back to Earth. Luna 17 (Nov. 10, 1970) soft-landed a robot vehicle for exploration. It also contained television equipment, by means of which it transmitted live pictures of several kilometres of the Moon’s surface. Luna 22 (May 29, 1974) orbited the Moon 2,842 times while conducting space research in its vicinity. Luna 24 (Aug. 9, 1976) returned with lunar soil samples taken from a depth of seven feet (about two metres) below the surface.