Question

On which planets have humans landed spacecraft

Answer 1

The planets on which humans have (successfully) landed spacecraft  are Venus and Mars.

On December 15, 1970 an unmanned Soviet spacecraft , Venera 7, became the first spacecraft to land on another planet. This was followed in 1972 by Venera 8 and  Venera 9 in 1975. In total, the Soviet Union sent seven Venera spacecraft onto Venus with the last being Venera 14 in 1982.

On December 2 1971, the  Soviet Union's Mars 3 spacecraft landed on Mars. The spacecraft however only transmitted for 20 seconds perhaps due to dust storms on the planet's surface.

Less than five years later, NASA's Viking 1 touched down on Chryser planitia, a smooth circular plain in the northern equatorial region of Mars. This was quickly followed by its twin Viking 2 . NASA has  expanded its exploration of Mars by landing rovers on the planet's surface, from the rover  Sojourner in 1977 to Curiosity in 2012.