Middle of november 1971.
Mariner 9 orbited Mars in November 13, 1971.
The first Mars space probe expeditions that did not land on Mars were the Mariner missions, specifically Mariner 4, Mariner 6, and Mariner 7. These missions provided the first close-up images of Mars and valuable data about the planet's environment.
NASA's mariner 4,6,7 and 9 NASA's viking land 2 the mars global surveyor and the pathfinder
It was a 1971 Mars Orbiter.
May 19 - Mars probe program: Mars 2 is launched by the Soviet Union.May 30 - Mariner program: Mariner 9 is launched toward Mars.Nov 13 - Mariner program: Mariner 9 becomes the first spacecraft to enter Mars orbit successfully.
The Mariner 9.
November 30, 1971
Mariner 9 orbited Mars from November 14, 1971, to October 27, 1972, making it the first spacecraft to orbit another planet. It conducted extensive studies of the Martian surface and atmosphere, sending back thousands of images of the planet.
Mariner 9, Mariner5, Viking 1 and Viking 2
Mariner 4 was the first ship to visit Mars.
Mariner 4 (USA) was the first successful fly by mission, which was launched in 1964. Mariner 9 (USA) was the first probe to orbit another planet (Mars) when it entered into orbit around Mars on November 14, 1971. Mars 2 & 3(USSR) were the first probes to "land" on Mars - probably crashed in 1971 Viking 1 & 2 (USA) were the first probes to successfully land in 1976. See related link for more information.
Mariner 9 was sent out by NASA to orbit Mars and study the planet's surface, atmosphere, and climate. It was the first spacecraft to orbit another planet and provided valuable data on Mars, including detailed images of the surface that revealed features like volcanoes and valleys.