Mariner 9

Mariner 9 (Mariner Mars '71 / Mariner-I) was a robotic spacecraft that contributed greatly to the exploration of Mars and was part of the NASA Mariner program. Mariner 9 was launched toward Mars on May 30, 1971, from LC-36B at Cape Canaveral Air Force Station, Florida, and reached the planet on November 14 of the same year, becoming the first spacecraft to orbit another planet – only narrowly beating the Soviet probes Mars 2 (launched May 19) and Mars 3 (launched May 28), which both arrived at Mars only weeks later. After the occurrence of dust storms on the planet for several months following its arrival, the orbiter managed to send back clear pictures of the surface. Mariner 9 successfully returned 7,329 images over the course of its mission, which concluded in October 1972. Mariner 9 was designed to continue the atmospheric studies begun by Mariner 6 and 7, and to map over 70% of the Martian surface from the lowest altitude () and at the highest resolutions (from 1 kilometer to 100 meters (1,100 to 110 yards) per pixel) of any Mars mission up to that point. An infrared radiometer was included to detect heat sources in search of evidence of volcanic activity. It was to study temporal changes in the Martian atmosphere and surface. Mars' two moons were also to be analyzed. Mariner 9 more than met its objectives. Under original plans, a dual mission was to be flown like Mariners 6–7, however the launch failure of Mariner 8 ruined this scheme and forced NASA planners to fall back on a simpler one-probe mission. NASA still held out hope that another Mariner probe and Atlas-Centaur could be readied before the 1971 Mars launch window closed. A few logistical problems emerged, including the lack of an available Centaur payload shroud of the correct configuration for the Mariner probes, however there was a shroud in NASA's inventory which could be modified. Convair also had an available Centaur stage on hand and could have an Atlas readied in time, but the idea was ultimately abandoned for lack of funding.