Mariner 9 was a NASA spacecraft launched on May 30, 1971, to explore the planet Mars. It became the first spacecraft to orbit another planet, entering Mars' orbit on November 14, 1971. The mission aimed to study the Martian surface, atmosphere, and weather patterns. During its mission, Mariner 9 transmitted over 7,000 images, revealing detailed features of Mars, including volcanoes, canyons, and polar ice caps. The data collected helped scientists understand the planet's geology and climate, significantly advancing our knowledge of Mars and laying the groundwork for future exploration missions.