1997年7月4日：旅居者号抵达红色星球
Hitching a ride on the Mars Pathfinder mission, the Sojourner rover arrived at the Red Planet on July 4, 1997. The mission was designed to demonstrate a low-cost method for delivering a set of science instruments to Mars, and served as the foundation for the Mars rovers of today. Pathfinder landed the rover using an air bag landing system and innovative petal design, which have been used since in various incarnations to land other rovers on the Red Planet. Sojourner spent 83 days of a planned seven-day mission exploring the Martian terrain, snapping photographs and taking chemical, atmospheric and other measurements. The lander, formally named the Carl Sagan Memorial Station following its successful touchdown, and the rover, named after civil rights pioneer Sojourner Truth, both…