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Ranger 9 was the last of the Ranger series of spacecraft launched in the 1960s to explore the moon and was designed to image and impact the moon's crater Alphonsus, which was thought to be the site of recent lunar volcanic activity.
Unlike its predecessors, Ranger 9 pointed its cameras directly in its direction of travel, yielding stunning photographs of the lunar surface. Data from the mission dramatically improved scientists' understanding of the moon's mass and lead to the discovery that the moon's center of mass is displaced from its geometric center.
- Imaging system