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.

The mission of Ranger 8 was to take high-resolution photographs of the Moon before impacting the lunar surface. Ranger 8 impacted the Moon about 15 miles (24 kilometers) from its target in the Sea of Tranquility, the area where Apollo 11 landed July 20, 1969, bringing the first humans to

The mission of Ranger 7 was to take high-resolution photographs of the Moon before impacting the lunar surface. The images taken by Ranger 7 helped scientists conclude the Apollo astronauts could safely land in the smooth mare regions (the "seas") of the Moon.

Ranger 6 was principally designed to transmit high-resolution photographs of the Moon before impacting the lunar surface. The spacecraft carried six television videocon cameras, however, due to a failure of the camera system, no images were returned.

Ranger 4 was designed to transmit pictures of the lunar surface to Earth stations during a period of ten minutes prior to impacting on the Moon.