Historical Photo Of The Month - July 2004

Ranger 7 Camera Views
Photograph Number P-3594B

In July, JPL celebrates the 40th anniversary of the successful launch of Ranger 7 and the data it returned -- welcome news after the disappointment of Rangers 1-6. The spacecraft was launched July 28, 1964 and impacted on the surface of the Moon three days later, at the Sea of Clouds. During the 17 minutes leading up to impact, Ranger 7 transmitted 4316 photographs to Earth.

The spacecraft carried a total of six television cameras. F_a and F_b were full-scan (400 optical line pairs) cameras. P₁, P₂, P₃, and P₄ were partial-scan (100 optical line pairs) cameras. The image above shows a mosaic of the Moon, with images taken from several observatories on Earth. Lines were added by the Ranger project team to show expected camera fields of view as a set of distorted squares, growing smaller as the spacecraft falls toward the surface of the Moon. The set of three larger squares on the left show the field of view for camera F_a and the three smaller squares to the right are for camera F_b. The vertical line at center is the terminator, where sunset was expected to happen near the impact sight. One of the challenges for the Ranger team was to make sure the spacecraft impacted on the sunlit side of the Moon, not the dark side.

For more information about Ranger, see the Space Programs Summary No. 37-29, Volume I, The Lunar Program, for the period July 1, 1964 to August 31, 1964, or contact the JPL Archives.

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