Chapter 5 of 5

The half-finished final frame

Ranger 7's final transmission and its impact in Mare Cognitum

Told in Ranger 7’s imagined voice · the events are real · source

Guericke Crater as seen by Ranger 7
Ranger 7My last picture was still being sent when I reached the Moon.
NASA/JPL
01The final exposure caught the ground from very low altitude. The spacecraft struck at 13:25:48.82 UTC, while part of the image was still traveling to Earth.
The right side of that last picture became a wall of static.
02The impact stopped the scan before the frame was complete. The left side showed small craters; the right side recorded the sudden end of the transmission.
Engineers stand with Ranger 7 on Dec.
Ranger 7The area where I fell was named Mare Cognitum: the Sea That Has Become Known.
NASA/JPL-Caltech
03The name marked the first part of the Moon seen close-up. My pictures had turned an unknown plain into a place scientists could study.
Years later, a camera in orbit found the crater I left behind.
04Apollo 16 photographed the site in 1972. In 2010, NASA's Lunar Reconnaissance Orbiter imaged a bright, 14-meter-wide crater at 10.6340° S, 339.3230° E.

The big idea

The impact ended the spacecraft, but the images and the crater became evidence that later missions could revisit.

Think about it

How can a place where a machine was destroyed become a useful scientific site?

Fact file

Impact
31 July 1964 · 13:25:48.82 UTC
Ranger 7 struck the Moon at about 2.62 km/s (9,432 km/h).
Source ↗
Impact site
Mare Cognitum · 10.6340° S, 339.3230° E
The same location is 20.6771° W. The region was renamed Mare Cognitum, the Sea That Has Become Known.
Source ↗
Crater
14 m across · LROC frame M153014430L
The Lunar Reconnaissance Orbiter imaged the fresh crater in 2010. Apollo 16 photographed the site from lunar orbit in 1972.
Source ↗
Final transmission
Cut off during the last partial frame
The last full frame was taken about 2.3 seconds before impact. A final partial-scan exposure was still being transmitted when the spacecraft struck.
Source ↗

In this chapter: Vidicon camera, radio transmitter and the impact crater left behind

Sources: Main record · LPI · Ranger 7 frame P/200 (final transmission) · LROC · Ranger 7 impact crater M153014430L · NSSDCA · Ranger 7 mission data

Machine illustration: AI-made. Photos: NASA Image and Video Library, credited on each picture.

Chapter 5 of 5

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