Spacecraft approaching the Moon.

An artist's concept of the Ranger spacecraft approaching the Moon. Credit: NASA/JPL-Caltech

What was Ranger 7?

Many historians call the success of Ranger 7 a turning point in the American space program. The seventh in a series of early U.S. lunar impact mission was the first win for NASA engineers after 13 failures in a row.

  • Ranger 7 turned on its cameras and started sending back images 17 minutes prior to impact.
  • The spacecraft took 4,316 stunning images before crashing into the lunar surface on the northern rim of the Sea of Clouds.
  • The images helped scientists conclude the Apollo astronauts could safely land in the smooth mare regions (the "seas") of the Moon.

Nation United States of America (USA)
Objective(s) Lunar Impact
Spacecraft P-54 / Ranger-B
Spacecraft Mass 806 pounds (365.6 kilograms)
Mission Design and Management NASA / JPL
Launch Vehicle Atlas Agena B (Atlas Agena no. 9 / Atlas D no. 250 / Agena B no. 6009)
Launch Date and Time July 28, 1964 / 16:50:07 UT
Launch Site Cape Canaveral Air Force Station, Fla. / Launch Complex 12
Scientific Instruments 1. Imaging System (Six TV Cameras)

Firsts

Ranger 7 was the first unequivocal success in U.S. efforts to explore the Moon.

Key Dates

July 28, 1964: Launch

July 31, 1964: Lunar Impact

In Depth: Ranger 7

Ranger 7, the second of the Block 3 Ranger series, was, after 13 consecutive failures, the first unequivocal success in U.S. efforts to explore the Moon.

In some ways, it marked a major milestone in American deep space exploration as the ratio in favor of successes increased dramatically after this point.

After a nominal course correction on July 29, 1964, Ranger 7 approached the Moon precisely on target two days later. Just fifteen minutes prior to impact, the suite of TV cameras began sending back spectacular photos of the approaching surface to NASA's Jet Propulsion Lab's Goldstone antenna in California.

The last of 4,316 images was transmitted only 2.3 seconds prior to impact at 13:25:49 UT July 31, 1964.

Cratered surface of the Moon from above.
This was one of more than 4,300 images Ranger 7 sent back before impact. Credit: NASA/JPL-Caltech

The impact point was at 10 degrees 38 minutes south latitude and 20 degrees 36 minutes west longitude on the northern rim of the Sea of Clouds.

Scientists on the ground were more than satisfied with the results. The image resolution was, in many cases, one thousand times better than photos taken from Earth.

Scientists concluded that an Apollo crewed landing would be possible in the mare regions of the lunar surface, given their relative smoothness.

Key Source

Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.

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