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  1. Home
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  3. July
  4. 31
  5. Ranger 7

Events on July 31 in history

Ranger 7
1964Jul, 31

Ranger program: Ranger 7 sends back the first close-up photographs of the moon, with images 1,000 times clearer than anything ever seen from earth-bound telescopes.

Ranger 7 was the first space probe of the United States to successfully transmit close images of the lunar surface back to Earth. It was also the first completely successful flight of the Ranger program. Launched on July 28, 1964, Ranger 7 was designed to achieve a lunar-impact trajectory and to transmit high-resolution photographs of the lunar surface during the final minutes of flight up to impact.

The spacecraft carried six television vidicon cameras two wide-angle (channel F, cameras A and B) and four narrow-angle (channel P) to accomplish these objectives. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality video pictures. Ranger 7 transmitted over 4,300 photographs during the final 17 minutes of its flight. After 68.6 hours of flight, the spacecraft landed between Mare Nubium and Oceanus Procellarum. This landing site was later named Mare Cognitum. The velocity at impact was 1.62 miles per second, and the performance of the spacecraft exceeded hopes. No other experiments were carried on the spacecraft.

Ranger 7Ranger 7
The Ranger program was a series of unmanned space missions by the United States in the 1960s whose objective was to obtain the first close-up images of the surface of the Moon. The Ranger spacecraft were designed to take images of the lunar surface, transmitting those images to Earth until the spacecraft were destroyed upon impact. A series of mishaps, however, led to the failure of the first six flights. At one point, the program was called "shoot and hope". Congress launched an investigation into "problems of management" at NASA Headquarters and Jet Propulsion Laboratory. After two reorganizations of the agencies, Ranger 7 successfully returned images in July 1964, followed by two more successful missions.

Ranger was originally designed, beginning in 1959, in three distinct phases, called "blocks". Each block had different mission objectives and progressively more advanced system design. The JPL mission designers planned multiple launches in each block, to maximize the engineering experience and scientific value of the mission and to assure at least one successful flight. Total research, development, launch, and support costs for the Ranger series of spacecraft (Rangers 1 through 9) was approximately $170 million (equivalent to $1.09 billion in 2020).

References

  • Ranger program
  • Ranger 7
  • Moon
  • Telescope

Choose Another Date

Events on 1964

  • 6Mar

    Muhammad Ali

    Nation of Islam leader Elijah Muhammad officially gives boxing champion Cassius Clay the name Muhammad Ali.
  • 26Apr

    Tanzania

    Tanganyika and Zanzibar merge to form Tanzania.
  • 12Jun

    Nelson Mandela

    Anti-apartheid activist and ANC leader Nelson Mandela is sentenced to life in prison for sabotage in South Africa.
  • 12Aug

    Apartheid in South Africa

    South Africa is banned from the Olympic Games due to the country's racist policies.
  • 28Nov

    Lyndon B. Johnson

    Vietnam War: National Security Council members agree to recommend that U.S. President Lyndon B. Johnson adopt a plan for a two-stage escalation of bombing in North Vietnam.

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