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THIS DAY IN HISTORY: Mariner V Launches from Florida’s Space Coast to Venus for Flyby Mission in 1967

By  //  June 14, 2023

June 14, 1967

Liftoff of Mariner 5 from Cape Kennedy Air Force Station, now Cape Canaveral Space Force Station in Florida. (NASA Image)

BREVARD COUNTY, FLORIDA – On June 14, 1967, Mariner V launched to Venus on a flyby mission to learn about the planet’s atmosphere.

With an atmospheric pressure more than 90 times Earth’s and a temperature of 527 °C, we learned Venus wasn’t so similar to Earth after all!

In 1967, as NASA continued preparations for the first human landing on the Moon, the agency once again turned its attention toward exploring Venus.

Engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, modified the backup Mariner 4 spacecraft to operate closer to the Sun, and on June 14, 1967, NASA launched Mariner 5 on a 127-day journey to the mysterious cloud-shrouded planet.

The spacecraft flew by Venus on Oct. 19, 1967, returning valuable information about the planet’s atmosphere and its radiation and magnetic field environment.

The Soviet Union launched their Venera 4 spacecraft during the same launch window, its capsule descending into the planet’s atmosphere before falling silent. Scientists from both countries jointly published the results from the two spacecraft.

Following its launch on June 14, 1967, the 540-pound Mariner 5 entered solar orbit on its way to Venus. A course correction maneuver on June 19 refined this trajectory.

During September and October, the spacecraft conducted joint observations of interplanetary space with Mariner 4, still operating in solar orbit after its Mars flyby. On Oct. 19, Mariner 5 flew within 6,309 miles from the center of Venus, about 10 times closer than its predecessor, Mariner 2, did in December 1962. Mariner 5 conducted seven investigations to study the planet as well as interplanetary space before and after the encounter:

  • The solar plasma probe to monitor the properties of the solar wind.
  • The helium magnetometer to measure the direction and strength of the magnetic field.
  • The trapped-radiation detector to measure the flux of energetic particles.
  • The ultraviolet photometer to detect atomic hydrogen and oxygen in Venus’ upper atmosphere.
  • The celestial mechanics investigation to help refine the orbits of Earth and Venus.
  • The S-band radio occultation experiment to measure the density of Venus’ atmosphere as the spacecraft passed behind the planet.
  • The dual-frequency propagation experiment to provide information on Venus’ ionosphere.