Flybys-Mariners:

Back in 1962 and 1973, NASA’s Jet Propulsion Laboratory designed and built 10 spacecrafts named Mariner to explore the inner solar system for visiting Venus, Mars and Mercury for the first time.

Mariners were all relatively small robotic explorers. Each launched on an Atlas rocket with either an Agena or Centaur upper-stage booster, while weighing less than half a ton, without onboard rocket propellant.

Mariner 3 and 4 launched simultaneously in 1964, and were identical spacecraft designed to carry out the first flybys of Mars. Mariner 3’s shroud encasing the spacecraft on its rocket failed to open properly, and therefore Mariner 3 did not get to Mars. But three weeks later, on November 28, 1964, Mariner 4 was launched successfully on an eight-month voyage to the red planet.

Mariner 4 spacecraft flew past Mars on July 14, 1965, collecting the first close-up photographs of another planet. The pictures, played back from a small tape recorder over a long period, showed lunar-type photographs at close range from the Moon, some of them touched with frost in the chill Martian evening. The spacecraft was not expected to survive much longer than the eight months to its Mars flyby encounter, but actually lasted about three years in solar orbit, continuing long-term studies of the solar wind environment.

But the mission was confined to the outer space of Mars and did not enter the Martian Planet. Mariner 6 & 7, which followed the above two are also flyby. Objective was to just get an idea of another planet.

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