In June of 1967, five years after Mariner 2's first visit, Venus was once again the destination. Mariner 5 made its closest encounter with Venus on October 19, at a distance of a mere 2500 miles. The instruments on board measured the planet's magnetic field, ionosphere, radiation belts and temperatures. The collected data confirmed that extremely harsh surface conditions existed on Venus.
The average surface temperature on Venus is 900 degrees Fahrenheit, hot enough to melt lead! More detailed information such as the make-up of Venus' atmosphere, and the look of the terrain that is constantly blocked from view by cloud cover, would be revealed by future missions.
