The Summer of 1969 was an incredible time for anybody interested in space exploration. Plenty has been written about the historical mission of Apollo 11 and the first ever moon walk. July 20th is an unforgettable date for those of us who were glued to our teevees and witnessed the culmination of that amazing mission.
What most of us have forgotten, was that another historical space mission was in progress at the same time as the Apollo Eleven events. The dual-spacecraft mission to Mars was also a very important aspect of the exploration of the Solar System.
Mariner 6 and 7 were twin, unmanned crafts designed to study the structure and ecology of the planet Mars. Mariner 6 was launched February 24, 1969 and Mariner 7 Launched March 27th. Both crafts were identical. They were constructed around an octagonal magnesium frame. A cone-shaped structure on top of the frame held the four solar panels and the high-gain antenna. When deployed, the tip to tip spans of the solar panels were 5.79 metres. The total height of each craft was 3.35 metres.
The closest fly-by approach of Mariner 6 happened on July 31, 1969. It came as close as 3,431 kilometres (2,132 miles) above the surface of Mars. The craft transmitted 49 “far encounter” and 26 “near encounter” images of the planet Mars.
Less than a week later, on August 5th, the closest approach for Mariner 7 took place. It managed to get 1 kilometre closer than its twin. The distance of 3,430 kilometres was also less than half of the distance achieved by the previous Mariner 4 fly-by mission in late 1964. Mariner 7 managed to transmit 93 “far encounter” and 33 “near encounter” images of Mars.
Together, Mariner 6 and 7 discovered that the Martian surface is quite different from that of our Moon. The Martian, south polar cap was discovered to be predominantly carbon dioxide (dry ice). The atmospheric pressure and makeup were also analyzed. Likewise, the mass, radius and shape of Mars was refined.
The joint mission was proclaimed to be a success, in that the crafts had accomplished their missions. Important data was gathered in order to help plan and carry out future missions to Mars.
The Blue Jay of Happiness reminds you that Mariner 5 was a scientific measurement mission and fly-by of the planet Venus.