February 25, 2022
On this date in 1969, NASA’s Mars mission Mariner 6 launched. It reached its closest approach to Mars five months later, on July 31. Both Mariner 6 and its twin mission Mariner 7 flew by the equator and south polar region to analyze the atmosphere and send back images of the surface. These were the first up close images of the surface of Mars. These photos helped prove the absence of the “canals” that several 19th century astronomers believed to have seen while using ground-based telescopes.
Mariner 6 (shown on the left) and 7 photographed approximately 20% of Mars’ surface. This was the first time astronomers were able to see that there are no canals on Mars – an idea that was popularized by astronomer Percival Lowell. The sketch on the right shows the dark canals as Lowell saw them. It is believed that what he was seeing was an optical illusion. Image credit: NASA/Mars Exploration Program (left), Right: NASA/GSFC (right)
