Science Results
The total data return for Mariners 6 and 7 was 800 million bits. Mariner 6 returned 49 far encounter and 26 near encounter images of Mars, and Mariner 7 returned 93 far and 33 near encounter images. Close-ups from the near encounter phases covered 20% of the surface. The spacecraft instruments measured UV and IR emissions and radio refractivity of the Martian atmosphere. Images showed the surface of Mars to be very different from that of the Moon, in some contrast to the results from Mariner 4. The south polar cap was identified as being composed predominantly of carbon dioxide. Atmospheric surface pressure was estimated at between 6 and 7 mb. Radio science refined estimates of the mass, radius and shape of Mars.