Mariner 6 television pictures: first report.

In July 1965, Mariner 4 flew past Mars and recorded 20 television pictures of the martian surface; the principal television result of that pioneering flight was the discovery that Mars' surface is heavily cratered and resembles the Moon more than it does the Earth (1). On 31 July 1969, the more advanced Mariner 6 spacecraft, carrying two television cameras, passed Mars and recorded 75 pictures. A twin spacecraft, Mariner 7, passed Mars on 5 August 1969. This report summarizes the results of a first, qualitative study of the Mariner 6 television pictures, carried out on the uncalibrated data within a few days after receipt on Earth.