Mariner 7

Mariner 7 was Mariner 6's companion in NASA/JPL's paired 1969 Mars flyby investigation. Its cameras, infrared and ultraviolet instruments, and radio-occultation experiment examined the surface and atmosphere during an August 5 encounter. Results from the earlier Mariner 6 passage allowed controllers to expand the second spacecraft's coverage of the southern polar region. A communications anomaly shortly before arrival forced engineers to recover the spacecraft through its low-gain antenna. Despite lost telemetry channels, Mariner 7 returned 93 far-encounter and 33 near-encounter images, documenting heavily cratered terrain, the Hellas region and the polar cap. Later analysis also identified Phobos in several frames. The images sampled selected flyby swaths; they did not provide the broad mapping later achieved from Mars orbit.