21h 6min, may 8, 1971 y - Mariner 8
Failed Mars flyby attempt (NASA)
Mariner 8, a twin to the successful Mariner 9, failed to reach Earth orbit.
Also commonly known as Mariner-H, was (along with Mariner 9) part of the Mariner Mars 71 project. It was intended to go into Mars orbit and return images and data.
Added to timeline:
the videos are in the parts of Mars Exploration Rover Spirit...