 Despite these problems Canyons 2 and 3 returned much useful intelligence information, particularly regarding Chinese military maneuvers during the winter of 1970-71 when tensions between China and the USSR were at an all-time high, and also intelligence on North Vietnam for the 1972 Christmas Bombing campaign.The fourth Canyon, launched on December 4, 1971, never made it to orbit.The Atlas booster's sustainer engine shut down early in the launch and the booster drifted off its path, leading to a Range Safety destruct less than two minutes after liftoff.