On Aug. 27, 1962, NASA launched Mariner 2, the world's first successful interplanetary spacecraft. br br Mariner 2 flew by Venus after a 3½-month voyage through space. The mission launched just one month after the Mariner 1 mission failed during launch. After departing from Cape Canaveral, Mariner 2 almost met the same fate when an electrical problem with the Atlas-Agena rocket caused it to start rolling, which made it unable to respond to any guidance commands from mission control.