Mariner 2 
NEUGEBAUER: It was just a hair-raising mission. Several things failed and then just recovered by themselves. It took about three miracles to get Mariner 2 to Venus. It just looked like the end several times along the way.
Fifty years ago, Marcia Neugebauer oversaw one of the experiments for the first successful mission to another planet. Mariner 2 flew less than 22,000 miles from Venus on December 14th, 1962.
In those early days of rocketry, missions failed as often as they succeeded. In fact, a twin Venus spacecraft, Mariner 1, had to be blown up less than five minutes after launch. And the United States still hadn’t even reached the Moon.
Mariner 2 was problem-plagued almost from the moment of launch. A sensor had a hard time tracking Earth, one of its solar panels failed, and it overheated. Yet even before it reached Venus, Mariner 2 was making important discoveries.
It resolved a dispute, for example, about the solar wind. Most physicists expected to find some sort of flow of charged particles from the surface of the Sun. But there was a major disagreement about the form of that flow. One leading scientist expected a million-mile-an-hour gale. But another expected more of a gentle breeze.
Within weeks, Mariner 2 resolved the issue — it discovered a high-speed solar wind that never let up during the long cruise to Venus.
But Mariner 2 is best known for transforming our concepts of Venus itself. More about that tomorrow.
Script by Damond Benningfield, Copyright 2012