In 1978 NASA launched the International Sun-Earth Explorer-3 (ISEE-3) into orbit between the Earth and the sun. Designed to give scientists a look at "solar wind" before it reached earth, the ISEE-3 was abandoned 17 years ago by NASA. It's wandered the interior of the solar system alone ever since. From the NASA website's page on the ISEE-3: Goals: International Sun-Earth … [Read more...]