The Voyager spacecraft were launched in 1977 and carry Faraday Cups built at MIT. Voyager 1 encountered Jupiter in 1979 and Saturn in 1980 and continues toward the interstellar medium, although the MIT experiment ceased working shortly after the Saturn encounter. Voyager 2 encountered Jupiter in 1979, Saturn in 1981, Uranus in 1986 and Neptune in 1989, completing the grand tour of the solar system. The MIT experiment is still returning data from over 100 AU, 14 light-hours away, and will make the first plasma measurements of the interstellar medium.