The Voyager program consists of two robotic interstellar probes, Voyager 1 and Voyager 2. Launched in 1977, they have provided invaluable data about the outer planets and are now exploring the interstellar medium, carrying the Golden Record as a message to potential extraterrestrial civilizations.
The Heliosphere is the vast, bubble-like region of space that encompasses the Solar System and is dominated by plasma emanated from the Sun, known as the solar wind.