The Planet of Neptune
In 1989, Voyager 2 traveled across the solar system and managed to get close to Neptune. While doing this, the spacecraft passed Triton and six other moons that hadn’t been discovered. It also discovered two rings wrapping around Neptune.
Planetary Phases
Once Voyager 2 had completed its flyby of Neptune, the planetary phases of the spacecraft’s mission had been completed. However, the craft didn’t come back to Earth. NASA decided to use the probe to learn more about interstellar space.