A rare alignment of the outer planets gave NASA a choice in 1980: prioritize one moon or gamble on reaching Pluto—they chose Titan, and it cost them the solar system. Voyager 1 is the most famous planet-hopper we have ever built but the thing most people don’t know is that it stopped hopping on purpose. Not because it broke. In 1980, the people running the mission made a deliberate choice to spend the spacecraft’s... [4563 chars]