How Voyager 2 Escaped the Sun’s Gravity

In the 1960s, a NASA engineer realized something extraordinary: Jupiter, Saturn, Uranus, and Neptune were about to line up in a way that only happens once every 176 years. That alignment meant a spacecraft could visit all four planets in a single mission using gravity assists to slingshot from one to the next. That spacecraft became Voyager 2. It had to travel fast enough to escape the Sun’s gravity entirely, while also passing each planet with pinpoint precision to set up the next flyby. One mistake, and the entire grand tour would fail. Somehow, it worked.