Cassini will meet its doom in Saturn's atmosphere

By any definition, NASA's Cassini spacecraft has been a massive success. The 20-year-old planetary probe has studied Saturn, its moon system, and its rings, since 2004. The mission was originally slated to last only four years, but it's been extended twice, and the damn thing is still going.

Cassini is finally running out of gas, and it will meet its doo…