This is Stardust, NASA's comet hunter about 312,000,000 kilometers from Earth. Yesterday, they ordered her main engines to burn at full throttle until they consumed all the available fuel, and then turned off her radio. But why?

Launched in February 7, 1999, the brave 661-pound spaceship was the first spacecraft in history to return to Earth samples from a comet (Wild 2) and the first to record the sound of the dust of a comet (Temple 1) hitting her instruments.

During her more than 12 years lifetime it has performed 40 major flight maneuvers, firing her rockets a combined 2 million times for a total of 5.67 billion kilometers (3.52 billion miles) burning most of her 80 kilograms of fuel load. In all these years, Stardust's systems have completed her main and extended missions. In fact, the spacecraft was still healthy, humming across the solar system with Temple 1 way behind her stern now.

Why Is NASA Burning Out Its Comet Hunting Spaceship?