Voyager Probes Begin Their Long Goodbye

Voyagers 1 and 2 have lived a remarkable life. We're at 45 years now, 15 years longer than I've lived, and yet they're still out there, still reporting back to an increasingly distant Earth. And if NASA has its way, they will continue to do so for another 10 years. But the Voyagers were not made to live forever. Their plutonium power supply is losing potency at a rate of 4 watts a year, and so, to keep the probes going as long as possible, some of their instruments will be shut down. The power just cannot be spared. 

But while the Voyagers will eventually run out of power, let's not forget all the work they've done over their long lives. That's a long article, but very informative. I didn't know that the engineers essentially snuck one over on the government, utilizing slightly more expensive parts to make the probes much hardier. They were only supposed to last a few years, not 50. Just think what we would have missed out on if they hadn't bent the rules.