Think about the different pieces of consumer technology you own: probably a cell phone, a computer, maybe a watch, an e-reader, a few other things here and there. How old are they? For my gadgets the average age is, I'd say, about three years. Perhaps the figure ticks up a bit if you take into account your car, your microwave and toaster over, and a trusty stand-mixer (those things, people like to say, can last "forever").
But these things are all babies -- babies -- when compared with our two Voyager spacecraft, the first of which celebrates its 35th birthday today. (Confusingly, that Voyager, the first one, is Voyager 2. Voyager 1 lifted off 16 days later.) Last Monday Voyager 2 became NASA's longest-operating spacecraft of all time. Voyager 1, which has traveled a more direct route, is on the verge of becoming the first man-made object to ever leave the heliosphere, the bubble of solar winds coming from our sun.
What's so incredible is that in the intervening 35 years, the Voyager spacecraft have journeyed billions -- literally billions -- of miles (Voyager 1 is now 11 billion miles away from the sun and Voyager 2 trails about two billion miles behind), borne the extreme cold of outer space (mission managers recently turned off a heater on Voyager 1 in order to conserve energy, bringing its temperature below minus 110 degrees Farenheit), and still, miraculously (in a strictly scientific sense, of course), the little Voyagers continue to send data back to Earth every single day, updating us on the very outer edge of the heliosphere known as the heliosheath.
NASA released a little video today showcasing some of the scientists who work on the Voyager mission:
Earlier this year I had the opportunity to speak with Edward Stone, featured above, who has been working on the Voyager mission since the 1970s. I asked Stone what we could expect as Voyager 1 leaves the heliosphere, and what it felt like to see this mission reach that historic achievement.
It would be nice, fulfilling even, if at the edge of the heliosphere there were, well, an actual edge, a boundary between our bubble and the cosmos. But, it's probably not going to be so cut and dried. "The boundary," Stone postulates, "will not be an instantaneous thing. [Voyager] won't suddenly be outside." Rather, the exit will be turbulent, "a mix of inside and outside," and the work of Stone and the other Voyager scientists is trying to square the different data -- the particles and the magnetic field -- to try to understand what that transition from inside to outside looks like. That turbulent region may take several months to get through.With that, we wish a very happy birthday to both the Voyagers, and many, many more.
But even without a clean break in the offing, it's hard not to sit on the edge of your seat to wait for this moment -- this months-long moment -- to pass. "We're looking at our data every day -- we listen to these spacecraft every day, for a few hours every day -- to keep track of what's going on. ... It's very exciting from a scientific point of view, when you're seeing something that nobody's seen before."
So perhaps Voyager won't make its mark with a sudden, defining event that echoes across generations as a sort of before-and-after dividing line through human history, like the line separating the time when a human's voice had never traveled across a wire to an ear miles away -- and when it had -- or before a human foot had left its imprint on the moon, and when that print was there. But Stone is okay with that: "Well you know actually Voyager has had a lot of those moments as we flew by Jupiter, Saturn, Uranus, and Neptune. One after the other, we found something that we hadn't realized was there to be discovered."