Voyager 1 is a lonely little machine, zapping through space at over 10 miles a second and billions of miles out from the sun--it's the furthest manmade object from home. But this week NASA revealed its instruments, still functioning after 35 years (and a testament to some innovative design that meant it used the first space-hardened electronics and some rigorous fault prevention) have found something new .
It's a new region of space, right at the edge of the influence of our Sun, where magnetic particles streaming out from the sun are mixing with magnetic particles shooting through deep interstellar space. In a kind of particle dance, NASA's scientists revealed  that the discovery wasn't something they'd been expecting, and it means that they're now "tasting" the particles from deep space. The news means the boundary between our solar system and interstellar space is a little further out than we'd thought--but at some point soon Voyager 1 really will sail into deep space, and become the first man-made emissary outside our home solar system.
But Voyager 1 has been making history almost since its launch in 1977, including a dramatic flyby of Saturn's moon Titan that showed us tantalizing glimpses of its atmosphere and thus directly influenced the Huygens mission that landed a probe on that moon in 2005. The Titan flyby also decided Voyager 1's fate--slingshotting it out of our solar system.
Powered by small nuclear generators that turn heat into electricity, the Voyager 1 and 2's systems were so well designed that Voyager 2 only turned off its data tape recorder in 2007, and switched to its backup thrusters--not its main ones, mind you--in November 2011. They were the first spacecraft to feature computers that could be reprogrammed after launch, which is now the standard design for spacecraft--and, if you think about it, your iPhone. And they were the first spacecraft to include fault protection so that they could catch their own errors. The probes' radio signals are now coming from such a huge distance that they're almost invisibly faint--a fact that in the late 1980s led NASA to combine radio telescope data from different telescopes together in a totally new way so that it could listen to the data being streamed from the probes. Just one of many Voyager "firsts."