Happy Birthday, Voyager 2: NASA's Oldest ActiveCraft Crests Into Interstellar Space

Just last week, Voyager 2 became NASA's longest operating spacecraft, and the mighty craft celebrates its 35th anniversary today. What a long way it has travelled!

Voyager 2 launched on August 20, 1977, 16 days before its twin Voyager 1 took off. (Yes, we realise that's confusing.) Voyager 2 and Voyager 1 are 145 billion kilometres and 177 billion kilometres from the sun respectively, placing them at the outermost reaches of the sun's heliosphere. As the probes leave the sun's shell and enter interstellar space, scientists will gain new insights as to what lies beyond our solar system. In particular, scientists predict that the direction of the magnetic field will change on the other side.

But if today's Voyager missions are all about going the distance, the earlier expeditions discovered oceans of interesting information about planets within our solar system. According to NASA's history:

Notable discoveries by Voyager 2 include the puzzling hexagonal jet stream in Saturn's north polar region, the tipped magnetic poles of Uranus and Neptune, and the geysers on Neptune's frozen moon Triton. Although launched second, Voyager 1 reached Jupiter and Saturn before Voyager 2, first seeing the volcanoes of Jupiter's moon Io, the kinky nature of Saturn's outermost main ring, and the deep, hazy atmosphere of Saturn's moon Titan. Voyager 1 also took the mission's last image: the famous solar system family portrait that showed our Earth as a pale blue dot.

How many technologies built 35 years ago are still running? Hardly a one. NASA estimates the two probes should have enough electrical power to run until 2020 and possibly until 2025. Godspeed! [NASA via The Atlantic]