Still transmitting, the three-decade-old craft encounters turbulence in solar wind.

Hurtling through space 31 years after its launch, the Voyager 2 spacecraft has sent back the most detailed view yet of the shock wave that marks the thinning of the solar wind, the charged particles streaming from the sun.

That would mean they have exited the solar system and entered the interstellar medium. NASA engineers estimate that both probes' plutonium power packs have the potential to keep them broadcasting data until 2025.

If we're lucky, Jokippi says, they'll let us know what they find.