The New Horizons spacecraft reached the dwarf planet Pluto in July 2015.
NASA's twin probes are going where no one has gone before.
Voyager 1 is farther away than any other spacecraft from Earth.
Voyager 2 is the only spacecraft to have visited all four giant outer planets in the solar system and is now the second spacecraft to reach interstellar space.
The rocky planet circling the closest star to the sun got hammered by a superpowerful flare last year, a new study reports. That's a bit of bad news for anyone hoping that the alien world, known as Proxima b, hosts life.