The Grand Departure

The story

1. 1977: two spacecraft leave home, riding a once-in-176-years alignment of the planets.

   • · Voyager 2 launched first, on 20 August 1977; Voyager 1 followed 16 days later.
   • · Each carries a Golden Record — sounds and images of Earth for whoever finds it.

2. First stop: the king of planets — and a gravity slingshot toward the outer dark.

   • · The 1979 fly-bys discovered volcanoes on Io — the first active volcanism seen beyond Earth.
   • · Jupiter's gravity flung the Voyagers onward, trading a little planetary momentum for enormous speed.

3. Voyager 1 traded the remaining planets for one close look at Titan — and left the ecliptic forever.

   • · The 1980 Titan fly-by bent Voyager 1's path up and out of the planetary plane.
   • · Voyager 2 carried on alone toward the ice giants.

4. 1986: the only spacecraft ever to visit the sideways planet.

   • · Voyager 2 found ten new moons and a magnetic field tilted 59° from the spin axis.
   • · Uranus spins tipped over at about 98° — likely the scar of an ancient collision.

5. 1989: the last portrait — supersonic winds at the edge of the planetary system.

   • · Voyager 2 skimmed 4,950 km above Neptune's clouds — its closest approach of the whole tour.
   • · It caught Triton's nitrogen geysers erupting at −235 °C.

6. Now in interstellar space — the farthest human-made object, still calling home.

   • · Voyager 1 crossed the heliopause into interstellar space in 2012.
   • · Its signal takes nearly a full day to reach Earth.

7. The only spacecraft to visit all four giant planets — and it's still going.

   • · Voyager 2 entered interstellar space in 2018, six years after its twin.
   • · Both Voyagers run on decaying plutonium heat that will fade during the 2030s.