Voyager

Two spacecraft launched in 1977, now the most distant human-made objects. Both still transmit data daily. Signal travel time exceeds 22 hours one-way.

Current position (approx.)

• Voyager 1 — ~24 billion km from the Sun (160 AU)
• Voyager 2 — ~20 billion km from the Sun (135 AU)
• Transmitter power: 23 watts — about the same as a refrigerator light bulb
• Power source: 3 RTGs (plutonium-238); losing ~4W/year
• Estimated communications: until ~2025–2030 before signal too weak

Timeline

1. Aug 20, 1977 V2 — Voyager 2 launched

   Launched 16 days before Voyager 1, on a slower "grand tour" trajectory via Jupiter, Saturn, Uranus, Neptune.

2. Sep 5, 1977 V1 — Voyager 1 launched

   Atlas-Centaur rocket, Cape Canaveral. Faster trajectory, Jupiter then Saturn only.

3. Mar 5, 1979 V1 — Jupiter flyby

   Discovered active volcanoes on Io — the first active volcanoes seen anywhere beyond Earth. Also found a thin ring system around Jupiter.

4. Jul 9, 1979 V2 — Jupiter flyby

   Confirmed the ring. Close approach to Europa revealed a smooth icy surface with almost no craters, suggesting a subsurface ocean.

5. Nov 12, 1980 V1 — Saturn flyby

   Revealed complex ring structure — thousands of ringlets — and shepherd moons. Confirmed Titan has a dense nitrogen atmosphere.

6. Aug 25, 1981 V2 — Saturn flyby

   Closest approach to Titan at 666,000 km. Discovered or confirmed 3 new moons.

7. Jan 24, 1986 V2 — Uranus flyby

   Only spacecraft ever to visit Uranus. Discovered 10 new moons, 2 new rings. Found Uranus's magnetic field is tilted 60° from its rotation axis.

8. Aug 25, 1989 V2 — Neptune flyby

   Closest approach: 4,950 km above Neptune's north pole. Discovered geysers on Triton (−235°C, one of the coldest surfaces in the solar system). Passed 5 hours later — mission complete.

9. Feb 14, 1990 V1 — Pale Blue Dot

   Carl Sagan convinced NASA to turn Voyager 1's camera back toward the inner solar system. Earth appears as a 0.12-pixel speck — "a mote of dust suspended in a sunbeam."

10. Feb 17, 1998 V1 — Most distant human object

    Overtook Pioneer 10 to become the most distant human-made object in space.

11. Aug 25, 2012 V1 — Interstellar space

    Crossed the heliopause — the boundary where the solar wind is stopped by interstellar plasma. First human-made object in interstellar space.

12. Nov 5, 2018 V2 — Interstellar space

    Crossed the heliopause at a different angle, providing the first two-point measurement of the heliosphere's boundary.

"Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives... on a mote of dust suspended in a sunbeam."