Spacecraft

Voyager 2

NASA's space probe launched in 1977, the only spacecraft to visit Uranus and Neptune.

Measured

144 AU. To cross it:

Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.

Launched on 20 August 1977, it is the only probe to fly past Uranus (1986) and Neptune (1989).
It entered interstellar space in November 2018.
Before Jupiter it was too slow to ever leave the Sun: 10.5 km/s, with 18.8 needed there. Jupiter took it just past the line.
Jupiter, 9 July 1979: 10.5 → 19.5 km/s against the Sun.
Saturn, 26 August 1981: 15.8 → 20.3 km/s against the Sun.
Uranus, 24 January 1986: 18.0 → 19.7 km/s against the Sun.
Neptune, 25 August 1989: 18.9 → 16.7 km/s against the Sun.
Neptune slowed it: the close pass over the planet's north pole bent its path south, out of the planets' plane. It no longer needed the speed.
Speeds from its trajectory, about two to three months each side of the pass (JPL Horizons).

JPL Horizons heliocentric ephemeris, 2026-10-25 (Voyager 1 172.15 AU, Voyager 2 144.29 AU, New Horizons 65.90 AU)

Every catalogue Ouranos draws is credited on the credits page.

Spacecraft

NASA's space probe launched in 1977, the only spacecraft to visit Uranus and Neptune.

144 AU. To cross it:

Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.

Launched on 20 August 1977, it is the only probe to fly past Uranus (1986) and Neptune (1989).
It entered interstellar space in November 2018.
Before Jupiter it was too slow to ever leave the Sun: 10.5 km/s, with 18.8 needed there. Jupiter took it just past the line.
Jupiter, 9 July 1979: 10.5 → 19.5 km/s against the Sun.
Saturn, 26 August 1981: 15.8 → 20.3 km/s against the Sun.
Uranus, 24 January 1986: 18.0 → 19.7 km/s against the Sun.
Neptune, 25 August 1989: 18.9 → 16.7 km/s against the Sun.
Neptune slowed it: the close pass over the planet's north pole bent its path south, out of the planets' plane. It no longer needed the speed.
Speeds from its trajectory, about two to three months each side of the pass (JPL Horizons).

JPL Horizons heliocentric ephemeris, 2026-10-25 (Voyager 1 172.15 AU, Voyager 2 144.29 AU, New Horizons 65.90 AU)

Every catalogue Ouranos draws is credited on the credits page.