Planet Uranus – interesting facts

September 3, 2010 | In: Space Facts

No spacecraft had ever visited the distant planet Uranus. Then, in 1986, NASA’s Voyager 2 spacecraft, which had flown by Jupiter and Saturn, arrived at the planet.

Uranus is one of the four giant planets (the others being Jupiter, Saturn and Neptune), all of which lie outside the orbit of Mars. It’s one of the smallest of the four, being 50,800 kilometers (32,000 miles) in diameter. It’s one-third the size of Jupiter and just three percent larger than Neptune.

Uranus is unusual in that it’s tilted on its side, with its south pole currently pointing toward the Sun and its equator lying perpendicular to the solar system.

Uranus has five medium-sized moons that orbit it in the plane of its equator. Starting closest to the planet, these are Miranda, Ariel, Umbriel, Titania and Oberon.

At Jupiter and Saturn, the spacecraft approached with the moons’ orbits essentially edge-on, so it took a week or so to fly through the system. But because Uranus and its moons are tilted perpendicular to the rest of the solar system, they looked like a bull’s eye to Voyager.

The spacecraft shot like an arrow through the Uranus system in just a couple of days. This made it much harder to make corrections if the camera were pointed wrong, but by careful measurements and planning, they got good pictures of all of them.