Thirtieth anniversary of Voyager 2’s encounter with Uranus

Upon reaching Uranus on 24 January 1986, Voyager 2 encountered a blue sphere with very delicate features. A layer of haze obscured the majority of the planet's cloud characteristics. Uranus boasts a diameter four times that of Earth and completes an orbit around the Sun every 84 years, situated at a distance of 1.8 billion miles (2.9 billion kilometers) — 19 times farther away than our own planet. Image credit: NASA/JPL-Caltech.

Humanity visited Uranus only once, precisely 30 years ago when NASA's Voyager 2 spacecraft conducted a close study of the distant, mysterious, gaseous planet on 24 January 1986. The spacecraft captured and transmitted stunning images of Uranus and its moons during the flyby, allowing for approximately 5½ hours of detailed observation. Voyager 2 approached within 50,600 miles (81,500 kilometres) of Uranus during this encounter. Ed Stone, the project scientist for the Voyager mission at the California Institute of Technology in Pasadena, anticipated surprises due to Uranus's unique sideways orientation. Stone, who has been the project scientist since 1972, continues in that role to this day. Uranus emerged as the coldest planet in our solar system, despite not being the most distant from the Sun, as it lacks an internal heat source. Scientists determined that Uranus's atmosphere consists of 85 percent hydrogen and 15 percent helium, with indications of a boiling ocean approximately 500 miles (800 kilometres) beneath the cloud tops. The magnetic field of Uranus differed significantly from those of Mercury, Earth, Jupiter, and Saturn, with the poles being closer to the equator. Stone noted that Neptune exhibited a similar magnetic field misalignment. The surface magnetic field of Uranus was also stronger than Saturn's. Voyager 2 data revealed that Uranus's magnetic tail forms a helix stretching 6 million miles (10 million kilometres) in the direction opposite the Sun. Understanding the interaction between planetary magnetic fields and the Sun is crucial for NASA's mission to comprehend the nature of space. Exploring the Sun-planet connection not only offers insights valuable for space exploration but also illuminates the origins of planets and their potential to support life.

VVoyager 2 discovered 10 new moons, bringing the total to 27, along with two new rings at the planet. Miranda, an icy moon, unveiled a diverse landscape and signs of past geologic activity. Despite its small size of about 300 miles (500 kilometers) in diameter, Miranda features immense canyons, potentially up to 12 times deeper than the Grand Canyon in Arizona. Additionally, Miranda showcases three distinct structures known as "coronae," consisting of lightly cratered formations of ridges and valleys. Scientists speculate that this moon might have experienced fragmentation and subsequent reformation. Voyager 2's encounter with Uranus was meticulously planned to utilize a gravity assist for its journey towards Neptune. In 1989, Voyager 2 captured the first-ever close-up images of Neptune, expanding its impressive exploration repertoire. Suzanne Dodd, the project manager for Voyager at NASA's Jet Propulsion Laboratory in Pasadena, California, expressed her enthusiasm for the Uranus encounter, marking her first planetary mission to an uncharted celestial body. Voyager 2, launched on 20 August 1977, just 16 days ahead of its counterpart Voyager 1, is anticipated to venture into interstellar space in the coming years, following Voyager 1's historic milestone in August 2012.