5 reasons why Ice Giants need a space mission

While orbiters, landers, and probes have explored every other planet in the solar system, we’ve only glimpsed Uranus and Neptune close up once — in 1986 and '89, using the Voyager 2 spacecraft.

Many planetary scientists think it’s time to send a mission to the Uranus and Neptune, collectively known as the Ice Giants.

1. Both planets are similar to the most common type of exoplanet scientists have found in the Milky Way, deemed Mini-Neptunes.

Exploring our own Ice Giants would help us understand why planets in this size range (roughly 4 times the size of Earth) are so common throughout the galaxy.

2. Their moons are fascinating.

Neptune’s moon Triton is erupting, and scientists wonder whether it holds an internal ocean. Triton also orbits Neptune in the opposite orbit as the planet’s other moons, which means it could be a captured object from the Kuiper Belt.

3. We have only some idea of what the Ice Giants are made of.

The basic composition of the Ice Giants include hydrogen, helium, methane, water, ices, and possibly rock. We need more close-up observations to further understand.

4. Their compositions can help us understand how the solar system formed.

Planets form in a primitive disk of material, and because we know what kind of material would have been closer or further from the Sun, their compositions tell us where in that disk they likely formed.

Some scientists think the Ice Giants formed much closer to the Sun and then moved outwards — but we won’t be able to confirm or refute this hypothesis until we can study Uranus and Neptune up close.

5. On a similar note, we’d love to know why Uranus is tilted 98 degrees — it rotates on its side!