“It’s certainly possible that when we get more data, we’ll have a eureka moment,” he says. “But the more interesting and exciting thing is that maybe as we get more data, we realize there’s something totally new going on here.”And there are other properties that make the case for an ice giants mission. Both planets have rings and moons that are unique. For example, scientists aren’t certain what makes up Uranus’ ring particles. They’re too dark to be pure water ice like Saturn’s rings.And Neptune’s moon Triton is the only large satellite in the solar system with a retrograde orbit — one that runs opposite from the way the planet spins. This and other evidence indicates that Triton is a captured Kuiper Belt object like Pluto. Its strange cantaloupe terrain and smokestack plumes also hint at an active world and possibly a subterranean ocean.Currently, Hofstadter’s team is looking at a broad set of potential mission architectures. And they’ve already learned a few things even at this early stage.“You cannot (currently) fly a single vehicle from Uranus and then to Neptune,” he says. “The planets are just not aligned properly to do that.”Instead, his team is studying a single spacecraft that would go to one planet or the other. And they’re also exploring how they might use one rocket to send two spacecraft — one for each ice giant — something that’s never been tried before.The mission is not dependent on the enormous Space Launch System rockets NASA is currently developing, however, the launch vehicle’s capabilities are something the team is considering.In the coming weeks, the team will identify the top science goals for their spacecraft. And in the months after that, they’ll identify roughly 10 different potential mission architectures to meet those science goals. By fall, Hofstadter expects to report back to NASA with an initial strategy.Whatever the final architecture, NASA’s plans to visit an ice giant should crystallize by year’s end.