Ice Giant Exploration
Since Voyager 2, no spacecraft has gotten up close and personal with our solar system’s ice giants, Uranus and Neptune. Mission proposals to explore these planets and their moon systems — similar to the Galileo spacecraft’s tour of Jupiter or Cassini’s flights around Saturn — have come up from time to time.
During the most recent planetary science decadal survey, officials selected a Uranus probe as their number three most-wanted mission. But the $2.7 billion estimated price tag means that such a mission is unlikely to happen any time soon. British scientists have also proposed the much cheaper $600 million Uranus Pathfinder mission to the European Space Agency, though officials have yet to make a decision.
Why no love for Neptune? Its moon, Triton, is known to be geologically active, with icy volcanoes spewing nitrogen from its surface. Unfortunately, Neptune’s great distance and the fact that closer Uranus remains mostly unexplored mean that the farthest planet in our solar system sits a little lower on the list of potential exploration. Perhaps with enough time and money, Neptune may one day get its turn.
Images: 1) Uranus and its moons. NASA Ice Giants Decadal Study 2) Possible probe for a Uranus or Neptune mission. NASA Ice Giants Decadal Study