It was 24 January 1986 when Voyager 2 flew by Uranus on its never-ending outbound journey from the solar system. Three and a half years later, on 25 August 1989, the probe flew past Neptune and became the only spacecraft to ever visit Uranus and Neptune.<\/p>\n
After those flybys, the ice giants passed from space agencies\u2019 immediate plans in favor of missions to Mars, Jupiter, Saturn, and Mercury that would largely help human exploration into the solar system.<\/p>\n
But why haven\u2019t we been back to Uranus and Neptune? Certainly those planets are harder to reach than Mars, Jupiter, and Saturn. But if three of Earth\u2019s prominent space agencies (NASA, ESA, and JAXA) are willing to send three spacecraft on six year journeys just to reach and enter orbit of Mercury and only then begin their actual science missions, why not commit to such missions for Uranus and Neptune?<\/p>\n
Part of the problem has certainly been constrained budgets from federal officials and a limited number of missions that can be successfully funded. But that alone doesn\u2019t explain why none of the proposed missions to the ice giants of our solar system since the 1980s have ever been approved.<\/p>\n
The truth is somewhat a mix of two things:<\/p>\n