In 1963, Convair wrote up some plans to continue space exploration beyond the Apollo missions. These are plans for entire manned expeditions by humans throughout the solar system, including the outer planets. There were three: conservative, intermediate, and ambitious, and each had missions planned up to the year 2000.

The conservative plan called for manned missions to Jupiter by 2000, the intermediate called for manned missions to Saturn by 2000, and the ambitious plan called for manned missions to Uranus and Neptune by 2000.

Even with the conservative plan, we’d be decades ahead in space exploration than we are today. They were all amazing plans, but we never went through with them, despite its weird aspects (humans to Uranus before Saturn).