After the cancellation of Apollos 18-20, it looked unlikely that NASA would be allowed to return to the Moon. The attitude in the legislature was one of “been there, done that”. Human spaceflight had been re-aimed at low Earth orbit space stations and spaceplanes, while robotic missions were going ever further into the deepest recesses of the solar system. In 1977, the final death-knell for American lunar exploration seemed to have been struck when the funding to monitor the Apollo Lunar Surface Experiment Packages (ALSEPs) ran out, and the perfectly good autonomous stations were deactivated.
Perhaps this is why the first return to the Moon since Apollo was not exclusively a NASA project. In 1994, on January 25, the Clementine spacecraft blasted off from Vandenberg Air Force Base aboard a Titan II rocket (military surplus; the rocket had previously lived in a missile silo). All of the refurbished ICBM Titan II launches were for one customer: the United States Air Force. The USAF realistically had no particular interest in the Moon, but their Ballistic Missile Defense Organization had a number of crucial new technologies that it wanted to develop, and somewhere along the way, someone came up with the bright idea of testing them out in a spacecraft that would also orbit the Moon. This allowed them to get NASA on board, and also the French agency CNES, significantly reducing the amount each agency would need to spend. On February 19, the spacecraft arrived in lunar orbit, and on May 3, it became the first spacecraft to do something else remarkable: it departed lunar orbit to leave the Earth-Moon system altogether. The only spacecraft to have left lunar orbit previously were all sending capsules back to Earth. After leaving lunar orbit, the spacecraft then left Earth orbit, conducting a burn designed to put it on course to rendezvous with the asteroid 1620 Geographos; unfortnately, a thruster malfunction ruined that plan, and they ended up putting the spacecraft into a heliocentric orbit designed to take it one more time through the Earth’s Van Allen Belts for further study. Contact was lost in June of 1994.
Clementine was a short-lived probe, and one which, like the girl in the song, is now lost and gone forever. But it did something important in the meantime: it proved there was still a reason to go to the Moon.