IT'S BEEN 50 YEARS SINCE HUMANS WALKED ON THE MOON.

• Author: Mangu-Ward, Katherine
• Position: FUTURE

WE WERE SUPPOSED to go back to the moon last week. We were also supposed to go back five weeks before that in mid-September, and six months before that. We were maybe supposed to go back to the moon during the George W. Bush administration. And we were definitely supposed to go back to the moon shortly after what ended up being the final Apollo mission.

Yet no one has been to the moon for 50 years.

That so much time has elapsed since mankind's last lunar foray is somehow shocking, even to those of us who are too young to remember the moon landings. Those few round trips to plant flags, gather rocks, take photos, and play golf are so central to our sense of ourselves as a nation--and as a species--that it's jarring to contemplate what it means that so much time has passed without a repeat performance.

The last time a group of astronauts was preparing for a manned moon mission, Bob Barker was making his Price Is Right debut. The first pocket scientific calculator was appearing in stores. Pong was newly released for Atari. Comedian George Carlin had just been arrested for "Seven Words You Can Never Say On Television."

When Apollo 17 returned to Earth on December 19, 1972--after a 12-day mission in which Gene Cernan and Harrison Schmitt became the last two men to walk on the lunar surface--no one involved thought it was the end of an era. Public opinion was turning against government space spending at the time, but popular literature, music, and movies were full of visions of lunar colonies and more. The final frontier remained very much alive in the popular imagination, and humanity's conquest of it felt inevitable.

Yet five decades have slipped by without a single new footprint in the regolith. If we can put a man on the moon, why can't we put a man on the moon? Conventional wisdom holds that the moon race was little more than Cold War peacocking, with both sides demonstrating their ability to burn resources and genius on a project with no immediate practical payoff--other than perhaps vaguely hedging against the...