Why has it taken so long to return to the Moon?

At 13:24:59 Central Standard Time on December 19 1972, the Apollo 17 command module splashed down in the Pacific Ocean, about 350 nautical miles south-east of Samoa, concluding the last mission to the Moon.

During his career, Apollo 17’s commander, Eugene A. Cernan, logged 566 hours and 15 minutes in space, of which more than 73 hours were spent on the surface of the Moon. Cernan was the second American to have walked in space, and the last person to leave his footprints on the surface of the Moon.

The conclusion of the Apollo 17 journey marked not only the end of a mission, but the close of an era. Between 1969 and 1972, 12 astronauts walked on the Moon over the course of six separate landings.

Half a century later, Nasa is preparing to return under its Artemis programme. For the Artemis II mission, set to launch on April 1 2026, four astronauts will travel in a loop around the Moon in Nasa’s next-generation Orion crew capsule.

More than 50 years is a long gap, and it is only natural to ask if Americans could reach the Moon routinely in the early 1970s, why did it take so long for them to try to go back?

The answer is not simple. It has little to do with technology and much more with how politics, money and global support work. The place to start is with Apollo itself: its model of exploration was not built to last, and was clearly not sustainable.

On May 25 1961, before a joint session of Congress, President John F. Kennedy committed the US to the goal, before the decade was out, of landing a man on the Moon and returning him safely to the Earth.

After Kennedy’s assassination in 1963, President Lyndon B. Johnson ensured that this Moon landing goal was met. But rising costs from the Vietnam war and domestic reforms reduced his appetite for further space investment.

In fact, Nasa’s budget peaked in 1966 and began falling even before Apollo’s success, undermining prospects for sustained exploration. Further funding was declined, planned missions were cancelled, and Apollo ended in 1972 – not because it failed, but because it had accomplished its task.

Sustainable exploration (in space as on Earth) requires stable political commitment, predictable funding, and a clear long-term purpose. After Apollo, the US struggled to maintain all three at once.

Policymakers began to ask what direction Nasa should take next. In 1972, President Richard Nixon directed the space agency to begin building the space shuttle. It would lead Nasa to shift its focus away from deep space exploration towards operations in low-Earth orbit.

Marketed as a reusable “space truck”, the space shuttle was intended to make orbital access routine and affordable. However, it would turn out to be a vehicle of incredible complexity, marred by technical failures and human tragedies – the Challenger and Columbia accidents in which 14 astronauts’ lives were lost.

Eight years into the shuttle programme, some in the space community believed it was time for the US to once again set its sights on the Moon – and the tantalising prospect of a landing on Mars. On July 20 1989, the 20th anniversary of Apollo 11’s first Moon landing, President George H.W. Bush announced the Space Exploration Initiative (SEI).

The plan aimed for a long-term commitment to construct Space Station Freedom, return astronauts to the Moon “to stay”, and finally send humans to the red planet.

However, the high estimated costs of SEI, reaching hundreds of billions of dollars, led to its downfall. Weak support in Congress along with other factors led to its cancellation under Bill Clinton’s presidential administration.

During the 1990s, the International Space Station (ISS) project cemented low-Earth orbit as the priority for human exploration. The space shuttle was the US’s means of building the station and transporting crews to and from the orbiting outpost.

The ISS became a symbol of scientific cooperation and technical prowess. Experiments carried out on the station generated valuable insights into everything from medical research to materials science. However, it also soaked up resources that might otherwise have supported deep-space exploration.

The Columbia disaster in 2003 – in which a space shuttle broke up over Texas with the loss of its crew – led to another rethink of America’s direction in space. As a result, President George W. Bush announced the Vision for Space Exploration.

The aim of this proposal, which would give rise to what was known as the Constellation programme, was to rebuild Nasa’s capability for reaching the Moon, with Mars as its longer-term goal. But independent reviews warned that costs and schedules were unrealistic. Congress never really gave full financial support to Constellation, leading to its cancellation in 2010 during Barack Obama’s presidency.

This repeated cycle of cancelled space projects exposes some inherent limitations to the system for funding lunar exploration. A sustainable Moon programme needs strong multi-sector commitment, and mechanisms in place for guaranteed multi-decade funding.

But such large programmes must compete each year with defence, healthcare and social spending. Electoral turnover and shifting committee leadership in the US further weaken the prospect of continuity.

Lunar exploration has also suffered from an unresolved strategic question: why go back at all? Apollo’s purpose was largely geopolitical, and after the cold war no equally compelling justification really emerged.

Scientific returns from human space missions are limited compared with robotic exploration. Commercial prospects remain uncertain, and prestige alone rarely sustains or secures large budgets.

Maybe a more fitting question is: why does Artemis appear to have escaped the pattern? Well, Nasa argues that sending astronauts back to the lunar surface – and in particular, establishing a sustained presence there – will help researchers learn “how to live and work on another world as we prepare for human missions to Mars”. That is true, up to a point.

Nasa also emphasises that Artemis will be built through commercial partnerships and international cooperation, creating the first long-term human foothold on the Moon.

The programme seems to sit at a carefully crafted intersection of US government leadership, commercial launch capabilities, and a broad coalition of international partners brought together under the Artemis Accords. The accords are a set of common principles regarding the use of the Moon and other targets in outer space, agreed between the US and other countries.

The main difference from previous promises to return to the Moon is that this, at least in theory, spreads risk and widens the base of political support. In practice, though, Artemis remains costly and exposed to shifting budgets and priorities.

There is also a cultural dimension to this question. Apollo created a powerful – albeit fragile – myth of swift, heroic technological advance. Artemis is building its large technological base in societies and democratic contexts where investments and commitments tend to evolve slowly, shaped by negotiation, compromise and competing interests.

If Artemis succeeds, it will be because all the political, economic, societal and scientific incentives have finally aligned in a durable way. But until that alignment is proven, the 50-year gap between Apollo and Artemis is less an engineering puzzle than a reminder of how difficult sustained exploration is for modern democracies.

Domenico Vicinanza does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.