While I was leading a tour of the National Air and Space Museum in January 2026, a visitor posed this insightful question: “Why has it taken so long to return to the Moon?”
After all, NASA had the know-how and technology to send humans to the lunar surface more than 50 years ago as part of the Apollo program. And, as another tour guest reminded us, computers today can do so much more than they could back then, as evidenced by the smartphones most of us carry in our pockets. Shouldn’t it be easier to get to the Moon than ever before?
The truth is that sending humans into space safely continues to be difficult, especially as missions increase in complexity.
New technologies require years of study, development and testing before they can be certified for flight. And even then, systems and materials can behave in ways that surprise and worry engineers and mission planners; look no further than Boeing’s Starliner CFT mission or the performance of the Orion heat shield on Artemis I.
Issues with Starliner’s thrusters led NASA to return the spacecraft from the International Space Station without its crew. Unanticipated chipping of the Orion heat shield resulted in years of research, culminating in NASA altering the atmospheric reentry plans for the Artemis II mission.
NASA’s programs also require sustained political will and financial support across multiple presidential administrations, Congresses and fiscal years. As a historian of human spaceflight, I have studied the space agency’s efforts to engage the broader public to convince American taxpayers that their programs hold value for the nation.
NASA is now on the eve of the first crewed flight to the Moon since the Apollo era: Artemis II. A crew of four will conduct a lunar flyby, laying the groundwork, the agency hopes, for a landing on the Artemis IV mission.
The story of NASA’s effort to return humans to the Moon is long and winding, demonstrating the complexities of turning grand ambitions into real missions.
Post-Apollo
In early 1970, with two successful Moon landings on the books, President Richard Nixon sought to reduce NASA’s budget to better align with his administration’s priorities. This decision put the space agency in a difficult position, which ultimately led to the cancellation of three planned Apollo missions to conserve funding for its plans for long-term human activity in low Earth orbit.
NASA repurposed the third stage of a Saturn V rocket to create the first U.S. space station, Skylab, which operated from 1973 to 1974. The space agency used leftover Saturn IB rockets and Apollo command and service modules to send crews to the station.
Over the next three decades, NASA developed and operated the space shuttle. The fleet of space shuttle orbiters supported satellite deployment and microgravity research on orbital missions of up to 17 days. This work was meant to enable future long-duration human missions and provide benefits to people on Earth. For example, data from protein crystal growth experiments have informed the development of medicines.
The space shuttle program facilitated the construction, maintenance and staffing of a continuously inhabited research platform in orbit, the International Space Station. The first modules launched in late 1998.
Where to next?
As the new millennium approached, the Clinton administration tasked NASA to think beyond the space station. What could robots and humans do next in space? And where could they do it? Notably, the White House expressed an interest in locations beyond low Earth orbit.
NASA, it turned out, was well positioned to meet the administration’s request. NASA Administrator Daniel Goldin was already thinking about preparing proposals for the next presidential administration and had recently sponsored a human lunar return study. In 1999, he established a team to investigate new technologies, missions and destinations for the 21st century.
This work took on new significance following the tragic loss of the space shuttle Columbia crew in February 2003. Many people, including those in the new George W. Bush White House, wondered whether the human spaceflight program should continue – and, if so, how.
Administration discussions culminated in Bush’s Vision for Space Exploration in 2004, which directed NASA to retire the space shuttle after the completion of the space station. It called for returning humans to the Moon on a crew exploration vehicle designed for destinations beyond low Earth orbit.
It also called for continuing robotic exploration of Mars and engaging companies and international partners in space. Fifteen years earlier, President George H. W. Bush had also announced a Moon and Mars exploration program, but congressional concerns about cost kept space travelers close to home.
The Constellation program’s legacy
In December 2004, NASA began the process of finding a manufacturer for the crew exploration vehicle. By August 2006, the space agency awarded Lockheed Martin the contract to build the capsule, which it had named Orion – the same Orion planned to carry Artemis astronauts to the Moon.
Years of research, development and testing followed for Orion as well as the Ares I crew and Ares V cargo launch vehicles. Together, these technologies made up the Constellation program.
Constellation had two primary objectives: in the near term, to help transport crew to and from the space station after the space shuttle program ended; in the long term, to enable human lunar exploration.
Building systems that could work in both Earth orbit and around the Moon was supposed to save the time and cost of developing two vehicles. Similarly, adapting space shuttle program hardware could supposedly cut costs.
During the first months of Barack Obama’s presidency in 2009, the administration initiated an independent review of NASA’s human spaceflight plans. The Augustine Committee, chaired by retired aerospace executive Norman Augustine, found that the agency’s ambitions outstripped its limited budget, leading to significant delays. The first Orion spacecraft was likely to arrive after the space station ceased operations.
The committee proposed several paths forward at the current funding level, which prioritized space shuttle and space station programs. An additional annual investment of US$3 billion would allow for human exploration beyond low Earth orbit.
Ultimately, the Obama administration canceled Constellation, but two of its technologies lived on, thanks to U.S. senators from states that would have been affected by cuts.
The NASA Authorization Act of 2010 funded Orion’s continued development, shifting responsibility for space station crew transportation to commercial vehicles. It also directed NASA to develop the space launch system, a redesigned Ares V heavy booster, to send Orion to the Moon. The technical strategy had political benefits, too, preserving jobs in numerous congressional districts by providing continuity for aerospace contractors.
In December 2014, a Delta IV heavy rocket launched the first Orion capsule on a test flight, providing engineers with data on spacecraft systems and the heat shield. By October 2015, the space launch system had completed a critical design review, the last step before manufacturing could begin.
Introducing Artemis
In December 2017, the new Trump administration issued a policy directive shifting the focus of NASA’s human spaceflight program back to the Moon. The space agency would use Orion and the space launch system in a race to meet an ambitious 2024 landing date. NASA officially named the program Artemis in May 2019.
The 25-day Artemis I mission, launched in November 2022, was a major milestone for the program. This uncrewed flight was the first flight of the space launch system and the first to integrate SLS and Orion. It laid the groundwork for Artemis II, which will be the first crewed flight of the SLS.
Over more than 50 years, each new presidential administration has reassessed the place of spaceflight among its priorities, either encouraging or curtailing NASA’s efforts to return humans to the lunar surface.
Each crewed flight requires the alignment of technical expertise, political will and financial support over years if not decades. For the space fans who plan to watch the Artemis II launch, the wait for countdown may feel long. But it’s just a blink in NASA’s long journey back to the Moon.
This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Emily A. Margolis, Smithsonian Institution
Read more:
- NASA’s Artemis II crewed mission to the Moon shows how US space strategy has changed since Apollo – and contrasts with China’s closed program
- Meet the next four people headed to the Moon – how the diverse crew of Artemis II shows NASA’s plan for the future of space exploration
- Scientists and space agencies are shooting for the Moon – 5 essential reads on modern lunar missions
Emily A. Margolis does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
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