Nothing can diminish the historical significance of humankind’s first visit to another celestial body four decades ago. But for many, the 40th anniversary of the Apollo 11 lunar landing serves as yet another reminder that this event, which occurred just 12 years into the space age, still stands as the crowning achievement for NASA and for human spaceflight.

Space travelers have been confined to low Earth orbit since the last Apollo Moon landing in 1972. NASA was handed a mandate in 2004 by then-President George W. Bush to return to the Moon in preparation for trips to destinations beyond, but the agency has since struggled for traction due to budgets well short of what it needs to develop the necessary hardware. Congress has endorsed the key facets of the so-called Vision for Space Exploration, as has President Barack Obama. But Mr. Obama envisions spending even less on NASA than his predecessor over the next several years and has ordered up an independent review of the agency’s human spaceflight program that has clouded exploration’s future outlook.

While frustration with the situation is understandable, those who criticize NASA as an agency adrift are in a sense doing injustice to the achievement that was Apollo; getting to the Moon in less than 10 years, a goal set in 1961 by then-U.S. President John F. Kennedy, was nothing less than extraordinary. And whether they mean to or not, the critics also tend to give short shrift to NASA’s post-Apollo accomplishments, including the Hubble Space Telescope, numerous robotic Mars missions and other endeavors that have transformed our understanding not only of the universe but also of Earth.

It goes without saying that Apollo was carried out under vastly different circumstances than NASA finds itself in today. The world was less complex in 1961, when the massive expenditures necessary to put men on the Moon could be justified in the context of the Cold War competition with the
Soviet Union
. The lack of that kind of compelling rationale today is compounded by the fact that what NASA is trying to do has been done before. By NASA. Forty years ago.

Space exploration was brand new in the 1960s: not only was the public imagination – globally, not just in the
United States
– captured by NASA’s quest, there were few if any entrenched space programs and constituencies competing for agency dollars; there was no space shuttle, no international space station and no vocal Earth and space science communities. To the extent that there is public interest in NASA’s activities these days, it is based as often as not on narrow parochial concerns.

NASA’s human spaceflight program continues to enjoy strong political support despite a high cost that makes it controversial even within the space community. But having such a program, and actually using it to explore space, are two different things: few if any politicians worry that repeatedly deferring missions to destinations beyond low Earth orbit will get them voted out of office.

One of the conclusions of the panel that investigated the 2003 Space Shuttle Columbia tragedy was that many of NASA’s problems – including funding woes – stemmed from a lack of a guiding vision. Mr. Bush provided that vision, but neither he nor Congress backed it with adequate funding. The Obama administration supports the vision but also has made clear that other NASA activities such as Earth science and aeronautics will be a big priority.

The current circumstances make it all but impossible for NASA to generate and sustain the momentum that will put astronauts back on the Moon anywhere near 2020, the target date set by Mr. Bush and endorsed by Mr. Obama. It is time for the United States to consider a different approach, one that takes advantage of perhaps the biggest development of the post-Apollo years: the emergence of a slew of increasingly capable spacefaring nations, many if not most of which would be eager to join the United States in exploring space beyond low Earth orbit.

As the space station experience amply demonstrated, large cooperative endeavors in space are messy: they are difficult to arrange, inefficient, move at an agonizingly slow pace and unquestionably tie the hands of the parties involved. But one also can make a good case that without the binding international commitments at the foundation of space station partnership, the project would have been abandoned long ago. International politics – rather than a compelling scientific or strategic rationale – has, in effect, kept the space station alive.

To date, NASA has treated the Vision for Space Exploration as a largely go-it-alone affair, arguing that for strategic reasons the United States cannot cede any of the so-called critical path hardware – those systems essential for getting back to the Moon – to international partners. It may be, however, that the surest path to destinations beyond low Earth orbit is one that involves not just the
United States
but the world’s other spacefaring nations in a meaningful way.