That setback serves as a reminder of just how difficult such programmes can be – but also, perhaps, the political pressures on them. That's likely to be the case in the United States if Trump wins a second term, with the president tearing up an Obama-era plan to land on an asteroid to prioritize the perhaps more easily grasped concept of the moon then Mars.
NASA last week demoted two of its longest-serving senior officials who had headed up manned exploration. In their place it appointed Ken Bowersox, a former astronaut who has also worked for Elon Musk's SpaceX, to head the programme.
Trump would clearly revel in a moon landing in his final year in office – but the moon mission appears part of a wider political agenda, not least backed by Vice President Mike Pence. His March speech argued NASA's organization should change rather than its mission to get back to the moon by 2024 – when he may well be running for the White House himself.
As in India and China – which sent a probe to the dark side of the moon in January – space exploration is intrinsically tied to the political drives of those in charge. In Russia, the memory of Sputnik and Yuri Gagarin – the one point at which the country appeared ahead of the West in science and technology during the Cold War – is still a point of major national pride. So is the fact that Russian rockets kept putting U.S. and European astronauts into orbit after the U.S. space shuttle programme ended.
The mere fact NASA can bring in space experts from the private sector shows how things have changed. The largest rocket currently launching satellites into orbit, the Falcon Heavy, is owned, designed and operated by Musk's firm. A growing number of space projects in the United States and beyond are now heavily collaborative, if not entirely private. When and if humanity reaches Mars with people, it may well be a commercial as much as a government venture.
The stakes are very high. When the last batch of U.S. astronauts left the lunar surface in the 1972, less than three and a half years after Apollo 11, there was a feeling NASA had exhausted all the immediately useful activities it could conduct. Apollo missions had tested a moon buggy, even hit a golf ball. The technology to take things further, however, simply wasn't there.
In the decades that followed, the U.S. space programme chose to concentrate on reusable space shuttles, deep space probes and telescopes, and lower earth orbit activities such as the International Space Station. That, together with other new technology and better survey work of the moon and Mars, make today's space race very different. Nations are heading back to the moon because they wish to ultimately stay there.
Signs of water on the moon from recent Chinese, Indian and U.S. probes are a game changer. That be used to support colonists, and also broken down into oxygen and hydrogen for fuel.
It would give whoever gets a foothold on the moon a considerable advantage in exploiting both its resources and those of the rest of space. The most efficient way of doing that would be through cooperation - one reason the European Space Agency suggests an international "Moon Village".
Cooperation, however, does not necessarily drive speed as much as competition – and in the current febrile global climate, it's no surprise this has become another field of international rivalry. It also comes at the same time as the wider militarization of space, evidenced by Trump's planned "space force" and an apparent Indian anti-satellite weapons test earlier this year.
When they left the moon, Armstrong and Aldrin left behind a plaque reading: "we came in peace for all mankind." We must hope the next men and women there feel the same way.
*** Peter Apps is a writer on international affairs, localisation, conflict and other issues. He is the founder and executive director of the Project for Study of the 21st Century; PS21, a non-national, non-partisan, non-ideological think tank. Paralysed by a war-zone car crash in 2006, he also blogs about his disability and other topics. He was previously a reporter for Reuters and continues to be paid by Thomson Reuters. Since 2016, he has been a member of the British Army Reserve and the UK Labour Party, and is an active fundraiser for the party.
(Editing by Giles Elgood) ((firstname.lastname@example.org))