Most likely, this is the best-known picture of a flag ever taken: Buzz Aldrin standing next to the first U.S. flag planted on the Moon. For those who knew their world history, it also rang some alarm bells. Only less than a century ago, back on Earth, planting a national flag in another part of the world still amounted to claiming that territory for the fatherland. Did the Stars and Stripes on the moon signify the establishment of an American colony?
When people hear for the first time that I am a lawyer practicing and teaching something called “space law,” the question they ask most frequently, often with a big smile or a twinkle in the eye, is: “So tell me, who owns the moon?”
Of course, claiming new national territories had been very much a European habit, applied to non-European parts of the world. In particular the Portuguese, the Spanish, the Dutch, the French and the English created huge colonial empires. But while their attitude was very Europe-centric, the legal notion that planting a flag was an act of establishing sovereignty quickly stuck and became accepted worldwide as part and parcel of the law of nations.
Obviously, the astronauts had more important things on their mind than contemplating the legal meaning and consequences of that planted flag, but luckily the issue had been taken care of prior to the mission. Since the beginning of the space race the United States knew that for many people around the world the sight of a U.S. flag on the Moon would raise major political issues. Any suggestion that the moon might become, legally speaking, part of U.S. backwaters might fuel such concerns, and possibly give rise to international disputes harmful to both the U.S. space program and U.S. interests as a whole.
By 1969, decolonization may have destroyed any notion that non-European parts of the world, though populated, were not civilized and thus justifiably made subject to European sovereignty — however, there was not a single person living on the moon; even life itself was absent.
Still, the simple answer to the question of whether Armstrong and Aldrin by way of their small ceremony did transform the moon, or at least a major part thereof, into U.S. territory turns out to be “no.” They, nor NASA, nor the U.S. government intended the U.S. flag to have that effect.