Preserving things that belong to no one

On Earth, multiple layers of legislation, both international and domestic, protect many sites of humanity’s heritage, an array including the megaliths at Stonehenge, Yosemite National Park and the recently listed Smith-Carter House in Madison, Tenn.

In space, it is different. As decreed by the United Nations’ Outer Space Treaty in 1967 — signed by a multitude of nations while the United States and Soviet Union battled for primacy in orbit — space “shall be free for exploration and use by all,” with open access to all areas of celestial bodies.

Put simply, space is the province of humankind. No nation can “own” it or claim it, by means of use or occupation or otherwise.

That complicates setting up protected areas or restricting activities in or under the six Apollo landing sites. Or the spot where the Soviet Luna 2 spacecraft landed in 1959 and became the first human-made piece of hardware to touch another world. Or the site where, in January, China’s Chang’e-4 spacecraft achieved the first landing on the far side of the moon.

“Arguably, by saying, ‘Oh, this bootprint is an artifact, don’t step on it’ — the U.S. would be making a territorial claim to the area where that bootprint is,” Ms. Hanlon said. “And as you can imagine, that would not be a very diplomatic thing to do.”

To be clear, she added, individual objects on the moon remain the property of the nations that put them there; that is laid out in Article VIII of the Outer Space Treaty. (So, fair warning, retrieving and selling the golf balls Apollo 14’s Alan Shepard lobbed into oblivion or painting a smiley face on China’s Yutu rover will most likely land you in a world of trouble.)