Can we protect historic sites on the moon from the coming lunar rush?

The moon is a historical landmark — a celestial body continually peppered with robotic landers shot from our home planet, as well as human footprints planted there by a dozen visiting moonwalkers from 1969 to 1972.

A recent gathering in Italy of the International Scientific Committee on Aerospace Heritage (ISCAH) looked at protecting lunar heritage with an eye toward developing guidelines for spacecraft deorbiting onto the moon's surface.

Particular attention was paid to the risks posed by the impacts of deorbited satellites and rocket stages, recently highlighted by the crash of a SpaceX Falcon 9 upper stage into the moon last August.

As pointed out in the meeting, as lunar traffic increases, controlled crash landings of moon orbiters and rocket stages are becoming an attractive end-of-mission disposal strategy.

And that's a problem.

Limited knowledge

There is limited knowledge regarding ejecta modeling and the effects produced by these impacts, said Luca Forassiepi. He spoke at the Sept. 14 meeting in Piza, which was called "Protecting Lunar Heritage: Developing Guidelines and Recommendations for Controlled Lunar Deorbiting."

"These effects have only been observed, and only partially, in a handful of historical cases. As a result, much of our current understanding relies on simulations, which necessarily involve a number of simplifications compared with reality," Forassiepi told Space.com.

Strong incentive

"Because the moon is an airless world, any movement on the surface is going to stir up sticky, abrasive dust that erodes human materials," pointed out associate professor Alice Gorman, an Australian archaeologist and heritage consultant at Flinders University.

"This is a problem for cultural heritage sites," Gorman said. "Imagine the iconic Apollo 11 landing module, the Eagle, being worn away until it crumbles into dust itself."

"It's also going to be a problem for habitation and mining installations," she added. "So there is a strong incentive for [the] space industry to minimize the impacts of rocket and satellite crashes, protecting both heritage places and new surface missions."

End-of-life planning

Gorman pointed to 51 hard spacecraft impacts on the moon to date, a number that includes nine rocket bodies and 19 lunar orbiters.

"We've reached an inflection point where spacecraft craters aren't just new archaeological sites, they're an environmental hazard that may cause irreversible damage," Gorman told Space.com.

Under the 1967 Outer Space Treaty, Gorman observed, nations are liable for any damage their space hardware causes to the property of other nations. "We could be looking at a situation where a state could demand compensation for a rocket body crash harming its cultural heritage. End-of-life planning is going to become critical."

Cultural landscape

Also taking part in the meeting was Beth O'Leary, a cultural anthropology and archaeology specialist and college professor emerita at New Mexico State University in Las Cruces.

"The moon is part of the cultural landscape of Earth," she said. As such, its environment and heritage deserve international attention.

It's now been more than 60 years since the first successful soft landing on the moon, that of the Soviet Union's Luna 9 spacecraft in February 1966. And lunar traffic is poised to increase greatly in the coming years, as both the United States and China aim to build bases near the moon's south pole.

Given this landscape, "we seek to address the challenges of lunar traffic from crashes, deorbiting spacecraft, and intentional landings and to understand those risks to our aerospace heritage. Our committee attempts to estimate the real consequences of the impacts," O'Leary said.

With global experts in planetary geoarchaeology, site formation processes and heritage management, ISCAH is analyzing and increasing the knowledge base that could prevent the irreversible destruction of the significant historic cultural resources on the lunar surface.

Far-reaching consequences

"Our recommendations should inform consensus-based decisions and support international best practices and policies," said O'Leary.

The ongoing work of the group provides the best opportunities for lunar preservation and protection by and for humanity, she added.

"In our short three years," O'Leary said, "we will have had three conferences, created a mission statement, received World Monuments Fund listing, and will continue as a delegation to the United Nations Committee on the Peaceful Uses of Outer Space."

O'Leary told Space.com that all these issues are complex scientifically and legally, "but it is so important to rely on excellent research and proven heritage management principles in order to make good decisions about preservation which have far-reaching consequences."

Planetary geoarchaeology

One goal the group is addressing is a "post-mission gap," particularly regarding lunar projects.

That is, what happens to lunar heritage following the completion of a successful mission and in the decades that follow?

Also, what are the appropriate end-of-mission practices, and how can we ensure the long-term protection of spacecraft, robotics and other material remains associated with these missions?

Those questions are being deliberated by Justin Holcomb, an assistant research professor with the Kansas Geological Survey, a research unit of the University of Kansas in Lawrence.

Planetary geoarchaeology provides one way to address this issue, by identifying the natural (geological) and anthropogenic (human) processes operating within these environments "that may threaten lunar heritage, while also identifying environmental settings that are more conducive to its long-term preservation," Holcomb told Space.com.

Lunar practices

Forassiepi said that future points of action are on the agenda.

"There is certainly ongoing and continuous work by the ICOMOS International Scientific Committee on Aerospace Heritage on this aspect," said Forassiepi.

ICOMOS is the International Council on Monuments and Sites, a non-governmental organization working to conserve and protect cultural heritage sites on our planet — and off it as well.

"In active collaboration with the World Monuments Fund, we will further refine our research into the potential risks associated with deorbiting and crash landings," Forassiepi noted.

Over the coming months, Forassiepi said, the group will move into a second phase focused on listening and dialogue with all relevant stakeholders in the sector, from space agencies and the scientific community to private actors, heritage experts and communities with social and religious values associated with the moon that could be affected or disrupted by certain lunar practices.

Ultimate goal

"The aim is to initiate an open dialogue and exchange among all these different actors, with a view to collectively developing guidelines based on broad consensus," Forassiepi said.

These will then be presented in the context of the United Nations Committee on the Peaceful Uses of Outer Space in 2027, with the hope that, over time, they may evolve into "internationally recognized standards of behavior" and be adopted and followed by all space actors, Forassiepi added.

"The ultimate goal is to build a lunar future that is sustainable not only from an operational perspective, but also in terms of scientific research and the protection of the earliest traces of human presence in the history of space," he stressed. "These are two irreplaceable forms of heritage, and their damage would represent an enormous loss for future generations."